[Phil Allison]

"Eeysore the Lunatic "

Anyone that can't hear the distortion of QSC USA or MX series must
have severely damaged hearing.

** Shame how the rest of us do not have any of the defective examples
YOU claim YOU came across that lacked forward bias current in the
output devices.

The classic QSC arrangement with grounded collectors has no qiescent
current in the output devices.

** Massive BLATANT LIE !!

You are ridiculous, stupid damn LIAR Stevenson.

You have it 100% incorrect.


** Five QSC MX series amps I have here RIGHT NOW prove you WRONG.

All have about 20 mA per output BJT at idle - more when hot.

I suppose you set them that way.


** That is they are - from the factory.

YOU are NOT in any position to know how QSC set the bias current.

YOU have no proof WHATEVER of your MAD & WRONG assertion.


Stevenson is completely INSANE with:


1. Congenital autism.

2. Massive narcissism.

3. Manic personality disorder.


He tells massive lies, thousands of them.




...... Phil

[Phil Allison]

"Eeysore the Lunatic "

Anyone that can't hear the distortion of QSC USA or MX series
must
have severely damaged hearing.

** Shame how the rest of us do not have any of the defective
examples
YOU claim YOU came across that lacked forward bias current in the
output devices.

The classic QSC arrangement with grounded collectors has no qiescent
current in the output devices.

** Massive BLATANT LIE !!

You are ridiculous, stupid damn LIAR Stevenson.

You have it 100% incorrect.

** Five QSC MX series amps I have here RIGHT NOW prove you WRONG.

All have about 20 mA per output BJT at idle - more when hot.

You have no proof whatever of you MAD & WRONG assertion.

BORING


** What a completely insane reply.




....... Phil

[Phil Allison]

"Eeysore the Lunatic "


The classic QSC arrangement with grounded collectors has no qiescent
current in the output devices.

** Massive BLATANT LIE !!

FACT.


** But it is not fact.

And you have no proof.

Cos it is simply not true.




....... Phil

[MooseFET]

On Sep 24, 7:43 am, Eeyore
wrote:
Don Klipstein wrote:
krw wrote:
says...

Your phrase "good enough for audio" does not inspire confidence. I work in the professional /
production area of audio. 'Good enough' usually isn't for us. Indeed, for a host of reasons I'd also
probably want to transmit 24 bit audio. Some customers might want 96 kHz sampling too.

Yes, I know you're a "professional" audiophool. If you can't hear
it, it's good enough. Fer instance, millisecond is good enough as
long as all channels are together. They all get the same signal.

Go on. Ask why !

Why? I could care less about "professional" audiophoolery. BTW, we
were talking about powered speakers, not "professional" grade audio.
96kHz? What nonsense.

I occaisionally hear artifacts in 16 bit 44.1 KHz, in music.

It is easy to make a test signal turn up severe artifacts with 44.1 KHz
sample - see what happens with a sinewave at a higher audio frequency that
is several Hz off a frequency that the sample frequency is a multiple of.

Since I only occaisionally hear artifacts in music with 44.1 KHz 16 bit,
and when I do I usually find them minor, I would expect a sample rate
twice as high as that to be OK.

For some reason 88.2 kHz never caught on. It's always been 96, double the 48kHz sampling used in some other
digital audio products, as far as I can remember.


48KHz is the DAT tape rate.


Graham

[Phil Allison]

"Eeysore the Lunatic "


The classic QSC arrangement with grounded collectors has no qiescent
current in the output devices.

** Massive BLATANT LIE !!

You are ridiculous, stupid damn LIAR Stevenson.

That's what you always say when you're caught out.


** This is a simple matter of fact where opinion is of no relevance.

But the congenitally mentally defective Stevenson lunatic cannot see that
crucial point.

What pathetic, sub human creature he has become.





...... Phil

[JosephKK[_2_]]

On Mon, 22 Sep 2008 18:42:31 -0700 (PDT), RichD
wrote:

On Sep 19, Eeyore wrote:
Who do MOSFET sound better than bipolar, as an audio
amp output driver?

As a driver ?
Now if you said as an output stage it might make sense.

There's a difference?

Damn right there is.

I'm thinking of the bits that attach to the
copper thingy which loops around the
magnets which make the air move.

An unusual design but the copper thingy is very likely
heatsink, in which case you're referring to the actual output
devices.

The copper thingy is flexible, about 15' long,
attaches to the box with the magnets at one end.

It would indeed be unusual to use that
as heatsink, but perhaps novel and efficient.

They in turn usually have devices called 'drivers'
which precede them, although it's
less necessary with mosfets, only for ultimate performance..

So the output driver feeds the output stage?
Is that the standard jargon?

Yes. And not only in audio power amplifiers, it occurs in RF power
amplifiers as well.

[JosephKK[_2_]]

On Thu, 18 Sep 2008 18:26:25 -0000, "Jorden Verwer"
wrote:

Eeyore wrote:
given that you've apparently never heard of the term
offset.

Offset is IRRELEVANT to output devices you complete MORON !
I know that, and I never claimed otherwise. Offset is a form of noise, in a
sense. And like noise, it is caused almost completely by the input
transistors. I'm well aware of all that.

Do do you know what a 'closed loop' means ?
Yes.


Offset is a form of noise???? This is the first time i have ever
heard that. There is no engineering reason to look at it that way. It
is fundamentally a different property with different physics.

[JosephKK[_2_]]

On Thu, 18 Sep 2008 18:45:40 -0000, "Jorden Verwer"
wrote:

Eeyore wrote:
Jorden Verwer wrote:
Offset is a form of noise, in a sense.

Every one a cracker. Maybe he hasn't heard of DC vs AC analysis ?
Let me put it this way...

Noise-like phenomena, in increasing order of bandwith:
Offset == 1/f noise == white noise


OK alligator, where does shot noise fall in the spectrum?

[JosephKK[_2_]]

On Fri, 19 Sep 2008 15:21:19 GMT, "Kevin Aylward"
wrote:

it.

Not at all in any remote way shape or form.
Don't you at least agree there are many similarities between 1/f
noise and offset?


Actually, I do. By and large, they amount to the same thing. Its all low
frequency variations. For example, if one designs a chopper amp to get low
offset, it also kills/corrects for 1/f noise as well. If one has 1/f
problems in an system, one immediately thinks about using a chopper..well I
do any way...


Kevin Aylward
www.anasoft.co.uk
SuperSpice


I am less sure about it killing 1/f (flicker) noise rather than band
shifting it to a place where is can be filtered out. It is not
offset, though the chopper amplifiers can mask it out. Ah, yes, noise
shaping; making some undesired near band interfering signal content
terms go where they are easier to separate from the desired signal.

[Don Pearce]

Eeyore wrote:

Phil Allison wrote:

"Eeysore the Lunatic "

** Gobbledegook plus a massive non-sequitur.
Read how it works.
** Insane false logic.

Anyone that can't hear the distortion of QSC USA or MX series must have
severely damaged hearing.
** Shame how the rest of us do not have any of the defective examples
YOU claim YOU came across that lacked forward bias current in the output
devices.
The classic QSC arrangement with grounded collectors has no qiescent
current in the output devices.
** Massive BLATANT LIE !!

You are ridiculous, stupid damn LIAR Stevenson.

You have it 100% incorrect.

But then for a toaster repair man it's not too surprising.

If Kevin or Don Pearce were to re-enter the thread, they'd know EXACTLY what I'm
driving at. Actually, Larkin probably does too but maybe he's just trying to
stir it up ?

Graham


Just had a look at a few QSC schematics, and it is apparent that the
output transistors are biased - not quite to zero current, but certainly
a very low current. Certainly a long way below what I would consider a
normal bias level. This is held in position a by a long time constant RC
pair, which I suspect doesn't track LF-induced temperature variations
too well.

d

[Phil Allison]

"Don Pearce Pommy Liar Extrordaire"


Just had a look at a few QSC schematics, and it is apparent that the
output transistors are biased - not quite to zero current, but certainly a
very low current.


** Wot absolute ****ing drivel.

Only seeing a REAL example of a QSC amp allows one to tell what the bias
current setting is.

As it depends critically on the adjustment of a trim pot.


This is held in position a by a long time constant RC pair,


** There is no such RC pair involved - you congenital, criminal dim wit.




...... Phil

[Jan Panteltje]

On a sunny day (Wed, 24 Sep 2008 20:49:00 -0700 (PDT)) it happened MooseFET
wrote in
:

For some reason 88.2 kHz never caught on. It's always been 96, double the 48kHz sampling used in some other
digital audio products, as far as I can remember.


48KHz is the DAT tape rate.

It is also what is normally used in digital TV.
That means digital recordings from TV use 48KHz.

Maybe when CDs die, then 44.1 is dead?

[MooseFET]

On Sep 25, 7:42 pm, Jan Panteltje wrote:
On a sunny day (Wed, 24 Sep 2008 20:49:00 -0700 (PDT)) it happened MooseFET
wrote in
:

For some reason 88.2 kHz never caught on. It's always been 96, double the 48kHz sampling used in some other
digital audio products, as far as I can remember.

48KHz is the DAT tape rate.

It is also what is normally used in digital TV.
That means digital recordings from TV use 48KHz.

Maybe when CDs die, then 44.1 is dead?

Many computers sound cards are made to produce 44.1K exactly and many
digital recordings are already made at 44.1. It will likely stay
around as a standard.

[Phil Allison]

"Jan Panteltje"



48KHz is the DAT tape rate.

It is also what is normally used in digital TV.
That means digital recordings from TV use 48KHz.


** Nonsense - DTV is all MP3 encoded.

There is no defined sampling rate.



...... Phil

[Don Pearce]

Phil Allison wrote:
"Don Pearce Pommy Liar Extrordaire"

Just had a look at a few QSC schematics, and it is apparent that the
output transistors are biased - not quite to zero current, but certainly a
very low current.


** Wot absolute ****ing drivel.

Only seeing a REAL example of a QSC amp allows one to tell what the bias
current setting is.

As it depends critically on the adjustment of a trim pot.


There are no trim pots on the three schematics I've looked at.


This is held in position a by a long time constant RC pair,


** There is no such RC pair involved - you congenital, criminal dim wit.




..... Phil



R35 with C22. That is on the CX302

d

[Michael A. Terrell]

Kris Krieger wrote:

Rich Grise wrote in
news
On Wed, 24 Sep 2008 08:33:17 -0400, Arny Krueger wrote:
"Eeyore" wrote in
I expect the phone would be good enough for you ?

Depends on the phone. If I make a phone up out of a good vocal mic and
some studio monitors, it will be pretty good. These days really good
electret mics cost pennies, while good earphone elements are relatively
small and cheap compared to speakers. Most of the inherent losses in
modern phones are in the communications channel, which is wildly
bandwidth-reduced. As bandwidth becomes cheaper, there is a possibility
that good-sounding telephones will become commonplace.


If NASA can send broadcast quality video down from the shuttle or ISS,
howcome their audio still sounds like a fast food clown?

Thanks,
Rich


I wonder, tho', whether their secure/encrypted comms are as bad. I'd suspect
not - I'd imagine that a secure channel woudl be able to carry mroe data, and
therefore be "cleaner". But that's just a guess...




They have plenty of bandwidth on the system I built. It has a maximum
bandwidth of 40 Mb/sec. It al depends on what part they allocate to
each channel. they are on the KU band, where wide channels are no
problem. It also makes it difficult to track for casual monitoring.
Part of the problem is the type of microphones used. They are not very
sensitive, and are noise canceling which affects audio quality.


--
http://improve-usenet.org/index.html

aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm


There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.

[Phil Allison]

"Don Pearce Pommy Liar Extraordinaire


Just had a look at a few QSC schematics, and it is apparent that the
output transistors are biased - not quite to zero current, but certainly
a very low current.


** Wot absolute ****ing drivel.

Only seeing a REAL example of a QSC amp allows one to tell what the bias
current setting is.

As it depends critically on the adjustment of a trim pot.


There are no trim pots on the three schematics I've looked at.


** Then you have NOT looked at any USA or MX or even the PL series amps.


AS IS 100% REQUIRED BY THE CONTEXT !!!



YOU VILE, LYING ASININE ASD ****ED PILE OF POMMY EXCREMENT !!!






...... Phil

[Arny Krueger]

"Eeyore" wrote in
message
Arny Krueger wrote:

"Eeyore" wrote
Arny Krueger wrote:
"Eeyore" wrote
krw wrote:
says...

Your phrase "good enough for audio" does not inspire
confidence. I work in the professional / production
area of audio. 'Good enough' usually isn't for us.
Indeed, for a host of reasons I'd also
probably want to transmit 24 bit audio. Some
customers might want 96 kHz sampling too.

Yes, I know you're a "professional" audiophool.

Just a professional.

But one with a pretty fair track record for hearing
urban myths like the crossover distortion that you
claim exists in some power amplifiers.

BECAUSE IT'S SO AUDIBLE IT STICKS OUT LIKE A SORE THUMB.

Everyplace but on test equipment, and in careful
listening tests.

It stands out like a sore thumb on test equipment too.
It's HIGHLY visible and occurs typically at critical
listening levels (around the 100mW - 1W area).

Yes, and when it doesn't happen, it is very clear that it isn't happening.

Let the record show that I have a number of QSC amps on
hand to test, have done so, and reported the results to
Graham on Usenet. He has no such resources at hand.

Uh ? I don't have access to it at the moment but my
measurements have been made on such amplifiers using AP
test Equipment - the industry standard and capable of
incredible resolution. I may also shortly get my hands on
a Prism Sound dScope 3.
http://ap.com/products/index.html
I personally love the Portable One to bits since it's so
intuitive and fast to use and totally self contained.
With System Ones you often had to turn off the PC monitor
to get accurate results.
http://www.prismsound.com/test_measu...scope_home.php

Short answer - Graham has no immediate practical experience with measuring
QSC amps, just like I said.

Your precious ABX testing guarantees only a 'lowest
common denominator' result.

Horsefeathers.

As I read how ABX testing works,

Short answer - Graham has no immediate practical experience with ABX, just
like I said.

If I say, you had a group
30 listeners and 3 were consistently about to determine A
from B and the other 27 couldn't, then you would say the
products were indistinguishable, i.e. discard the results
of the 3 that could determine a difference.

If you had a group of 30 well-chosen, well-trained listeners, then there
would be no such thing as "...30 listeners and 3 were consistently about to
determine A from B and the other 27 couldn't..."

That's what I mean by 'lowest common denominator'. All it
proves is that most people have crap hearing.

Nobody with a brain uses "most people" for critical listening tests.

For example, the Stereo Review amplifier tests published in 1989 were done
using about 20 people, some audiophiles, some audio engineers, some
production people, some musicans, etc. We had been working with them for up
to 14 years. Yes, we had worked with some of them since 1975.

The 20 listeners were picked from a group of about 100 people that we had
already done any number of tests with. These tests particular tests were
done by invitation. We simply didn't invite the people who really didn't
really care, couldn't really hear, or were likely to be disruptive.


If I have misunderstood these principles, my apologies.

It is worse than "misunderstood" Graham, you simply have no clue about ABX
tests are run or analyzed.

However I WILL NOT engage in futile discussion about
things *I* know I *can* hear.

All the audiophool golden ears say *exactly* the same thing. If you want to
put yourself above the crowd Graham, you have to behave better than the
crowd. Part of that is doing your homework. You've just explicitly admitted
that you haven't even cracked the book, let alone done your homework.
Passing grades go only to people with fresh, relevant, worked-out answers.

Some of my colleagues
recently used me as the 'professional ears' to track down
a curious hum that a studio mix engineer had reported but
they couldn't hear themselves. I eventually found it. It
was a slightly humming wall wart in the back of an
equipment rack. If it was much louder than 10 phons I'd
be surprised.

Good. Been there, done that many times. However there is no relevance
between this and properly-run ABX tests.

[Arny Krueger]

"John Larkin"
wrote in message
news
What is it about audio that makes people so angry and
profane? I thought music was supposed to make people
happy. Peace Train, All you Need is Love, stuff like that.

Since you haven't noticed, I guess its up to me to point it out to you.

This isn't a music listening session.


Is it because most of you guys can't afford decent test
equipment, so everything becomes subjective?

I have more highly sensitive audio test gear by accident then most people
have on purpose. I probably shouldn't admit this because it shows a certain
kind of carelessness.

And, as one of the people who developed some of the industry standard
subjective testing procedures that people are using effectively to this day,
I don't see anything wrong with basing opinions on properly-run subjective
tests.

[Jan Panteltje]

On a sunny day (Thu, 25 Sep 2008 23:15:52 +1000) it happened "Phil Allison"
wrote in :


"Jan Panteltje"



48KHz is the DAT tape rate.

It is also what is normally used in digital TV.
That means digital recordings from TV use 48KHz.


** Nonsense - DTV is all MP3 encoded.

There is no defined sampling rate.



..... Phil

First it is mp2 encoded, and second most is 48KHz sampled.
Here is an example:

mplayer -ao oss:/dev/dsp1 goldfinger.ts
MPlayer 1.0pre7try2-3.3.6 (C) 2000-2005 MPlayer Team
CPU: Advanced Micro Devices Duron Spitfire (Family: 6, Stepping: 1)
Detected cache-line size is 64 bytes
CPUflags: MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 0 SSE2: 0
Compiled for x86 CPU with extensions: MMX MMX2 3DNow 3DNowEx


Linux RTC init error in ioctl (rtc_irqp_set 1024): Inappropriate ioctl for device
Try adding "echo 1024 /proc/sys/dev/rtc/max-user-freq" to your system startup scripts.
Playing goldfinger.ts.
TS file format detected.
DEMUX OPEN, AUDIO_ID: -1, VIDEO_ID: -1, SUBTITLE_ID: -1,
PROBING UP TO 2000000, PROG: 0
VIDEO MPEG2(pid=2342)AUDIO MPA(pid=2343) NO SUBS (yet)! PROGRAM N. 0
Opened TS demuxer, audio: 50(pid 2343), video: 10000002(pid 2342)...POS=10340
VIDEO: MPEG2 544x576 (aspect 3) 25.000 fps 10000.0 kbps (1250.0 kbyte/s)
================================================== ========================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
AUDIO: 48000 Hz, 2 ch, s16le, 192.0 kbit/12.50% (ratio: 24000-192000)
Selected audio codec: [mp3] afm:mp3lib (mp3lib MPEG layer-2, layer-3)
================================================== ========================
vo: X11 running at 1440x900 with depth 24 and 32 bpp (":0.0" = local display)
================================================== ========================
Opening video decoder: [mpegpes] MPEG 1/2 Video passthrough
VDec: vo config request - 544 x 576 (preferred csp: Mpeg PES)
Could not find matching colorspace - retrying with -vf scale...
Opening video filter: [scale]
The selected video_out device is incompatible with this codec.
VDecoder init failed
Opening video decoder: [libmpeg2] MPEG 1/2 Video decoder libmpeg2-v0.4.0b
Selected video codec: [mpeg12] vfm:libmpeg2 (MPEG-1 or 2 (libmpeg2))
================================================== ========================
Checking audio filter chain for 48000Hz/2ch/s16le - 48000Hz/2ch/s16le...
AF_p 48000Hz/2ch/s16le
AO: [oss] 48000Hz 2ch s16le (2 bps)
Building audio filter chain for 48000Hz/2ch/s16le - 48000Hz/2ch/s16le...
Starting playback...
VDec: vo config request - 544 x 576 (preferred csp: Planar YV12)
VDec: using Planar YV12 as output csp (no 0)
Movie-Aspect is 1.78:1 - prescaling to correct movie aspect.
VO: [xv] 544x576 = 1024x576 Planar YV12


-------------------------------------------------

You make too much noise, make yourself look ridiculous.
It sort of invalidates the rest of your remarks, as when you are so wrong
about this, how should I pay attention to the other stuff you scream?

[Phil Allison]

"Jan Panteltje"


48KHz is the DAT tape rate.

It is also what is normally used in digital TV.
That means digital recordings from TV use 48KHz.


** Nonsense - DTV is all MP3 encoded.

There is no defined sampling rate.



First it is mp2 encoded, and second most is 48KHz sampled.


** ROTFLMFAO !!

WOT COMPLETE ******** !!!!!!!!!!


MP2 is a ****ing VIDEO format - you MORON !!!!!!!!!!!

Wot a pathetic, ridiculous ASD ****ed, wog IMBECILE !!!


Go DROP ****ING DEAD

- NOW !!!!!!!!!!!!!!!!!!!!!!!!!!!



..... Phil

[Eeyore]

JosephKK wrote: "Jorden Verwer" wrote:

Eeyore wrote:
Jorden Verwer wrote:
Offset is a form of noise, in a sense.

Every one a cracker. Maybe he hasn't heard of DC vs AC analysis ?
Let me put it this way...

Noise-like phenomena, in increasing order of bandwith:
Offset == 1/f noise == white noise

OK alligator, where does shot noise fall in the spectrum?

LOL ! I'd toyed with suggesting that one myself but I'd got tired of his
idiocy.

Graham

[Eeyore]

Don Pearce wrote:

Eeyore wrote:
Phil Allison wrote:
"Eeysore the Lunatic "

** Gobbledegook plus a massive non-sequitur.
Read how it works.
** Insane false logic.

Anyone that can't hear the distortion of QSC USA or MX series must have
severely damaged hearing.
** Shame how the rest of us do not have any of the defective examples
YOU claim YOU came across that lacked forward bias current in the output
devices.
The classic QSC arrangement with grounded collectors has no qiescent
current in the output devices.
** Massive BLATANT LIE !!

You are ridiculous, stupid damn LIAR Stevenson.

You have it 100% incorrect.

But then for a toaster repair man it's not too surprising.

If Kevin or Don Pearce were to re-enter the thread, they'd know EXACTLY what I'm
driving at. Actually, Larkin probably does too but maybe he's just trying to
stir it up ?

Just had a look at a few QSC schematics, and it is apparent that the
output transistors are biased - not quite to zero current, but certainly
a very low current. Certainly a long way below what I would consider a
normal bias level. This is held in position a by a long time constant RC
pair, which I suspect doesn't track LF-induced temperature variations
too well.

How did you establish that ? I don't recall the schematics giving any clues like that
away. The typical quiescent Vbe of the ultimate output devices is in the 0.5V region
from memory.

As you say though, it's certainly not 'conventional' biasing.

Their higher end models have reverted to emitter followers btw. Incidentally you can
do the same trick with these too.

Graham

[Eeyore]

Phil Allison wrote:

"Don Pearce Pommy Liar Extrordaire"

Just had a look at a few QSC schematics, and it is apparent that the
output transistors are biased - not quite to zero current, but certainly a
very low current.

** Wot absolute ****ing drivel.

Only seeing a REAL example of a QSC amp allows one to tell what the bias
current setting is.

AFTER you've erroneously fiddled with the trimpot ?

Graham

[Don Pearce]

Eeyore wrote:

Don Pearce wrote:

Eeyore wrote:
Phil Allison wrote:
"Eeysore the Lunatic "

** Gobbledegook plus a massive non-sequitur.
Read how it works.
** Insane false logic.

Anyone that can't hear the distortion of QSC USA or MX series must have
severely damaged hearing.
** Shame how the rest of us do not have any of the defective examples
YOU claim YOU came across that lacked forward bias current in the output
devices.
The classic QSC arrangement with grounded collectors has no qiescent
current in the output devices.
** Massive BLATANT LIE !!

You are ridiculous, stupid damn LIAR Stevenson.
You have it 100% incorrect.

But then for a toaster repair man it's not too surprising.

If Kevin or Don Pearce were to re-enter the thread, they'd know EXACTLY what I'm
driving at. Actually, Larkin probably does too but maybe he's just trying to
stir it up ?
Just had a look at a few QSC schematics, and it is apparent that the
output transistors are biased - not quite to zero current, but certainly
a very low current. Certainly a long way below what I would consider a
normal bias level. This is held in position a by a long time constant RC
pair, which I suspect doesn't track LF-induced temperature variations
too well.

How did you establish that ? I don't recall the schematics giving any clues like that
away. The typical quiescent Vbe of the ultimate output devices is in the 0.5V region
from memory.

As you say though, it's certainly not 'conventional' biasing.

Their higher end models have reverted to emitter followers btw. Incidentally you can
do the same trick with these too.

Graham


In a conventionally biased amp there is a biasing transistor between the
two op bases which is thermally linked as closely as possible to the
output devices - this (to some extent) tracks the Vbe changes through a
slow bass cycle and maintains the bias point. In the QSC design, the
bias feedback circuit has been deliberately lowpass filtered so it can't
do this. So as the output devices heat up and cool down through a slow
cycle, the bias point will shift significantly.

d

[Eeyore]

Arny Krueger wrote:

Short answer - Graham has no immediate practical experience with measuring
QSC amps, just like I said.

What's 'immediate' got to do with it ? I've measured plenty of QSCs and the
MX1500 I had was shocking. The RMXs are a bit better but still nothing to write
home about. I refined the RMX design for a semi-cloner of the output stage btw
and knocked the THD down significantly with some of my little tricks like
pole-zero compensation and also made the input to the amp 'module' quasi balanced
to reduce 50/100 etc hum pickup..

I've also measured the Powerlights but I don't exactly recall their THD now
mainly because my enduring memory of them is that the short circuit protection
doesn't work if you short out a 'live signal'. Thankfully it was under guarantee.
It probably works if powered up with a short on the output. It's easy to see why.
Their protection method is ****. Read the patent. There's too much stored charged
in those 2 electrolytic caps.

Graham

[Eeyore]

Arny Krueger wrote:

If you had a group of 30 well-chosen, well-trained listeners, then there
would be no such thing as "...30 listeners and 3 were consistently about to
determine A from B and the other 27 couldn't..."

And how exactly do you determine that ?

You just proved that ABX testing ignores those with the most sensitive or highly
trained hearing and is therefore merely a lowest common denominator test.
Suitable say for determining the quality of TV sound.

Graham

[Eeyore]

Arny Krueger wrote:

However I WILL NOT engage in futile discussion about
things *I* know I *can* hear.

All the audiophool golden ears say *exactly* the same thing.

And as I said it was chalk and cheese.

Not stupid liquid nitrogen dipped speaker cables or that kind of garbage.

Graham

[Eeyore]

Arny Krueger wrote:

I have more highly sensitive audio test gear by accident then most people
have on purpose. I probably shouldn't admit this because it shows a certain
kind of carelessness.

Not more sensitive than Audio Precision or Prism Sound.

Graham

[Phil Allison]

"Don Pearce Congenital ASD ****ed LIAR "


Just had a look at a few QSC schematics,


** WRONG ONES - you ****ING IDIOT !!


In a conventionally biased amp there is a biasing transistor between the
two op bases which is thermally linked as closely as possible to the
output devices - this (to some extent) tracks the Vbe changes through a
slow bass cycle and maintains the bias point. In the QSC design,


** WRONG ONES - you ****ING IDIOT !!





...... Phil

[Eeyore]

Jan Panteltje wrote:

"Phil Allison" wrote
"Jan Panteltje"


48KHz is the DAT tape rate.

It is also what is normally used in digital TV.
That means digital recordings from TV use 48KHz.

** Nonsense - DTV is all MP3 encoded.

There is no defined sampling rate.

First it is mp2 encoded, and second most is 48KHz sampled.
Here is an example:

mplayer -ao oss:/dev/dsp1 goldfinger.ts
MPlayer 1.0pre7try2-3.3.6 (C) 2000-2005 MPlayer Team
CPU: Advanced Micro Devices Duron Spitfire (Family: 6, Stepping: 1)
Detected cache-line size is 64 bytes
CPUflags: MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 0 SSE2: 0
Compiled for x86 CPU with extensions: MMX MMX2 3DNow 3DNowEx

Linux RTC init error in ioctl (rtc_irqp_set 1024): Inappropriate ioctl for device
Try adding "echo 1024 /proc/sys/dev/rtc/max-user-freq" to your system startup scripts.
Playing goldfinger.ts.
TS file format detected.
DEMUX OPEN, AUDIO_ID: -1, VIDEO_ID: -1, SUBTITLE_ID: -1,
PROBING UP TO 2000000, PROG: 0
VIDEO MPEG2(pid=2342)AUDIO MPA(pid=2343) NO SUBS (yet)! PROGRAM N. 0
Opened TS demuxer, audio: 50(pid 2343), video: 10000002(pid 2342)...POS=10340
VIDEO: MPEG2 544x576 (aspect 3) 25.000 fps 10000.0 kbps (1250.0 kbyte/s)
================================================== ========================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
AUDIO: 48000 Hz, 2 ch, s16le, 192.0 kbit/12.50% (ratio: 24000-192000)
Selected audio codec: [mp3] afm:mp3lib (mp3lib MPEG layer-2, layer-3)
================================================== ========================
vo: X11 running at 1440x900 with depth 24 and 32 bpp (":0.0" = local display)
================================================== ========================
Opening video decoder: [mpegpes] MPEG 1/2 Video passthrough
VDec: vo config request - 544 x 576 (preferred csp: Mpeg PES)
Could not find matching colorspace - retrying with -vf scale...
Opening video filter: [scale]
The selected video_out device is incompatible with this codec.
VDecoder init failed
Opening video decoder: [libmpeg2] MPEG 1/2 Video decoder libmpeg2-v0.4.0b
Selected video codec: [mpeg12] vfm:libmpeg2 (MPEG-1 or 2 (libmpeg2))
================================================== ========================
Checking audio filter chain for 48000Hz/2ch/s16le - 48000Hz/2ch/s16le...
AF_p 48000Hz/2ch/s16le
AO: [oss] 48000Hz 2ch s16le (2 bps)
Building audio filter chain for 48000Hz/2ch/s16le - 48000Hz/2ch/s16le...
Starting playback...
VDec: vo config request - 544 x 576 (preferred csp: Planar YV12)
VDec: using Planar YV12 as output csp (no 0)
Movie-Aspect is 1.78:1 - prescaling to correct movie aspect.
VO: [xv] 544x576 = 1024x576 Planar YV12

-------------------------------------------------

You make too much noise, make yourself look ridiculous.
It sort of invalidates the rest of your remarks, as when you are so wrong
about this, how should I pay attention to the other stuff you scream?

True. Once he gets into rage mode, it all goes to pot.

In the meantime it seems he's been mis-biasing QSC amplifiers for years.

Graham

[Phil Allison]

"Eeysore Congenital MORON

Arny Krueger wrote:

If you had a group of 30 well-chosen, well-trained listeners, then there
would be no such thing as "...30 listeners and 3 were consistently about
to
determine A from B and the other 27 couldn't..."

And how exactly do you determine that ?

You just proved that ABX testing ignores those with the most sensitive or
highly
trained hearing


** What a total non- sequitur !!

As ****ing usual from the Stevenson autistic LYING Criminal Nut Case.





..... Phil

[Don Pearce]

Phil Allison wrote:
"Don Pearce Congenital ASD ****ed LIAR "


Just had a look at a few QSC schematics,


** WRONG ONES - you ****ING IDIOT !!


In a conventionally biased amp there is a biasing transistor between the
two op bases which is thermally linked as closely as possible to the
output devices - this (to some extent) tracks the Vbe changes through a
slow bass cycle and maintains the bias point. In the QSC design,


** WRONG ONES - you ****ING IDIOT !!





..... Phil



The discussion has moved on. kindly butt out

d

[Phil Allison]

"Eeysore"


= Graham Stevenson = a CRIMINAL LIAR

and a RABID AUTISTIC NUT CASE


The loopy ****ing pommy imbecile is on medication for mental issues

- but not nearly enough.





...... Phil

[Eeyore]

Phil Allison wrote:

"Jan Panteltje"

48KHz is the DAT tape rate.

It is also what is normally used in digital TV.
That means digital recordings from TV use 48KHz.

** Nonsense - DTV is all MP3 encoded.

There is no defined sampling rate.

First it is mp2 encoded, and second most is 48KHz sampled.

** ROTFLMFAO !!

WOT COMPLETE ******** !!!!!!!!!!

MP2 is a ****ing VIDEO format - you MORON !!!!!!!!!!!

http://en.wikipedia.org/wiki/MP2

"MP2 or MP-2 may be:
MPEG-1 Audio Layer II audio codec and .mp2 files" etc etc

http://en.wikipedia.org/wiki/MPEG-1_Audio_Layer_II

"MPEG-1 Audio Layer II (MP2, sometimes incorrectly called Musicam) [1]
is an audio codec defined by ISO/IEC 11172-3. While MP3 is much more
popular for PC and internet applications, MP2 remains a dominant
standard for audio broadcasting.

MP2 began in the late 1980s as part of the ISO's Moving Picture Experts
Group (MPEG) effort to standardize digital audio and video encoding for
digital radio and TV broadcasting (DAB, DMB, DVB), and use on Video
CD.[2] The MPEG-1 standard, including the three audio "layers" (encoding
techniques) now known as MP1, MP2 and MP3, was finalized by the around
the end of 1992. MPEG audio was further promoted due to its Layer III
(MP3) component, which allowed for even lower bitrates."

You're confusing it with MPEG-2 which also delivers audio in addition to
video.

So Phyllis, you're simply WRONG WRONG WRONG !

Graham

[Eeyore]

Phil Allison wrote:

"Eeysore the Lunatic "

Anyone that can't hear the distortion of QSC USA or MX series must
have severely damaged hearing.

** Shame how the rest of us do not have any of the defective examples
YOU claim YOU came across that lacked forward bias current in the
output devices.

The classic QSC arrangement with grounded collectors has no qiescent
current in the output devices.

** Massive BLATANT LIE !!

You are ridiculous, stupid damn LIAR Stevenson.

You have it 100% incorrect.


** Five QSC MX series amps I have here RIGHT NOW prove you WRONG.

All have about 20 mA per output BJT at idle - more when hot.

I suppose you set them that way.

** That is they are - from the factory.

YOU are NOT in any position to know how QSC set the bias current.

YOU have no proof WHATEVER of your MAD & WRONG assertion.

Stevenson is completely INSANE with:

1. Congenital autism.

2. Massive narcissism.

3. Manic personality disorder.

He tells massive lies, thousands of them.

It's possible the MXs do have some quiescent I don't think I measured that
back then. But the RMXs certainly don't.

Graham

[Eeyore]

Phil Allison wrote:

"Eeysore the Lunatic "

The classic QSC arrangement with grounded collectors has no qiescent
current in the output devices.

** Massive BLATANT LIE !!

FACT.

** But it is not fact.

And you have no proof.

Cos it is simply not true.

It can improve the THD performance though which is probably why they did it
in the RMXs.

Graham

[Phil Allison]

"Eeysore"

Phil Allison wrote:

"Jan Panteltje"

48KHz is the DAT tape rate.

It is also what is normally used in digital TV.
That means digital recordings from TV use 48KHz.

** Nonsense - DTV is all MP3 encoded.

There is no defined sampling rate.

First it is mp2 encoded, and second most is 48KHz sampled.

** ROTFLMFAO !!

WOT COMPLETE ******** !!!!!!!!!!

MP2 is a ****ing VIDEO format - you MORON !!!!!!!!!!!


You're confusing it with MPEG-2 which also delivers audio in addition to
video.


** The audio is funking MP3 "perceptually compressed " ****e.

So no defined bit rate exists.

YOU ****ING STUPID ASS.





.......... Phil

[Phil Allison]

"Eeysore the Lunatic "

The classic QSC arrangement with grounded collectors has no qiescent
current in the output devices.

** Massive BLATANT LIE !!

You are ridiculous, stupid damn LIAR Stevenson.

You have it 100% incorrect.


** Five QSC MX series amps I have here RIGHT NOW prove you WRONG.

All have about 20 mA per output BJT at idle - more when hot.

I suppose you set them that way.


** That is they are - from the factory.

YOU are NOT in any position to know how QSC set the bias current.

YOU have no proof WHATEVER of your MAD & WRONG assertion.

Stevenson is completely INSANE with:

1. Congenital autism.

2. Massive narcissism.

3. Manic personality disorder.

He tells massive lies, thousands of them.



It's possible the MXs do have some quiescent


** He tells massive lies, thousands of them.

Stevenson is completely INSANE with:

1. Congenital autism.

2. Massive narcissism.

3. Manic personality disorder.

A TOTAL LIAR !!!!!!!!!!!!!!!!!!






...... Phil

[Eeyore]

Don Pearce wrote:

Eeyore wrote:
Don Pearce wrote:
Eeyore wrote:
Phil Allison wrote:
"Eeysore the Lunatic "

** Gobbledegook plus a massive non-sequitur.
Read how it works.
** Insane false logic.

Anyone that can't hear the distortion of QSC USA or MX series must have
severely damaged hearing.
** Shame how the rest of us do not have any of the defective examples
YOU claim YOU came across that lacked forward bias current in the output
devices.
The classic QSC arrangement with grounded collectors has no qiescent
current in the output devices.
** Massive BLATANT LIE !!

You are ridiculous, stupid damn LIAR Stevenson.
You have it 100% incorrect.

But then for a toaster repair man it's not too surprising.

If Kevin or Don Pearce were to re-enter the thread, they'd know EXACTLY what I'm
driving at. Actually, Larkin probably does too but maybe he's just trying to
stir it up ?
Just had a look at a few QSC schematics, and it is apparent that the
output transistors are biased - not quite to zero current, but certainly
a very low current. Certainly a long way below what I would consider a
normal bias level. This is held in position a by a long time constant RC
pair, which I suspect doesn't track LF-induced temperature variations
too well.

How did you establish that ? I don't recall the schematics giving any clues like that
away. The typical quiescent Vbe of the ultimate output devices is in the 0.5V region
from memory.

As you say though, it's certainly not 'conventional' biasing.

Their higher end models have reverted to emitter followers btw. Incidentally you can
do the same trick with these too.


In a conventionally biased amp there is a biasing transistor between the
two op bases

Actually in the voltage drive chain driving the bases and configured as a multiplier to
suit as many devices as may be on the heatsink (the drivers may be too - or the output
devices may be darlingtons).

which is thermally linked as closely as possible to the
output devices - this (to some extent) tracks the Vbe changes through a
slow bass cycle and maintains the bias point. In the QSC design, the
bias feedback circuit has been deliberately lowpass filtered so it can't
do this. So as the output devices heat up and cool down through a slow
cycle, the bias point will shift significantly.

They've messed about with it over the years. Check the RMX series which are still in
current production.

What really ****es me off are those companies including QSC who use a 1N4001 pressed up
against the heatsink with a dob of thermapath to do the sensing.. It's so amateurish.

Graham