Re: Amp input selector
Jim K
> Slightly off topic, but ...
>
> I have an Arcam Alpha 9 audio amplifier. The input select switch has gone
> very noisy, rendering it almost unusable. I've already tried squirting
> RS switch cleaner in it, which improved matters for a few weeks, but
> now it's worse than ever. Several people have recommend Deoxit switch
> cleaner so I have ordered some ("*How* effing much?"). Arcam say the switch is
> globally unavailable, which has been confirmed by several repair companies
> I've spoken to. Another said that dismantling the switch (which is big,
> complicated, well soldered to the motherboard and motor driven) is both
> long winded, complicated and doesn't work for any length of time.
>
> So ... I now have a perfectly good and quite expensive (although quite old)
> amplifier that's unusable. Any suggestions as to where to go from here? I
> suppose I'm wanting to be talked into replacing it, but I'm not happy.
>
> (What's even more irritating is that I gave away my perfectly servicable
> Trio KA-2000A a few months ago, so I can't play any bloody music at the
> moment.)
>
> --
> Today is Pungenday, the 63rd day of Chaos in the YOLD 3177
> Science flies people to the moon; Religion flies people into skyscrapers.
don't/didn;t QED make an auxilliary input selector? could you "fix it"
on one channnel and use something else (QED styley) to switch inputs?
Jim K
Dave Plowman (News)
same level (ie not including an LP pickup) you could replace the switch
with a simple rotary type. Or wire out the original and use an external
one.
--
*Frankly, scallop, I don't give a clam
Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.
Jim K
also read ebay item 120690760925
Jim K
Dave Liquorice
> Another said that dismantling the switch (which is big, complicated,
> well soldered to the motherboard and motor driven) is both long winded,
> complicated and doesn't work for any length of time.
What does the switch actually do? Just audio from the various inputs
(post EQ in the case of a record deck input) or does it also switch
the required EQ in/out depending on the input selected?
If it's just audio could a multiple position, multiple pole rotary
switch be fitted and wired to the board?
How is the motor controlled from the front panel? Rotary selector
inter-locked push buttons?
--
Cheers
Dave.
Donwill
> Slightly off topic, but ...
>
> I have an Arcam Alpha 9 audio amplifier. The input select switch has gone
> very noisy, rendering it almost unusable. I've already tried squirting
> RS switch cleaner in it, which improved matters for a few weeks, but
> now it's worse than ever. Several people have recommend Deoxit switch
> cleaner so I have ordered some ("*How* effing much?"). Arcam say the switch is
> globally unavailable, which has been confirmed by several repair companies
> complicated, well soldered to the motherboard and motor driven) is both
> long winded, complicated and doesn't work for any length of time.
>
> amplifier that's unusable. Any suggestions as to where to go from here? I
> suppose I'm wanting to be talked into replacing it, but I'm not happy.
>
> (What's even more irritating is that I gave away my perfectly servicable
> Trio KA-2000A a few months ago, so I can't play any bloody music at the
> moment.)
>
>
goodness sake, is the younger generation incapable of turning a rotary
switch??
Don
Jules Richardson
> Another said that
> dismantling the switch (which is big, complicated, well soldered to the
> motherboard and motor driven) is both long winded, complicated and
> doesn't work for any length of time.
Did they give a reason for the "doesn't work for any length of time"
statement? I'm not sure what the failure mode would be such that it can
be cured for a short length of time but will just re-occur?
If switch contacts have worn away, then surely you're not going to fix it
at all and dismantling is pointless. If they've oxidised, then you're
probably going to be able to fix it for as long as it takes to suffer
oxidisation problems again - which IME with switches is quite a long time
(and I'm not sure why the period would be shorter for whatever Arcam used)
Maybe the Arcam switches (as with many) are riveted or use folded-over
tabs which are prone to breaking - and poor solutions might result in a
switch that essentially kept on coming apart at the seams; perhaps that's
what the person you spoke to meant?
Anyway, that's a long-winded way of me saying that I think you need to
look at the physical design and see how easy you think it'll be to
dismantle the thing - and to put it back together in such a way that it
stays together :-)
cheers
Jules
Tabby
> Slightly off topic, but ...
>
> I have an Arcam Alpha 9 audio amplifier. The input select switch has gone
> very noisy, rendering it almost unusable. I've already tried squirting
> RS switch cleaner in it, which improved matters for a few weeks, but
> now it's worse than ever. Several people have recommend Deoxit switch
> cleaner so I have ordered some ("*How* effing much?"). Arcam say the switch is
> globally unavailable, which has been confirmed by several repair companies
> complicated, well soldered to the motherboard and motor driven) is both
> long winded, complicated and doesn't work for any length of time.
>
> amplifier that's unusable. Any suggestions as to where to go from here? I
> suppose I'm wanting to be talked into replacing it, but I'm not happy.
>
> (What's even more irritating is that I gave away my perfectly servicable
> Trio KA-2000A a few months ago, so I can't play any bloody music at the
> moment.)
As said, either replace the switch with a standard nonmotorised one,
or use an external switch. It should be simply a 5 way 2 pole switch.
One can determine which connections are the power amp in terminals by:
an audio signal fed to the right 2 will keep coming out of the
speakers no matter what position the switch is in. Note that position
may affect the volume a fair bit on such a test, but wont kill the
signal, as long as you use a low impedance source.
If you dont understadn that at all, you could connect an external
audio input selector to random switch terminals, when you hit the
right ones it'll work. The downside of this is you wont be using the
internal record desk pickup preamp.
NT
Andy Dingley
> I have an Arcam Alpha 9 audio amplifier. The input select switch has gone
> very noisy, rendering it almost unusable.
Angle grinder. Hack out the old switch, replace with a modern
replacement, without the motor. Simples.
I'd be surprised if you even get any trouble from the record preamp
input. The circuit for these input selectors is usually very simple,
just a multi-way changeover.
Motorized volume controls have some use, as you can adjust them from
your favourite listening position. However switching inputs usually
involves disk changing, so you're up there anyway.
Make sure you use leaded solder.
The Natural Philosopher
> On 2011-03-04, Jules Richardson <jules.richa...@gmail.com> wrote:
>> On Fri, 04 Mar 2011 12:44:24 +0000, Huge wrote:
>>
>>> Another said that
>>> dismantling the switch (which is big, complicated, well soldered to the
>>> motherboard and motor driven) is both long winded, complicated and
>>> doesn't work for any length of time.
>> Did they give a reason for the "doesn't work for any length of time"
>> statement?
>
>
>> I'm not sure what the failure mode would be such that it can
>> be cured for a short length of time but will just re-occur?
>>
>> If switch contacts have worn away, then surely you're not going to fix it
>> at all and dismantling is pointless. If they've oxidised, then you're
>> probably going to be able to fix it for as long as it takes to suffer
>> oxidisation problems again - which IME with switches is quite a long time
>> (and I'm not sure why the period would be shorter for whatever Arcam used)
>>
>> Maybe the Arcam switches
>
> them any more. At least not on their web site. Perhaps I should contact
> them, if I can get a part number off the switch....
>
Alps used to custom make switches..to special order :-(
If you are lucky some white haired old boy will know where there are a
dozen tucked away somewhere.
Or the actual contact parts may be standard items - need to usually take
it off the board,. unscrew a couple of bolts and pull the wafers off the
shaft, and fit new ones..
>> (as with many) are riveted or use folded-over
>> tabs which are prone to breaking - and poor solutions might result in a
>> switch that essentially kept on coming apart at the seams; perhaps that's
>> what the person you spoke to meant?
>
> Could well be. I'll take the amp to pieces once the Deoxit arrives and have
> another look. I may be able to replace the switch with flying leads and some
> kind of rotary switch arrangement. After all, the amp is scrap anyway.
Thats a shame..
The Natural Philosopher
> On Mar 4, 12:44 pm, Huge <H...@nowhere.much.invalid> wrote:
>> Slightly off topic, but ...
>>
>> I have an Arcam Alpha 9 audio amplifier. The input select switch has gone
>> very noisy, rendering it almost unusable. I've already tried squirting
>> RS switch cleaner in it, which improved matters for a few weeks, but
>> now it's worse than ever. Several people have recommend Deoxit switch
>> cleaner so I have ordered some ("*How* effing much?"). Arcam say the switch is
>> globally unavailable, which has been confirmed by several repair companies
>> I've spoken to. Another said that dismantling the switch (which is big,
>> complicated, well soldered to the motherboard and motor driven) is both
>> long winded, complicated and doesn't work for any length of time.
>>
>> So ... I now have a perfectly good and quite expensive (although quite old)
>> amplifier that's unusable. Any suggestions as to where to go from here? I
>> suppose I'm wanting to be talked into replacing it, but I'm not happy.
>>
>> (What's even more irritating is that I gave away my perfectly servicable
>> Trio KA-2000A a few months ago, so I can't play any bloody music at the
>> moment.)
>
> As said, either replace the switch with a standard nonmotorised one,
> or use an external switch. It should be simply a 5 way 2 pole switch.
Not if its quality, and has a phono amp.
You often had to disable that to prevent crosstalk when playing a record
but switched to something else.
Probably it will be shorted to deck at the output EXCEPT when selected.
John Rumm
> Slightly off topic, but ...
>
> I have an Arcam Alpha 9 audio amplifier. The input select switch has gone
> very noisy, rendering it almost unusable. I've already tried squirting
> RS switch cleaner in it, which improved matters for a few weeks, but
> now it's worse than ever. Several people have recommend Deoxit switch
I had a similar problem with the volume control and input selector
switch on a Kenwood KA3020, and also a noisy volume knob on a Arcam
Alpha 8R.
For the Kenwood I (hushed voice) /squirted some WD40/ into the pot and
the switch mechanism and worked them back and forth for a few mins.
Couple of years later they are still working flawlessly.
On the Arcam I tried a similar trick but with proper contact cleaning
solvent. It also worked, but has not lasted as well in the sense that
some noise is creeping back into it as you rotate it.
> cleaner so I have ordered some ("*How* effing much?"). Arcam say the switch is
> globally unavailable, which has been confirmed by several repair companies
> I've spoken to. Another said that dismantling the switch (which is big,
> complicated, well soldered to the motherboard and motor driven) is both
> long winded, complicated and doesn't work for any length of time.
Don't suppose it has an identical (or similar) switch right next to it
for Rec Out selection? If so could they be swapped?
--
Cheers,
John.
/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/
Dave Plowman (News)
Donwill <Donwill...@invalid.invalid> wrote:
> Why should an amplifier input selector switch be motor driven for
> goodness sake, is the younger generation incapable of turning a rotary
> switch??
It allows remote control from a zapper.
--
*I finally got my head together, now my body is falling apart.
Jim K
> On 2011-03-04, John Rumm <see.my.signat...@nowhere.null> wrote:
>
> > Don't suppose it has an identical (or similar) switch right next to it
> > for Rec Out selection? If so could they be swapped?
>
>
> --
> Today is Pungenday, the 63rd day of Chaos in the YOLD 3177
> Science flies people to the moon; Religion flies people into skyscrapers.
good old google
" Found this quick fix to bypass switch
Seams to be a real common problem, I found this solution on another
forum:
'You can fix the problem in less than a minute with a phono lead, but
you will have to sacrifice both tape loops. Connect "Tape 1 out" to
"Tape 2 in" and press the Tape 2 button. You can now use the "Tape 1"
switch to select the input you want to listen to (you cannot listen to
tape 1 of course).
Unfortunately, the faulty "listen" switch effectively becomes the
Tape2 "record selection" switch, so the static now appears on
recordings made from "Tape 2 out".'
It works great for me "
Jim K
Tabby
wrote:
Whether thats necessary is another matter. If it proved an issue its
not much of a challenge to stop the vinyl record when listening to
something else.
NT
Tabby
On old amps the rec out is simply connected direct to the selected
input, making it trivially easy to bypass internal switching entirely.
NT
Jim K
Should have added - that solution was googled and culled from a thread
the first line of which says:-
"The listen knob which selects the input (tuner, phono, CD etc) seems
to be faulty on my Arcam Alpha 9 amp. "
IF anyone cares to google the text they will be able to read for
themselves.
Jim K
Terry Casey
Huge <Hu...@nowhere.much.invalid> wrote:
>
> Slightly off topic, but ...
>
> I have an Arcam Alpha 9 audio amplifier. The input select switch has gone
> very noisy, rendering it almost unusable. I've already tried squirting
> RS switch cleaner in it, which improved matters for a few weeks, but
> now it's worse than ever.
Here's an idea for you. Provided that the switch isn't mechanically
disintegrating, the problem will usually be the silver plated contacts
tarnishing.
Years ago, in the days of 405 line TV, this was a common problem with the
contacts in the VHF tuner unit.
The usual solution, if you'll pardon the pun, was RS Switch Cleaner - though
Electrolube was better and longer lasting.
Some switches, though, defied all efforts at cleaning - particularly if the
mating surfaces were inaccessible - until, one day, we found a cure. Silvo!
We applied it sparingly to the accessible parts of the contacts, then operated
the switch repeatedly, as usual, to get it inside and between the mating
surfaces. If the contacts could be reached, we'd apply addition pressure to
really obstinate cases using a match stick. Then flush it away with switch
cleaner and, after the carbon tet had evaporated, finish off with Electrolube.
If it worked without causing problems to circuitry operating at 200MHz,it won't
be a problem for audio!
You could do worse than give it a try.
--
Terry
The Natural Philosopher
REALLY good switches used to be (solid) silver buttons that wiped across
each other.
Cheap is gold plated brass. No oxidation until the gold wears off..
Really cheap is just bronze :-)
Adrian C
> Slightly off topic, but ...
>
> I have an Arcam Alpha 9 audio amplifier. The input select switch has gone
> very noisy, rendering it almost unusable.
Replace it? Even an upgrade?
Secondhand market for tasty hi-fi kit is in freefall. Forget eBay, try
and hunt down an event like audio jumble which happens twice a year.
http://www.youtube.com/watch?v=73Qwr-yU4bY
You'll find hardly used decent and audiophile kit at silly prices with
plenty of life and spec left.
And there is a similar event on April 17th in Reading, the Thames Valley
Audiofayre.
www.thamesvalleyaudiofayre.co.uk
And there should be similar events up and down the country, these events
have taken the place of radio rally interest for some.
--
Adrian C
Owain
> Except ... what's Silvo?
It's like Brasso, but for silver.
Owain
Terry Casey
Huge <Hu...@nowhere.much.invalid> wrote:
>
> On 2011-03-05, Terry Casey <kt...@example.invalid> wrote:
> > In message <8tc558...@mid.individual.net> on 4 Mar 2011 12:44:24 GMT
> > Huge <Hu...@nowhere.much.invalid> wrote:
> >>
> >> Slightly off topic, but ...
> >>
> >> I have an Arcam Alpha 9 audio amplifier. The input select switch has gone
> >> very noisy, rendering it almost unusable. I've already tried squirting
> >> RS switch cleaner in it, which improved matters for a few weeks, but
> >> now it's worse than ever.
> >
> > Here's an idea for you. Provided that the switch isn't mechanically
> > disintegrating, the problem will usually be the silver plated contacts
> > tarnishing.
> >
> > Years ago, in the days of 405 line TV, this was a common problem with the
> > contacts in the VHF tuner unit.
> >
> > The usual solution, if you'll pardon the pun, was RS Switch Cleaner
>
>
> > Some switches, though, defied all efforts at cleaning - particularly if the
> > mating surfaces were inaccessible - until, one day, we found a cure. Silvo!
> >
> > We applied it sparingly to the accessible parts of the contacts, then operated
> > the switch repeatedly, as usual, to get it inside and between the mating
> > surfaces. If the contacts could be reached, we'd apply addition pressure to
> > really obstinate cases using a match stick. Then flush it away with switch
> > cleaner and, after the carbon tet had evaporated, finish off with Electrolube.
> >
> > If it worked without causing problems to circuitry operating at 200MHz,it won't
> > be a problem for audio!
> >
> > You could do worse than give it a try.
>
> Except ... what's Silvo?
This:
http://www.heritage-homeandgarden.co.uk/reckitt-silvo-tarnish-guard-liquid-
150ml-p-21225.html
or
although it doesn't seem so easy to find in liquid form these days and wadding
is obviously of no use at all.
This:
http://www.scjohnson.co.uk/nqcontent.cfm?a_id=6006
looks similar and may be easier to find - just take a look on the supermarket
shelves.
On the other hand, one can of Silvo would probably last you a couple of hundred
years so instead, why not ask around and see if anybody's got a can languishing
away in a cupboard somewhere that you could borrow - you won't need much!
--
Terry
Terry Casey
The Natural Philosopher <t...@invalid.invalid> wrote:
>
I don't recall ever needing to perform this trick on the same set twice and,
despite the wear such contacts get over time, the Silvo never succeeded in
removing the silver plating.
Of course, if somebody decides to use Brasso instead, all bets are off!
Incidentally, the sets we had the worst problems with were Bush. All other
manufacturers used 13 channel turrets and variants thereof and it was usually
possible to get to all the contacts, both fixed and moving, with a little
dismantling.
Bush used an incremental tuning system with a band switch to select Band I and
Band III. These had standard wafer switch contacts in the form of two fixed
fingers, which gripped a sliding contact that performed the switching action.
Therefore, all the contact surfaces were hidden on the underside and only the
top surface of the sliding contact was partially accessible.
--
Terry
Lobster
> On 2011-03-04, Donwill<Donwill...@invalid.invalid> wrote:
>> On 04/03/2011 12:44, Huge wrote:
>>> Slightly off topic, but ...
>>>
>>> I have an Arcam Alpha 9 audio amplifier. The input select switch has gone
>>> very noisy, rendering it almost unusable. I've already tried squirting
>>> RS switch cleaner in it, which improved matters for a few weeks, but
>>> cleaner so I have ordered some ("*How* effing much?"). Arcam say the switch is
>>> globally unavailable, which has been confirmed by several repair companies
>>> I've spoken to. Another said that dismantling the switch (which is big,
>>> complicated, well soldered to the motherboard and motor driven) is both
>>> long winded, complicated and doesn't work for any length of time.
>>>
>>> So ... I now have a perfectly good and quite expensive (although quite old)
>>> amplifier that's unusable. Any suggestions as to where to go from here? I
>>> suppose I'm wanting to be talked into replacing it, but I'm not happy.
>>>
>>> (What's even more irritating is that I gave away my perfectly servicable
>>> Trio KA-2000A a few months ago, so I can't play any bloody music at the
>>> moment.)
>>>
>>>
>> goodness sake,
>
...for the younger generation who are incapable of getting out of their
armchairs ;)
>
>> is the younger generation incapable of turning a rotary
>> switch??
>
> Younger generation? Bwahahahahahahahahahahaha. Tosser.
The Natural Philosopher
> On 2011-03-05, Terry Casey <kt...@example.invalid> wrote:
>> In message <8tferk...@mid.individual.net> on 5 Mar 2011 18:48:20 GMT
>> Huge <Hu...@nowhere.much.invalid> wrote:
>
>>> Except ... what's Silvo?
>> This:
>>
>> http://www.heritage-homeandgarden.co.uk/reckitt-silvo-tarnish-guard-liquid-
>> 150ml-p-21225.html
>
>
> OK, I shall try that as well, then. And failing that, off to the
> audio jumble. (An Arcam Alpha 10 sells for well over £300 on eBay. That's
> a lot of money, in my book.) The only issue is, what to buy? Perhaps the
> Quad lineup I fancied in my youth?
>
Quad 303 is relative crap, also 405..tested both.
Quad lost it when they moved away from valves,.. its built well, but the
actual sound is nowhere near as good.
You probably want to go for a specialist brand in the post 1980 period:
MOST of the issues of slow transistors and high crossover distortion
were solved by then.
Technics and Sony are both surprisingly good, and Yamaha.
But my money would be on a specialist small UK firm..
Steve Firth
> > But my money would be on a specialist small UK firm..
>
> Mine also.
>
> As long as they keep a reasonable stock of spare parts.
I've no complaints about my Mission Cyrus. Built like a brick outhouse,
still sounds good 21 years after I bought it. If I were buying a new amp
I'd buy a Cyrus Cyrus 6[1]. If I had the thick end of a grand to spend
on one that is.
If you want something to fill a gap and not crackle a s/h Cyrus One
would cost about £25.
[1] A bit confusing now the company has changed its name to Cyrus. Is it
a Cyrus 6 or a Cyrus Cyrus 6?
tony sayer
<t...@invalid.invalid> scribeth thus
>Huge wrote:
>> On 2011-03-05, Terry Casey <kt...@example.invalid> wrote:
>>> In message <8tferk...@mid.individual.net> on 5 Mar 2011 18:48:20 GMT
>>> Huge <Hu...@nowhere.much.invalid> wrote:
>>
>>>> Except ... what's Silvo?
>>> This:
>>>
>>> http://www.heritage-homeandgarden.co.uk/reckitt-silvo-tarnish-guard-liquid-
>>> 150ml-p-21225.html
>>
>>> http://www.scjohnson.co.uk/nqcontent.cfm?a_id=6006
>>
>> OK, I shall try that as well, then. And failing that, off to the
>> audio jumble. (An Arcam Alpha 10 sells for well over £300 on eBay. That's
>> a lot of money, in my book.) The only issue is, what to buy? Perhaps the
>> Quad lineup I fancied in my youth?
>>
>Quad 303 is relative crap, also 405..tested both.
Would you be able to identify a good to spec one, 303 say, in a blind
listening test?...
The 33 wasn't up to much..
>
>Quad lost it when they moved away from valves,.. its built well, but the
>actual sound is nowhere near as good.
>
>You probably want to go for a specialist brand in the post 1980 period:
>MOST of the issues of slow transistors and high crossover distortion
>were solved by then.
>
>Technics and Sony are both surprisingly good, and Yamaha.
>
>But my money would be on a specialist small UK firm..
Audiolab were and still are good...
--
Tony Sayer
tony sayer
<Hu...@nowhere.much.invalid> scribeth thus
>On 2011-03-05, Terry Casey <kt...@example.invalid> wrote:
>> Huge <Hu...@nowhere.much.invalid> wrote:
>>>
>>> Slightly off topic, but ...
>>>
>>> I have an Arcam Alpha 9 audio amplifier. The input select switch has gone
>>> very noisy, rendering it almost unusable. I've already tried squirting
>>> RS switch cleaner in it, which improved matters for a few weeks, but
>>> now it's worse than ever.
>>
>> Here's an idea for you. Provided that the switch isn't mechanically
>> disintegrating, the problem will usually be the silver plated contacts
>> tarnishing.
>>
>> Years ago, in the days of 405 line TV, this was a common problem with the
>> contacts in the VHF tuner unit.
>>
>> The usual solution, if you'll pardon the pun, was RS Switch Cleaner
>
Theres a switch cleaner called "Servisol" we us in our workshop. I've
never known it Not to work, tried that once?..
Just a thought .. you haven't somewhere perhaps got excessive DC leakage
somewhere that can cause very noisy pots and sometimes switches?..
--
Tony Sayer
tony sayer
<Hu...@nowhere.much.invalid> scribeth thus
>On 2011-03-06, tony sayer <to...@bancom.co.uk> wrote:
>> In article <8tferk...@mid.individual.net>, Huge
>><Hu...@nowhere.much.invalid> scribeth thus
>
>>
>>
>> Theres a switch cleaner called "Servisol" we us in our workshop. I've
>> never known it Not to work, tried that once?..
>>
>> Just a thought .. you haven't somewhere perhaps got excessive DC leakage
>> somewhere that can cause very noisy pots and sometimes switches?..
>
>
>
Might be difficult to know exactly without a manual, but it can and does
happen. However I expect that the makers would be aware of that if it
were a problem in that amp..
Does seem odd the way you describe it as a normal input switch isn't
that complex in that its normally multiway from the input sockets to the
input of the amp there shouldn't be anything during switching to develop
a current that could cause noise if you see what I mean, unless your
switching amp stages in and out so if you or anyone does have a manual
be interesting to see..
--
Tony Sayer
Dave Plowman (News)
> Would you be able to identify a good to spec one, 303 say, in a blind
> listening test?...
Of course he wouldn't. But more easy to tell it against a valve amp with
their poor damping factor...
> The 33 wasn't up to much..
It's disc pre-amp was marginal on the high gain setting. Fine with higher
output cartridges. Sadly most wanted the Shure V15 in those days.
--
*It's a thankless job, but I've got a lot of Karma to burn off
The Natural Philosopher
> In article <pVgpLLDJ...@bancom.co.uk>,
> tony sayer <to...@bancom.co.uk> wrote:
>>> Quad 303 is relative crap, also 405..tested both.
>
>> Would you be able to identify a good to spec one, 303 say, in a blind
>> listening test?...
>
> Of course he wouldn't. But more easy to tell it against a valve amp with
> their poor damping factor...
303 had poor x-over distortion. Back then I COULD tell it apart from a
good amp. There's a light edginess you can hear with X-over. Or a
certain silkiness if its absent. What you need is low level complex
harmonies..choirs or strings are good. If you can pick out each voice or
instrument seperately, its a good amp for X-over.
Dunno if the lugholes are up to it these days.
valves better on X-over but worse on freq response, overall high power
distortion and as you say, damping. However the ears are more tolerant
of that.
What I designed in the 70s was better than both, but never went into
production. That format of circuit was used widely in Jap amps in the 80s.
I don't know what went on inside the UK independents, but by then it was
possible to get some really good power devices that made the job a lot
simpler of getting almost undetectable (with instruments) X-over
distortion and general harmonic distortion right down into the noise floor.
>
>> The 33 wasn't up to much..
>
> It's disc pre-amp was marginal on the high gain setting. Fine with higher
> output cartridges. Sadly most wanted the Shure V15 in those days.
>
I was quite proud of mine, Got within about 3dB of ultimate thermal
noise limits.
What I am saying is that by the time I left audio design in 1981, it
was possible to make an amp better than ears could tell them apart, if
you bothered to do it right. And it wasn't actually that hard to do it.
For me there was no money and no challenge left, so I went software instead.
I think that's when the complete and utter bullshit of audio took over,
there being no other way to differentiate between upper level kit.
Whiter than white etc.
But 70's kit was a compromise. Either valves with their issues, or
inadequate transistors with theirs.
tony sayer
<t...@invalid.invalid> scribeth thus
>Dave Plowman (News) wrote:
>> In article <pVgpLLDJ...@bancom.co.uk>,
>> tony sayer <to...@bancom.co.uk> wrote:
>>>> Quad 303 is relative crap, also 405..tested both.
>>
>>> Would you be able to identify a good to spec one, 303 say, in a blind
>>> listening test?...
>>
>> Of course he wouldn't. But more easy to tell it against a valve amp with
>> their poor damping factor...
>
>303 had poor x-over distortion. Back then I COULD tell it apart from a
>good amp. There's a light edginess you can hear with X-over. Or a
>certain silkiness if its absent. What you need is low level complex
>harmonies..choirs or strings are good. If you can pick out each voice or
>instrument seperately, its a good amp for X-over.
>
I think you'll find there was a "sort of" MK1 303 and a MK2 all to do
with the biasing. In the earlier unit they used an arrangement of Four
diodes of which they had a wide spread of values and could not set the
bias as consistently as it ought. Later versions had a transistor and
pot adjuster and that was better. I had the wife's 303 in here a while
ago to change the caps etc and the bias was quite critical in its
setting Distortion was very low with no visible residual on the scope
all in the noise..
>Dunno if the lugholes are up to it these days.
Yes time .. canna do much about that;!..
>
>valves better on X-over but worse on freq response, overall high power
>distortion and as you say, damping. However the ears are more tolerant
>of that.
>
>What I designed in the 70s was better than both, but never went into
>production. That format of circuit was used widely in Jap amps in the 80s.
>
>I don't know what went on inside the UK independents, but by then it was
>possible to get some really good power devices that made the job a lot
>simpler of getting almost undetectable (with instruments) X-over
>distortion and general harmonic distortion right down into the noise floor.
>
>
>
>
>>
>>> The 33 wasn't up to much..
>>
>> It's disc pre-amp was marginal on the high gain setting. Fine with higher
>> output cartridges. Sadly most wanted the Shure V15 in those days.
>>
>
>I was quite proud of mine, Got within about 3dB of ultimate thermal
>noise limits.
>
>What I am saying is that by the time I left audio design in 1981, it
>was possible to make an amp better than ears could tell them apart, if
>you bothered to do it right. And it wasn't actually that hard to do it.
>For me there was no money and no challenge left, so I went software instead.
>
>I think that's when the complete and utter bullshit of audio took over,
>there being no other way to differentiate between upper level kit.
>Whiter than white etc.
>
>But 70's kit was a compromise. Either valves with their issues, or
>inadequate transistors with theirs.
--
Tony Sayer
The Natural Philosopher
> In article <il2i1l$id9$1...@news.albasani.net>, The Natural Philosopher
> <t...@invalid.invalid> scribeth thus
>> Dave Plowman (News) wrote:
>>> In article <pVgpLLDJ...@bancom.co.uk>,
>>> tony sayer <to...@bancom.co.uk> wrote:
>>>>> Quad 303 is relative crap, also 405..tested both.
>>>> Would you be able to identify a good to spec one, 303 say, in a blind
>>>> listening test?...
>>> Of course he wouldn't. But more easy to tell it against a valve amp with
>>> their poor damping factor...
>> 303 had poor x-over distortion. Back then I COULD tell it apart from a
>> good amp. There's a light edginess you can hear with X-over. Or a
>> certain silkiness if its absent. What you need is low level complex
>> harmonies..choirs or strings are good. If you can pick out each voice or
>> instrument seperately, its a good amp for X-over.
>>
>
> I think you'll find there was a "sort of" MK1 303 and a MK2 all to do
> with the biasing. In the earlier unit they used an arrangement of Four
> diodes of which they had a wide spread of values and could not set the
> bias as consistently as it ought. Later versions had a transistor and
> pot adjuster and that was better. I had the wife's 303 in here a while
> ago to change the caps etc and the bias was quite critical in its
> setting Distortion was very low with no visible residual on the scope
> all in the noise..
>
Ive built almost exactly a duplicate circuit to the later 303, and
believe me, if you push your frequencies up beyond the usual 1Khz, and
look at distortion at say 1W output - which is still pretty loud for
most people with good speakers - you will find its there allright.
Its inherent in any class B design that fully switches off bipolar
transistors ..
The solution is to never quite switch them off or better still, use
FETS. (or valves!)
My design accomplished the former, but temperature stability was hard to
achieve. Technics ripped that (my) design off and integrated the bias
stuff into a large hybrid output chip. Nice if you have a tame chip fab
plant.
But by the 80's power FETS N and P channel were available, as were much
faster output transistors..so any of those plus a bit of careful design
could get you an 'AAB' class amp* that really worked bloody well.
* or whatever silly nomenclature they used to describe it.
I only played a bit with power FETS but the initial circuit I breadboard
looked amazingly good. very little X over. at all. In fact sub 1W the
thing was all class A anyway.
Hence my assertion that a top class tranny couldn't match a bog standard
valve amp till about 1980, after that easily could, and there was no
excuse to make the bloody things basically so that all imperfections
were totally inaudible. At which point the HiFi buffs had to reinvent
themselves as magicians, not technicians.
Then the imperfections were in the disc pickups, and the loudspeakers,
and in early CD players whose D->A convertors suffered 'orrible X-over
distortion. Oversampling and better design fixed that by the 90s.
Essentially there should be no real difference between any quality amp
post 1980, in actual sound quality.
And to be honest, a well built valve POWER amp is probably better than
any 60's or early 70's tranny amp. You can get better noise out of a
tranny disc pre-amp tho. Not that anyone uses disc much.
My cousin, I believe, is still manufacturing valve amps..seems to make a
living. Haven't seen him in 45 years..
tony sayer
Was it the same circuit I wonder, as the residual was in the noise what
there was off it?..
--
Tony Sayer
yac...@gmail.com
http://www.condoraudio.com/wp-content/uploads/Projects/Arcam-Alpha9-Amplifier-Upgrade-Switch-Repair.pdf
Menahem Yachad
www.condoraudio.com
Israel
Graham.
>On 2014-06-13, yac...@gmail.com <yac...@gmail.com> wrote:
>> This is the permanent solution to the problematic Arcam Alpha 9 Input Selector switch
>>
>> http://www.condoraudio.com/wp-content/uploads/Projects/Arcam-Alpha9-Amplifier-Upgrade-Switch-Repair.pdf
>
>
>Can I order a switch from you?
Not a bad result for someone who always posts with XNA:Yes ;-)
https://groups.google.com/d/msg/uk.d-i-y/khMBP_VHhMs/kVgsfBWv2x4J
--
Graham.
%Profound_observation%
Andy Burns
> Graham <m...@privicy.net> wrote:
>
>> Not a bad result for someone who always posts with XNA:Yes ;-)
>> https://groups.google.com/d/msg/uk.d-i-y/khMBP_VHhMs/kVgsfBWv2x4J
>
I think they disregard XNA for a few days, then honour it; of course if
someone quotes you (as in this case) and they don't request XNA, then
google archive that, including the quote of your XNA'd message.