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-   -   book-audio power amplifier by Douglas Self (http://www.diyaudio.com/forums/solid-state/22765-book-audio-power-amplifier-douglas-self.html)

mikee12345 15th November 2003 11:29 AM

book-audio power amplifier by Douglas Self
 
Good book!
very in depth! slightly over my head in parts,im gona get it out again after my eletrotech exams so i can read properly

:D

topics

the 'fear' of -ve feedback (hehe)
small input stages
output stage 1,2
compensation,slew rate and stability
power supplies and PSRR
class A
FET output stages
Thermal compensation and thermal dynamics
Protection
Grounding and practical matters


i like the 8 distortions part of the book,very good.action packed goodness!

he has distortion down to 0.005%and finds out that a certain technique lowers it by four fold by complicating the circuit by about 4x, but the distortions get very low from what he does.

He goes through each topology ,input /output stage type and its features- its good! i havent seen a book like it here in NZ

Cheers!
have u read? what do u think?!!!

ashok 15th November 2003 02:45 PM

Great book.
 
I think this is a great book. It does examine the distortions as you said. It's not all maths and lots of it has measured results.

The only catch is that while one can keep trying to get distortions down , will it reallly show up well in listening tests ? The no feedback tube amps sound very good with large doses of distortion. Probably there should be a chapter devoted to the audible implications of distortions with some mention of some great amps and their audible performance and their electrical specifications.

I have this book and it needs to be read many times .
Cheers.

SY 15th November 2003 03:34 PM

Self's stuff is very good indeed. It's not comprehensive, but in context, enormously useful.

I'm unconvinced that reducing distortion from, say, 0.1% to 0.001% makes much difference to the ear, but it's an interesting exercise to see how it's done. The biggest missing x-factor in Self's work is the thing that I've found actually makes real audible differences between otherwise-well-designed amps: overload recovery and clipping behavior. The comprehensive book on that for solid state circuits has yet, to my knowledge, been written. (Crowhurst repeatedly pounded that drum for tube circuits, and he was absolutely right)

mrfeedback 15th November 2003 03:59 PM

Quote:

Originally posted by SY
I'm unconvinced that reducing distortion from, say, 0.1% to 0.001% makes much difference to the ear, but it's an interesting exercise to see how it's done. The biggest missing x-factor in Self's work is the thing that I've found actually makes real audible differences between otherwise-well-designed amps: overload recovery and clipping behavior.
Yes, I agree that vanishingly low (sinewave) distortion is not mandatory.
Sonically acceptable overload behaviour however is mission critical to good sonics.
Many amplifiers suffer 'stiction' when recovering from momentary overload, and this is both ear and speaker damaging.
Clean and benign overload behaviour is a lot of what differentiates a good sounding amplifier from a 'bad' one.
Soar protection circuitry can also be a culprit here.

Eric.

Richard C 15th November 2003 06:16 PM

An essential book, but narrow in its scope. I get the impression that Self considers anyone who judges an amplifier by sound quality to be completely mad.

It's possible to design very low distortion conventional class-B power amplifiers... so what?:confused:

JensRasmussen 15th November 2003 07:30 PM

Books
 
I found the book (second edition) very interesting. I like the way itís based on experiments combined with reason. Iím looking forward to reading the latest third edition.

However, I donít understand why Douglas Self completely avoids the topic about symmetric amplifiers.

This topic is covered to some detail in Randy Slones book on power amplifiers, but I would like some more theory and detail in this book.

Also, I need a book (maybe just a chapter in one of the mentioned books) on how different sounding amplifiers can measure more or less the same. Iíd also like to read more about no feedback amps.

\Jens

mrfeedback 15th November 2003 11:59 PM

The first difference would be that most published distortion figures are into a resistive load, and most amplifiers change when driving a reactive load.

Perhaps a measurement standard should be devised for measuring distortion when driven into a specified amount of overload - this may be revealling of overload behaviour in spec sheets.

Eric.

MikeW 16th November 2003 12:23 AM

Built?
 
Good book. I would have liked to see more amps built. I don't see alot of feedback from people that built these designs.

mikee12345 16th November 2003 01:16 AM

id prefer to simply buy a chip than make a blameless amp as designed in his book

:-P

life is short! ( il compromise on amps for awhile)
ive got stuff to do!

like 2 basshorns that i have plans for to build before christmas lol

:smash: :rolleyes:


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