Champ "class A" ?

ccuwan · March 15th, 2004, 08:47 AM

I've heard a number of people refer to the Champ as a class A amplifier. Is this unusual or do most tube amps of that era run a class a circuit.

zook · March 15th, 2004, 10:03 AM

A class A amp is one in which the output tubes are always driving. A single ended tube amp like a Champ can only be Class A since it only has one output tube. A push-pull class A amp will have both tubes pushing constantly, as opposed to a class AB where one tube pushes while the other rests. Picture rowing a boat. Two oars up and out of the water together, then pulling both at the same time, class A. Alternate oars, Class AB.

Most Push pull amps are class AB. They are more efficient and kinder on the tubes. Most of what you hear referriing to "Class A" is hype.

Read Randall Aiken's treatise on Class A at:

www.aikenamps.com

That will give you all the technical details.

Winnie

MJ Harnish · March 15th, 2004, 11:09 AM

I'd agree: Virtually every amp out advertised today is not actually class A; manufacturers seem to mislead people and label anything that's cathode biased as "Class A." The Vox AC30 is probably the most famous non "Class A" amp that everyone refers to as Class A.

It's gotten so ridiculous that the deceptive labelling has now spilled over into FX pedals.

Paul G. · March 15th, 2004, 02:54 PM

But then I thought about it.

The amps purported to be operating in Class A are Vox, Dr Z., Matchless, etc., and they are loud.

What they have in common is large transformers, large stiff speaker cabs, and high-quality (efficient) speakers.

So now we know that Quality amps are loud, regardless of class of operation.

P.

Tremo · March 15th, 2004, 04:12 PM

Yeppers, the Champ is indeed Class A. All the small 5 Watt type amps that use a single output tube run Class A. Way back when, Gibson even made an amp that ran a pair of 6V6s paralled single ended, which again would be Class A.

Most of the confusion and (intentional) misconception these days comes from marketing departments which want to call anything cathode biased as "Class A", which is definitely not true. Most of the push-pull cathode biased amps actually are Class AB1. It's all hype to get you to throw your money their way.

You can get a LOT of volume out of a low Watt amp by using efficient speakers. You'd be surprised at how loud a 20 Watt DR can be.

You can have a well made, excellent sounding amp that is not cathode biased or Class A. A lot of the classic exemplary recorded guitar tracks were made with AB1 amplifiers. Marshalls, Fenders, Hiwatts, Ampegs, and yes, Vox.

Some of the most badass sounding tracks were made with wierdo obscure amps that you see at the used equipment stores. Supros, Valcos, Silvertones, Airlines, Mascos, Aristocrats, Danelectros, etc... Who cares what class it runs, what's important is how it sounds.

ccuwan · March 15th, 2004, 06:10 PM

Thanks for all the feedback. I primarily agree with the final statement...."who cares what class it is if it sounds good" and certainly that describes the champ.

March 15th, 2004, 08:47 AM	#1 (permalink)
ccuwan TDPRI Member Join Date: Feb 2004 Location: Toronto Posts: 14	Champ "class A" ? I've heard a number of people refer to the Champ as a class A amplifier. Is this unusual or do most tube amps of that era run a class a circuit.

March 15th, 2004, 10:03 AM	#2 (permalink)
zook Tele-Holic Join Date: Aug 2003 Location: Northeast Kingdom, Vermont Posts: 833	A class A amp is one in which the output tubes are always driving. A single ended tube amp like a Champ can only be Class A since it only has one output tube. A push-pull class A amp will have both tubes pushing constantly, as opposed to a class AB where one tube pushes while the other rests. Picture rowing a boat. Two oars up and out of the water together, then pulling both at the same time, class A. Alternate oars, Class AB. Most Push pull amps are class AB. They are more efficient and kinder on the tubes. Most of what you hear referriing to "Class A" is hype. Read Randall Aiken's treatise on Class A at: www.aikenamps.com That will give you all the technical details. Winnie __________________ I have noticed that happy people are often evaluating themselves and unhappy people are always evaluating others. -William Glasser

March 15th, 2004, 11:09 AM	#3 (permalink)
MJ Harnish Tele-Meister Join Date: Mar 2003 Location: Hattingen, Germany Posts: 457	I'd agree: Virtually every amp out advertised today is not actually class A; manufacturers seem to mislead people and label anything that's cathode biased as "Class A." The Vox AC30 is probably the most famous non "Class A" amp that everyone refers to as Class A. It's gotten so ridiculous that the deceptive labelling has now spilled over into FX pedals. __________________ MJ Harnish Suburbs: Where they cut down all the trees and then name the streets after them.

March 15th, 2004, 02:54 PM	#4 (permalink)
Paul G. Tele-Holic Join Date: Mar 2003 Location: Rhode Island Posts: 885	Well...for a while they got me on the "Class A amps are But then I thought about it. The amps purported to be operating in Class A are Vox, Dr Z., Matchless, etc., and they are loud. What they have in common is large transformers, large stiff speaker cabs, and high-quality (efficient) speakers. So now we know that Quality amps are loud, regardless of class of operation. P. __________________ Listen to your mother

March 15th, 2004, 04:12 PM	#5 (permalink)
Tremo Banned Friend of Leo's Join Date: Mar 2003 Location: Silicon Valley, CA, USA Posts: 3,803	Yeppers, the Champ is indeed Class A. All the small 5 Watt type amps that use a single output tube run Class A. Way back when, Gibson even made an amp that ran a pair of 6V6s paralled single ended, which again would be Class A. Most of the confusion and (intentional) misconception these days comes from marketing departments which want to call anything cathode biased as "Class A", which is definitely not true. Most of the push-pull cathode biased amps actually are Class AB1. It's all hype to get you to throw your money their way. You can get a LOT of volume out of a low Watt amp by using efficient speakers. You'd be surprised at how loud a 20 Watt DR can be. You can have a well made, excellent sounding amp that is not cathode biased or Class A. A lot of the classic exemplary recorded guitar tracks were made with AB1 amplifiers. Marshalls, Fenders, Hiwatts, Ampegs, and yes, Vox. Some of the most badass sounding tracks were made with wierdo obscure amps that you see at the used equipment stores. Supros, Valcos, Silvertones, Airlines, Mascos, Aristocrats, Danelectros, etc... Who cares what class it runs, what's important is how it sounds.

March 15th, 2004, 06:10 PM	#6 (permalink)
ccuwan TDPRI Member Join Date: Feb 2004 Location: Toronto Posts: 14	Thanks for all the feedback. I primarily agree with the final statement...."who cares what class it is if it sounds good" and certainly that describes the champ.