Dual 505

[Sumatriptan]

Yesterday, I got a Dual 505 on Ebay for £77. I know there are Denons,
Thorens etc. around but I have a budget...

Here's why I chose it:

The price was right! I've seen them on sale for £120+ and another Dual
505 on Ebay for 'spares or repairs' went for £60 just after I snagged mine.

A reputation for solid, long lasting performance. Made in Germany before
manufacturing went to China in 2000.

Unlike the 506, the headshell will take standard cartridges which brings
me to..

It has a M55E cartridge which the seller tells me was recently fitted.

Comes with Dual's ultra low mass tone arm.

With manual and in original packaging.

Support and spares such as belts seem to be readily available, although
the seller says he isn't aware of any issues.

I see a few people doubting if vinyl-->digital is worth it. Rationally,
I'm not sure either but I think it will be fun trying.

[David B]

"Sumatriptan" <tonylac...@nu-ware.com> wrote in message
news:<mbstbe$1mu$1...@dont-email.me>...

They are perfectly reasonable turntables although probably not my choice.
Whether it's worth it or not is totally a personal decision but if you're
listening to your LPs anyway then why not copy them while at it?
My suggestion would be to simply keep the turntable and use it to listen to
your albums (assuming you have a moving magnet phono stage on your
amplifier).
Personally I've not been happy with the mastering on the vast majority of
CDs I've bought compared to the vinyl equivalent, yes, the CD format SHOULD
be better but I've not found that. A lot have very compressed dynamic range
which may be good for listening to in a car but not when at home.
--
David

[Java Jive]

I hope for your sake that it doesn't turn out to have a hum, but after
my experiences with my Dual 601, I'm inclined to think it most
probably will ...

On Mon, 16 Feb 2015 14:04:17 +0000, Sumatriptan
<tonylac...@nu-ware.com> wrote:

> Yesterday, I got a Dual 505 on Ebay for £77. I know there are Denons,
> Thorens etc. around but I have a budget...

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[Sumatriptan]

Yes, recording to lossless digital was my original interest..see the
Vinyl to digital thread.

I do have an ancient amplifier with mm phono input (anyone remember the
Texan amp kit?) to do initial testing but my aim is to get a preamp to
convert to line level for PC input. I may get a battery preamp as
suggested by Jim in the other thread.

My feelings regarding CD mastering are similar to yours. They are often
'in yer face' and seem harsh compared to my memories of the same
material on vinyl. Will be interesting to know if it is just nostalgia
or if I can really hear much difference.

Tony

[Sumatriptan]

On 16/02/2015 14:24, Java Jive wrote:
> I hope for your sake that it doesn't turn out to have a hum, but after
> my experiences with my Dual 601, I'm inclined to think it most
> probably will ...
>

Thanks for the info. Any reason for thinking that the problem may be
common to all Dual models?

[Jim Lesurf]

In article <mbstbe$1mu$1...@dont-email.me>, Sumatriptan

<tonylac...@nu-ware.com> wrote:
> Yesterday, I got a Dual 505 on Ebay for £77. I know there are Denons,
> Thorens etc. around but I have a budget...

> It has a M55E cartridge which the seller tells me was recently fitted.

If you don't already have a suitable test LP in good condition I'd
recommend getting a copy of one. I have a set of different examples, right
back to HFS69 (the age is hinted at by the number 8-]), The old ones aren't
available unused any more. However I think the

"Analogue Productions Ultimate Analogue Test LP"

is still available.

As with many test LPs the white/pink noise, isn't. :-) But the tones are
OK.

You can then use it to check that your cartridge, etc, are working OK.
Initially check 'by ear' that it tracks reasonably well. Adjust the playing
force ('weight') and bias to suit. Then check by making a digital recording
and seeing how much distortion, rumble, hum, etc there is.

Once happy with it, adjust the levels so your recordings don't clip. FWIW I
tend to set levels so a 0dB RIAA tone would come out somewhere around -15
to -18dB in the digital file. This gives headroom for loud sounds and means
you can simply leave the recording gain set from then on. No need to fiddle
with it from one LP to the next or worry about clipping. Makes life easier.

> I see a few people doubting if vinyl-->digital is worth it. Rationally,
> I'm not sure either but I think it will be fun trying.

Experiment is often the best way to decide since it'll depend on you and
the LPs, etc. Have fun and enjoy the music rather than regard it as a task
to be ground though.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

[Java Jive]

The way mine was wired (*), and assuming that yours is not likely to
be very different. Mine was a very old model, though, bought c1974,
and if yours is not of the same vintage hopefully things will have
improved. Nevertheless, I wouldn't bank on it, my impression being
that less, not more, care is taken over decks these days. I think the
manufacturers tend to think: "This is never going to have comparable
output to a good CD deck, so we'll make it cheap and cheerful!" That
means a ceramic cartridge and not much attention given to things like
hum suppression. I hope for your sake that I'm wrong, but time will
soon tell.

* The wiring mistakes were as follows ...

:-( The deck was made of metal, yet originally supplied with a
two-core, that is unearthed, mains cable. Very early on in its life,
I changed the mains lead for a three-core one with the earth attached
to the deck metal. Not only was this a lot safer in theory, in
practice it also meant that when dismounting a record I didn't get
electric shocks from static having built up from the normal action of
the stylus in the groove. When I first did this, I was using a
properly earthed amp, so didn't notice any increase in hum, IIRC quite
the reverse in fact, but by the time a couple of years ago when I was
doing the digitisation, I was using an amp with a two-core mains lead,
that is, although it had an earth point for a deck, it itself was not
earthed, and the deck now gave a big hum.

:-( When analysing this hum, the next thing I noticed was that the
arm and cartridge holder were grounded to the deck metal. Just
cutting, or in my case unsoldering, the cartridge holder earth
underneath the deck and instead taking it out the back to the earth
point on the amp made quite a bit of difference, but didn't get rid of
the hum entirely.

:-( Then I realised, and proved it with a resistance meter, that
the tone arm was not electrically insulated from the deck metal, which
meant that even after the above link had been fixed, the wiring to the
cartridge still picked up hum from being surrounded by the metal tube
of the tone arm. What follows is definitely not something to be
recommended, but it being a very, very old and already beat up deck
with zilch second-hand value, for example the lid hinges had broken
within a couple of years of purchase, I didn't mind hazarding breaking
it altogether, and so completely dismantled the tone arm, replacing
the wiring with the smallest stereo coaxial wiring I could find, so
that the outer sheath being grounded protected the signal wires
within, and this completely fixed the hum. However such cable is a
lot less flexible than the original very thin and delicate wiring that
is commonly used to wire between the terminals of the cartridge and
the outputs at the back, so this introduced tracking problems which
took a lot of trial and error to fix, which is why it's not something
to be generally recommended.

So if yours has a hum, my advice would be to repatriate it immediately
as not being "fit for purpose".

On Mon, 16 Feb 2015 14:49:38 +0000, Sumatriptan
<tonylac...@nu-ware.com> wrote:
>
> Thanks for the info. Any reason for thinking that the problem may be
> common to all Dual models?

[Java Jive]

If by phone input you mean one with RIAA bias-correction, then why not
just take the line out of that amp to your soundcard instead. That's
what I did, the results were very acceptable, and I reckoned it was a
lot easier than faffing around with a preamp, and trying to avoid it
introducing hum that I'd already spent so many hours trying to remove.

On Mon, 16 Feb 2015 14:47:58 +0000, Sumatriptan
<tonylac...@nu-ware.com> wrote:
>
> I do have an ancient amplifier with mm phono input (anyone remember the
> Texan amp kit?) to do initial testing but my aim is to get a preamp to
> convert to line level for PC input. I may get a battery preamp as
> suggested by Jim in the other thread.

[Eiron]

On 16/02/2015 17:49, Java Jive wrote:
> If by phone input you mean one with RIAA bias-correction, then why not
> just take the line out of that amp to your soundcard instead. That's
> what I did, the results were very acceptable, and I reckoned it was a
> lot easier than faffing around with a preamp, and trying to avoid it
> introducing hum that I'd already spent so many hours trying to remove.
>
> On Mon, 16 Feb 2015 14:47:58 +0000, Sumatriptan
> <tonylac...@nu-ware.com> wrote:
>>
>> I do have an ancient amplifier with mm phono input (anyone remember the
>> Texan amp kit?)

Is the Texan phono input stage good enough? I doubt it.

--
Eiron.

[Woody]

"Java Jive" <ja...@evij.com.invalid> wrote in message
news:9d84ea9t9ulpj5vgs...@4ax.com...

Going back 30+ years most kit was only two core, the only three-core
being on the amp so that there would never be any hum loops. Even now
I have
Hitachi DD T/T
Denon TU260LII
Sony MD???
Marantz CD5400SE
NAD 312
Denon 555 dual cassette
Rotel RB850
and the only item there with a three-core cable is the turntable. The
turntable earth is only to the motor body and is completely isolated
from the audio connections but I have not a glimmer of hum anywhere.


--
Woody

harrogate3 at ntlworld dot com

[Sumatriptan]

It is RIAA but when I powered my Texan up a few years ago it had some
hum so I'm going to have to 'faff around' to fix it if I use it. Here's
a schematic:

http://www.angelfire.com/sd/paulkemble/sound8h.html

Love this, 'covering 5Hz-->500kHz'

The line out is simply a potential divider across the speaker output. I
might try it as per Java Jive's suggestion. Haven't even got the tt yet
so nothing is definite atm.

[Sumatriptan]

On 16/02/2015 17:42, Java Jive wrote:
>
> So if yours has a hum, my advice would be to repatriate it immediately
> as not being "fit for purpose".
>

OK, noted. I have chased earth-loop hum in other contexts so I know how
tricky it can be to track down. My fingers are crossed.

[Sumatriptan]

On 16/02/2015 14:58, Jim Lesurf wrote:

>
> "Analogue Productions Ultimate Analogue Test LP"
>
> is still available.
>

OK, on my accessories list.

<aside> A few minutes ago I watched an unused, genuine Shure N55E stylus
in original packaging auction for £52.66 on Ebay. Phew!

>
> to -18dB in the digital file. This gives headroom for loud sounds and means
>

Understood

> the LPs, etc. Have fun and enjoy the music rather than regard it as a task
> to be ground though.
>

Absolutely.

[John R Leddy]

Sumatriptan;93653 Wrote:
> Yesterday, I got a Dual 505 on Ebay for £77.

> I've seen them on sale for £120+ and another Dual 505 on Ebay for
> 'spares or repairs' went for £60 just after I snagged mine.

Which model of 505 did you buy?
Inflation aside, £77.00 isn't far off what a CS 505-1 cost when it was
new.

Back in the day, the mags would have us believe a
Dual CS 505-1 turntable + New Acoustic Dimension 3020 integrated
amplifier + a pair of Acoustic Research AR19 loudspeakers
was the best buy budget system to own.

Ah, dreams of Rega Planar 3 and A&R Cambridge A60...




--
John R Leddy

[Trevor Wilson]

On 17/02/2015 1:04 AM, Sumatriptan wrote:
> Yesterday, I got a Dual 505 on Ebay for £77. I know there are Denons,
> Thorens etc. around but I have a budget...
>
> Here's why I chose it:
>
> The price was right! I've seen them on sale for £120+ and another Dual
> 505 on Ebay for 'spares or repairs' went for £60 just after I snagged mine.

**The 505 was a disaster. You WILL be sorry. The 505-1 & 505-2 ,etc were
brilliant. The original 505 was a fine turntable with an extremely
crappy 'headshell'. They ALL fail. New headshells have not been
available for a very long time. Before supplies completely dried up, I
had seen them sell for as much as US$40.00 each! The only potential
replacements I've seen recently appear to be 3D printed ones. eBay
sellers have them at around US$20.00 ~ $25.00 each. They look very
flimsy and I doubt they will last. The subsequent 505 models used a far
superior headshell, which doesn't fall apart.

I wish you had consulted us before you purchased.

>
> A reputation for solid, long lasting performance. Made in Germany before
> manufacturing went to China in 2000.

**Dual was sold to Thorens. AFAIK, Thorens is still made in Germany.
They still use some of the Dual items in their turntables.

>
> Unlike the 506, the headshell will take standard cartridges which brings
> me to..
>
> It has a M55E cartridge which the seller tells me was recently fitted.
>
> Comes with Dual's ultra low mass tone arm.
>
> With manual and in original packaging.
>
> Support and spares such as belts seem to be readily available, although
> the seller says he isn't aware of any issues.

**The drive belt is easy. They can be sourced from a variety of sellers.
The speed control belt is not so easy to source, but that is not a major
problem. The headshell, OTOH, IS a major problem.

>
> I see a few people doubting if vinyl-->digital is worth it. Rationally,
> I'm not sure either but I think it will be fun trying.

**Fitted with a really nice cartridge, the Dual 505-2, 3, etc will
provide excellent results.


--
Trevor Wilson
www.rageaudio.com.au

---
This email has been checked for viruses by Avast antivirus software.
http://www.avast.com

[Trevor Wilson]

**No. Dual turntables were some of the best resolved turntables in their
price class. I doubt you will have any problems, unless it has been
worked on by an idiot.

[Sumatriptan]

Dreams indeed

It's a CS 505-1

[Trevor Wilson]

**That is bad news. Send it back if you can.

[Trevor Wilson]

On 17/02/2015 7:11 AM, Trevor Wilson wrote:
> On 17/02/2015 1:04 AM, Sumatriptan wrote:
>> Yesterday, I got a Dual 505 on Ebay for £77. I know there are Denons,
>> Thorens etc. around but I have a budget...
>>
>> Here's why I chose it:
>>
>> The price was right! I've seen them on sale for £120+ and another Dual
>> 505 on Ebay for 'spares or repairs' went for £60 just after I snagged
>> mine.
>
> **The 505 was a disaster. You WILL be sorry. The 505-1 & 505-2 ,etc were
> brilliant.

**OOps. Should read: "The 505-2 & 505-3, etc...."

There never was a 505-1. It was just the 505.

[Sumatriptan]

On 16/02/2015 21:17, Trevor Wilson wrote:
> On 17/02/2015 7:11 AM, Trevor Wilson wrote:
>> On 17/02/2015 1:04 AM, Sumatriptan wrote:
>>> Yesterday, I got a Dual 505 on Ebay for £77. I know there are Denons,
>>> Thorens etc. around but I have a budget...
>>>
>>> Here's why I chose it:
>>>
>>> The price was right! I've seen them on sale for £120+ and another Dual
>>> 505 on Ebay for 'spares or repairs' went for £60 just after I snagged
>>> mine.
>>
>> **The 505 was a disaster. You WILL be sorry. The 505-1 & 505-2 ,etc were
>> brilliant.
>
> **OOps. Should read: "The 505-2 & 505-3, etc...."
>
> There never was a 505-1. It was just the 505.
>

Whatever, it was the first of the 505s.

As you will realise, it has a headshell adapter fitted to accomodate the
Shure cartridge.

So, why was this model 'a disaster' ?

[Trevor Wilson]

**The headshell falls apart IN EVERY SINGLE ONE. The headshells are NLA.

Send it back.

[Woody]

"John R Leddy" <John.R.Led...@audiobanter.co.uk> wrote in
message news:John.R.Led...@audiobanter.co.uk...

>
> Sumatriptan;93653 Wrote:
>> Yesterday, I got a Dual 505 on Ebay for £77.
>> I've seen them on sale for £120+ and another Dual 505 on Ebay for
>> 'spares or repairs' went for £60 just after I snagged mine.
> Which model of 505 did you buy?
> Inflation aside, £77.00 isn't far off what a CS 505-1 cost when it
> was
> new.
>
> Back in the day, the mags would have us believe a
> Dual CS 505-1 turntable + New Acoustic Dimension 3020 integrated
> amplifier + a pair of Acoustic Research AR19 loudspeakers
> was the best buy budget system to own.
>

+1

> Ah, dreams of Rega Planar 3 and A&R Cambridge A60...
>
>
>


--

[Jim Lesurf]

In article <mbthta$20s$1...@dont-email.me>,

Sumatriptan <tonylac...@nu-ware.com> wrote:

> <aside> A few minutes ago I watched an unused, genuine Shure N55E stylus
> in original packaging auction for £52.66 on Ebay. Phew!

Getting a 'new' stylus for ancient cartridges can be a bit like being in a
shooting gallery blindfolded. Genuine 'new old stock' risks having
deteriorated. New 'third party' replacements may fit physically, but not be
like the originals in performance. Alas, much as I love my old Shure V15
I'm hesitant about modern replacement styli. So take care.

If you find the existing stylus or replacements aren't satisfactory, then
an alternative is someone like the 'Expert Stylus Company' who will
refurbish an old stylus.

You may be better off with the M55 than some other models, though as I
think that sort of level of Shure remained popular with 'DJs'. And probably
sold in bigger numbers than V15s.

[Sumatriptan]

On 16/02/2015 21:58, Trevor Wilson wrote:
>>
>
> **The headshell falls apart IN EVERY SINGLE ONE. The headshells are NLA.
>
> Send it back.
>

I see people discussing fitting of CS505-3 or later headshells. (Not a
trivial task, apparently) But my understanding was that this was related
to cartridge compatibility and an alternative to the adapter kits. I
haven't seen any online info on the early ones actually falling apart.
If you could point me to such info on the mode of failure I would be
interested.

From the photos, the adapter on this CS505 does not look pretty and
must add some mass and therefore may affect performance. I'll take a
good look when it arrives.

[Sumatriptan]

On 17/02/2015 09:57, Jim Lesurf wrote:
> In article <mbthta$20s$1...@dont-email.me>,
> Sumatriptan <tonylac...@nu-ware.com> wrote:
>
>> <aside> A few minutes ago I watched an unused, genuine Shure N55E stylus
>> in original packaging auction for £52.66 on Ebay. Phew!
>
> Getting a 'new' stylus for ancient cartridges can be a bit like being in a
> shooting gallery blindfolded. Genuine 'new old stock' risks having
> deteriorated. New 'third party' replacements may fit physically, but not be
> like the originals in performance. Alas, much as I love my old Shure V15
> I'm hesitant about modern replacement styli. So take care.
>
> If you find the existing stylus or replacements aren't satisfactory, then
> an alternative is someone like the 'Expert Stylus Company' who will
> refurbish an old stylus.
>
> You may be better off with the M55 than some other models, though as I
> think that sort of level of Shure remained popular with 'DJs'. And probably
> sold in bigger numbers than V15s.
>
> Jim
>

Yup, prices of genuine 'New Old Stock' versus 'will fit M55E' items at
£12 a pop says something. I don't know what stylus is fitted to this one.

[John R Leddy]

Trevor Wilson;93679 Wrote:
> There never was a 505-1. It was just the 505.

Of course there was a Dual CS 505-1.

Here's a link to an image of a genuine service manual cover:
http://tinyurl.com/ldrqqhk
Here's another link to further info: 'DUAL 505-1 Turntable'
(http://dual-reference.com/tables/CS505-1.htm)
Here's a video clearly showing CS 505-1 on its model ID sticker and
505-1 on its serial number sticker:
https://www.youtube.com/watch?v=zWOt5UNFKds

Here's a link to a 505/506-1 service information sheet dated 1980:
http://tinyurl.com/klw9f5g

Here's a link to an image for a CS 505 instruction manual:
http://dual.pytalhost.eu/505/cs505_1.jpg

Printing errors aside, it may not be that far-fetched to assume there
are worldwide variations which include models: 505, CS 505, CS 505-1, CS
505-2, etc.
Whatever the accuracy of this assumption, it's an inescapable fact you
couldn't walk down Tottenham Court Road without tripping over a CS
505-1.




--
John R Leddy

[RJH]

On 17/02/2015 10:28, Sumatriptan wrote:
> On 16/02/2015 21:58, Trevor Wilson wrote:
>>>
>>
>> **The headshell falls apart IN EVERY SINGLE ONE. The headshells are NLA.
>>

Nonsense. I had one with near daily use for over 10 years, with and
without the 1/2" converter. Never missed a beat.

Can't speak for Antipodean imports :-)

>> Send it back.
>>
>
> I see people discussing fitting of CS505-3 or later headshells. (Not a
> trivial task, apparently) But my understanding was that this was related
> to cartridge compatibility and an alternative to the adapter kits. I
> haven't seen any online info on the early ones actually falling apart.
> If you could point me to such info on the mode of failure I would be
> interested.
>

Don't hold your breath :-)

> From the photos, the adapter on this CS505 does not look pretty and
> must add some mass and therefore may affect performance. I'll take a
> good look when it arrives.

It looks a little clumsy but works surprisingly well - and adds
considerable versatility, of course.

I like the Dual 505. A big thing for me is speed stability, and I found
the Dual good for a belt drive. The best I found was a Pink Triangle LPT
- which considering the Heath Robinson appearance I found amazing.

I use an old Technics 1200 at the moment - very pleased.

--
Cheers, Rob

[Trevor Wilson]

On 17/02/2015 9:28 PM, Sumatriptan wrote:
> On 16/02/2015 21:58, Trevor Wilson wrote:
>>>
>>
>> **The headshell falls apart IN EVERY SINGLE ONE. The headshells are NLA.
>>
>> Send it back.
>>
>
> I see people discussing fitting of CS505-3 or later headshells. (Not a
> trivial task, apparently)

**A nonsensically complicated job. Forget it.

But my understanding was that this was related
> to cartridge compatibility and an alternative to the adapter kits. I
> haven't seen any online info on the early ones actually falling apart.
> If you could point me to such info on the mode of failure I would be
> interested.

**The headshell falls apart. I suspect the plastic used is not a stable
product like ABS, but is something inferior. As for reports, just do a
search. You'll receive a large number of results.

>
> From the photos, the adapter on this CS505 does not look pretty and
> must add some mass and therefore may affect performance. I'll take a
> good look when it arrives.

**Send it back. Look for a later model.

[Don Pearce]

On Wed, 18 Feb 2015 09:13:55 +1100, Trevor Wilson
<tre...@SPAMBLOCKrageaudio.com.au> wrote:

>On 17/02/2015 9:28 PM, Sumatriptan wrote:
>> On 16/02/2015 21:58, Trevor Wilson wrote:
>>>>
>>>
>>> **The headshell falls apart IN EVERY SINGLE ONE. The headshells are NLA.
>>>
>>> Send it back.
>>>
>>
>> I see people discussing fitting of CS505-3 or later headshells. (Not a
>> trivial task, apparently)
>
>**A nonsensically complicated job. Forget it.
>
>
> But my understanding was that this was related
>> to cartridge compatibility and an alternative to the adapter kits. I
>> haven't seen any online info on the early ones actually falling apart.
>> If you could point me to such info on the mode of failure I would be
>> interested.
>
>**The headshell falls apart. I suspect the plastic used is not a stable
>product like ABS, but is something inferior. As for reports, just do a
>search. You'll receive a large number of results.
>
>
>
>>
>> From the photos, the adapter on this CS505 does not look pretty and
>> must add some mass and therefore may affect performance. I'll take a
>> good look when it arrives.
>
>**Send it back. Look for a later model.

ABS is not UV stable. There is an alternative called PCABS which is
used instead.

d

[Trevor Wilson]

**Thanks for that info. I thought ABS was quite stable.

[David B]

"RJH" <patch...@gmx.com> wrote in message
news:<mbvvs4$ivp$1...@dont-email.me>...

I'm down to one Pink Triangle now (PT1) and a Townshend Rock. I still think
the PT sounds considerably better than a seriously upgraded LP12.
What arm have you got on your SL1200?

--
David

[Don Pearce]

On Wed, 18 Feb 2015 16:58:22 +1100, Trevor Wilson

I've just had a bunch of satellite LNB housings tested - 200 hours and
they where white and powdery. All I expect is some colour shift. I
told them before we started testing what would happen.

d

[mick]

That's a phones output. There isn't a line output. I'd try taking an
output from pin 6 of IC1 via a resistor - I'd experiment around 4.7k to
see what sounds ok. Ideally you should use a high input impedance buffer
but you might not be wanting to do that (although a cheap dual op-amp
would do it nicely).

[Sumatriptan]

On 18/02/2015 21:00, mick wrote:

>
> That's a phones output. There isn't a line output. I'd try taking an
> output from pin 6 of IC1 via a resistor - I'd experiment around 4.7k to
> see what sounds ok. Ideally you should use a high input impedance buffer
> but you might not be wanting to do that (although a cheap dual op-amp
> would do it nicely).
>

Good point. Actually, there's already an output from pin 6 with a 4.7k
series resistor...it is the Texan 'Tape output'.


How the low impedance Texan 'phones output' level compares with line
level I don't know right now but a moot point since, initially, I just
want to see if the tt works. I'll simply plug it in and try it with the
Texan amp into a pair of speakers. See what I get and then decide what
to do next. I will need to make up some leads to connect to those
horrible Texan DIN input sockets.

The Dual tt arrived this morning....we were out so awaiting redelivery.

[Sumatriptan]

On 18/02/2015 17:06, Don Pearce wrote:

>>>> **Send it back. Look for a later model.
>>>
>>> ABS is not UV stable. There is an alternative called PCABS which is
>>> used instead.
>>>
>>
>> **Thanks for that info. I thought ABS was quite stable.
>
> I've just had a bunch of satellite LNB housings tested - 200 hours and
> they where white and powdery. All I expect is some colour shift. I
> told them before we started testing what would happen.
>
> d
>

Hmm...maybe Trevor's experience with disintegrating Dual ABS headshells
is related to cumulative UV exposure of which there is rather more where
he lives than here in Wales.

Awaiting redelivery, we were out when it arrived this morning.

[Trevor Wilson]

**I don't know what kind of plastic is used in the headshells. It could
be some other plastic, other than ABS. I can promise you one thing: They
all fail. Every single one. And, contrary to popular (Pommy) belief, not
all Aussies use their turntables in bright Sunlight.

[RJH]

The standard arm. Seems fine with either an AT MM or MC. I did have a
1200 with an SME. TBH, can't hear much difference, but the SME looked
nicer :-)

--
Cheers, Rob

[Sumatriptan]

On 16/02/2015 14:04, Sumatriptan wrote:
> Yesterday, I got a Dual 505 on Ebay for £77.

Hi all,

More from a born again vinyl user..

When the tt arrived it was packed in the original Dual packing which
would have been fine, except the transit screws were not tightened and
the counterweight was left attached to the tone arm for transit. The 505
counterweight has a plastic stem, unlike later 505-x models. Sure
enough, it was broken and the weight was rattling around in the package.

The sender agreed to compensate me for purchase of a replacement if I
could locate one. A few messages at the Vinyl Engine forum resulted in this:

http://www.dualfred.de/

Alfred and his wife who run this shop in Munich have a large stock of
apparently new Dual and Thorens turntable parts. I saw the exact part I
needed on their website. It took a week to arrive and the brand new
boxed part is labeled 'Original Dual Zubehor'

As I don't have a fully functional preamp and the main point of this
exercise is to get some/all of my collection digitised I decided to
obtain a Behringer phono-USB UFO202 interface to quickly get up and
running.

I haven't done a proper setup yet apart from tracking weight adjustment
to try out the tt for basic operation. All seems well so far, after a
listen via Audacity...except for one issue. There is significant mains
hum which I haven't tried to fix yet.

And that's where I'm at.

[Java Jive]

I did rather fear for you. If you can't find a SIMPLE fix without
hacking things around, send it back as not fit for purpose.
Frustrating I know, when you're eager to get going, but you really
don't want the hassle of trying to fix a hum - to convince yourself,
read again what I had to do to get rid of the one on my old deck, you
really don't want to be going anywhere near there if you don't
absolutely HAVE to.

On Thu, 26 Feb 2015 20:09:31 +0000, Sumatriptan
<tonylac...@nu-ware.com> wrote:
>
> There is significant mains
> hum which I haven't tried to fix yet.

--
=========================================================
UK Residents: If you feel can possibly support it
please sign the following ePetition
before closing time of 30/03/2015 23:59:

http://epetitions.direct.gov.uk/petitions/71556
=========================================================
Please always reply to ng as the email in this post's
header does not exist. Or use a contact address at:
http://www.macfh.co.uk/JavaJive/JavaJive.html
http://www.macfh.co.uk/Macfarlane/Macfarlane.html

[Trevor Wilson]

**The hum is likely to be one of the following:

* Dodgy RCA connectors/leads.
* Dodgy arm wiring (unlikely).
* Dodgy headshell (most likely).

If it is the headshell (the detachable bit that hold the cartridge),
send it back.

[mick]

Now you have to look at the earth wiring.
There are almost certainly 4 wires to the cartridge, via headshell
connectors. When they leave the arm at the bottom, 2 of the wires become
L and R signals and the others become signal grounds. Note that none of
them must be connected to the chassis in any way whatsoever! The signal
grounds are only earthed in the amplifier.

Wire colours are probably:
Blue - outside - left channel ground
white - pin - left channel signal
Red - pin - right channel signal
Green - outside - right channel ground
To clean the connectors on the headshell try the eraser on a pencil.

The chassis *should* have a connection to mains earth for safety reasons
and that's all. This is sometimes via a separate wire to a screw terminal
on the preamp or amplifier.

Have fun... :)

[Sumatriptan]

Thanks all for comments.

Trevor, as per one of your suggestions...The biggest source of hum was
right channel RCA plug with screen intermittent O/C. Fixed that and
replaced both with gold plated versions while I was at it.

Java, I *like* a challenge so am happy to to chase hum. This tt has a 2
core mains lead, as expected, with the earthing being provided by a
earth wire connected to the pre-amp. Also, a continuity check showed
that the tone arm *is* isolated from the tt body, although a temporary
connection to it made no difference to the hum level.

Mick..thnks for cartridge wiring details, actually 5 wires including the
black earth wire from the tt metalwork to the headshell via the tone arm.

The hum level is now slight but perceptible at normal listening levels
in this room. Here's some figures from Audacity with record input set to
max for this test and tt connected to the phono-usb unit.

TT mains off, hum/noise RMS < -60 dB
TT mains on, hum/noise RMS around -55 dB but varies a lot, see below.
Test track used at -20 dB RMS -6 dB peaks (not worried about headroom
for testing)
Motor on/off made no change.
Tone arm position gives no change.

Moving tt position in this office/workshop gave large, up to 15 dB,
changes in hum/noise. Maybe due to lots of mains wiring underfloor as
well as trailing extension leads to PCs etc. So...

I moved the tt to an acoustically and electrically quieter room and
tried it with my Pioneer amp (I had forgotten all about it in my earlier
posts). Result...hum not audible to me at normal listening levels.

Looks like my efforts will be aimed at finding somewhere in my office
that is electrically quiet for recording to PC. Or perhaps the problem
is with my phono-USB unit. Or the tt earthing which is getting to it via
UPS/power conditioning/PC chassis.

Comments please?

[Jim Lesurf]

In article <md4p3v$t0q$1...@dont-email.me>, Sumatriptan

<tonylac...@nu-ware.com> wrote:

> TT mains off, hum/noise RMS < -60 dB TT mains on, hum/noise RMS around
> -55 dB but varies a lot, see below. Test track used at -20 dB RMS -6 dB
> peaks (not worried about headroom for testing) Motor on/off made no
> change. Tone arm position gives no change.

> Moving tt position in this office/workshop gave large, up to 15 dB,
> changes in hum/noise. Maybe due to lots of mains wiring underfloor as
> well as trailing extension leads to PCs etc. So...

Interesting that tone arm position had no effect but moving the entire unit
did. Did the move require changing the mains socket used?

Here I can measure changes in hum+noise level as the arm is moved, but I
can't compare that with what you get as I don't know the details of your
'test track'. The hum here is inaudible, though, regardless of where I play
the recordings or if I use speakers or headphones. cf below.

> I moved the tt to an acoustically and electrically quieter room and
> tried it with my Pioneer amp (I had forgotten all about it in my earlier
> posts). Result...hum not audible to me at normal listening levels.

A complication is that how audible 'hum' may be will depend on more than
its simple measured level at the amp.

A) Depends on the room acoustics, speakers, etc. One room setup may make it
higher in level at the listener's ears than another.

B) Is the hum pure 50Hz? Or does it have a lot of harmonics? That can make
a big difference to audibility.

Check the spectrum of the 'hum' and the above. Otherwise there might be a
risk that you make recordings with the hum level 'sounding low' but then
hear it when you play the results back elsewhere.

[Sumatriptan]

Hi Jim,

>
> Interesting that tone arm position had no effect but moving the entire unit
> did. Did the move require changing the mains socket used?
>

No, this was from a socket shared with the PC it was tried horizontally
and vertically within the radius of the 1.5M mains lead. Changing
sockets resulted in somewhat worse hum.

> Here I can measure changes in hum+noise level as the arm is moved, but I
> can't compare that with what you get as I don't know the details of your
> 'test track'. The hum here is inaudible, though, regardless of where I play
> the recordings or if I use speakers or headphones. cf below.
>

Test track was from an acoustic guitar album from the 1980's to get a
ballpark volume setting.

>> not audible to me at normal listening levels.
>
> A complication is that how audible 'hum' may be will depend on more than
> its simple measured level at the amp.
>

I appreciate that.

> A) Depends on the room acoustics, speakers, etc. One room setup may make it
> higher in level at the listener's ears than another.
>

Agreed, all of the above were different. I'm just trying to determine
how big a problem it is for me and how much time/effort I should spend
on chasing it. All ultimately subjective :-)

> B) Is the hum pure 50Hz? Or does it have a lot of harmonics? That can make
> a big difference to audibility.
>

It is harmonic rich although the main component is 50Hz.

> Check the spectrum of the 'hum' and the above.

Picture = 1000 words, see here:

http://www.nu-ware.com/Misc/Screenshots/Dual505A.png

Notes
1) The spectrum was obtained before I normalised the audio track to
examine the waveform.

2) Hum is with mains on at tt, motor off, tonearm in resting position.

3) As explained, I can reduce the Audacity measured RMS hum level to
around -55dB in this room by repositioning...moving it around while
looking at the levels.

>
> Otherwise there might be a
> risk that you make recordings with the hum level 'sounding low' but then
> hear it when you play the results back elsewhere.
>

I'm in no rush...I'll be making test recordings and trying them on other
systems before I spend too much effort on the 'real thing'.

[Java Jive]

On Wed, 04 Mar 2015 19:09:58 +0000, Sumatriptan
<tonylac...@nu-ware.com> wrote:

> Mick..thnks for cartridge wiring details, actually 5 wires including the
> black earth wire from the tt metalwork to the headshell via the tone arm.

If you are prepared to lose the right to return the unit, I would say
detach that black lead from the TT metalwork and take it out the back
to the amp earth. Can you simply unscrew it, or would it be a matter
of cutting the connection? The former gives you some possibility of a
reversible test without losing the ability to return it, as long as
you're careful not to leave marks on the screw.

> http://www.nu-ware.com/Misc/Screenshots/Dual505A.png
>
> Notes
> 1) The spectrum was obtained before I normalised the audio track to
> examine the waveform.
>
> 2) Hum is with mains on at tt, motor off, tonearm in resting position.
>
> 3) As explained, I can reduce the Audacity measured RMS hum level to
> around -55dB in this room by repositioning...moving it around while
> looking at the levels.

Wow, that's real dirty! I'm no expert at electronics, and would
always bow to the greater experience of those in this ng such as Jim,
but this suggests to me that this is not just a straightforward earth
loop problem.

My suspicions would now rest on the deck or the PC's PSU. It would be
useful to know:

1) Is the deck powered by a wall-wart or an inline unit and
low-voltage DC actually coming into the deck, or is it mains coming in
and its motor works directly off it? If the former, I'd suspect the
PSU.

2) What sort of PC is it? A desktop, or a laptop powered by a
wall-wart or inline unit as described for the deck? If the latter, I
had some weird my experiences comparing between using a laptop's
inline PSU and powered via its docking station, and would again
suspect the PSU:

"... I got the normal PSU for the laptop, and removed the
docking station. Big, big hum! Replaced the docking station. Back
to normal. Removed it again. Big, big hum! Replaced it again. Back
to normal.

I conclude that the DS has a decent PSU, while that supplied for the
laptop is crap."

If you want or need to read all of the original very long post
covering a wide range of points about digitising analogue sound
sources, including some concerning hum that I've already mentioned in
these recent posts in reply to you, the original post is here:

Java Jive: ROT: PC Audio Recording & Playback (was: Holst and a
Headache), 6/12/11
https://groups.google.com/d/msg/uk.tech.digital-tv/7C4j39e-SFk/a7R64KmusM8J

[Sumatriptan]

>
> If you are prepared to lose the right to return the unit, I would say
> detach that black lead from the TT metalwork and take it out the back
> to the amp earth.
>

Yes, that is on my list. Might try it disconnected completely as well.

> Can you simply unscrew it, or would it be a matter
> of cutting the connection?
>

Probably be an unsoldering job, but that's fine.

>
> Wow, that's real dirty! I'm no expert at electronics, and would
> always bow to the greater experience of those in this ng such as Jim,
> but this suggests to me that this is not just a straightforward earth
> loop problem.
>

Most are higher order harmonics of 50Hz mains but some change in level
and frequency over periods of seconds and minutes.

> My suspicions would now rest on the deck or the PC's PSU. It would be
> useful to know:
>

What do you mean by the 'deck'? The interface between tt and PC is a
single unit containing pre-amp and RIAA eq. and a ADC followed by a USB
interface. It is powered via the USB from the PC.

With tt input disconnected from the pre-amp front end, hum/noise is too
low to be measurable using Audacity. S/N ratio is given in the specs as
89 dB @1 kHz

> 1) Is the deck powered by a wall-wart or an inline unit and
> low-voltage DC actually coming into the deck, or is it mains coming in
> and its motor works directly off it? If the former, I'd suspect the
> PSU.
>

Motor is mains. If this mains supply is disconnected the hum level falls
by about 5 dB

> 2) What sort of PC is it? A desktop, or a laptop powered by a
> wall-wart or inline unit as described for the deck?
>

Desktop powered by mains.

>
> Java Jive: ROT: PC Audio Recording & Playback (was: Holst and a
> Headache), 6/12/11
> https://groups.google.com/d/msg/uk.tech.digital-tv/7C4j39e-SFk/a7R64KmusM8J
>

I just had a quick skim and your mention of laptops reminded me that I
do have a laptop available that I could try on battery power.

I am aware of the headshell contact issues with this turntable so will
be looking at that when I get more time to play.

[Java Jive]

On Thu, 05 Mar 2015 00:55:31 +0000, Sumatriptan
<tonylac...@nu-ware.com> wrote:
>
> What do you mean by the 'deck'?

I meant how is the deck powered, by mains AC, or low-voltage DC from a
wall-wart or inlne PSU block, but you've answered that below.

> The interface between tt and PC is a
> single unit containing pre-amp and RIAA eq. and a ADC followed by a USB
> interface. It is powered via the USB from the PC.
>
> With tt input disconnected from the pre-amp front end, hum/noise is too
> low to be measurable using Audacity. S/N ratio is given in the specs as
> 89 dB @1 kHz

So, that would seem to make it the actual deck then - nothing else
seems to fit the facts.

> > 1) Is the deck powered by a wall-wart or an inline unit and
> > low-voltage DC actually coming into the deck, or is it mains coming in
> > and its motor works directly off it? If the former, I'd suspect the
> > PSU.
> >
>
> Motor is mains. If this mains supply is disconnected the hum level falls
> by about 5 dB

Do you mean actually pulling the plug out of the wall, or just
switching off, which might leave the deck still attached to neutral?
(I can't remember for sure whether power-points have double-pole
switches, but I think not.)

That also suggests that the hum may have two, or more, sources, and by
doing that you are fixing a less important one.

> > 2) What sort of PC is it? A desktop, or a laptop powered by a
> > wall-wart or inline unit as described for the deck?
>
> Desktop powered by mains.

Wouldn't have expected problems with that, though ISTR that Jim thinks
PC PSUs are noisy, electrically-speaking. Nevertheless I've digitised
stuff via a SB Live soundcard on a standard, homebuilt PC without any
difficulty. However, thinking about it, that may mostly have been
using an optical input, as described in the previously linked post, or
another of around that time, and that of course wouldn't hum!

> > Java Jive: ROT: PC Audio Recording & Playback (was: Holst and a
> > Headache), 6/12/11
> > https://groups.google.com/d/msg/uk.tech.digital-tv/7C4j39e-SFk/a7R64KmusM8J
> >
>
> I just had a quick skim and your mention of laptops reminded me that I
> do have a laptop available that I could try on battery power.

Certainly worth a try.

> I am aware of the headshell contact issues with this turntable so will
> be looking at that when I get more time to play.

Good luck.

[Trevor Wilson]

**Brand and model of cartridge would be helpful.

[Sumatriptan]

Sorry, thought I had already said. M55E with Dual adapter.

[Jim Lesurf]

In article <830ffat7oiub03f9s...@4ax.com>, Java Jive

<ja...@evij.com.invalid> wrote:
> On Wed, 04 Mar 2015 19:09:58 +0000, Sumatriptan
> <tonylac...@nu-ware.com> wrote:

> > http://www.nu-ware.com/Misc/Screenshots/Dual505A.png
> >
> > Notes 1) The spectrum was obtained before I normalised the audio track
> > to examine the waveform.
> >
> > 2) Hum is with mains on at tt, motor off, tonearm in resting position.
> >
> > 3) As explained, I can reduce the Audacity measured RMS hum level to
> > around -55dB in this room by repositioning...moving it around while
> > looking at the levels.

> Wow, that's real dirty! I'm no expert at electronics, and would always
> bow to the greater experience of those in this ng such as Jim, but this
> suggests to me that this is not just a straightforward earth loop
> problem.

Yes, it certainly doesn't look like a neat 50Hz physical loop!

> My suspicions would now rest on the deck or the PC's PSU.

Mine tend to be that the cartridge or its wiring are picking up stray
magnetic fields from currents elsewhere. i.e. that the coils in the
cartridge and its wiring are having currents inducted from nearby mains
wirings. This tends to be supported by finding that moving things around
alters the hum. But I don't know enough about the deck, etc, and can't
experiment from here.

[Jim Lesurf]

In article <md89gj$no7$1...@dont-email.me>, Sumatriptan

<tonylac...@nu-ware.com> wrote:


> Most are higher order harmonics of 50Hz mains but some change in level
> and frequency over periods of seconds and minutes.

Again, that seems like the cartridge and its wiring are acting like a
pickup for EM fields around them.

Is it possible for you to try something like a 10 Ohm resistor in series
with the deck's ground wire to the amp? And if you have a spare headshell,
try that with its wires open and then connected to make shorts?

No idea if that will help, but its the kind of experiment I'd try to get
some more info to think about.

> Motor is mains. If this mains supply is disconnected the hum level falls
> by about 5 dB

By "disconnected" do you mean 'pull plug from wall socket' or 'using the
switch on the deck'? Do they give different results?

[Jim Lesurf]

In article <9maffatervdouu1ub...@4ax.com>, Java Jive

<ja...@evij.com.invalid> wrote:
> Wouldn't have expected problems with that, though ISTR that Jim thinks
> PC PSUs are noisy, electrically-speaking. Nevertheless I've digitised
> stuff via a SB Live soundcard on a standard, homebuilt PC without any
> difficulty. However, thinking about it, that may mostly have been using
> an optical input, as described in the previously linked post, or another
> of around that time, and that of course wouldn't hum!

The problem is that its a matter of chance what kind of PSU you get in a
computer. Some may be OK, others may be a disaster.

I just got a new machine to use as an 'AV' box with my new HDTV. The
supplier who put it together for me tried the standard PSU that comes with
the main box. Found it produced so much crap that it stopped wired ethernet
working! Changed to a different external brick, no problems.

FWIW I routinely now use a computer to record from LP, etc, and it works
fine. I could probably get the noise and hum down, but in practice it rises
as soon as the stylus hits a real LP anyway! So no point in doing so. <pun
alert!>

I do use an external USB ADC, though.

[Sumatriptan]

>
> So, that would seem to make it the actual deck then - nothing else
> seems to fit the facts.
>

Could be, see below regarding laptop test.

>>
>> Motor is mains. If this mains supply is disconnected the hum level falls
>> by about 5 dB
>
> Do you mean actually pulling the plug out of the wall,
>

Yes, unplugging.

>
> That also suggests that the hum may have two, or more, sources, and by
> doing that you are fixing a less important one.
>

A reduction of 5 dB is worth looking for. Subjectively, it reduces hum
from perceptible to only just perceptible on quiet passages under my
listening conditions here.

I would imagine that there are often multiple hum sources and the object
is to reduce/eliminate enough of them so that what remains is not a
problem to the listener (me).

>>
>> I just had a quick skim and your mention of laptops reminded me that I
>> do have a laptop available that I could try on battery power.
>
> Certainly worth a try.
>

I tried it with my laptop. With laptop PSU plugged in Audacity gave
exactly the same hum levels as with the desktop.

With laptop PSU unplugged the hum drops by about 6 dB. This is almost
identical to the drop in level when I unplug the turntable mains supply
when connected to desktop. At this lower level the turntable sounds very
quiet. (In this room, with these speakers...etc etc.)

(BTW, I've been calling this 'hum' but with components up to and beyond
3 kHz I know hum/noise is a better description)

Above makes me think the problem is earth loop related but I can't see
how, yet. Would be interesting to isolate the tt motor supply with a 1:1
transformer to see if that 'breaks the loop'. I may have one around
somewhere, would be good if it had an isolating screen...

>> I am aware of the headshell contact issues with this turntable so will
>> be looking at that when I get more time to play.
>
> Good luck.
>

I would have expected a headshell contact problem to result in erratic
and rapid signal level changes or discrepancies in hum between channels
etc. Still, something to check if all else fails.

Thanks for the ideas.

[Sumatriptan]

On 05/03/2015 09:40, Jim Lesurf wrote:
> In article <md89gj$no7$1...@dont-email.me>, Sumatriptan
> <tonylac...@nu-ware.com> wrote:
>
>
>> Most are higher order harmonics of 50Hz mains but some change in level
>> and frequency over periods of seconds and minutes.
>
> Again, that seems like the cartridge and its wiring are acting like a
> pickup for EM fields around them.
>
> Is it possible for you to try something like a 10 Ohm resistor in series
> with the deck's ground wire to the amp? And if you have a spare headshell,
> try that with its wires open and then connected to make shorts?
>
> No idea if that will help, but its the kind of experiment I'd try to get
> some more info to think about.
>

Yes, what is suggestive of EM pickup is the preponderance of higher
order components. As you will know, EM coupling is dependent on frequency.

Haven't tried the 10 Ohm resistor yet but pursuing the wiring EMC idea
has given an interesting result. I wondered if it was movement of the
phono leads and USB cable rather than tt itself that causes the
hum/noise levels to change. Maybe they were acting as the pickup
antenna. The Behringer interface USB lead is almost 2M long so I tried
'shortening' it. Not physically! I just sort of scrumbled it up so it
formed a quite small EM antenna.

Result....the hum level dropped by 5 dB and is now very close to
satisfactory when listening. For me :-)

Removing the mains supply to the turntable gives a further 5 dB
reduction and there may be a second hum source. Doing this gives a RMS
hum/noise level below the -60 dB 'floor' of the Audacity level meters.
Not sure if I need to achieve this but will be fun trying.

I'll do some more tests later.

>
>
>> Motor is mains. If this mains supply is disconnected the hum level falls
>> by about 5 dB
>
> By "disconnected" do you mean 'pull plug from wall socket' or 'using the
> switch on the deck'? Do they give different results?
>

Unplugging and switching off give the sane result...a 5 dB reduction as
mentioned above.

[Jim Lesurf]

In article <md9ka3$lq7$1...@dont-email.me>, Sumatriptan

<tonylac...@nu-ware.com> wrote:
> On 05/03/2015 09:40, Jim Lesurf wrote:
> > In article <md89gj$no7$1...@dont-email.me>, Sumatriptan
> > <tonylac...@nu-ware.com> wrote:

> > Is it possible for you to try something like a 10 Ohm resistor in
> > series with the deck's ground wire to the amp? And if you have a spare
> > headshell, try that with its wires open and then connected to make
> > shorts?
> >
> > No idea if that will help, but its the kind of experiment I'd try to
> > get some more info to think about.
> >

> Yes, what is suggestive of EM pickup is the preponderance of higher
> order components. As you will know, EM coupling is dependent on
> frequency.

Yes. As a rule of thumb at these low frequencies I tend to expect it to
'differentiate' the signal, so leading to a rise in sensitivity
proportional to frequency. The currents on mains systems (and to a lesser
extent, the voltages) tend to pick up a wild set of harmonics due to the
way other PSUs around the place react. Hence the fairly hairy result that
looks nothing like a 50Hz sinewave! Alas, that makes the result much more
audible than a pure 50Hz tone. :-/

> Haven't tried the 10 Ohm resistor yet but pursuing the wiring EMC idea
> has given an interesting result. I wondered if it was movement of the
> phono leads and USB cable rather than tt itself that causes the
> hum/noise levels to change. Maybe they were acting as the pickup
> antenna. The Behringer interface USB lead is almost 2M long so I tried
> 'shortening' it. Not physically! I just sort of scrumbled it up so it
> formed a quite small EM antenna.

IIRC you're using one of the UCA series - i.e. in the same series as the
one I tested and reported on at

http://www.audiomisc.co.uk/HFN/ADC/USBrecording.html

but I can't recall if you're using one that includes the RIAA.

If you're not already doing so, you may get better results by using a
dedicated RIAA preamp and having longer coax leads from its output to the
Behringer. This would keep the fields from the Behringer and computer
further away from the low level signals from cartridge to RIAA preamp.

A problem with using the RIAA in the Behringer is that you'd have to use
longer signal leads at low level to move the unit away, and so that may not
help - or make things worse! Better to keep low-level signal leads short,
the snag being if that also moves the source of interference closer! catch
22.

FWIW I did some more recordings here this morning so can give some values
for reference. Here I get about -72 to -74 dB hum+noise before the needle
drops onto the LP. This is with the 0dB RIAA reference level at about
-15dB. So the nominal level of hum+noise is in the ballpark of -60
dB(RIAA). However the hum is almost pure 50Hz and some of the value is
noise over a wide band as I'm using a 96k sample rate. In practice, the
noise goes up as soon as the needle finds the groove. Dominated by LF
rumbles for the best LPs as the system goes down to below 10Hz.

Here this is with the 'PC' next to the deck and the ADC just under it. But
the 'PC's power supply is a brick down on the floor.

FWIW The RIAA preamp I use does have a 10 Ohm lift resistor in the
grounding. I found this made a measureable improvement in hum in most
circumstances of normal use.

Ignore the hum values given in handbooks and reviews. They tend to use a
weighting filter and reference level that is, erm, 'kind' compared with a
straight measurement like the above.

FWIW2 I've just been doing some theory estimates of thermal noise for other
reasons. (Comparing MM with MC as a result of a daft assertion in a
magazine! Old campaigners can probably guess the source given that the
assertion showed 'innocence' of the physics of thermal noise. :-) ) So in
context this is an interesting comparison between ideal world and reality.

[Sumatriptan]

On 05/03/2015 14:01, Jim Lesurf wrote:

>
> IIRC you're using one of the UCA series - i.e. in the same series as the
> one I tested and reported on at
>
> http://www.audiomisc.co.uk/HFN/ADC/USBrecording.html
>

I'm using a Behringer UFO202. Looks almost identical to the ones in your
review.

> but I can't recall if you're using one that includes the RIAA.
>

Yes, I am.

> If you're not already doing so, you may get better results by using a
> dedicated RIAA preamp and having longer coax leads from its output to the
> Behringer. This would keep the fields from the Behringer and computer
> further away from the low level signals from cartridge to RIAA preamp.
>
> A problem with using the RIAA in the Behringer is that you'd have to use
> longer signal leads at low level to move the unit away, and so that may not
> help - or make things worse! Better to keep low-level signal leads short,
> the snag being if that also moves the source of interference closer! catch
> 22.
>

That was something I hadn't considered when getting the UFO 202 but moot
point for now, see below.

> FWIW I did some more recordings here this morning so can give some values
> for reference. Here I get about -72 to -74 dB hum+noise before the needle
> drops onto the LP. This is with the 0dB RIAA reference level at about
> -15dB. So the nominal level of hum+noise is in the ballpark of -60
> dB(RIAA).
> However the hum is almost pure 50Hz and some of the value is
> noise over a wide band as I'm using a 96k sample rate. In practice, the
> noise goes up as soon as the needle finds the groove. Dominated by LF
> rumbles for the best LPs as the system goes down to below 10Hz.
>
> Here this is with the 'PC' next to the deck and the ADC just under it. But
> the 'PC's power supply is a brick down on the floor.
>
> FWIW The RIAA preamp I use does have a 10 Ohm lift resistor in the
> grounding. I found this made a measureable improvement in hum in most
> circumstances of normal use.
>

I tried a 10 Ohm resistor and it did give a small reduction of around 1
dB according to Audacity, so I will keep it. Every bit helps.

I also tried an (enormous 500VA) isolating transformer in the turntable
mains feed and this reduced the hum by quite a large amount.

Total reduction in hum from the 3 changes: ground lift, shielded
isolation transformer and electrically shortened turntable leads amounts
to around 10 dB overall reduction of the 50Hz component. The isolation
transformer contributed much larger reductions of the more troublesome
higher order harmonics and general hash. Some were eliminated entirely.
Compare the original here:

http://www.nu-ware.com/Misc/Screenshots/Dual505A.png

With this:

http://www.nu-ware.com/Misc/Screenshots/Dual505B.png

>
> FWIW2 I've just been doing some theory estimates of thermal noise for other
> reasons. (Comparing MM with MC as a result of a daft assertion in a
> magazine! Old campaigners can probably guess the source given that the
> assertion showed 'innocence' of the physics of thermal noise. :-) ) So in
> context this is an interesting comparison between ideal world and reality.
>

Reality wins out, every time :-)

My last tussle with thermal noise was modification of a ccd (not cmos)
camera for astronomical use. Peltier chips for refrigeration of the ccd,
image stacking to average out thermal noise etc. etc.

I'm happy with the Dual 505 hum level for now and will be moving on to a
workout of my test LP. No doubt I will be pestering you all with more
questions. Thank you so much all for your ideas and comments so far,
Jim, Java, Trevor, Mick.

[Johny B Good]

On Wed, 04 Mar 2015 19:09:58 +0000, Sumatriptan
<tonylac...@nu-ware.com> wrote:

Wow! That's impressively rich in HF harmonics which suggests the use
of an unscreened[1] transformer for powering the RIAA pre-amp[2]
allowing capacitive coupling of the higher frequency harmonics and
noise to dominate the mains hum interference.

The actual plot of the waveform bears absolutely no resemblence to
what I see via cheap 6v ac wallwart transformer used to supply a
nominal 1v level sampling of the mains via a simple resistive
attenuator for feeding into the line input of a laptop for comparitive
measurements between the real mains and a petrol generator I foolishly
thought would make a good IT kit standby supply a few years ago.

The resulting waveform in CoolEdit's window looked indistinguishable
from an oscilloscope's trace of its own mains derived 1v Pk2Pk
'calibration source' which quite clearly showed that the mains was far
from being a pure sinewave (essentially it looked like a sinewave with
the tops slightly but most definitely clipped with a slight downward
tilt to the 'flat tops' on the positive peaks and vice versa for the
negative peaks.

When I first observed this nearly two decades ago, I just assumed it
was an effect of the transformer. It was only much later when I
repeated the test with a SmartUPS2000 in line that I discovered this
was not so since the waveform of the UPS looked a perfect example of a
sinewave, except for some very low level sample switching artifacts
(around the 5KHz mark afaicr).

>
>Notes
>1) The spectrum was obtained before I normalised the audio track to
>examine the waveform.
>
>2) Hum is with mains on at tt, motor off, tonearm in resting position.
>
>3) As explained, I can reduce the Audacity measured RMS hum level to
>around -55dB in this room by repositioning...moving it around while
>looking at the levels.
>
>
> >
> > Otherwise there might be a
> > risk that you make recordings with the hum level 'sounding low' but then
> > hear it when you play the results back elsewhere.
> >
>
>I'm in no rush...I'll be making test recordings and trying them on other
>systems before I spend too much effort on the 'real thing'.
>

[1] I'm referring to the inter-winding screen not a whole transformer
shield which would typically be either mu-metal or soft iron unless a
toroidal transformer is being used to make such magnetic screening
totally redundent as I well know from experience.

[2] I've assumed you're using an RIAA pre-amp of some sort in the TT
itself (quite honestly _the_ only place to do the RIAA
pre-amplification).

You'll have enough trouble competing against the millivolt or so of
mains hum at line levels even when the equalised cartridge signal is
safely boosted into the volts range in the hum loop free environment
of the confnes of the TT itself before it has to bully its way past
the hum loop afflicted line level interconnection to the main amp's
auxilliary input.

Unless you take extreme measures to eliminate hum loop noise, feeding
the cartidge output directly to the phono input of the main amp via a
yard or so of high quality screened cable often leaves you on a hiding
to nothing.

Mention of "high quality screened cable" reminds me of another
possible reason for the predominence of HF harmonics and other noise
in your test signal. Some, so called screened cable can have very poor
screening, in some cases just 3 or 4 strands spiral wrapped around the
signal wire, which makes them very prone to pick up electric fields
radiated by nearby (and sometimes, not so nearby) mains wiring around
the room. I'd certainly be examining the 'screened' cabling very
closely if I were in your current predicament (not forgetting that
phono plugs can fail to make a proper earth return connection in the
socket which can also produce the same symptoms).
--
J B Good

[Phil Allison]

Johny B Good wrote:

>
> Mention of "high quality screened cable" reminds me of another
> possible reason for the predominence of HF harmonics and other noise
> in your test signal. Some, so called screened cable can have very poor
> screening, in some cases just 3 or 4 strands spiral wrapped around the
> signal wire, which makes them very prone to pick up electric fields
> radiated by nearby (and sometimes, not so nearby) mains wiring around
> the room.

** Gotta back you up on that one.

Typical light gauge RCA leads from China have no screening at all - the insulated inner core simply runs parallel with bare copper strands up one side of the core.

The only thing they are good for is low impedance, line level signals with the proviso you never run them alongside speaker wires.

Plus, some of the heavy gauge RCA leads are little better, having only a thick outer cover and much the same inside as the light gauge ones.

I expect you will have to pay a fair old price to get decent quality, woven shield, low capacitance RCA leads that are suitable for connection of a MM or MC phono cartridge to an RIAA stage.

When repairing guitar amps, the leads to and from the Reverb Tank can need replacing and the cheap Chines ones are a disaster - producing loud buzzing hum and even high frequency oscillation if installed in the back of a combo amp.



.... Phil

[Jim Lesurf]

In article <gtrhfath1pp3jg597...@4ax.com>, Johny B Good

<johnny...@invalid.ntlworld.com> wrote:

> >http://www.nu-ware.com/Misc/Screenshots/Dual505A.png

> Wow! That's impressively rich in HF harmonics which suggests the use
> of an unscreened[1] transformer for powering the RIAA pre-amp[2]
> allowing capacitive coupling of the higher frequency harmonics and
> noise to dominate the mains hum interference.

Yes. It may also be that the transformer has a noticable external magnetic
field. I've come across mains transformers where you had to rotate the
transformer to find a 'minimum hum pickup' for nearby wires because of
external fields.

> [2] I've assumed you're using an RIAA pre-amp of some sort in the TT
> itself (quite honestly _the_ only place to do the RIAA
> pre-amplification).

I think he's using the RIAA inside the Behringer - which is powered via the
5v line of its USB connection.

Which makes me wonder if it would also be wise to try using that via a
decent USB hub with its own external power. I've had problems with other
USB ADCs for such reasons. Not as bad as reported here, but then I only
used line level inputs not RIAA.

Echo the comments about choice of cable. But if changing this keep in mind
that the cable capacitance also matters for MM cartridges.

[Jim Lesurf]

In article <mda8nd$d4l$1...@dont-email.me>, Sumatriptan

<tonylac...@nu-ware.com> wrote:

> I tried a 10 Ohm resistor and it did give a small reduction of around 1
> dB according to Audacity, so I will keep it. Every bit helps.

> I also tried an (enormous 500VA) isolating transformer in the turntable
> mains feed and this reduced the hum by quite a large amount.

> Total reduction in hum from the 3 changes: ground lift, shielded
> isolation transformer and electrically shortened turntable leads amounts
> to around 10 dB overall reduction of the 50Hz component. The isolation
> transformer contributed much larger reductions of the more troublesome
> higher order harmonics and general hash. Some were eliminated entirely.
> Compare the original here:

> http://www.nu-ware.com/Misc/Screenshots/Dual505A.png

> With this:

> http://www.nu-ware.com/Misc/Screenshots/Dual505B.png

Interesting. What has struck me is how much your initial 'dirty' hum looks
a lot like the kind of pickup you can get simply by touching the probe of a
high impedance scope input.

I'm wondering if in Germany[1] the domestic mains system doesn't have the
UK's 'unbalanced' line-neutral. i.e. the 505 isn't designed to cope with a
situation where the line and neutral return both have non zero voltages but
with values that differ. I'm also wondering of you have a fair bit of 'dc'
on your mains. That can upset mains transformers that aren't well specified
and enhance hum harmonics.

Many years ago I went though a period where I and others at Armstrong took
home a wooden board and assorted transformers each night to try them out
and assess the *mechanical* buzz they made when presented with mains power
waveform/size/line-neutral imbalance, etc. They varies a lot from one
design to another, and from place to place and time to time. Alas, many
transformer makers seemed to have no interest in this. Ditto for good
sheilding.

cf comments in another posting.

Jim

[1] I'm assuming Dual is German, but my memory may be wrong here as I've
never used or owned one.

[Dave Plowman (News)]

In article <a510c23d-d50e-4a94...@googlegroups.com>,

Phil Allison <palli...@gmail.com> wrote:
> Typical light gauge RCA leads from China have no screening at all - the
> insulated inner core simply runs parallel with bare copper strands up
> one side of the core.

> The only thing they are good for is low impedance, line level signals
> with the proviso you never run them alongside speaker wires.

> Plus, some of the heavy gauge RCA leads are little better, having only a
> thick outer cover and much the same inside as the light gauge ones.

> I expect you will have to pay a fair old price to get decent quality,
> woven shield, low capacitance RCA leads that are suitable for connection
> of a MM or MC phono cartridge to an RIAA stage.

You're right there. And, of course, the only way to find out with moulded
on plugs is to cut one off.

Ages ago a bought 100 metres of good quality braided screen low
capacitance audio co-ax from RS. Even buying decent phono plugs, still
works out cheaper than buying ready made - and know what you're getting.

Standard impedance cartridges are just about the only thing on a Hi-Fi
were the connecting leads can make an audible difference, even under
normal circumstances.

--
*Why don't you ever see the headline "Psychic Wins Lottery"?

Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.

[Sumatriptan]

On 06/03/2015 09:41, Jim Lesurf wrote:

>
> Interesting. What has struck me is how much your initial 'dirty' hum looks
> a lot like the kind of pickup you can get simply by touching the probe of a
> high impedance scope input.
>

I think it is the same mechanism....pickup of stray fields from house
wiring etc.

> I'm wondering if in Germany[1] the domestic mains system doesn't have the
>

Yes, Dual is German. They are still making turntables.

> UK's 'unbalanced' line-neutral. i.e. the 505 isn't designed to cope with a
> situation where the line and neutral return both have non zero voltages but
> with values that differ. I'm also wondering of you have a fair bit of 'dc'
> on your mains. That can upset mains transformers that aren't well specified
> and enhance hum harmonics.
>

I just checked with a DC meter and it reads zero across the mains. What
is 'different' here is that the mains is via overhead line and is a PME
system. So the earth isn't a real earth, it is bonded to the neutral
conductor at the meter.

[Jim Lesurf]

In article <mdc5u8$qro$1...@dont-email.me>, Sumatriptan

<tonylac...@nu-ware.com> wrote:
> On 06/03/2015 09:41, Jim Lesurf wrote:

> >
> > Interesting. What has struck me is how much your initial 'dirty' hum
> > looks a lot like the kind of pickup you can get simply by touching the
> > probe of a high impedance scope input.
> >

> I think it is the same mechanism....pickup of stray fields from house
> wiring etc.

Ok. That isn't an 'earth loop' in the way the term is normally used. This
kind of pickup can happen in systems with a single earth path. In effect,
your arm/deck wiring and the cartridge become a field-probe.

Ideally the metal arm and body of the deck would act as a shield to some
extent. Hence the use of a separate ground wire from the deck to do that
and keep any resulting currents away from the signal ground. But for that
to work you rely on the construction of the deck, arm, etc being
appropriate.

Jim

[Dave Plowman (News)]

In article <54a018...@sick-of-spam.invalid>,

Bob Latham <b...@sick-of-spam.invalid> wrote:
> > Standard impedance cartridges are just about the only thing on a Hi-Fi
> > were the connecting leads can make an audible difference, even under
> > normal circumstances.

> OK, I'll bite.

> Speaker cables are *often* audibly different from one another.

Yes, you could make a speaker cable which sounded different. But why would
you?

> If you cannot here this I would give give very similar suggestions as to
> someone who said (and many do) that they cannot tell the difference
> between HD and SD tv.

Do they? Can't say I know anyone who can't see the difference between SD
and HD - provided it's an HD signal which is being transmitted.

> God knows I should know better that to say this on this group but I can't
> help it if you're all deaf or much more likely never tried it much, if at
> all. After all, the theory says its not audible so why bother trying it.

> Tin hat on, I'm ready.

The answer is simple. If you can reliably tell the difference between
adequately specified cables in a proper test, you'd have a point. But
no-one ever has been able to.

--
*You! Off my planet!

[Jim Lesurf]

In article <54a02ae...@davenoise.co.uk>, Dave Plowman (News)

<da...@davenoise.co.uk> wrote:
> The answer is simple. If you can reliably tell the difference between
> adequately specified cables in a proper test, you'd have a point. But
> no-one ever has been able to.

That pretty much sums up my state of mind on this. For *decades* a large
cash 'prize' was on offer for trying in conditions that seemed perfectly
reasonable to me. The snag was that *none* of those saying the differences
were 'obvious', etc, would take the test. Not one. It was made clear that
it wasn't a 'bet' and they didn't have to pay anything if they couldn't
tell the cables apart in the test. So all they would have 'lost' would have
been some time and the risk of looking mistaken if they hadn't been able to
show they could tell a difference. But no triers at all. So no progress.

For some it might have been inconvenient to go and put in the time. But
that does get a bit shakey as the reason when so many made the claim but
*none* of them took the test. And if they "didn't care what others think",
why say the difference was so clear and obvious in the first place?

I'm still waiting, but I guess that by now the people who put up the cash
have wandered away and are doing something else because no-one would even
try.

I'm quite happy to accept others can hear things that pass me by. But
where's the beef?

[Dave Plowman (News)]

In article <54a0354...@audiomisc.co.uk>,

Jim Lesurf <no...@audiomisc.co.uk> wrote:
> I'm quite happy to accept others can hear things that pass me by. But
> where's the beef?

I'm happy to accept others may hear things differently too. But then you
get comments like 'you must be deaf if you can't hear the difference I
can'. In which case it should be easy to identify the 'better' cable
without seeing what is in use.

Of course having spent a lot of money on new cables - obviously expecting
them to be better otherwise why bother - its easy to convince yourself
there is a difference.

Seems the cash prize may still be on offer:-

http://gizmodo.com/305549/james-randi-offers-1-million-if-audiophiles-can-prove-7250-speaker-cables-are-better

--
*Why don't you ever see the headline "Psychic Wins Lottery"?

[Sumatriptan]

On 06/03/2015 12:50, Jim Lesurf wrote:
> In article <mdc5u8$qro$1...@dont-email.me>, Sumatriptan
> <tonylac...@nu-ware.com> wrote:
>> On 06/03/2015 09:41, Jim Lesurf wrote:
>
>>>
>>> Interesting. What has struck me is how much your initial 'dirty' hum
>>> looks a lot like the kind of pickup you can get simply by touching the
>>> probe of a high impedance scope input.
>>>
>
>> I think it is the same mechanism....pickup of stray fields from house
>> wiring etc.
>
> Ok. That isn't an 'earth loop' in the way the term is normally used. This
> kind of pickup can happen in systems with a single earth path. In effect,
> your arm/deck wiring and the cartridge become a field-probe.
>
> Ideally the metal arm and body of the deck would act as a shield to some
> extent. Hence the use of a separate ground wire from the deck to do that
> and keep any resulting currents away from the signal ground. But for that
> to work you rely on the construction of the deck, arm, etc being
> appropriate.
>

Understood. Perhaps this explains why adjusting positions of any
attached leads varies the hum level. I did some more adjustments of the
phono leads and the turntable mains lead and have achieved a setup where
audible hum is completely overwhelmed by surface noise as soon as stylus
contacts vinyl. Here's a pic:

http://www.nu-ware.com/Misc/Screenshots/Dual505C.png

Left spectrum is hum, motor running, stylus up.
Right spectrum is stylus down on lead-in before audio starts.
Waveform display normalised to -1.0 dB after spectrum analysis.


Being a pragmatic soul, I'll settle for that.

[Johny B Good]

On Fri, 06 Mar 2015 09:48:36 +0000 (GMT), Jim Lesurf
<no...@audiomisc.co.uk> wrote:

>In article <gtrhfath1pp3jg597...@4ax.com>, Johny B Good
><johnny...@invalid.ntlworld.com> wrote:
>
>> >http://www.nu-ware.com/Misc/Screenshots/Dual505A.png
>
>> Wow! That's impressively rich in HF harmonics which suggests the use
>> of an unscreened[1] transformer for powering the RIAA pre-amp[2]
>> allowing capacitive coupling of the higher frequency harmonics and
>> noise to dominate the mains hum interference.
>
>Yes. It may also be that the transformer has a noticable external magnetic
>field. I've come across mains transformers where you had to rotate the
>transformer to find a 'minimum hum pickup' for nearby wires because of
>external fields.
>
>
>
>> [2] I've assumed you're using an RIAA pre-amp of some sort in the TT
>> itself (quite honestly _the_ only place to do the RIAA
>> pre-amplification).
>
>I think he's using the RIAA inside the Behringer - which is powered via the
>5v line of its USB connection.

One possible workaround, using such an RIAA USB ADC, is to fit it
into the TT itself, along with a USB B socket and either locally
supply the 5v from an analogue PSU using a small toroidal mains
transformer or quality Mu-metal screened (with interwinding foil
shielding connected to the local ground return point of the amplifier)
or else a battery sourced 5v supply. You might actually get away with
using the 5v from the USB host but, since you already have a mains
feed for the TT motor, it's best to avoid use of the host supplied 5v
feed.

>
>Which makes me wonder if it would also be wise to try using that via a
>decent USB hub with its own external power. I've had problems with other
>USB ADCs for such reasons. Not as bad as reported here, but then I only
>used line level inputs not RIAA.
>
>Echo the comments about choice of cable. But if changing this keep in mind
>that the cable capacitance also matters for MM cartridges.
>

Surely, you must have meant Moving iron or variable reluctance
cartridges with a notional 47K ohms impedance where this does actually
matter rather than the very low impedance MM types, typically 10 to 30
ohm impedance, which even several hundred pF's worth won't disturb in
the slightest.
--
J B Good

[Phil Allison]

Johny B Good wrote:

>
> One possible workaround, using such an RIAA USB ADC, is to fit it
> into the TT itself, along with a USB B socket and either locally
> supply the 5v from an analogue PSU using a small toroidal mains
> transformer or quality Mu-metal screened (with interwinding foil
> shielding connected to the local ground return point of the amplifier)
> or else a battery sourced 5v supply.

** There are no Mu-metal shielded mains transformers.
Normally, a copper strap around the outside suffices or a wrap made from transformer steel or simply a steel box.

Don't think Mu-metal can be used, as inrush surges and saturation of the core would likely cause the material to become magnetised.

> >Echo the comments about choice of cable. But if changing this keep in mind
> >that the cable capacitance also matters for MM cartridges.
> >
>
> Surely, you must have meant Moving iron or variable reluctance
> cartridges with a notional 47K ohms impedance where this does actually
> matter rather than the very low impedance MM types, typically 10 to 30
> ohm impedance, which even several hundred pF's worth won't disturb in
> the slightest.

** MM = moving magnet, the most common type of magnetic PU cartridge.

Most have about 500 to 700 ohms DC resistance, 0.5H of inductance and a recommended load of 47kohms in parallel with 250pF.

Moving coil ( MC ) cartridges have low resistances, generally from about 1ohm to 30ohms.



... Phil

[Sumatriptan]

On 07/03/2015 01:58, Johny B Good wrote:
>
> One possible workaround, using such an RIAA USB ADC, is to fit it
> into the TT itself, along with a USB B socket and either locally
> supply the 5v from an analogue PSU using a small toroidal mains
> transformer or quality Mu-metal screened (with interwinding foil
> shielding connected to the local ground return point of the amplifier)
> or else a battery sourced 5v supply. You might actually get away with
> using the 5v from the USB host but, since you already have a mains
> feed for the TT motor, it's best to avoid use of the host supplied 5v
> feed.
>

Makes sense, but I don't think it is the 5v USB feed causing the
problem. I'm now convinced it is stray field pickup due to the poor
quality, long phono leads. I tried 'shortening' the leads by wrapping
them into a small volume and the hum level reduced considerably. That
workaround plus the isolating transformer in the motor 50Hz feed has
given this result:

http://www.nu-ware.com/Misc/Screenshots/Dual505C.png

Left spectrum is motor running, stylus raised. Right spectrum is stylus
lowered into the lead-in groove. Hum is now considerably lower than
vinyl surface noise.

The waveform shows the (normalised to -1 dB) signal before/after the
stylus contacts the lead-in and before any audio is played.

I consider this to be good enough for my needs since I can't hear any
hum with this workaround, even at higher than normal listening levels.

>
> Surely, you must have meant Moving iron or variable reluctance
> cartridges with a notional 47K ohms impedance where this does actually
> matter rather than the very low impedance MM types, typically 10 to 30
> ohm impedance, which even several hundred pF's worth won't disturb in
> the slightest.
>

See my reply to Phil.

[Jim Lesurf]

In article <35mkfadlink1hus5s...@4ax.com>, Johny B Good

Erm... Its normal to refer to moving iron or variable reluctance as 'MM' or
moving magnet as a class to distinguish them from MC or moving coil.

As Phil has pointed out MMs tend to have coil resistances much higher than
the "10 to 30" you state. I've just been doing some stats on this for
reasons I mentioned a while ago. And again as he says, the load capacitance
affects MMs and the makers tend to recommend values. (I've only found one
or two MC with recommended load capacitances. These being above 1 *micro*
Farad because their coil inductance is so small.)

FWIW since I did go though old reviews to collate values I can give some
results here:

http://jcgl.orpheusweb.co.uk/temp/trans.png

shows the sensitivity and coil resistance (not the recommended loading)
of some MM and MC examples. It also shows the effect of using an x10 or
x20 voltage step-up transformer with the MCs.


Perhaps you're confusing the recommended *loading* with the actual
cartridge impedances, and saying MM when you mean MC?

[Sumatriptan]

On 07/03/2015 04:02, Phil Allison wrote:

>
> ** MM = moving magnet, the most common type of magnetic PU cartridge.
>
> Most have about 500 to 700 ohms DC resistance, 0.5H of inductance and a recommended load of 47kohms in parallel with 250pF.
>
> Moving coil ( MC ) cartridges have low resistances, generally from about 1ohm to 30ohms.
>

Spot on. Cartridge I'm using is MM, a M55E. According to Shure spec DC
resistance = 630 Ohms, inductance = 730 mH preferred load = 47k Ohms,
and about 400 pF

Which led me here:
http://www.tnt-audio.com/sorgenti/load_the_magnets_e.html

[Dave Plowman (News)]

In article <mdei3m$eje$1...@dont-email.me>,

Sumatriptan <tonylac...@nu-ware.com> wrote:
> I'm now convinced it is stray field pickup due to the poor
> quality, long phono leads. I tried 'shortening' the leads by wrapping
> them into a small volume and the hum level reduced considerably. That
> workaround plus the isolating transformer in the motor 50Hz feed has
> given this result:

If it's hum pickup in the cables, you can usually prove this by moving
them, and see if it changes.

--
*He who laughs last, thinks slowest.

[Johny B Good]

Drat! I misread (Gawd knows why!) MM as MC. Yeah, Moving Magnet is in
the same class as Moving Iron / variable reluctance which allows for a
stronger magnetic flux without trying to move a relatively heavy
magnet around, along with the luxury of static windings with enough
turns of wire to generate higher voltages into more sane load
impedances, notwithstanding the necessity to aim for a preferred
capacitive loading to help hold up the frequency response at the high
end by making use of the resulting high inductance of the pickup coil
windings to provide a rather damped LC parallel resonance voltage
magnification effect.

Modern MM carts using today's wonder rare earth Neodium magnets would
probably compete well against variable reluctance designs in terms of
both output sensitivity and transient response.

Apologies to Jim for picking up on an a non-error.

Obviously I was referring to MC types with my low impedance remarks.
I just misread MM as MC and failed to realise the error even when
typing the response. :-(
--
J B Good

[Johny B Good]

This last bit, conflating MM as MC (in my mind) as you may already
have seen in my previous reply to Phil's post[1], is the error I'm
totally guilty of. Once you translate my use of MM as MC, my post then
makes perfect sense (other than for the fact that it was a pointless
response to yours).

[1] In my embarassed response to the mistake so eloquently picked up
by Phil, I overlooked his remarks about transformer shielding.

Mu-metal shielding _is_ sometimes employed, not internally but as a
total shroud around the transformer to screen magnetically sensitive
components from the inevitable stray leakage flux of classic E&I (T&U)
cored designs.

In this case, the flux levels are only a tiny fraction of that which
links the windings so doesn't represent a saturation risk to the
Mu-metal[2]. Although it can slightly mag up the Mu-metal or soft
steel often used as a cheaper substitute, this permanent magnetism
isn't a problem to nearby pickup coils (tape heads and phono
cartridges) which, in any case, is confined to the screening material
used, whether it be Mu-metal or soft steel.

Toroidal transformers otoh, so effectively confine their magnetic
flux, they don't normally require any such screening, not even when
placed inside the confines of an IBM 14 inch CRT monitor originally
designed for 120v mains in order to convert it to 240v mains. A feat
not possible with a conventional transformer even when placed outside
of said monitor if not a good 60 cms or more away as I discovered two
decades back.

[2] Is Mu-metal any worse than soft iron for self magnetisation? If
so, it seems a strange choice for the pole pieces of magnetic
replay/recording heads, especially since it has such poor wear
properties.
--
J B Good

[Johny B Good]

On Sat, 07 Mar 2015 09:58:59 +0000, Sumatriptan
<tonylac...@nu-ware.com> wrote:

>On 07/03/2015 01:58, Johny B Good wrote:
>>
>> One possible workaround, using such an RIAA USB ADC, is to fit it
>> into the TT itself, along with a USB B socket and either locally
>> supply the 5v from an analogue PSU using a small toroidal mains
>> transformer or quality Mu-metal screened (with interwinding foil
>> shielding connected to the local ground return point of the amplifier)
>> or else a battery sourced 5v supply. You might actually get away with
>> using the 5v from the USB host but, since you already have a mains
>> feed for the TT motor, it's best to avoid use of the host supplied 5v
>> feed.
>>
>
>Makes sense, but I don't think it is the 5v USB feed causing the
>problem. I'm now convinced it is stray field pickup due to the poor
>quality, long phono leads. I tried 'shortening' the leads by wrapping
>them into a small volume and the hum level reduced considerably. That
>workaround plus the isolating transformer in the motor 50Hz feed has
>given this result:

I concur with your analysis on the source of the noise being a matter
of poor electric screening rather than hum loop problems. I only
suggested isolating the 5v USB power feed if the RIAA equalised ADC
were to be installed in the deck itself as a means of guarding against
the possibility of other computers with noisier supplies being used in
the future (after all, the deck will have an existing supply of mains
voltage by which to power a noise free analogue source of the required
5 volts).

>
>http://www.nu-ware.com/Misc/Screenshots/Dual505C.png
>
>Left spectrum is motor running, stylus raised. Right spectrum is stylus
>lowered into the lead-in groove. Hum is now considerably lower than
>vinyl surface noise.
>
>The waveform shows the (normalised to -1 dB) signal before/after the
>stylus contacts the lead-in and before any audio is played.
>
>I consider this to be good enough for my needs since I can't hear any
>hum with this workaround, even at higher than normal listening levels.

It looks like you've cracked the problem then. You'll probably just
need to rewire using quality cable and connectors to convert your
'workaround' solution into a permanent fix.

>
>>
>> Surely, you must have meant Moving iron or variable reluctance
>> cartridges with a notional 47K ohms impedance where this does actually
>> matter rather than the very low impedance MM types, typically 10 to 30
>> ohm impedance, which even several hundred pF's worth won't disturb in
>> the slightest.
>>
>
>See my reply to Phil.

As I've already stated. I made a mistake in misreading MM as MC (with
apologies to Jim for picking up a non-mistake). Likewise apologies all
round to anyone thinking "This Granny needed to be taught how to suck
eggs."

I don't need egg sucking lessons so much as 'comprehension' and "not
misinterpreating what others type" lessons. :-( Gah!
--
J B Good

[Phil Allison]

Johny B Good wrote:

>
> [1] In my embarassed response to the mistake so eloquently picked up
> by Phil, I overlooked his remarks about transformer shielding.
>
> Mu-metal shielding _is_ sometimes employed, not internally but as a
> total shroud around the transformer to screen magnetically sensitive
> components from the inevitable stray leakage flux of classic E&I (T&U)
> cored designs.

** Sometimes = extremely rarely, not in typical items of audio equipment and not available off the shelf. So your advice was pointless.

> In this case, the flux levels are only a tiny fraction of that which
> links the windings so doesn't represent a saturation risk to the
> Mu-metal[2].

** Small ( like 5VA ) e-core transformers operate the core heavily into saturation - if you want a strong 50Hz AC field just pick up any plug-pak that uses one. Also, Mu-metal is ineffective at high flux levels while the other techniques I mentioned ( copper and steel bands) are very effective.

> Toroidal transformers otoh, so effectively confine their magnetic
> flux, they don't normally require any such screening, not even when
> placed inside the confines of an IBM 14 inch CRT monitor originally
> designed for 120v mains in order to convert it to 240v mains. A feat
> not possible with a conventional transformer even when placed outside
> of said monitor if not a good 60 cms or more away as I discovered two
> decades back.

** Toroidals do have an external field and I often see steel bands wrapped around them to reduce it. These bands seem to be made from the same material as is used for the cores.

The magnitude of the field depends on the size of the transformer, any lack of symmetry in the windings - PLUS the level of magnetisation in the core. The biggest effect seems to be that toroidals are invariably run below core saturation while most e-cores are run well into core saturation.

> [2] Is Mu-metal any worse than soft iron for self magnetisation? If
> so, it seems a strange choice for the pole pieces of magnetic
> replay/recording heads, especially since it has such poor wear
> properties.

** Ever see a tape head demagnetiser ?

Every hi-fi shop sold them once.

I certainly do not want a large magnet anywhere near the mu-metal shield covering the tube inside my scope, as it would be a real bugger to demagnetise.


.... Phil


> --
> J B Good

[Sumatriptan]

On 07/03/2015 12:57, Johny B Good wrote:

>
> It looks like you've cracked the problem then. You'll probably just
> need to rewire using quality cable and connectors to convert your
> 'workaround' solution into a permanent fix.
>

I've now got to the stage of trying a test record and immediately found
several issues. The two most important are wiring errors resulting in
L-R reversal and a phase reversal on the left channel. In other words,
it's a pigs ear. Tone arm wire colours are correct so the errors must be
where they connect to the external phono leads. I could correct by
swapping cartridge connectors around but I may as well do it properly
and make the hum fix permanent at the same time.

[Java Jive]

As I said earlier, these days manufacturers take even less care with
vinyl than they do with other media sources.

CD technology could and should have given us a flat FR from near DC up
to 25kHz, easily covering the range of human hearing. Even going up
to 22kHz it still covers quite comfortably the range of older
listeners such as myself. So to all intents and purposes we could and
should be getting near perfect audio reproduction. But what do we
actually get? While there are some very good quality CDs available,
even of those recordings originally released on vinyl, there are also
too many examples where the sound has been ruined by over-processing.
As has been said many times before, the fault lies not in the
technology, but in the people who use it

It's sad that with each passing generation music in particular and
artistic endeavour in general seem to become less 'art' and more of a
commodity, to be bought, sold, resampled, even stolen.

On a lighter note, not even musical names are safe from this process.
I have come to realise that up here in Scotland, there's a flourishing
humorous line in 'resampled' names for bands, tunes, and songs:
Ceilidh Minogue
Def Shepherd
Red Hot Chilli Pipers
Top Of The Crops
Tradivarious
... and close, but no cigar ...
Bah Hamburg Part II
The Band From Rockall
The Last Tango in Harris

I know there was another I particularly liked, but I can't remember it
now.

Cue a long off-topic subthread where everyone offers their own
suggestions ...

On Sun, 08 Mar 2015 11:34:47 +0000, Sumatriptan
<tonylac...@nu-ware.com> wrote:
>
> I've now got to the stage of trying a test record and immediately found
> several issues. The two most important are wiring errors resulting in
> L-R reversal and a phase reversal on the left channel. In other words,
> it's a pigs ear.

--
=========================================================
UK Residents: If you feel can possibly support it
please sign the following ePetition
before closing time of 30/03/2015 23:59:

http://epetitions.direct.gov.uk/petitions/71556
=========================================================
Please always reply to ng as the email in this post's
header does not exist. Or use a contact address at:
http://www.macfh.co.uk/JavaJive/JavaJive.html
http://www.macfh.co.uk/Macfarlane/Macfarlane.html

[Phil Allison]

Java Jive wrote:
>
>
> CD technology could and should have given us a flat FR from near DC up
> to 25kHz, easily covering the range of human hearing. Even going up
> to 22kHz it still covers quite comfortably the range of older
> listeners such as myself.

** What a load of bollocks.

The CD format was designed to record and reproduce MUSIC with no audible loss of quality compared to the original signal.

The format will reproduce signals containing frequencies up to 20kHz with no change.

With MUSIC signal, extensive testing showed that no-body could hear components beyond that frequency.

That some young people can detect steady tones above 20kHz, when reproduced at a high enough level, is irrelevant.


... Phil

[Trevor Wilson]

On 9/03/2015 2:15 AM, Java Jive wrote:
> As I said earlier, these days manufacturers take even less care with
> vinyl than they do with other media sources.
>
> CD technology could and should have given us a flat FR from near DC up
> to 25kHz, easily covering the range of human hearing.

**Bullshit. With a sampling rate of 44.1kHz, Nyquist tells us that the
theoretical maximum of CDs is 22.05kz.

Even going up
> to 22kHz it still covers quite comfortably the range of older
> listeners such as myself.

**It actually covers pretty much everyone over the age of 10.

So to all intents and purposes we could and
> should be getting near perfect audio reproduction. But what do we
> actually get? While there are some very good quality CDs available,
> even of those recordings originally released on vinyl, there are also
> too many examples where the sound has been ruined by over-processing.
> As has been said many times before, the fault lies not in the
> technology, but in the people who use it

**Duh.


--
Trevor Wilson
www.rageaudio.com.au

---
This email has been checked for viruses by Avast antivirus software.
http://www.avast.com

[Dave Plowman (News)]

In article <54a199...@sick-of-spam.invalid>,
Bob Latham <b...@sick-of-spam.invalid> wrote:
> Did you not in the late 70s replace twin flex speaker cables that came
> with the speakers with QED 79 strand? I did and couldn't believe how much
> difference it made.

I've never had speakers that 'came with twin flex'

But adequately rated twin flex is just fine. Or even adequately rated
solid core.

--
*All men are idiots, and I married their King.

[Dave Plowman (News)]

In article <54a199...@sick-of-spam.invalid>,
Bob Latham <b...@sick-of-spam.invalid> wrote:
> If I could arrange for the above test to be done in my room with my kit
> in particular the speakers and with a range of speaker cables I have
> some say in, I'm confident I could pass the test.

The very fact you have a range of speaker cables suggests you expect to
hear a difference. And when you expect such a thing, you often think you
do.

--
*Go the extra mile. It makes your boss look like an incompetent slacker *

[Jim Lesurf]

In article <54a199...@sick-of-spam.invalid>, Bob Latham
<b...@sick-of-spam.invalid> wrote:
> In article <54a03c6...@davenoise.co.uk>, Dave Plowman (News)

> <da...@davenoise.co.uk> wrote:
> > In article <54a0354...@audiomisc.co.uk>, Jim Lesurf
> > <no...@audiomisc.co.uk> wrote:
> > > I'm quite happy to accept others can hear things that pass me by.
> > > But where's the beef?

> > I'm happy to accept others may hear things differently too. But then
> > you get comments like 'you must be deaf if you can't hear the
> > difference I can'. In which case it should be easy to identify the
> > 'better' cable without seeing what is in use.

> > Of course having spent a lot of money on new cables - obviously
> > expecting them to be better otherwise why bother - its easy to
> > convince yourself there is a difference.

> > Seems the cash prize may still be on offer:-

> > http://gizmodo.com/305549/james-randi-offers-1-million-if-audiophiles-can-prove-7250-speaker-cables-are-better

> Did you not in the late 70s replace twin flex speaker cables that came
> with the speakers with QED 79 strand? I did and couldn't believe how
> much difference it made.

I assume you're asking Dave that. FWIW I tried various cables many years
ago and then settled on the one with the lowest series resistance and
modest series inductance. Not really because of any difference I could hear
but simply because it made sense in principle to minimise any change in
frequency response given that I could.

> If I could arrange for the above test to be done in my room with my kit
> in particular the speakers and with a range of speaker cables I have
> some say in, I'm confident I could pass the test.

> I will admit I've not heard cables sound different on other speakers or
> in others rooms but to be honest I can't recall ever trying.

> I'm only qualifying the cables choice to prevent the examiner providing
> 3 pretty identical cables. I've never thought I could hear differences
> in all cables.

> Oh and I can't prove one cable is better than another. I can under the
> right circumstances characterise them and pick my personal preference.

The test referred to was never about showing which was 'best'. Just to find
out if someone could actually *show* they could hear the differences they
claimed when they only had the sound to decide with.

As I'm sure you know full well already (but others reading this may not)
the basic problems here are that;

1) Its easy to show that people hear 'differences' even when faced with the
same source material played on exactly the same setup (inc cables). Reason
being that human perceptions change with time, and with having previously
heard sounds.

2) That people are affected by expectations and other cues. So knowing what
change has or had not been made can affect the results even when the person
believes it hasn't.

Hence it is good practice to do tests in ways that deal with those factors
and see if someone could tell when a change had been made when they *only*
have the sounds to go on.

[Jim Lesurf]

In article <54a19a...@sick-of-spam.invalid>, Bob Latham

<b...@sick-of-spam.invalid> wrote:

> > That pretty much sums up my state of mind on this. For *decades* a
> > large cash 'prize' was on offer for trying in conditions that seemed
> > perfectly reasonable to me. The snag was that *none* of those saying
> > the differences were 'obvious', etc, would take the test. Not one.

> So you are basically saying that your co-writers on HiFi news are either
> lying or too simple minded to arrange a test where self delusion wasn't
> possible.

<sigh> Shame you have to try and shift the issue in that way. Particularly
as I think you've asked that in the past and I've explained. But I'll do so
again.

No. I'm not saying they are "lying" or "simple minded". I am saying they
might be right and they might be wrong, and that might vary from one case
to another. To tell, I'd need to see the results of a suitable test.

As it is, I note their beliefs and conclusions, but don't necessarily share
them.

What I *have* seen over the years is many examples of errors in reasoning
or science or experimental proceedure which generated results said to
'show' various 'effects' that - if true - would help explain the claimed
differences. Sometimes the flaws were quite subtle or basic. See for
example the one I examine at

http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/audio/cableshift/cp.html

The authors claimed they'd found an 'effect' where the cable delayed
signals by an amount that varied with the current level. But when I looked
at the details I noticed that they'd changed something in their test rig
without realising the consequences. I think the authors were honest. But
people make mistakes.


> [Snip]

> > I'm quite happy to accept others can hear things that pass me by.

Note what I said above. It meant you had no need to ask if I thought anyone
was "lying" or "simple minded".

However, they may be wrong, though.

Humans can make mistakes and can believe things that are errors. Until
people take tests of the kind referred to its hard to say more. All I can
note is that dozens of people made the claim and *none* took the test so
far as I recall. I can happily accept some would have found it
inconvenient. But given their (sometimes aggressive) zeal it seems strange
*none* took the test. And it gets us no-where towards resolving the issue.

Since I can't hear the differences as being so 'obvious', I can't resolve
the question by taking the test. Its up to those making the claim if they
want to do more than simply present their belief and insist they must be
right.

Again, as I've said in the past, I'd welcome finding such test results
showed people *can* hear the claimed difference when they only have the
sound to go on. It would imply some interesting new factors were out there
and I like finding out about 'new' things. But I can't work with assertions
beliefs alone when I can't replicate the claims myself.

> > But where's the beef?

> The beef for me is seeing things written that I know from personal
> experience to be untrue. I am quite happy if people say they've never
> heard XYZ but very unhappy when people say XYZ doesn't exist.

Since it is well established that people hear differences when nothing has
changed, the question becomes how you can be totally certain that your
belief as to *why* you hear a "difference" is the right one. No-one else
can answer that if you don't take a suitable test. All we can do is wonder
if you're right or mistaken.

Perhaps also curious, that the makers of fancy cables don't arrange and
take such tests in a scutinised way. If their claims are true, the results
would help them sell cables and make money I'd have thought. But maybe
they're doing fine as it is and don't care while they have sales.

[Java Jive]

On Mon, 09 Mar 2015 12:58:54 +1100, Trevor Wilson
<tre...@SPAMBLOCKrageaudio.com.au> wrote:

> On 9/03/2015 2:15 AM, Java Jive wrote:
> > As I said earlier, these days manufacturers take even less care with
> > vinyl than they do with other media sources.
> >
> > CD technology could and should have given us a flat FR from near DC up
> > to 25kHz, easily covering the range of human hearing.
>
> **Bullshit. With a sampling rate of 44.1kHz, Nyquist tells us that the
> theoretical maximum of CDs is 22.05kz.

As it was actually implemented it was something of a compromise,
sacrificing FR to give greater playing time, but the space available
on the prototype technology "COULD AND SHOULD" (note what I actually
wrote) have been allocated differently to give us a shorter playback
time at a higher sampling rate that would have covered the range of
human hearing.

> Even going up
> > to 22kHz it still covers quite comfortably the range of older
> > listeners such as myself.
>
> **It actually covers pretty much everyone over the age of 10.

I and several others tested the range of our hearing in the Physics
Lab at college when I was about 17 or 18, and I wasn't the only one in
the group who could hear above 23KHz at that age.

> So to all intents and purposes we could and
> > should be getting near perfect audio reproduction. But what do we
> > actually get? While there are some very good quality CDs available,
> > even of those recordings originally released on vinyl, there are also
> > too many examples where the sound has been ruined by over-processing.
> > As has been said many times before, the fault lies not in the
> > technology, but in the people who use it
>
> **Duh.

Duh indeed!

[Don Pearce]

On Mon, 09 Mar 2015 14:27:49 +0000 (GMT), Jim Lesurf
<no...@audiomisc.co.uk> wrote:

>http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/audio/cableshift/cp.html
>
>The authors claimed they'd found an 'effect' where the cable delayed
>signals by an amount that varied with the current level. But when I looked
>at the details I noticed that they'd changed something in their test rig
>without realising the consequences. I think the authors were honest. But
>people make mistakes.

I wrote to the author about this. He had changed the current in part
by changing the load resistor. This, naturally enough, interacted with
the cable reactances to give a different group delay. I'm not sure he
really understood (a background in microwaves really helps), and I
never saw a retraction.

d

[Dave Plowman (News)]

In article <1herfa557dbf3hv0p...@4ax.com>,

Java Jive <ja...@evij.com.invalid> wrote:
> As it was actually implemented it was something of a compromise,
> sacrificing FR to give greater playing time, but the space available
> on the prototype technology "COULD AND SHOULD" (note what I actually
> wrote) have been allocated differently to give us a shorter playback
> time at a higher sampling rate that would have covered the range of
> human hearing.

The reasons for the original CD spec are all based around the limits of
the PCM recorders of the day - basically a semi-pro video recorder
(U-matic).

As we know from later, CD itself is capable of a longer playing time.

I doubt there's much in the way of musical information above about 15 kHz
anyway. Excepting some electronic stuff.

--
*I stayed up all night to see where the sun went. Then it dawned on me.*

[Jim Lesurf]

In article <54fdcf0a...@news.eternal-september.org>, Don Pearce

<sp...@spam.com> wrote:
> On Mon, 09 Mar 2015 14:27:49 +0000 (GMT), Jim Lesurf
> <no...@audiomisc.co.uk> wrote:

> >http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/audio/cableshift/cp.html
> >
> >The authors claimed they'd found an 'effect' where the cable delayed
> >signals by an amount that varied with the current level. But when I
> >looked at the details I noticed that they'd changed something in their
> >test rig without realising the consequences. I think the authors were
> >honest. But people make mistakes.

> I wrote to the author about this. He had changed the current in part by
> changing the load resistor. This, naturally enough, interacted with the
> cable reactances to give a different group delay.

Indeed.

> I'm not sure he really understood (a background in microwaves really
> helps), and I never saw a retraction.

FWIW I did know one of the authors (Harrison, or 'Harry') enough to
exchange some emails with him at one point. This was because he was one of
the editors of HFN at the time I started writing for them. [1] I'd guess
his main involvment was in writing and being interested in the topic. So
the 'technical' side was, I guess, done by Ben Duncan.

Alas, I am less then entirely 'whelmed' by some other things Ben Duncan has
written. e.g the reports he wrote for Uncle Russ about RFI and fancy mains
cables.

So I'm curious to know which one you wrote to, and what reply he made if
any. My guess is you tried Ben Duncan.

Jim

[1] He beat me to buying a collection of back issues of HFN that reached
back to issue one! Damn! I still lack a few issues from the first few
volumes. :-/

[Don Pearce]

On Mon, 09 Mar 2015 18:38:18 +0000 (GMT), Jim Lesurf

Yes it was Ben Duncan. The article was so detailed - and so wrong. It
was the first time I had thought to set a published record straight.

d

[Java Jive]

On Mon, 09 Mar 2015 17:37:01 +0000 (GMT), "Dave Plowman (News)"
<da...@davenoise.co.uk> wrote:
>
> The reasons for the original CD spec are all based around the limits of
> the PCM recorders of the day - basically a semi-pro video recorder
> (U-matic).
>
> As we know from later, CD itself is capable of a longer playing time.

Well that rather goes to show that it would have been better to have
chosen from the start a spec that completely encompassed the range of
human hearing, rather than one that almost does.

> I doubt there's much in the way of musical information above about 15 kHz
> anyway. Excepting some electronic stuff.

Are you claiming that there is no difference between Audio-Cassette,
which rolls off about there, and open-reel, vinyl, and CD, all of
which had higher roll-offs?. I suspect that most people would be able
to tell the difference immediately between the frequency response of
AC and those other types - I certainly could and still can with no
problem at all.

After some searching I've just found some AC recordings of tracks from
an album that I now have on CD, it's Barbara Dickson's seminal folk
album "From The Beggar's Banquet", 1970. The AC recordings were
originally made from a library copy of the LP, while the CD is a
re-issue of 5 or 6 years ago that I feel most fortunate to have
obtained. The difference between the two is utterly unmistakable.

[Trevor Wilson]

On 10/03/2015 2:29 AM, Java Jive wrote:
> On Mon, 09 Mar 2015 12:58:54 +1100, Trevor Wilson
> <tre...@SPAMBLOCKrageaudio.com.au> wrote:
>
>> On 9/03/2015 2:15 AM, Java Jive wrote:
>>> As I said earlier, these days manufacturers take even less care with
>>> vinyl than they do with other media sources.
>>>
>>> CD technology could and should have given us a flat FR from near DC up
>>> to 25kHz, easily covering the range of human hearing.
>>
>> **Bullshit. With a sampling rate of 44.1kHz, Nyquist tells us that the
>> theoretical maximum of CDs is 22.05kz.
>
> As it was actually implemented it was something of a compromise,
> sacrificing FR to give greater playing time, but the space available
> on the prototype technology "COULD AND SHOULD" (note what I actually
> wrote) have been allocated differently to give us a shorter playback
> time at a higher sampling rate that would have covered the range of
> human hearing.
>
>> Even going up
>>> to 22kHz it still covers quite comfortably the range of older
>>> listeners such as myself.
>>
>> **It actually covers pretty much everyone over the age of 10.
>
> I and several others tested the range of our hearing in the Physics
> Lab at college when I was about 17 or 18, and I wasn't the only one in
> the group who could hear above 23KHz at that age.

**AT WHAT LEVEL?

The human ear does not have a 'brickwall filter' at 20kHz. No one ever
suggested it did. I recall visiting a warehouse owned by the company I
worked for when I was around 25 years old. I was assaulted by the most
appalling 'feeling' and I had to immediately leave. Curious, I decided
to work out what was going on. Turns out I was reacting to the
ultrasonic burglar alarm system. A microphone, preamp, oscilloscope and
frequency counter showed me that the space in the warehouse was
constantly flooded with a high intensity acoustic signal of
approximately 26kHz. OTOH, using conventional hearing tests, my hearing
extended to around 19kHz at the time.

MORAL: With sufficient intensity, human hearing can extend way past
20kHz. That intensity is NEVER achieved with any commercial recordings.

[Phil Allison]

Java Jive wrote:

>
> I and several others tested the range of our hearing in the Physics
> Lab at college when I was about 17 or 18, and I wasn't the only one in
> the group who could hear above 23KHz at that age.

** Fraid that has been thoroughly proven to have nothing to do with music reproduction.

No matter how many naïve audiophools think it does.



.... Phil

[Phil Allison]

Dave Plowman ( Raving Nutcase) wrote:

>
> The reasons for the original CD spec are all based around the limits of
> the PCM recorders of the day - basically a semi-pro video recorder
> (U-matic).
>

** The CD spec was *tweaked* to be compatible with those recorders - hence sampling at 44.1kHz instead of some other very similar number. It is NOT a quality limitation.

> As we know from later, CD itself is capable of a longer playing time.

** The original CD was smaller than the final 12cm dia version, chosen to increase the playing time to well over 1 hour.

44.1kHz and 16 bit gives audibly perfect reproduction plus a comfortable margin beyond. 100dB s/n and 0.005% THD are well beyond what is necessary.


... Phil

[Phil Allison]

Trevor Wilson wrote:

>
> **AT WHAT LEVEL?


** Certainly over 100dB SPL.

Easily achieved with headphones or a tweeter held close to one's ear while being fed from a sine wave generator and amplifier.



... Phil