lateral mosfets vs. bjts in audio amplifier design

[Eeyore]

Well, neither. I was suggesting a fast opamp

They would have to be fast for sure with decent DC and AC precision.

*per fet*, with feedback
from the source, to make each fet look like an ideal transconductance
device, perfectly linear, no offset or threshold, all exactly matched,
with very low input capacitance.

But how does improving and parallelizing gate drives cost speed? It
makes my amps faster and a lot more stable. Your amp (the one you
never built) has a couple of wimpy current sources driving 10 fets in
parallel;

Does it ? Hadn't looked closely enough.

I'm suggesting a beefy voltage source per fet gate,

That's what I do too

with local feedback.

Only overall in my case to linearise the output section. All previous gain stages
have local feedback within the overall loop though.

Graham

 

[Eeyore]

Well, neither. I was suggesting a fast opamp *per fet*, with feedback
from the source, to make each fet look like an ideal transconductance
device, perfectly linear, no offset or threshold, all exactly matched,
with very low input capacitance.

But how does improving and parallelizing gate drives cost speed? It
makes my amps faster and a lot more stable. Your amp (the one you
never built) has a couple of wimpy current sources driving 10 fets in
parallel; I'm suggesting a beefy voltage source per fet gate, with
local feedback.

Well, despite the occasional frayed temper and bruised ego, we've certainly got
one humdinger of a design discussion going here !

Graham

 

[Eeyore]

If you really had that much involvement in projects as you speak of,
I'll wager the majority of them are off of some one else's back.!

You're as much of a cnut as I always thought.

Here's an example of the above btw.
http://cgi.ebay.co.uk/Studiomaster-...ryZ23785QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

It was available with various numbers of channels (the above is the largest) and a DSP
reverb option.

Totally my own design thank you, although obviously I had guys working on stuff like pcb
layout and metalwork for me as part of a 3 man team.

Graham

 

[Jamie]

Jamie wrote:




As ever you're quite clueless.

What do you a PCB / chassis mount professional audio XLR 3 pin gold-plated
connector should cost for example ?

Or an NE5532 ?


Graham

Something beyond you..

Cat whisker diodes.

http://webpages.charter.net/jamie_5"

 

[Eeyore]

As ever you're quite clueless.

What do you [think] a PCB / chassis mount professional audio XLR 3 pin gold-plated
connector should cost for example ?

Or an NE5532 ?

Something beyond you..

Cat whisker diodes.

I see you can't even begin to answer the question.

Graham

 

[Eeyore]

Being it's audio, there shouldn't be any legality issues since that
field has no secrets, you twit!

Clueless arse.

Graham

 

[Jamie]

:




I am a true audio expert Michael, John Fields is not. Each to their own.

Graham

Please direct me to a product that you designed your
self!................................
Being it's audio, there shouldn't be any legality issues since that
field has no secrets, you twit!


http://webpages.charter.net/jamie_5"

 

[Eeyore]

Being it's audio, there shouldn't be any legality issues since that
field has no secrets, you twit!

My DSP reverb code is definitely secret. Just to take one tiny example.

Graham

 

[john jardine]

Well, neither. I was suggesting a fast opamp *per fet*, with feedback
from the source, to make each fet look like an ideal transconductance
device, perfectly linear, no offset or threshold, all exactly matched,
with very low input capacitance.

But how does improving and parallelizing gate drives cost speed? It
makes my amps faster and a lot more stable. Your amp (the one you
never built) has a couple of wimpy current sources driving 10 fets in
parallel; I'm suggesting a beefy voltage source per fet gate, with
local feedback.

John

Servo arrangement summat like this?.
http://img518.imageshack.us/my.php?image=eloadte9.png
[An 'electronic load' project (scrapped). Occasionally blew opamps
consequent to particular dynamics on the Red wire. Traced to Drain/gate
feedback transients coupled with slightly dissimilar current source slew
rates.]

 

[Jamie]

Jamie wrote:




You're as much of a cnut as I always thought.

Here's an example of the above btw.
http://cgi.ebay.co.uk/Studiomaster-...ryZ23785QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

It was available with various numbers of channels (the above is the largest) and a DSP
reverb option.

Totally my own design thank you, although obviously I had guys working on stuff like pcb
layout and metalwork for me as part of a 3 man team.

Gramm

Oh please! A mixer, Ouuuhhh...

I made mixers, pre amps and power amps years ago. I was most likely
one of the first in my area to have a 400 W RMS per channel stereo
amplifier for mobile use. It may have not been the most power efficient
amplifier but it generate quality sound equal to any high end, line
service unit.. I then made a commercial power supply option unit to
operate it on 120 V mains, by passing the inverter when needed. I would
used it for a few disc jockey gigs now and then..

THis was 30 years ago now using old technology. AT least that is what
you call it.

You have nothing special to offer that enlightens me.

http://webpages.charter.net/jamie_5"

 

[Eeyore]

Well, neither. I was suggesting a fast opamp *per fet*, with feedback
from the source, to make each fet look like an ideal transconductance
device, perfectly linear, no offset or threshold, all exactly matched,
with very low input capacitance.

But how does improving and parallelizing gate drives cost speed? It
makes my amps faster and a lot more stable. Your amp (the one you
never built) has a couple of wimpy current sources driving 10 fets in
parallel; I'm suggesting a beefy voltage source per fet gate, with
local feedback.

Servo arrangement summat like this?.
http://img518.imageshack.us/my.php?image=eloadte9.png
[An 'electronic load' project (scrapped). Occasionally blew opamps
consequent to particular dynamics on the Red wire. Traced to Drain/gate
feedback transients coupled with slightly dissimilar current source slew
rates.]

Surely would have been fixable with a reverse biased diode from op-amp o/p to V+
and another one from the - i/p to ground, but you'd have needed a small series
R.

Graham

 

[Eeyore]

---
And yet you didn't know that the sum of output currents from active IOs
can't exceed the stated maximum current into Vcc or out of GND of logic
chips?

Curious, that...

SOD OFF. God, you're a pest. Of course it wouldn't get past me on a design review.

Graham

 

[Jamie]

Jamie wrote:

As ever you're quite clueless.

What do you [think] a PCB / chassis mount professional audio XLR 3 pin
gold-plated

connector should cost for example ?

Or an NE5532 ?

Something beyond you..

Cat whisker diodes.

I see you can't even begin to answer the question.

Graham

Answer what question?

Why would I care about toys.. Because that is all that crap is
that you're referring to.

Let me give you some advise like you did to one other, we are
not longer in the dark ages. The world has moved on, why have you
not?

And to answer your idiotic question, I don't buy those things, my
employer does that for me at my request. I don't care what they cost.

And as the younger generation would put it, asking a retarded question
like that only shows your ignorance.

If that is the kind of ammo you used for interrogation, you've lost
the battle before it even started...



I thought for you Graham.

"SOME PEOPLE ARE LIKE SLINKIES. NOT REALLY GOOD FOR ANYTHING BUT
THEY BRING A SMILE TO YOUR FACE WHEN PUSHED DOWN THE STAIRS.
http://webpages.charter.net/jamie_5"

 

[Eeyore]

Oh please! A mixer, Ouuuhhh...

WTF did you expect for audio ? A mouse trap.

Prefer an amplifier ? 1200W. We made tons of these too.
http://cgi.ebay.co.uk/StudioMaster-...ryZ69962QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
There was a 700W and 1600W version too in the same form factor.

I made mixers, pre amps and power amps years ago.

But not 100,000 of them.

I was most likely one of the first in my area to have a 400 W RMS per channel stereo
amplifier for mobile use.

Oh lucky you !

I was running a 1 - 2 kW PA rig back then using horn loaded cabs of monitor standard (Electrovoice Sentry IVs) and it used my own quite serious mixer I designed and
built with help from friends in 1971. That's *37* years ago. All discrete btw with class A complementary output stages capable of driving low-Z loads.

You WILL NOT beat my audio experience or expertise.

Graham

 

[Jamie]

Jamie wrote:




My DSP reverb code is definitely secret. Just to take one tiny example.

Graham

Cough, Cough.................................

Jesus Christ...

Who the hell would want your reverb code.

Do you honestly believe people out there can not do their
own DSP coding?

What planet are you from any ways....

I hate to spoil your parade but, DSP use for doing reverbs
isn't rocket science.

Please don't flatter your self, because it's only you that's
gawking.

You're so full of your self it's pitiful.


http://webpages.charter.net/jamie_5"

 

[Jamie]

Jamie wrote:




WTF did you expect for audio ? A mouse trap.

Prefer an amplifier ? 1200W. We made tons of these too.
http://cgi.ebay.co.uk/StudioMaster-...ryZ69962QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
There was a 700W and 1600W version too in the same form factor.





But not 100,000 of them.





Oh lucky you !

I was running a 1 - 2 kW PA rig back then using horn loaded cabs of monitor standard (Electrovoice Sentry IVs) and it used my own quite serious mixer I designed and
built with help from friends in 1971. That's *37* years ago. All discrete btw with class A complementary output stages capable of driving low-Z loads.

You WILL NOT beat my audio experience or expertise.

Graham

Frankly speaking, I don't think I would waste the time to exceed you
since it wouldn't yield me any results that helps me or man kind.!

But if it makes you feel any better, keep up the good work and while
your at it, put a hand crank horn in your next design. It most likely
goes well with your current designs.


http://webpages.charter.net/jamie_5"

 

[Eeyore]

A plain lie.


Hardly selfish since I've agonised over it.

Denying them access to the truth means that you're setting yourself up
as a judge of who should and should not have access to the truth because
of what your predictions dictate will happen when the truth is revealed.

Would you want me to damage a marriage ?

You're behaving like a child Fields.

Graham

 

[Eeyore]

Cough, Cough.................................

And how much DSP reverb code have you written ?
http://www.studiomaster.com/products/162bpx.htm
http://www.studiomaster.com/products/C3&C3X.htm
http://www.studiomaster.com/products/VMS.htm
http://www.studiomaster.com/reviews/c3x-0205a.pdf
http://www.studiomaster.com/reviews/c3x-0205b.pdf
http://www.studiomaster.com/reviews/c3x-0505.pdf

Jesus Christ...

Who the hell would want your reverb code.

The MD of the company I used to consult for who's now desperate to have me
back. However I've also pretty much committed to another project last Monday.

Graham

 

[Eeyore]

Yes, one controls the system, the crunching is done is smaller
processors, not the CENTRAL processor. Those subsystems are worthless
without something to load the code on bootup, and to send commands.

Therefore what you initially wrote "Digitize every input, do everything in the CPU"
is total garbage. I've been familiar with DSP mixers for 20 YEARS FFS.

The phrase you're looking for is DSP processors.

Graham

 

[Eeyore]

You miss the point, as usual. The whole concept is crap, and people
who bought them have been returning them as soon as they realize what a
crappy concept it is. You can't have a station down, even overnight to
do an emergency exchange on unrepairable equipment. If you think the
concept is ancient, it doesn't matter, because its still shit. So much
for you being so great at audio design. There is no reason to use a
digital abortion like that, when analog is simpler, sufficient, and can
be field serviced. Any broadcast engineer worth his pay would run from
crap like that.

AMS-Neve don't seem to have that problem. Read the client list.

Graham