PV JSX Guitar Amp

[John L Stewart]

Just finished servicing a PV JSX. My Grandson Jamie is as happy as a
Tomcat in a Creamary. That PV sure is loud! It runs 4X 6CA7 in PPP.

I found it to be OK & simply reset the bias. Along the way did a lot of
tests of both the amp & speaker. Quite different than HIFI. But it sure
makes Jamie happy.

Did an Impedance Plot for the speaker. I need to get me a white & pink
noise source. Would make that kind of measurement easier. Found
resonances at 137 & 626 Hz. This the one at 626 Hz is a buzz in the
cabinet.

For anyone who is interested-

PV Test Results April 2012

Line at 117 Volts

Standby TP68 500 Volts

Run TP68 479 Volts
TP67 484

TP19 262
TP18 318

TP17 318
TP16 440

Bias Set at –39 Volts
Cathode Current each EL34/6CA7 40 mA

Frequency & Time measurements made using a Pico Technologies ADC216
Virtual Instrument fronted by a Pico Tech M1053 Differential Probe.

Made my own Bias Probe. There is a one ohm resistor inside the octal
plug cover barely visible in the photo of the opened assembly. The leads
connect to a voltmeter where one millivolt indicates one milliamp of
cathode current. Forty (40) milliamps at 484 volts will keep the plate &
screen dissipation at a safe level, totaling less than 20 Watts.

At clipping this PV puts 110 Watts into a 16 ohm resistive load at 1000
Hz.
Power measured directly using a MetraHit 29S Precision DMM & Power
Meter.

THD measured by HP 334A
THD at 16 Watts was 0.9%
THD at 100 Watts was 2.8%

Cheers to all, John


+-------------------------------------------------------------------+
|Filename: Bias Probe 6W.jpg |
|Download: http://www.audiobanter.com/attachment.php?attachmentid=279|
+-------------------------------------------------------------------+



--
John L Stewart

[Phil Allison]

"John L Stewart"

> Did an Impedance Plot for the speaker. I need to get me a white & pink
> noise source. Would make that kind of measurement easier.

** How so ??

Impedance plots are best done with a slow sine wave sweep while feeding the
speaker from a high impedance ( 600ohms plus) source.



.... Phil

[Patrick Turner]

For speaker Z measurements, I use a sine wave sig gene feeding a power
amp with 1k0 series R to speaker. I set the amp to 10Vrms. Then a
nearly constant 10mA rms flows, and Z can be plotted while watching a
trace on CRO, or by measuring with wideband volt meter. If VLs =
0.08Vrms, then Z = 0.08V / 0.01A = 8 ohms, easy to do mentally, and
sound in speakers is not loud while testing, and voltages measured are
large enough to measure and display on CRO easily. To avoid noise at
higher F, using a 0.05 uF across the LS is wise, assuming speaker Z <
100 ohms above 5kHz.

For speaker acoustic response I use pink noise and for crossover
electronic response, sine waves from amp, both with amp with Rout < 1
ohm.

The trick is to get the crossovers electronic response tailored to
give a flat acoustic response, while making the speakers present a
mainly resistive load to amp, and be free of serious dips in Z along
the band. Not easy, and something many manufacturers get entirely
wrong, and a classic bad example are AR9 speakers from 1975.

Patrick Turner.
>
> ....  Phil

[Don Pearce]

On Fri, 13 Apr 2012 11:01:21 +1000, "Phil Allison" <phi...@tpg.com.au>
wrote:

It is also vital that the speaker be placed well clear of the floor
and any other obstructions. Anything like that will show up as an
error in the impedance plot.

d

[Phil Allison]

"Don Pearce"
"Phil Allison"

>>
>>"John L Stewart"
>>
>>> Did an Impedance Plot for the speaker. I need to get me a white & pink
>>> noise source. Would make that kind of measurement easier.
>>
>>** How so ??
>>
>>Impedance plots are best done with a slow sine wave sweep while feeding
>>the
>>speaker from a high impedance ( 600ohms plus) source.

>>
>

> It is also vital that the speaker be placed well clear of the floor
> and any other obstructions. Anything like that will show up as an
> error in the impedance plot.

** Bollocks.

[Phil Allison]

"John L Stewart"

** DO NOT SNIP THE CONTEXT !!!!!!!

> Over in thread IBM 1953 Phil said-

** No fucking way did I post ANYTHING in that tread !!!

Now: RESTORING the ESSENTIAL CONTEXT !!!

" Did an Impedance Plot for the speaker. I need to get me a white & pink
noise source. Would make that kind of measurement easier. "

>> ** How so ??
>
>> Impedance plots are best done with a slow sine wave sweep while feeding
>> the speaker from a high impedance ( 600ohms plus) source.
>
>

> PV Speaker Test Hookup
>
> For the speaker impedance test run I used an HP 200CD (600 ohm) as the
> audio source. Connected that thru a Hammond 1700 Series OPT so that
> there was a conversion from 2500 ohms to 16 ohms. Then another 150R
> straight into the 16 ohm box, much as Phil suggested.
>
> All done with the speaker box outside (open field) in order to avoid
> reflections. Can't afford & don't need an anechoic chamber, long as it
> don't rain.
>
> The results were stored with the Pico Technology ADC216 Virtual
> Instrument set to Peak mode. Very time consuming.


** Huh ??

Impedance curves for a woofer (with no box) or guitar speaker take about 2
minutes using only an audio generator and a scope.

There is a single impedance peak at resonance and a broad dip around 150 to
400Hz - then it climbs doubling for every two octaves. Plot about a dozen
spots and you have it.


> I think with a good
> audio noise source one could set up the equipment & let it run to
> completion.


** I still see no sign of an explanation of what the fuck you are on about.

Wot a tedious wanker.


... Phil

[Don Pearce]

On Sat, 14 Apr 2012 10:20:37 +1000, "Phil Allison" <phi...@tpg.com.au>
wrote:

>

Not bollocks at all. Particularly with a high efficiency speaker, you
can see the impedance plot squirm as you move things around near the
speaker. Bear in mind that it is a two way device, and can operate as
a sort of audio version of RADAR.

d

[Phil Allison]

"Don Pearce"
"Phil Allison"

>"Don Pearce"
>> "Phil Allison"
>>>>
>>>>"John L Stewart"
>>>>
>>>>> Did an Impedance Plot for the speaker. I need to get me a white & pink
>>>>> noise source. Would make that kind of measurement easier.
>>>>
>>>>** How so ??
>>>>
>>>>Impedance plots are best done with a slow sine wave sweep while feeding
>>>>the
>>>>speaker from a high impedance ( 600ohms plus) source.
>>
>>>>
>>>
>>> It is also vital that the speaker be placed well clear of the floor
>>> and any other obstructions. Anything like that will show up as an
>>> error in the impedance plot.
>>
>>** Bollocks.
>>
>
> Not bollocks at all.

** It is utter bollocks.

You asinine PEDANTIC twat.


... Phil

[Patrick Turner]

> ...  Phil- Hide quoted text -
>
> - Show quoted text -

Who could ever have hoped that grown men would not argue about speaker
Z measurements? Nobody?

Anyway, keeping speakers away from sound reflecting surfaces does have
a significance. Only a fool would test a driver with its front face
sitting on a bench, or with a wall a foot away.

But what about enclosure effects on drivers?

To make a speaker, ie, enclosure with driver mounted in it, and with
baffles and sound absorbant materials, one needs to know the raw data
about the driver when it is well away from an enclosure or reflecting
wall. Testing in an average room with driver with magnet down and
sitting on a an upright housebrick on a bench, or dangled on a wire
from cieling will negate 95% of effects on Z by nearby objects. The Z
plot will reveal the Fo, the resonance in free air. There are other
tests one can do to determine all of the Thiele and Small parameters,
and then these may be entered into a program like WinISP which will
give you a calculated box size for a predictable bass response. Then
the speaker box + driver fixed in can be completed, and another
impedance test then made with speaker set up in a workshop in similar
situation to how it is used in a typical listening room. It is done
without any crossover, and the use of a power amp set at 10Vrms output
feeding through 1k0 gives a virtually constant 10mAac, and so tweeters
can't be damaged with bass F. The Z at the lowest part of a given
driver's F band will be quite difference from the free air test out of
any box. This Z is the real and relevant Z which must be matched to
work with a crossover filter to give the wanted acoustic response.
Once the Z is known, the acoustic response of each driver in turn can
be tested with pink noise without any X-over with the same level of
applied LOW voltage at all F, ie, with say 0.1Vrms straight from the
amp which has Rout < 1 ohm.

If one builds a 3 way speaker, the acoustic responses of LF, MF and HF
should tell you where the lowest level of sound is made between 40Hz
and 20kHz. You might find these F are where LF and tweeter are -3dB.
In a typical speaker, you may find there is a level response ( +/-
2dB ) between say 80Hz and 200Hz and that this level is lower than
anywhere else above 200Hz and below 20kHz, so this acoustic level sets
the sensitivity of the completed speakers. Its not unusual for LF, MF
and HF drivers to have peaks in their response +12dB above the
REFERENCE level of say 80Hz to 200Hz. So some means of attenuating the
amp voltage reaching all drivers has to be designed to ensure a flat
input voltage gives a flat acoustic response, and that the L&C used
are "terminated" by sufficient R to avoid dips in Z due to resonances,
and that the driver always "see" a lowest possible R as it source. So
the work of making a good crossover is NEVER easy, and NEVER is a
simple task done by an online calculator, with no understanding or
experience with LCR theory.

Most ppl just shove a resistor in series with MF and HF to reduce the
higher acoustic output of MF and HF over the low bass output from most
bass drivers. Let us assume each and every driver has an R+C Zobel
strapped across it so that its mid band Z value is maintained at all F
above the midband. The Zobel adding is called "impedance equalizing,
and makes the driver look more like a pure resistance above the mid
band Z, and equal in ohms to the midband Z.

Let us assume the equalised Z of a driver in a box = 7 ohms. Just
adding say 7 ohms in series makes the total Z roughly 14 ohms, giving
6dB attenuation. The driver is now driven by 7 ohms plus amp Rout so
perhaps by 8 ohms source resistance. People could say this is no good,
because the damping factor has become hopelessly low, only about 1.0
in this case, when theory says we should have DF < 10. The LC filter
designed for 7 ohms will have very different attenuation slope rates
and X-over points if loaded with 14 ohms. One might then decide to
make the Z "seen by" the preceeding LC filter to be 7 ohms, and have
the driver "see a lower source R". This means that after the LC, one
has 3.5 ohms in series with driver and its parallel R&C zobel, but
with an additional 7 ohms across the driver, to make the driver Z look
like 3.5 ohms. The driver sees 3.5 ohms plus 7 ohms in parallel and
the F below the midband Z, ie, 2.67 ohms, and the driver is better
damped, and amp sees 7 ohms, and LC sees 7 ohms, and everyone is
happy, except that the sensitivity has halved for the driver. Well, if
you want a truly flat response with 3 drivers, you usually have to
sacrifice some power lost heating resistors if you are determined to
have a flat response. No free breakfast.

There are other ways to avoid losses in speakers due to driver Z
variatons and R losses. One might use tri-amping, very expensive with
tubes, and you'll waste fat more heat, or you have an audio speaker
voltage transformer for MF and HF. It usually is never necessary to
attenuate bass levels, considering so many speakers are bass deficent,
because they have been designed to sell well and be marketted easily
with high quoted sensitivity figures of at least 87dB/W@1M. The tranny
to attenuate MF and treble can have Fsat at 50Hz, at say 50Vrms input,
and have a series C between its primary and amp. It will need to be
very carefully designed so there is not a horrible low Z formed at the
Fo between the series C and primary inductance. Taps down a winding at
1.5dB steps are wise, giving 0dB to -12dB. By this means, the
crossovers and the following drivers are driven by a source resistance
lower than the amp Rout, so DF improves, ie, gets higher. The amp then
sees a higher load, welcomed, because most tube amps function best if
load R is higher. So if one has 2:1 tranny voltage ratio, with sec
load = 7 ohms, the amp will see 28 ohms, and no losses occur in series
& shunting R.

I don't know ONE manufacturer who uses transformer attenuators for
multi drivered dynamic speakers.
The exceptions are for ribbons and ESL which form a tiny % of speakers
sold.

So sure, speaker impedance is hugely important, if we wish to save our
amplifiers from overheating, and if we wish to hear the best sound,
from using the available electric energy most efficiently. Efficiency
becomes important when the Watts become expensive, or when we have
made the decision to have so few Watts at the outset, ie, chosen a
lone 300B to fill a large room with divorce causing sound levels at
low distortion.

Patrick Turner.

[Don Pearce]

On Sat, 14 Apr 2012 16:15:40 +1000, "Phil Allison" <phi...@tpg.com.au>
wrote:

>

So I've measured the utter bollocks for you (still in dB form because
Audition won't do the calculation needed to turn it to impedance).

http://www.soundthoughts.co.uk/look/speaker_imp.png

The speaker is fed via a 100 ohm resistor, and the output is read
across the speaker terminals themselves.

What you see here is the same speaker (Kef Cresta II) measured twice,
once with a book held a foot away from the cone. There are two effects
evident. The first is that the frequencies of the impedance peaks have
shifted up slightly with the book in place (blue trace), and secondly
there is considerable disturbance to the actual impedance, mainly at
the lower peak and the intermediate dip - but also in a considerable
modification to the upper slope of the top peak where there is a bit
of a wobble.

So yes, it is important to keep the area around the speaker clear of
clutter when you measure the impedance.

I have no doubt that Phil will try to come back with some guttersnipe
defence of his position, but as you see it is untenable.

d

[Don Pearce]

On Sun, 15 Apr 2012 09:48:56 GMT, sp...@spam.com (Don Pearce) wrote:


>So I've measured the utter bollocks for you (still in dB form because
>Audition won't do the calculation needed to turn it to impedance).
>
>http://www.soundthoughts.co.uk/look/speaker_imp.png
>
>The speaker is fed via a 100 ohm resistor, and the output is read
>across the speaker terminals themselves.
>
> What you see here is the same speaker (Kef Cresta II) measured twice,
>once with a book held a foot away from the cone. There are two effects
>evident. The first is that the frequencies of the impedance peaks have
>shifted up slightly with the book in place (blue trace), and secondly
>there is considerable disturbance to the actual impedance, mainly at
>the lower peak and the intermediate dip - but also in a considerable
>modification to the upper slope of the top peak where there is a bit
>of a wobble.
>
>So yes, it is important to keep the area around the speaker clear of
>clutter when you measure the impedance.
>
>I have no doubt that Phil will try to come back with some guttersnipe
>defence of his position, but as you see it is untenable.
>
>d

And while we are at it, just for interest, here is a Monitor Audio
RX2, measured with and without the port damper fitted. The port damper
is a light foam plug about 40mm long, which is a loose fit in the
reflex port. It has clearly been designed with care, because it does a
perfect job of removing the coupled resonance from the speaker.

http://www.soundthoughts.co.uk/look/port_damping.png

d

[Phil Allison]

"Don Pearce = Psycho Fuckwit Pommy Twat "

>
>
> Did an Impedance Plot for the speaker. I need to get me a white & pink
> noise source. Would make that kind of measurement easier.
>
>>> ** How so ??
>>>
>>>Impedance plots are best done with a slow sine wave sweep while feeding
>>>the speaker from a high impedance ( 600ohms plus) source.
>
>
>>>>> It is also vital that the speaker be placed well clear of the floor
>>>>> and any other obstructions. Anything like that will show up as an
>>>>> error in the impedance plot.
>>>>
>>>>** Bollocks.
>>>>
>>>
>>> Not bollocks at all.
>>
>>** It is utter bollocks.
>>
>> You asinine PEDANTIC twat.
>>
>

> So I've measured the utter bollocks for you (still in dB form because
> Audition won't do the calculation needed to turn it to impedance).
>
> http://www.soundthoughts.co.uk/look/speaker_imp.png
>
> The speaker is fed via a 100 ohm resistor, and the output is read
> across the speaker terminals themselves.
>
> What you see here is the same speaker (Kef Cresta II) measured twice,
> once with a book held a foot away from the cone.

** Thank you for proving precisely what a fucking CONTEXT SHIFTING twat you
are to the whole of usenet.

BTW:

Learn how to READ and write in the ENGLISH language some time.

As if there is ANY chance of that miracle.



... Phil

[Don Pearce]

On Sun, 15 Apr 2012 21:42:34 +1000, "Phil Allison" <phi...@tpg.com.au>
wrote:

>

And there we have it - exactly as predicted. I never knew what
predictive powers the science of human psychology possessed.

d

[Phil Allison]

"Patrick Turner"

Who could ever have hoped that grown men would not argue about speaker
Z measurements? Nobody?

** Anybody who has EVER dared to post a simple fact on usenet.

The one place you are most likely to be crucified for so doing.

Worse by far than Nazi Germany, Stalin's Russia or Communist China.

But maybe just tad safer than being a traitor to Scientology.



.... Phil

[Phil Allison]

Not for anyone as fucking AUSTITIC as Dickhead Pearce.




... Phi

[Lord Valve]

Austitic?

He's a tit from Down Under? WTF?


Lord Valve
Lying Criminal ASD-fucked autistic septic fuckwit (etc.)

[Arny Krueger]

"Don Pearce" <sp...@spam.com> wrote in message
news:4f8a972a...@news.eternal-september.org...

> So I've measured the utter bollocks for you (still in dB form because
> Audition won't do the calculation needed to turn it to impedance).
>
> http://www.soundthoughts.co.uk/look/speaker_imp.png
>
> The speaker is fed via a 100 ohm resistor, and the output is read
> across the speaker terminals themselves.

> What you see here is the same speaker (Kef Cresta II) measured twice,
> once with a book held a foot away from the cone. There are two effects
> evident. The first is that the frequencies of the impedance peaks have
> shifted up slightly with the book in place (blue trace), and secondly
> there is considerable disturbance to the actual impedance, mainly at
> the lower peak and the intermediate dip - but also in a considerable
> modification to the upper slope of the top peak where there is a bit
> of a wobble.

Looks like a pretty small differnce to me.

Proof of the pudding would be comparison of T/S parameters calculated from
each plot.

[Don Pearce]

On Sun, 15 Apr 2012 15:42:35 -0400, "Arny Krueger" <ar...@cocmast.net>
wrote:

I wish I was permitted such large tolerances in my design work. It's
an error. That's all the claim I made.

>Proof of the pudding would be comparison of T/S parameters calculated from
>each plot.
>

Good luck with that. These are speakers in cabinets.

d

[Phil Allison]

"Arny Krueger"
> "Don Pearce"

>> So I've measured the utter bollocks for you (still in dB form because
>> Audition won't do the calculation needed to turn it to impedance).
>>
>> http://www.soundthoughts.co.uk/look/speaker_imp.png
>>
>> The speaker is fed via a 100 ohm resistor, and the output is read
>> across the speaker terminals themselves.
>
>> What you see here is the same speaker (Kef Cresta II) measured twice,
>> once with a book held a foot away from the cone. There are two effects
>> evident. The first is that the frequencies of the impedance peaks have
>> shifted up slightly with the book in place (blue trace), and secondly
>> there is considerable disturbance to the actual impedance, mainly at
>> the lower peak and the intermediate dip - but also in a considerable
>> modification to the upper slope of the top peak where there is a bit
>> of a wobble.
>
> Looks like a pretty small differnce to me.

** SFA in fact.

The guitar speaker system in question is intended to sit on a floor - so
THAT IS HOW it should be when you measure its impedance.



.... Phil

[Patrick Turner]

The differences between red line and blue lines with and without a
book held near a speaker are to my mind quite negligible, leading some
ppl to argue that claiming significant Z differences due to nearby
objects is "bollocks", aka as bullshit or horse manure, bovine
fertilizer or even hiefer dust, ( the latter to not offend sensitive
older female farmers who'd always frown on the vulgarities speiled out
by the male species. ).

Presumably, a speaker box will affect the Z far more than a book held
a foot away. In fact, the Z curve with driver suspended in free air,
and in the geometric centre of a large room is somewhat a useless
curve to draw apart from deriving T&S parameters. The Z with driver in
box is VERY important.

Patrick Turner.


> d- Hide quoted text -

[Patrick Turner]

On Apr 15, 8:13 pm, s...@spam.com (Don Pearce) wrote:

Blocking the port in any way between not at all, and totally has a
profound effect on Z at the resonance at the low end of the band below
100Hz in your example. But hardly any effect on the F above 140Hz.

When building a speaker we need to know Fs, resonant F in free air,
and Fb, predictable resonance of the box with its port or without.
Transmission lines are where the box becomes the port, and the spead
of sound in air in the long port, or line, is artificially reduced by
hanging loose fill material in the line air, thus creating desired
phase relationship between output from the line end away from driver,
and the acoustic phase from the front of the cone. Correct me if I am
wrong, but the TL speaker is the only type which lowers the apparent
resonant F of speaker in an enclosure, and thus extends the mid band Z
over a lower range of F and thus making the speaker in box nearer to a
resistance load and thus loading the amp better, and all the while
making better sunding bass as so many transmission line fetishists
proclaim, while they throw turds at anyone persisting with a sealed
box, aperiodic port, or normal reflex port.
I've tried TL, and heard no bass improvements.

Making good bass in most rooms is a very uncertain undertaking, and
rooms affect bass response profiles pretty badly. But I prefer large
bass drivers in reflex box where there are two peaks in Z each side of
the Fb which if possible should be below 20Hz, as it is in most good
sub-woofers. This means everything produced about 35Hz is mainly from
the front of the cone, and from a driver looking mainly resistive in
Z.
Not all drivers of say 300mm dia will work the same in a given box and
port. Thiele and Small worked out what was going on mathematically to
give audio engineers some hope to make a box and port to optimise bass
productions. Luckily, today's world of online calculators liberates
most ppl from working out endless equations in which they are prone to
mistakes, especially if the don't much understand the concepts of what
Thiele and Small knew, and which could then be mathematicized.

[Patrick Turner]

> ....  Phil- Hide quoted text -

>
> - Show quoted text -

Guitar amp speakers are a little odd because they usually have an open
backed cab, so placing them up against a wall will change bass
response and Z considerably, but then most guitar amp bass drivers
have quite high Fs, and no matter what anyone does, they won't go
really low, and besides, most guitar bass notes don't go lower than
41Hz.

Phil's right, Z should be measured with speaker put into a normal
operating position and condition, and at most venues, it'll be on the
floor and away from rear walls, ( if there is one; if a previous Dark
Metal band has played ear crushingly LOUD in the previous bracket, the
rear wall may have been blasted off tha building ) But hey, there are
no strict rules about anything here involving non-hi-fi, ie, noise
musicians make using geetahs and amps. Have another beer. Forget Z.
See if you can score the blonde staring at you while ya play.

Patrick Turner.

[Patrick Turner]

Ah, so If Jesus Christ walked amoung us now, the last thing 'he'd
wanna do is post about religious issues at r.a.t.

He knew first hand what dreadful things can happen if you speak your
mind.

I'd like to see Jesus have a debate with Richard Dawkins. Since Jesus
is due to arrive any minute now in what ppl call a "second coming",
why don't you book an auditorium for the debate, and phone Auntie ABC
to lend us the Q&A team to run the debate?

Patrick Turner.

[Don Pearce]

You may be right, you may be wrong. I'll never know because there is
that about you which means I will never read a word you write.

d

[Don Pearce]

More blah blah blah.

d

[jh]

Patrick,

the Dark Metal Band will most propably have played sealed 4x12" cabinets....

*No* open back cabs allowed in this kind of music ;-)

The back of the building is completely save....


regards

Jochen

[Phil Allison]

"Patrick Turner"

Guitar amp speakers are a little odd because they usually have an open
backed cab,

** The VAST majority of *separate* speaker cabinets used for guitar or
bass guitar have sealed backs. Combo amps that use SS circuitry also have
sealed back cabinets, in the main.

It is only valve guitar amps that are combos where open back cabinets are
the norm - and then mainly to allow air to get to the inverted valves to
cool them.

JLS has not revealed whether his example of the PV JSX is a combo or a
head - but a resonant peak in the impedance at 137Hz suggests it is a head
with a sealed cabinet.


... Phil

[John L Stewart]

My Grandsons PV JSX that I worked on has 4X 12 inch speakers with the
back closed. There is a wooden post from the center of the front panel
to the rear, just a bit too long. So it is preloaded. Stiffens things up
a bit, so hopefully no rattling. Or perhaps some rock bands would want
that!

The PV JSX Amp has a variable full loop NFB system. But operator
variable.

With all this theory being spouted did anyone mention that DF don't
matter much beyond about 10 because speaker R gets in the way. Something
about Thevenin's Theorem. Better give Norton honorable mention too!

And the rock bands don't care much, they will do the damndest things to
make the equipment sound the way they want anyway.

Still can't figure out what all this has to do with IBM in 1953!


+-------------------------------------------------------------------+
|Filename: PV Speaker Box 7W.jpg |
|Download: http://www.audiobanter.com/attachment.php?attachmentid=283|
+-------------------------------------------------------------------+



--
John L Stewart

[flipper]

On Mon, 16 Apr 2012 03:32:22 -0700 (PDT), Patrick Turner
<in...@turneraudio.com.au> wrote:


>
>Guitar amp speakers are a little odd because they usually have an open
>backed cab,

It's called open baffle and used to be common as dirt, including the
gazillion Hi-Fi consoles that were virtually everywhere. And then
there were free standing units like the famous Wharfedale SFB/3 with a
published response of 30 C/S to 20000 C/S.

The biggest problem is baffle size but if one can live with it they're
very efficient and Warfedale advertised "full domestic volume from a
small amplifier, tape recorder, or any good radio set with more than 3
Watt output."

[jh]

I don't know what IBM 1953 has to do with it, for the "invention" of
the 4x12 took place in 1962....;-)

It's simply the "smallest" convenient enclosure for 4 12" drivers. The
slanted one (Marshall 1960A) had the slant only, because the amplifier
head (Marshall JTM45) looked "funny" sitting on top of the cab...

No technical explanation there - although the "explanation" for the
slant was "to project the sound over the crowd so the last rows can hear
something too".... when Jim Marshall and his crew was asked by curios
musicians.

BTW they can sound good on big stages. Almost useless in small venues.
The ears of the people sitting in the center of the "beaming area" are
almost "pierced"; the other ones - including the guitar hero don't hear
much of it....

"i can't hear my guitar" - "no i did not turn it up"

regards

Jochen

PS: and yes - they are noise generators - have nothing to to with sound
reproduction. Guitar speakers are part of the instrument - and a very
important one. Far from "perfect".

[Phil Allison]

"jh"

>
> It's simply the "smallest" convenient enclosure for 4 12" drivers. The
> slanted one (Marshall 1960A) had the slant only, because the amplifier
> head (Marshall JTM45) looked "funny" sitting on top of the cab...
>
> No technical explanation there - although the "explanation" for the slant
> was "to project the sound over the crowd so the last rows can hear
> something too".... when Jim Marshall and his crew was asked by curios
> musicians.

** The slant front 4 x 12 cab was built after requests from guitarists who
regularly played in venues that were cinemas. Typical cinemas of the era
were converted ( or doubled as) live theatres and so had " front stalls " at
ground level and a " dress circle " upstairs. Folk up stairs were missing
out on the higher tones from straight fronted cabs.

http://i55.tinypic.com/16acdg6.jpg

Many Fender combo amps were built with two, steel legs that allowed to amp
to tilt backwards at about 30 degrees for similar reasons - eg.

http://www.stratopastor.org.uk/strato/amps/prii/gallery/modified/francoistiltback.jpg


.... Phil

[jh]

> ..... Phil
>
>
>


...you don't believe Jim Marshall's own words?

[Phil Allison]

"jh"

>>
>> ** The slant front 4 x 12 cab was built after requests from guitarists
>> who
>> regularly played in venues that were cinemas. Typical cinemas of the era
>> were converted ( or doubled as) live theatres and so had " front stalls "
>> at
>> ground level and a " dress circle " upstairs. Folk up stairs were missing
>> out on the higher tones from straight fronted cabs.
>>
>> http://i55.tinypic.com/16acdg6.jpg
>>
>> Many Fender combo amps were built with two, steel legs that allowed to
>> amp
>> to tilt backwards at about 30 degrees for similar reasons - eg.
>>
>> http://www.stratopastor.org.uk/strato/amps/prii/gallery/modified/francoistiltback.jpg
>>
>>
>

> ...you don't believe Jim Marshall's own words?

** I am quoting him, from at least two magazine articles.

You bullshitting idiot.



... Phil

[Phil Allison]

"John L Stewart"

> My Grandsons PV JSX that I worked on has 4X 12 inch speakers with the
> back closed.

** Told ya.....

A few hours ago I posted this:

" JLS has not revealed whether his example of the PV JSX is a combo or a
head - but a resonant peak in the impedance at 137Hz suggests it is a head
with a sealed cabinet. "

> With all this theory being spouted did anyone mention that DF don't
> matter much beyond about 10 because speaker R gets in the way.

** Never come across a tube guitar amp with a DF of more than 5.

Some ( eg the VOX AC30 ) have a DF of about 0.1.



... Phil

[jh]

> .... Phil
>
>

Phil,

The history of Marshall has been quite consistent over the last 30+
years.... Not many contradictions by Mr. Marshall. He almost always told
his story the same way.

BTW - where is your source - as you're "quoting him" ???

For example: I have a german copy of "Jim Marshall - the father of loud"
2004 - handsigned by the man himself. There is a quote with this exact
content. Cosmetics was the intention.
The possibility, that the projection might improve, was purely by
accident. This told by "the man himself"

Unfortunately neither you nor me can ask him anymore...

So please leave baiting and show *your* sources

kindest regards

Jochen

[Phil Allison]

"jh"

>
>>> ...you don't believe Jim Marshall's own words?
>>
>>
>> ** I am quoting him, from at least two magazine articles.
>>
>> You bullshitting idiot.
>

> BTW - where is your source - as you're "quoting him" ???

** You quoted no source at all.

> For example: I have a german copy of "Jim Marshall - the father of loud"
> 2004 - handsigned by the man himself.

** But not written by him - so useless.

Fuck off cunthead.

[jh]

Am 17.04.2012 15:23, schrieb Phil Allison:
> "jh"
>>
>>>> ...you don't believe Jim Marshall's own words?
>>>
>>>
>>> ** I am quoting him, from at least two magazine articles.
>>>
>>> You bullshitting idiot.
>>
>> BTW - where is your source - as you're "quoting him" ???
>
> ** You quoted no source at all.

you did not either

where's your source -eh? written by him?



Phil - it's so easy with you - you have always been pretty predictable
- especially, when you're running out of arguments.

>
>
>> For example: I have a german copy of "Jim Marshall - the father of loud"
>> 2004 - handsigned by the man himself.
>
>
> ** But not written by him - so useless.
>
> Fuck off cunthead.

NO

:-)


Doyle the history of marshall - several interviews etc pp.
#

>
>
>
>

[Phil Allison]

"jh"


>>>> ...you don't believe Jim Marshall's own words?
>>>>
>>>>
>>>> ** I am quoting him, from at least two magazine articles.
>>>>
>>>> You bullshitting idiot.
>>>
>>> BTW - where is your source - as you're "quoting him" ???
>>
>> ** You quoted no source at all.
>
> you did not either

** FFS - get cause and effect figured out, fuckhead.

Then GO DROP FUCKING DEAD !!

You revolting, wog nut case retard.

[jh]

exactly....

> ** FFS - get cause and effect figured out, fuckhead.

Jim Marshall himself said several times, that he "invented" the slant
simply because he did not like the optics of the (fairly small) JTM45
head sitting on the straight cab. (for example: Page 12 - The History of
Marshall - and proofread by JM himself!!)

Your arguments? TGDFD??? You don't ´need to...



read back again in this thread - you chimed in, trying to prove that i'm
wrong - so back it up - nothing yet

baaah

[Phil Allison]

"jh" = RABID FUCKING NUTTER

> Jim Marshall himself said several times, that he "invented" the slant
> simply because he did not like the optics of the (fairly small) JTM45 head
> sitting on the straight cab. (for example: Page 12 - The History of
> Marshall - and proofread by JM himself!!)

** All depend what the fucking QUESTION was - you fucking ASD fucked
fuckwit !!!!!!!!!!!

The **PURPOSE** of the slanted front is to project sound upwards to an
elevated audience.

Now, whether or not Jim actually thought of it before making the suggestion
to his workers is MOOT !!!

FFS - Jim Marshall was a FUCKING DRUMMER with NO CLUE AT ALL about
either amplifiers or how sound works.

FFS - get cause and effect figured out, fuckhead.

Then GO DROP FUCKING DEAD !!

You revolting, wog nut case fucking retard.

[flipper]

http://www.thewho.net/whotabs/gear/guitar/marshallstack.html

The 'reason': "The stack derived from both a desire to project sound
better and a desire to have an intimidating backline. In 1964, John
first connected his Marshall JTM45 to, first one, then two
side-by-side Celestion G12-loaded Marshall 4x12s. Pete followed this
up by placing his Marshall 4x12 on a waist-high metal stand, thus
generating considerable feedback to the guitar’s pickups. Next,
possibly due to the small stages at the time, as well as to create an
imposing visual force, Pete stacked one cabinet atop another, driven
by his ’64 blonde Fender Bassman 50w head (gold sparkle grille, white
round knobs), and thus the “stack” was born. The bottom cabinet was
likely a dummy."


Townsend on why 'high':"“Where I stood on the stage was a piano, and I
stuck my cabinet on it and it was dead level with the guitar... And I
started to get these feedback effects that I really liked. When I went
to other gigs and put the speakers on the floor, it wouldn’t happen.
So I started to put it up on a chair and then I decided to stack the
things so that I could induce feedback.”


Townsend wants 100 Watts and a 'big 8': "I think that came about in
’65, when Townshend said he needed 100-watt heads. We made the first
three 100-watt heads for him. I asked him what sort of cabinet he
wanted, and he said he wanted eight 12s in one cabinet."


Marshall on the slant: "I said that a big square cabinet with a little
amplifier on top would look ridiculous" ... Marshall builds the 8x12
and slants the top two 12s, open back ... "I told him his roadies were
going to kill him, but he said, ‘They get paid.’ Two weeks later he
came back and told me I was right, and he asked if I could cut it in
half. I told him to leave it to me, and that I would redesign
something that would do the job. I went back to the straight 100 4 X
12, which is now the bottom cabinet, and put the angled one on top,
and the amplifier on top of that. The stack was born."

[Phil Allison]

"flipper"

> http://www.thewho.net/whotabs/gear/guitar/marshallstack.html


** Not one bit relevant to the issue.

The first ( 4 x 12) slant front cabs were sold to go with JTM45s that date
from late 1962.



.... Phil

[flipper]

On Wed, 18 Apr 2012 12:20:10 +1000, "Phil Allison" <phi...@tpg.com.au>
wrote:

>

Right, he cared for 'ridiculous' looking in 1965 but not in 1962.

From The History of Marshall: The Illustrated Story of "the Sound of
Rock," page 12

http://books.google.com/books?id=E90tMBs9_FEC&q=so+I+did+the+angle#v=onepage&q=angle%20match%20dimensions&f=false


"Then we had the idea of putting four 12" speakers in the smallest
enclosure we could. There was nothing brilliant about designing the
first 4x12; it was purely the most convenient size to get in the
transport the groups had in those days. I thought that it didn't look
very nice with just the amp sitting on top, so I did the angle to
match the dimensions of the amplifier and make it look like a neater
package. We were really proud when we finished it."

[Phil Allison]

"flipper = fuckhead "

>>
>>"flipper"
>>
>>> http://www.thewho.net/whotabs/gear/guitar/marshallstack.html
>>
>>
>>** Not one bit relevant to the issue.
>>
>>The first ( 4 x 12) slant front cabs were sold to go with JTM45s that date
>>from late 1962.
>>
>
> Right, he cared for 'ridiculous' looking in 1965 but not in 1962.

** HUH ??

What illegal drugs are you on - fuckhead ??


... Phil

[jh]

Phil,

running out of arguments you are?

If you imbecile would not have snipped my context, then you could read,
that the slant of the marshall cabs would not have been there if Jim had
liked the optics of a straight cab... Although he was a drummer, he did
not need a clue - as *his* name was printed on his amps.

Nothing bout purpose...

so back up or shut up

Jochen

[jh]

> .... Phil

>
>
>


"The History of Marshall: The Illustrated Story of "the Sound of Rock"

page 12

;-)


proof read and revised by Jim Marshall

[Phil Allison]

"jh" = RABID FUCKING NUTTER


>> Jim Marshall himself said several times, that he "invented" the slant
>> simply because he did not like the optics of the (fairly small) JTM45
>> head
>> sitting on the straight cab. (for example: Page 12 - The History of
>> Marshall - and proofread by JM himself!!)
>
>
** All depend what the fucking QUESTION was - you fucking ASD fucked
fuckwit !!!!!!!!!!!

The **PURPOSE** of the slanted front is to project sound upwards to an
elevated audience.

Now, whether or not Jim actually thought of it before making the suggestion
to his workers is MOOT !!!

FFS - Jim Marshall was a FUCKING DRUMMER with NO CLUE AT ALL about
either amplifiers or how sound works.

FFS - get cause and effect figured out, fuckhead.

Then GO DROP FUCKING DEAD !!

You revolting, wog nut case FUCKING retard.

[Phil Allison]

"jh" <j...@org.de>



What illegal drugs are you on - kraut fuckhead ??



.... Phil

[jh]

drugs which still allow me to read - and understand facts - kiwi

Jochen

[jh]

Aaah nothing

[Phil Allison]

[Phil Allison]

"jh" <j...@org.de>


What illegal drugs are you on ??

you ILLITERATE kraut fuckhead



.... Phil

[jh]

you've got no arguments

nada
niente
gar nix

and you won't come up with any




I highly regard your technical knowledge, but in this case you are *LOST*


over and out


Jochen

[Phil Allison]

"jh" <j...@org.de>


What illegal drugs are you on ??

you ILLITERATE Kraut fuckhead TROLL



.... Phil

[flipper]

On Wed, 18 Apr 2012 14:01:18 +1000, "Phil Allison" <phi...@tpg.com.au>
wrote:

>

>"flipper = fuckhead "
>
>>>
>>>"flipper"
>>>
>>>> http://www.thewho.net/whotabs/gear/guitar/marshallstack.html
>>>
>>>
>>>** Not one bit relevant to the issue.
>>>
>>>The first ( 4 x 12) slant front cabs were sold to go with JTM45s that date
>>>from late 1962.
>>>
>>
>> Right, he cared for 'ridiculous' looking in 1965 but not in 1962.
>
>
>** HUH ??

You wouldn't be "huh??" confused if you had read the rest instead of
snipping it.

[Phil Allison]

flipper = fuckhead "
>>
>>>
>>>>"flipper"
>>>>
>>>>> http://www.thewho.net/whotabs/gear/guitar/marshallstack.html
>>>>
>>>>
>>>>** Not one bit relevant to the issue.
>>>>
>>>>The first ( 4 x 12) slant front cabs were sold to go with JTM45s that
>>>>date
>>>>from late 1962.
>>>>
>>>
>>> Right, he cared for 'ridiculous' looking in 1965 but not in 1962.
>>
>>
>>** HUH ??
>
> You wouldn't be "huh??" confused if you had read the rest instead of
> snipping it.

** For CHRIST'S SAKE - you fucking fuckhead !!!

YOU did *NOT READ* what I wrote at all - as FUCKING USUAL !!!

FFS - GO BACK and FUCKING DO SO !!!!!

I absolutely know you won't -

cos you are an ASININE fucking SEPTIC PIG.



... Phil

[Patrick Turner]

On Apr 17, 1:42 am, s...@spam.com (Don Pearce) wrote:
> On Mon, 16 Apr 2012 02:46:46 -0700 (PDT), Patrick Turner
>
>
>
>
>
> <i...@turneraudio.com.au> wrote:
> >On Apr 15, 7:48 pm, s...@spam.com (Don Pearce) wrote:
> >> On Sat, 14 Apr 2012 16:15:40 +1000, "Phil Allison" <phi...@tpg.com.au>
> >> wrote:
>
> >> >"Don Pearce"
> >> >"Phil Allison"
> >> >>"Don Pearce"
> >> >>> "Phil Allison"
>
> >> >>>>>"John L Stewart"
>
> >> >>>>>> Did an Impedance Plot for the speaker. I need to get me a white & pink
> >> >>>>>> noise source. Would make that kind of measurement easier.
>
> >> >>>>>** How so ??
>
> >> >>>>>Impedance plots are best done with a slow sine wave sweep while feeding
> >> >>>>>the
> >> >>>>>speaker from a high impedance ( 600ohms plus) source.
>
> >> >>>> It is also vital that the speaker be placed well clear of the floor
> >> >>>> and any other obstructions. Anything like that will show up as an
> >> >>>> error in the impedance plot.
>
> >> >>>** Bollocks.
>
> >> >> Not bollocks at all.
>
> >> >**  It is utter bollocks.
>
> >> >   You asinine PEDANTIC  twat.
>
> >> >...  Phil
>
> >> So I've measured the utter bollocks for you (still in dB form because
> >> Audition won't do the calculation needed to turn it to impedance).
>
> >>http://www.soundthoughts.co.uk/look/speaker_imp.png
>
> >> The speaker is fed via a 100 ohm resistor, and the output is read
> >> across the speaker terminals themselves.
>
> >>  What you see here is the same speaker (Kef Cresta II) measured twice,
> >> once with a book held a foot away from the cone. There are two effects
> >> evident. The first is that the frequencies of the impedance peaks have
> >> shifted up slightly with the book in place (blue trace), and secondly
> >> there is considerable disturbance to the actual impedance, mainly at
> >> the lower peak and the intermediate dip - but also in a considerable
> >> modification to the upper slope of the top peak where there is a bit
> >> of a wobble.
>
> >> So yes, it is important to keep the area around the speaker clear of
> >> clutter when you measure the impedance.
>
> >> I have no doubt that Phil will try to come back with some guttersnipe
> >> defence of his position, but as you see it is untenable.
>
> >The differences between red line and blue lines with and without a
> >book held near a speaker are to my mind quite negligible, leading some
> >ppl to argue that claiming significant Z differences due to nearby
> >objects is "bollocks", aka as bullshit or horse manure, bovine
> >fertilizer or even hiefer dust, ( the latter to not offend sensitive
> >older female farmers who'd always frown on the vulgarities speiled out
> >by the male species. ).
>
> >Presumably, a speaker box will affect the Z far more than a book held
> >a foot away. In fact, the Z curve with driver suspended in free air,
> >and in the geometric centre of a large room is somewhat a useless
> >curve to draw apart from deriving T&S parameters. The Z with driver in
> >box is VERY important.
>
> >Patrick Turner.
>
> More blah blah blah.

Quite a few blahs with zero wisdom from you.

Patrick Turner.
>
> d- Hide quoted text -
>
> - Show quoted text -

[Patrick Turner]

> You may be right, you may be wrong. I'll never know because there is
> that about you which means I will never read a word you write.


I'm so utterly pleased and thrilled so POSITIVELY that you won't read
anything I type.

I'm at a stage in life where I have begun to hate having un-reasonable
fans, ie, those who don't like to ask awkward questions like I do.

Now WTF was it that you typed which was worth anyone reading?

Did anything you type make anyone question the world around them, so
they might become wiser?

Forget me, and yourself, but the world will always tolerate questions.

Patrick Turner.

[It's that Guy again...]

On Wed, 18 Apr 2012 15:34:42 +1000, "Phil Allison" <phi...@tpg.com.au>
wrote:

> ** All depend what the fucking QUESTION was - you fucking ASD fucked
> fuckwit !!!!!!!!!!!

Chill out for a second, dude... really.....

> The **PURPOSE** of the slanted front is to project sound upwards to an
> elevated audience.

Close, but not quite. When I worked for the importer of VOX, before
KORG, under the last remains of Rose-Morris, a company called Pr1mo,
they built a complete hunk of shit called the Concert 100, a 8-12
stack that sounded ok, but was built R-E-A-L badly.. I mean yuck..

The R-M folks were here, and I asked why they used the slant stack
look, instead of the VOX'ish look of a straight big cab. I was told:

Slant cabs sell better, they designed the model to compete. That
made sense. Then we talked about how the slant came to pass.

I was told the same story out of the book. It made the head sit
better on the cab. Marshall was the 1st to do it, they needed
something to stand out. Makes sense. BUT..it ALSO directed the
sound to the PLAYER's EARS without them needing to bend over.

That also made sense. Directing the sound to the top of the room
is just a added bonus, because even Marshall didn't think anyone
would use multi-stacks, making sound direction, um, 'moot'...

Believe that if ya want or not. But the source was real good.

> Now, whether or not Jim actually thought of it before making the suggestion
> to his workers is MOOT !!!

It was a marketing idea 1st. Also, after trying 8-12 single cabs, and
people sawing them in half, even a nutter would get the drift. The
roadies then would go on strike otherwise. Today, they hate to lift
even a Twin..heaven forbid, w/JBLs. Most 'roadies' 2day are wimps.

> FFS - Jim Marshall was a FUCKING DRUMMER with NO CLUE AT ALL about
> either amplifiers or how sound works.

That is NOT 100% true, JM had complete control over his product,
hired the best people (as ALL companies did/do) and face it, made
more $$ in this biz the you, me, and anyone here combined.

Not bad for a "..fucking drummer.."

> FFS - get cause and effect figured out, fuckhead.
>
> Then GO DROP FUCKING DEAD !!
>
> You revolting, wog nut case FUCKING retard.

Ya gotta go "..OWWWWWWWW...."



JJTj



*> SENT FROM CELL PHONE DECK# 873048HS <*
*> NO REPLY MODE GIGANEWS TZFXS-OfQ9 <*




I have always thought in the back of my mind

"Cheese and Onions".

I have always thought that the world was unkind

"Cheese and Onions".

Do I have to spell it out ?

"C-H-E-E-S-E A-N-D O-N-I-O-N-S"

oh ho no...

Man or machine (Man or machine)
Keep yourself clean (Keep yourself clean)
Or be a has-been (Ah-ah)
Like a Dinosaur, oh oh-oh.


Man of advise (Man of advise)
For ev'rything nice (Ev'rything nice)
You'd better think twice (Ah-ah)
At least once more, oh oh.

[flipper]

On Wed, 18 Apr 2012 19:43:31 +1000, "Phil Allison" <phi...@tpg.com.au>
wrote:

>flipper = fuckhead "
>>>
>>>>
>>>>>"flipper"
>>>>>
>>>>>> http://www.thewho.net/whotabs/gear/guitar/marshallstack.html
>>>>>
>>>>>
>>>>>** Not one bit relevant to the issue.
>>>>>
>>>>>The first ( 4 x 12) slant front cabs were sold to go with JTM45s that
>>>>>date
>>>>>from late 1962.
>>>>>
>>>>
>>>> Right, he cared for 'ridiculous' looking in 1965 but not in 1962.
>>>
>>>
>>>** HUH ??
>>
>> You wouldn't be "huh??" confused if you had read the rest instead of
>> snipping it.
>
>
>** For CHRIST'S SAKE - you fucking fuckhead !!!
>
> YOU did *NOT READ* what I wrote at all - as FUCKING USUAL !!!

Wrong. I read it and you're the one who perpetually 'edits' what
people say, not I.

>
> FFS - GO BACK and FUCKING DO SO !!!!!
>
> I absolutely know you won't -
>
> cos you are an ASININE fucking SEPTIC PIG.

Wrong again, and I'll quote it. You wrote

"** The slant front 4 x 12 cab was built after requests from
guitarists who regularly played in venues that were cinemas. Typical
cinemas of the era were converted ( or doubled as) live theatres and
so had " front stalls " at ground level and a " dress circle "
upstairs. Folk up stairs were missing out on the higher tones from
straight fronted cabs."

And, as has been shown from Marshall's own mouth, your quaint idea
didn't have a blessed thing to do with it. He slanted the 4x12 so it
would look good with the amp. In fact, he built the 4x12 *for* the
amp, while still a prototype, when the 2x12s didn't pass muster.


>... Phil
>
>
>
>
>
>

[Phil Allison]

"It's that Guy again..."

( ship piles of DRIVEL)

>> FFS - Jim Marshall was a FUCKING DRUMMER with NO CLUE AT ALL
>> about
>> either amplifiers or how sound works.
>
> That is NOT 100% true, JM had complete control over his product,

** Like hell he did.


> hired the best people


** He used a service guy and an apprentice to do the design work - such as
it was.

Jim had not one tiny clue about valve electronics or the business of
manufacturing.

His amplifier products are all a long litany of cobbed together POS that are
known everywhere as the most unreliable and trouble prone on the market.

Marshall has NEVER employed even one technically competent designer, silly
mistakes and bad designs of 40 years standing are still being installed in
new models made today.

Marshall = Scam.


.... Phil

[Phil Allison]

"flipper"

>
>> YOU did *NOT READ* what I wrote at all - as FUCKING USUAL !!!

** This is what you failed to READ !!

" The first ( 4 x 12) slant front cabs were sold to go with JTM45s that date
from late 1962."

Whatever the original motive or motives - they date from 1962 !!

You fucking RETARDED fuckwit.



.... Phil

[flipper]

On Thu, 19 Apr 2012 11:04:23 +1000, "Phil Allison" <phi...@tpg.com.au>
wrote:

>

No one is debating 'when' it was made, the topic was why he slanted
it, and from his own mouth he did that so it would look good with the
amp sitting on top.

>.... Phil

[Phil Allison]

"flipper" the FUCKING MORON

>
>>** This is what you failed to READ !!
>>
>>" The first ( 4 x 12) slant front cabs were sold to go with JTM45s that
>>date
>>from late 1962."
>>
>> Whatever the original motive or motives - they date from 1962 !!
>>
>> You fucking RETARDED fuckwit.
>

> No one is debating 'when' it was made, the topic was why ..


** YOU STILL CANNOT READ !!!

The design decision has a POINT in time and only Jim knows what he was and
was not thinking about.

In reality - it does not matter a HOOT what Jim Marshall says was his
purpose. The drum banging fool was apparently too stupid to realise the
immediate EFFECT of the slanted front was to improve vertical dispersion and
that this improvement would be beneficial to most users and audiences.

As I posted earlier - Fender added tilt legs to many models for the same
purpose.

Other makers used sloped fronts or made metal frames to raise an tilt back
amps on stages.


... Phil

[flipper]

On Thu, 19 Apr 2012 13:47:24 +1000, "Phil Allison" <phi...@tpg.com.au>
wrote:

>

>"flipper" the FUCKING MORON
>
>
>>
>>>** This is what you failed to READ !!
>>>
>>>" The first ( 4 x 12) slant front cabs were sold to go with JTM45s that
>>>date
>>>from late 1962."
>>>
>>> Whatever the original motive or motives - they date from 1962 !!
>>>
>>> You fucking RETARDED fuckwit.
>>
>> No one is debating 'when' it was made, the topic was why ..
>
>
>** YOU STILL CANNOT READ !!!

Obviously you were looking in the mirror.

>The design decision has a POINT in time and only Jim knows what he was and
>was not thinking about.

Which is why when he *tells* you what he was thinking it's
irrefutable.

>In reality - it does not matter a HOOT what Jim Marshall says was his
>purpose.

It 'matters a hoot' when he's the 'inventor'.

> The drum banging fool was apparently too stupid to realise the
>immediate EFFECT of the slanted front was to improve vertical dispersion and
>that this improvement would be beneficial to most users and audiences.

That may be but it's irrelevant because, according to the 'inventor'
himself, that wasn't 'the reason' he slanted the cab, as you had
claimed.

And it isn't terribly surprising that wasn't his motivation because,
according to all the narratives, no one was aware of, or at least they
never mentioned, any such 'problem' needing a 'solution'.

>As I posted earlier - Fender added tilt legs to many models for the same
>purpose.
>
>
>Other makers used sloped fronts or made metal frames to raise an tilt back
>amps on stages.

Also irrelevant because none of them are a Marshall 4x12.


>... Phil

[jh]

> .... Phil
>
>
>
>



Phil, you're stuck in your arguments. Prove that you are a man and admit
it ;-)


The Marshall Cab is slanted, because Jim Marshall did not like the cosmetics

< No it is slanted because of the request of musicians in Cinemas to
project sound...

But Jim Marshall stated it himself

< But it works

..by accident

< But it works and Marshall just did not know that

..but they simply wanted cosmetics

< Marshall was only a drummer, what did he know

.. cosmetics

< He could not even build an amp by himself

..

< Fender did it earlier

..

< All Marshalls are only POS

[Phil Allison]

flipper" the FUCKING MORON

>>
>>>>** This is what you failed to READ !!
>>>>
>>>>" The first ( 4 x 12) slant front cabs were sold to go with JTM45s that
>>>>date
>>>>from late 1962."
>>>>
>>>> Whatever the original motive or motives - they date from 1962 !!
>>>>
>>>> You fucking RETARDED fuckwit.
>>>
>>> No one is debating 'when' it was made, the topic was why ..
>>
>>
>>** YOU STILL CANNOT READ !!!
>

>>The design decision has a POINT in time and only Jim knows what he was and
>>was not thinking about.
>
> Which is why when he *tells* you what he was thinking it's
> irrefutable.

** Whoooo - another MASSIVE context shift !!

Plus a pile of steaming crap.

>>In reality - it does not matter a HOOT what Jim Marshall says was his
>>purpose.
>
> It 'matters a hoot' when he's the 'inventor'.

** ROTFLMAO !!

Retarded, hyperactive chimps can reason better !!!

>> The drum banging fool was apparently too stupid to realise the
>>immediate EFFECT of the slanted front was to improve vertical dispersion
>>and
>>that this improvement would be beneficial to most users and audiences.
>
> That may be but it's irrelevant because, according to the 'inventor'
> himself, that wasn't 'the reason' he slanted the cab, as you had
> claimed.

** But it was, according to "jh" :

" No technical explanation there - although the "explanation" for the slant
was "to project the sound over the crowd so the last rows can hear
something too".... when Jim Marshall and his crew was asked by curios
musicians. "

>>As I posted earlier - Fender added tilt legs to many models for the same
>>purpose.
>>
>>Other makers used sloped fronts or made metal frames to raise an tilt back
>>amps on stages.
>

> Also irrelevant ...


** Fraid it is 100% relevant to anyone who can read and think.

But not of course to a genetically fucked pile of sub human excreta.

Which is all you are.

[jh]

SNIP

twistin the twist, do you?

the "explanation" was given to the curious musicians, because he could
not simply say: "it just looks better" - also a statement given by the
man himself... it was not the "drive" of the invention of the slanted
Marshall 4x12.

Jochen

[flipper]

On Thu, 19 Apr 2012 23:03:39 +1000, "Phil Allison" <phi...@tpg.com.au>
wrote:

>flipper" the FUCKING MORON
>
>>>
>>>>>** This is what you failed to READ !!
>>>>>
>>>>>" The first ( 4 x 12) slant front cabs were sold to go with JTM45s that
>>>>>date
>>>>>from late 1962."
>>>>>
>>>>> Whatever the original motive or motives - they date from 1962 !!
>>>>>
>>>>> You fucking RETARDED fuckwit.
>>>>
>>>> No one is debating 'when' it was made, the topic was why ..
>>>
>>>
>>>** YOU STILL CANNOT READ !!!
>>
>>>The design decision has a POINT in time and only Jim knows what he was and
>>>was not thinking about.
>>
>> Which is why when he *tells* you what he was thinking it's
>> irrefutable.
>
>
>** Whoooo - another MASSIVE context shift !!
>
> Plus a pile of steaming crap.

Rational thinking isn't your strong suit and there is no 'context
shift'. You said "only Jim knows" so what he tells you is irrefutable
because "only Jim knows."

And "Jim" Marshall said he slanted the cab so it would look good with
the amp. Case closed.

>>>In reality - it does not matter a HOOT what Jim Marshall says was his
>>>purpose.
>>
>> It 'matters a hoot' when he's the 'inventor'.
>
>
>** ROTFLMAO !!
>
> Retarded, hyperactive chimps can reason better !!!

You should try a more advanced from of reasoning.

>>> The drum banging fool was apparently too stupid to realise the
>>>immediate EFFECT of the slanted front was to improve vertical dispersion
>>>and
>>>that this improvement would be beneficial to most users and audiences.
>>
>> That may be but it's irrelevant because, according to the 'inventor'
>> himself, that wasn't 'the reason' he slanted the cab, as you had
>> claimed.
>
>
>** But it was, according to "jh" :
>
>" No technical explanation there - although the "explanation" for the slant
> was "to project the sound over the crowd so the last rows can hear
> something too".... when Jim Marshall and his crew was asked by curios
> musicians. "

In the first place, misrepresenting what "jh" said only makes you look
dishonest. He gave what Jim Marshal said was 'the reason', the "no
technical" reason of cosmetics, and went on to say he came up with a
'better sounding' explanation for "curios musicians."

Gene Roddenberry did the same thing to 'explain' why Stardates weren't
'in order' in his Star Trek series. In fact, for the most part they
were, as filmed, but the network didn't air them in the same sequence.
But fans loved the 'better sounding' explanation because it made
'scientific sense' to them, despite having nothing whatsoever to do
with 'the reason', much as you love your 'scientific sense'
explanation for a slant 4x12 despite it having nothing to do with 'the
reason' he did it.

Second, "jh" isn't Jim Marshal and, in any discrepancy between "jh"
and "jm" about what "jm" was thinking, the irrefutable 'winner' is
"jm" since, as you said, "only Jim knows."

>>>As I posted earlier - Fender added tilt legs to many models for the same
>>>purpose.
>>>
>>>Other makers used sloped fronts or made metal frames to raise an tilt back
>>>amps on stages.
>>
>> Also irrelevant ...
>
>
>** Fraid it is 100% relevant to anyone who can read and think.

It's irrelevant because, by your own criteria, "only Jim knows" and
they aren't "Jim."

[jh]

Am 20.04.2012 02:49, schrieb flipper:

>

SNIP

>
> Gene Roddenberry did the same thing to 'explain' why Stardates weren't
> 'in order' in his Star Trek series. In fact, for the most part they
> were, as filmed, but the network didn't air them in the same sequence.
> But fans loved the 'better sounding' explanation because it made
> 'scientific sense' to them, despite having nothing whatsoever to do

> with 'the reason', ...

SNIP


Hi flipper,


what was the "explanation" of Steve Rodenberry?

regards

Jochen

[Patrick Turner]

I've had to repair a large number of Marshall amps and like so many
Big Brands of amps, their reliability has never improved from older
models to the latest. Most circuitry in ALL guitar amps looks like it
was designed by the same guy and all makers just have followed what
other blokes did before them to make the same kind of output stages
and tone stack stages. The original guy who designed the first guitar
amp was chosen for the job because he'd been brainwashed by
accountants to use as few tubes as possible.

Meanwhile, over the last 30 years in ALL brands of guitar amps, there
were more and more features added involving huge numbers of parts and
many opamps and other solid state stuff. Features sell well. Most
guitar amp owners are not very good musicians, and try to depend on
features but of course no amount of features makes up for a big lack
of real natural musical ability.

So, nearly all tubed guitar amps have vast double sided PCBs full of
bells and whistles that were not needed in 1960. There are now a
number of guitar amp makers who build "hand-crafted" amps which don't
have any PCBs, and do have tag strip point to point wiring everywhere,
don't have solid state opamps and do-dahs, bells, whistles, et all,
and these are MUCH easier to service and keep running. Many are
designed to work in class A mainly, with Ea = 350V max for 6L6, and
such amps are a real return to the retro sound of 1960. High power is
not needed. Tubes tend to last longer.

What on earth is the point of Heavy Metal, Dark Metal, and all the
screaming gits jiggling around on stages like dickheads in front of
purile fans and sounding like a bunch of tomcats with crackers up
their arses, turpentine on balls, while accompanied and almost drowned
out by expensive tube amps driven well into class C making continuous
THD and IMD totalling 35%, sort of like a continuous stream of
aeroplanes crashing on the venue?

The reliability of guitar amps is affected badly by the way output
tubes are biased and routinely over loaded, and the constant movement
from one gig to other, and occasional spilt glass of beer down into
the electronics. Tubes in guitar amps tend to become too noisy too
often too quickly, probably because the vibrations in cabinets or from
nearby sound sources rattles them up badly. So when some problem
occurs, amp owners swap tubes around, and of course after 10 years the
tube socket pin grippers get loose and maybe intermittent.

Cream floats to the surface, and so only very few performing artists
make it to the big time of rock and roll while leaving behind the vast
procession of wannabes. The guy who can really play well gets the nod
to the big dough, and he learns not to give a fuck about amp
technicals, because he can afford a collection of amps, and the
constant servicing they may need, and afford the special preamps to
voice his tone uniquely if possible. Mark Knofler, George Benson come
to mind.

There's usually a bit of scam in most human endeavours, especially
where money is paid for some toy like a guitar amp, hi-end hi-fi amp,
Masseratti, tennis racket, bicycle, etc.

Patrick Turner.

[flipper]

Gene's Stardate jig was "This time system adjusts for shifts in
relative time which occur due to the vessel's speed and space warp
capability. It has little relationship to Earth's time as we know it.
One hour aboard the U.S.S.Enterprise at different times may equal as
little as three Earth hours. The stardates specified in the log entry
must be computed against the speed of the vessel, the space warp, and
its position within our galaxy, in order to give a meaningful
reading."

Fans beamed "of course," general relativity and all that, so an
inconsistent airing sequence became one of Star Trek's famous
'scientific realism' features.

>regards
>
>Jochen

[jh]

Aaah,

thank you for the explanation

regards

Jochen