Help needed for research project on Class A vs. Class AB

[blacklight_uk]

Hi guys,

As part of my studies for university I'm conducting a research project on the sonic and measurable differences between Class A and Class AB output classes and single ended vs. push-pull output configurations in valve guitar amplifiers.

I was wondering if any of you could spare five minutes of your time to fill out a brief survey? It's not a technical survey, more a general questionnaire. I will be posting a second survey at a later date including audio examples for direct comparison, but for now I'm just looking for general opinions. You don't need to sign up for anything and the survey is anonymous.

http://kwiksurveys.com?u=joshmcardle" onclick="window.open(this.href);return false;

Additionally if anybody knows of any really good sources of information on the topic I'd be very grateful for your suggestions. Many of the papers I've read have addressed the differences in valve and solid state amplifiers or focused purely on transistor based designs.

Many thanks for your time,
Josh

[Randy Bass]

http://www.aikenamps.com/ClassA.htm

[blacklight_uk]

Thanks Randy Bass. That's a great article.

[blacklight_uk]

EDIT: I updated the survey to clarify that it's Class A single ended and Class AB push-pull output stages I'm looking for your thoughts on. Also added "Semi-professional Musician" to the list of options for "what best describes what you do".

Thanks to those of you who have contributed so far. I really do appreciate you taking the time to do this.

[a.hun]

More Aiken for you:
http://aga.rru.com/FAQs/general.html" onclick="window.open(this.href);return false;
http://aga.rru.com/FAQs/technical.html" onclick="window.open(this.href);return false;

Others:
http://www.duncanamps.com/technical/ampclasses.html" onclick="window.open(this.href);return false;

http://web.archive.org/web/200410310751 ... works.html" onclick="window.open(this.href);return false;
(That is from the great old sadly defunct Svetlana valves site via web.archive. Hope the link works for you!)

viewtopic.php?f=2&t=38650&start=15" onclick="window.open(this.href);return false;
My own little contribution...

Good luck with it all. Technically speaking the whole 'class A' thing is a minefield of opinion and (mis) information.


Andy.

[bassdrop]

Do everything you can to avoid Randall Smith's Class A article: long winded and not helpful in distinguishing the frequent cross-marketing of Class A and cathode biasing.

[blacklight_uk]

Do everything you can to avoid Randall Smith's Class A article: long winded and not helpful in distinguishing the frequent cross-marketing of Class A and cathode biasing.

Yes that was actually the first article I read! Although I found it quite useful in explaining the basics I felt it turned into an advert for the Lone Star Special at times...It did leave me a little confused about the whole Class A/cathode-biased AB thing too. The Aiken stuff is a great resource. Reading those articles has sent me off on various research missions to learn more about different parts of the circuits and forced me to revise the basics too. Feeling like I am learning a lot at the moment.

[blacklight_uk]

More Aiken for you:
http://aga.rru.com/FAQs/general.html" onclick="window.open(this.href);return false;
http://aga.rru.com/FAQs/technical.html" onclick="window.open(this.href);return false;

Others:
http://www.duncanamps.com/technical/ampclasses.html" onclick="window.open(this.href);return false;

http://web.archive.org/web/200410310751 ... works.html" onclick="window.open(this.href);return false;
(That is from the great old sadly defunct Svetlana valves site via web.archive. Hope the link works for you!)

viewtopic.php?f=2&t=38650&start=15" onclick="window.open(this.href);return false;
My own little contribution...

Good luck with it all. Technically speaking the whole 'class A' thing is a minefield of opinion and (mis) information.


Andy.

Andy, thanks very much! I'll check out those links when I get home and report back

[a.hun]

Do everything you can to avoid Randall Smith's Class A article: long winded and not helpful in distinguishing the frequent cross-marketing of Class A and cathode biasing.

Well the thing that always got me about that article is the way he (correctly) states...

What Class A really means is that: “Grid bias and alternating
grid voltages are such that plate current in
a tube flows at all times”.

...and then goes on to immediately forget about the 'at all times' bit!

Credit where credit is due though, he is a great amp designer and innovator. (Even if like many here you don't happen to like his amps! )


Andy.