MOSFET output stage

[Eeyore]

You engineer live sound in a music bar night after night?

No. And when I did engineer regularly it was probably only 2-3 times a well
and I was very careful not to expose myself to excessive sound levels.
Besides, for a couple of hours, and certainly not every day, it's almost
irrelevant.

After the period when I had been mixing live a lot, I happened to have an ear
problem. I was tested in an acoustic booth and my hearing was as the nurse
said "the best I've ever seen". The results were bang on the 0 phon line.

Speaks to your prejudice against the military Graham, and also your
inability to understand what I have reported again and again:

No prejudice whatever. My mother's side of the family contained many RAF
officers, My Grandfather being a Wing Commander and my best girlfriend ever's
father who was a superb guy was an ex RN Lieutenant Commander BUT the military
are reknowned for big *impulsive* bangs that are they most damaging type to
hearing.

Impulsive noise is vastly more damaging that continuous noise like music.
Hence all the sound level recommendations that were based on steel mills with
their anvils and the like are utterly irrelevent to music (except for the
drummer who typically goes deaf first if anyone is going to because it's
impulsive noise from the kit).

Graham

 

[Eeyore]

"Eeyore" wrote

(2) Test equipment doesn't lie - if it finds negligible low-level
distortion, no matter how bad the ops hearing is, the distortion isn't
there.

Too damn right it doesn't. It sees x'over distortion with a clarity clearly
unmatched by your hearing.

Have you noticed QSC have now abandoned the grounded collector arrangement in
newer and high-end models.

If it was so good why would they do that ?

In your case Graham it is all about prejudice and hysteria. Of course you
think QSC amps suck - they are a highly competitive product.

One of our OEMs offered us a QSC 'clone'. I managed to make it work better !
As in lower THD AND noise by a simple pcb re-layout and front-end tweak.

Don't forget I've met the guy who really designed the RMXs, Tim Lau. We
exchanged some very interesting ideas on amp design whilst I was in China
visiting them..

Graham

 

[Eeyore]

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

No-one cares.

Try listening in on VHF ATC messages to aircraft. It's a bloody disgrace. No
wonder they have accidents.

Graham

 

[Eeyore]

This is for the presence effect; otherwise you will think of ISS or
Shuttle as if it is something routine.

That happened fast enough to the Apollo missions too !

Graham

 

[Eeyore]

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.

God only knows.

If I can find a cute new way of putting an extra zero behind the decimal point
in a THD figure why should I lambasted for it ?

And as for hearing the difference between amps of 0.1% specified THD rating
and 0.01%, I discoverd about 30 years ago that it was like chalk and cheese.

Once you get to 0.00003% like some of Nat Semi's op-amps the argument is
hypothetical anyway. The ear would be incapable of resolving such a low figure
so why not use them anyway ? What harm could they do ?

Arny seems to be almost as bad as the tube afficionados who LIKE lots of
distortion.

Graham

 

[Phil Allison]

"Eeysore the Lunatic "

Read how it works.

** Insane false logic.

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.




....... Phil

 

[Eeyore]

"Eeysore the Lunatic "


** Insane false logic.


** 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

 

[Eeyore]

"Eeysore the Lunatic "


** Insane false logic.


** Massive BLATANT LIE !!

You are ridiculous, stupid damn LIAR Stevenson.

And you know nothing about amplifier design.

Graham

 

[Phil Allison]

"Eeysore the Lunatic "

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.




...... 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.




....... Phil

 

[Eeyore]

"Eeysore the Lunatic "

** 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.

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

Well lucky you. You simply don't understand electronic design and never will.

How many tens or hundreds of thousands of products of YOUR design have you sold
?

Graham

 

[Eeyore]

"Eeysore the Lunatic "


** Massive BLATANT LIE !!

FACT. Straight out of the factory.

Mind you, their Q/C might be sloppy enough to have misled you.

Graham

 

[Eeyore]

"Eeysore the Lunatic "

** 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

 

[Eeyore]

"Eeysore the Lunatic "

** Massive BLATANT LIE !!

You are ridiculous, stupid damn LIAR Stevenson.

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

Graham

 

[Eeyore]

How many tens or hundreds of thousands of products of YOUR design have you sold ?

Many hundreds of thousands and I still get congratulatory emails as to how their 23
your old unit is still working fine.

The only trouble is, the paint tend to wear off.

Graham

 

[Phil Allison]

"Eeysore the Lunatic "

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 "

BORING

** What a completely insane reply.




....... Phil

 

[Phil Allison]

"Eeysore the Lunatic "

FACT.

** But it is not fact.

And you have no proof.

Cos it is simply not true.




....... Phil

 

[MooseFET]

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.

 

[Phil Allison]

"Eeysore the Lunatic "

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