Re: lateral mosfets vs. bjts in audio amplifier design

[Eeyore]

Personally, I think any 'reverb' sucks.

Your personal opinion in this matter is irrelevant.

Graham

 

[Eeyore]

Only if he's buying such a piece of kit. The market generally likes reverb
to be available along with graphic equalisers (which I'm less keen on
since of its ability to **** the sound up wonderfully when abused) for
instance.

That doesn't mean I never design a graphic equaliser. In this case MY
opinion is irrelevant.

Purist higher end desks never have either installed since the user can
select his/her preference of reverb/equaliser form many brands and models
of rack mounting 'outboard' kit.

Graham

 

[[email protected]]

john jardine wrote: [...]

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

Yes. Fitted. The diodes only helped. Fast 30~40V, (external) incoming
edges through the Cgd's caused lock-up of one section, quickly
noticed by the others, nett result a few uS of chaotic transient
oscillations (and Cgd pumping) as they all settled into step. A few nH
of series strays didn't help either. A LF 'dominant pole' fixed the
problem but the setup was numb out beyond a few kc hence useless as a
'load'. Did the job at the time but would rethink next time round.

 

[Eeyore]

john jardine wrote: [...]

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.

Yes. Fitted. The diodes only helped. Fast 30~40V, (external) incoming
edges through the Cgd's caused lock-up of one section, quickly
noticed by the others, nett result a few uS of chaotic transient
oscillations (and Cgd pumping) as they all settled into step. A few nH
of series strays didn't help either. A LF 'dominant pole' fixed the
problem but the setup was numb out beyond a few kc hence useless as a
'load'. Did the job at the time but would rethink next time round.

Was this even with schottkies ?

Graham

 

[Eeyore]

There are no 'good ones'. The whole concept stinks.

Sorry Michael, but you've clearly never been a sound mixing engineer. I have (lots) as
well as tech, equipment designer, project leader, installer, coder for the software, you
name it.

Just a ROOM has natural reverb. Then think Cathedrals. Reverb is everwhere. Acoustic
singers often rely on it.

Graham

 

[Eeyore]

Your personal opinion in this matter is irrelevant, like in most
things you post. Reveb sucks. Period. It was done to death, along
with Echo effects and other novelty garbage 40+ years ago. Its just
another annoying form of distortion.

The whole audio industry disagrees with you. I doubt you've even heard a
good modern reverb or ADT. It's not springs any more you know.

Graham

 

[Eeyore]

There are no 'good ones'. The whole concept stinks.

You speak largely from a position of ignorance. Many early reverb effects were cruddy
and that's being kind to them.

It's a shame you're the other side of the pond or I could get you into some good studios
or live venues and you could see/hear for yourself.

Graham

 

[Eeyore]

Well good, does that mean we'll see a lot less of your vile here?

One of the few truly vile people round here is you.

Did you even bother following the links ?

Graham

 

[Eeyore]

I'm glad you have graduated out of the spring technology..

What is it now? 8 Track Endless loops?

Don't be stupid.

How much DSP code have YOU written ? I can tell you, when I took it on I
though it would be a challenge. Not writing the code per se, that's easy
enough but making it sound so right that reviewers glow over it.

Graham

 

[Jamie]

Jamie wrote:




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





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

Well good, does that mean we'll see a lot less of your vile here?


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

 

[Eeyore]

What is it now? 8 Track Endless loops?

With enough RAM, who needs tape ?

Graham

 

[Jamie]

:




The whole audio industry disagrees with you. I doubt you've even heard a
good modern reverb or ADT. It's not springs any more you know.

Graham

I'm glad you have graduated out of the spring technology..

What is it now? 8 Track Endless loops?


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

 

[john jardine]

[...]

Was this even with schottkies ?

Graham

Never progressed beyond Silicon diodes.
Opamps have CMOS output stages. Couldn't see a schottky threshold helping.
Problem looks simple enough to sort (trivial even!) but have picked up a
sixth sense over the years about the time and effort involved on 'working in
the margins', so am not averse to calling a halt.(Unless of course a
customer is paying for the investigation

 

[Jamie]

Jamie wrote:




Don't be stupid.

How much DSP code have YOU written ? I can tell you, when I took it on I
though it would be a challenge. Not writing the code per se, that's easy
enough but making it sound so right that reviewers glow over it.

Graham

LOL, I can tell you that you have a hard time reading between the lines.

I did a project years!!!!!!!!!! ago using a ISA bus card in a 486
computer that sampled up to 500K, this was used for harmonic spectrum
analyses reports using DFT/IDFT which later on was translated into
a FFT with coefficient tables. the PC was 100% dedicated to this
application under a DOS os with the time consuming code written in
ASM to help things along and the rest of it in C using custom graphic
code, also written by me..

The code had to isolate signals, remove unwanted signals etc..

Oh btw, I also wrote some 8 Bit FFT code in a uc controller for other
lesser important usage's for things like transferring video images over
low band radio via audio spectrum.. Then adopted that to a windows sound
card which really has it's fall backs with hardware quality and OS issues.

Your reverb code does interrest me just like my said above project
does not interest you and most likely every one else that is reading this.

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

 

[Eeyore]

LOL, I can tell you that you have a hard time reading between the lines.

You can tell me you can PISS OFF.

Anything else will from now on be regarded as legal harrassment.

Graham

 

[Eeyore]

I did a project years!!!!!!!!!! ago using a ISA bus card in a 486
computer that sampled up to 500K, this was used for harmonic spectrum
analyses reports using DFT/IDFT which later on was translated into
a FFT with coefficient tables.

And the connection with audio reverb is ?

Graham

 

[Eeyore]

Oh btw, I also wrote some 8 Bit FFT code in a uc controller

Really ?

Mine was 32 bit code. Work out how to do that eh ?

Graham

 

[Eeyore]

The audio industry is run by empty suits these days.

I understand where you're coming from better than you might imagine, but
thankfully no 'suit' knows how to mix.

I loathe the 'suits' too.

Rarely is anything produced that is fit to listen to.

There's a lot of that going on for sure. I prefer LIVE music myself
(including reverb and compression) and I might be mixing it myself..

I have, and I didn't like it.

I'm surprised. I doubt you've heard mine.

It's not springs any more you know.

Up yours.

Childish comment.

Graham

 

[Jamie]

Jamie wrote:




You can tell me you can PISS OFF.

Anything else will from now on be regarded as legal harrassment.

Graham

You wimp..

The Monarchy does not extend to me you tea gobbling twit.

If you have no back bone for it, why temp those that do?



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

 

[Jamie]

Jamie wrote:




Really ?

Mine was 32 bit code. Work out how to do that eh ?

Graham

Shit....
Any one that can't do higher precision in Uc's other than
what is supplied natively, does not belong coding in uc's

you're hitting bottom!..

and for you info, that was a 8 bit Uc but the FFT was 16 bit,.
more than enough.


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