Is part of the hype about Class A due to the name??

Paul G. · April 27th, 2005, 02:34 PM

I mean Class A sounds like a positive thing, you know, like Grade A, or A-OK.

If it had a geeky sounding name, like "Pfletogrotic Operation" would tattood salespeople, and your know-it-all acquaintences bandy it about?

P.

Rick S · April 27th, 2005, 03:33 PM

Absolutely. When the hypemeisters found that the uninformed would easily construe class of operation as a quality rating, it all snowballed from there.

Daddy Elmis · April 27th, 2005, 03:44 PM

Henceforth, I shall refer to all my amps as operating in the Pfletogrotic Paradigm :D

Tim Swartz · April 27th, 2005, 03:49 PM

Quote:

Originally Posted by Rick S

Absolutely. When the hypemeisters found that the uninformed would easily construe class of operation as a quality rating, it all snowballed from there.

Indeed, 99% of amps claiming to be class A are not.

Poppatwang · April 27th, 2005, 04:12 PM

claim to be Class A, but only 50% are.

tombm3 · April 27th, 2005, 05:03 PM

Well, the amps would be Class A at least 1/2 the time wouldn't they? About as good of a percentage as any local weatherman. :D

rmconner80 · April 27th, 2005, 05:30 PM

The funniest thing is that amps can't "be" class A or A/B.

Tubes operate in class A or class A/B, etc. But amps don't.

So I guess you could have a class A amp even though the tubes operate in a class A/B.

RWB · April 27th, 2005, 09:21 PM

Not to get too picky about it, but if an amp is advertised to be Class A or whatever, it's implied that the designation refers to the power amp section.

All preamp tubes in ANY amp I've seen run in class A operation.

Tremo · April 28th, 2005, 01:38 AM

Yes, but as was already pointed out, 99% of the amps that are advertised as "class a" are really class ab1 amplifiers.

It's all just a bunch of marketing hype to separate you from your money.

Dust my Broom · April 28th, 2005, 04:39 AM

Is a Bassman RI Class A?

Paul G. · April 28th, 2005, 06:35 AM

Simply put, what is meant by Class A operation is that your output section is biased so that each tube is carrying the full signal at all times. Most amps are working in Class A at very low volumes, but as soon as you turn up to "where the tone" is, not.

What it has come to describe is a cathode biased amp, often running somewhat hot, and sometimes having no negative feedback. Sometimes it just describes whatever somebody is trying to sell you, 'cause it sounds good, and what do you know?

Your Bassman RI does not operate in Class A.

Your Dr Z does not operate in Class A.

Your AC30 does not operate in Class A.

Your Matchless does not operate in Class A.

Your Peavey does not operate in Class A.

If you have more than one output tube the odds are 95-5 that your amp is not actually operating in Class A, no matter what the guy with the cocker spaniel haircut says.

Move along, nothing to see here.

P.

Smokey · April 28th, 2005, 06:57 AM

My next amp are gonna be Class A+. :D

Tim Swartz · April 28th, 2005, 11:20 AM

FWIW, a friend of mine has measured/tested scores of booteek and production amps; Matchless, Dr Z, tweeds, old Vox, new Vox, etc... Thus far, the only amp to be class A is the Allessandro English Coonhound, 4 EL84s producing about 15watts (about half of what a class A/B amp is capable of). FWIW, I played 2 examples of this amp and did not care for it. I much prefered the Allessandro Bloodhound which is a 2xEL34 class A/B amp. The Coonhounds were quite noisey at idle, spongey feeling and lacked touch sensivity. Is this a characteristic of a class A amp? Dunno, seeing as I've only ever played 2 (aside from SE amps).

tomtheguitarguy · April 28th, 2005, 12:35 PM

Well, fortunately Dr. Z doesn't advertise his amps as Class A - he just refers to them (the EL-84 powered) as self-biasing. At least that's how he advertises now - I don't recall seeing anything before, but I could be wrong.

tomtheguitarguy

Paul G. · April 28th, 2005, 12:53 PM

I don't recall anything out of Dr Z referring to Class Aosity, but I can assure you the store I bought it from was all over it like seagulls on a dumpster.

I buy amps with my ears, it's yielded me some fine sounding boxes, some of them fixed bias, some of the cathode bias, some of them with negative feedback, some without, some with tube rectifiers, some with diodes, some with ceramic speakers, some with alnicos... etc.

A well-made, well-designed amp will sound great, regardless of its style.

P.

Mik · April 28th, 2005, 01:57 PM

Someone (mfr, retailer, player, whoever) says "Class A" guitar amp, I know, you know what he's talking about. The sound, the tubes, the design, the performance, the usual suspects amps.

I just don't get all worked up about it.

Mik

Daddy Elmis · April 28th, 2005, 04:40 PM

Quote:

Originally Posted by Smokey

My next amp are gonna be Class A+. :D

I have my amp in tutoring to hopefully bring him up to Class A. I keep telling him, how you gonna get into a decent college as a Class A/B?

1612112 · April 28th, 2005, 08:17 PM

Quote:

Originally Posted by Paul G.

A well-made, well-designed amp will sound great, regardless of its style.
P.

Depends on the class of player, I'd say. Take for example Buddy Guy... I think he could make any amp sound sour.

B3Nut · April 29th, 2005, 04:28 PM

Randall Aiken wrote an excellent "white paper" on the topic of Class A. Basically, the true definition was full plate current conduction through all 360 degrees of the waveform, at the full unclipped output of the amplifier.

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

Elsewhere on his site he debunks the AC30 class-A mythology. Not to bash the amplifier, far from it - it's a fine amplifier. But it should be regarded as a fine amplifier because of how it sounds, not because of what topology and biasing scheme it happens to use. Same goes for any amp, really...bottom line is, does she sing to ya? :D

TP

cugel · April 29th, 2005, 07:28 PM

its funny in virtually every add for an ac30 you see it says class A. as mentioned above they aren't. that aside an ac30 is still my fave amp of all time even if it isnt top of the class. if i could only get my sfvc back from that kid i lent it too...it is (was) my only class A amp.

what about audiophile gear?? i swear i have seen preamps advertised as class A. what does that mean?

Paul G. · April 30th, 2005, 08:34 AM

At least in guitar amps.

It's the power section that gets the hype.

The problem is, if your amp operated in true Class A, you the same (or larger) PT, the same tube complement, the same amount of electronics to make less than half the power of an AB amp.

Audiophiles will pay thousands, or even tens of thousands for an 8 watt amp, you won't.

2 6L6s or EL34s would be struggling to make 25 watts in class A. You'd definitely need a fan.

The funny thing is that people hear what they want. In Aspen Pitmans book he refers to "spongy Class A circuitry". Now this is a guy who must know something about amps, he must have played a few and heard even more. Class A operation is the opposite of "spongy". Because the power supply is running full-on all the time, Class A has less compression, more definition and more clarity, but we've been told an AC30 is "spongy" so that's what he hears, and attributes to imaginary Class A operation.

It's a funny world. I don't get worked up about it, just amused.

P.

B3Nut · April 30th, 2005, 08:44 AM

Well, it's a classic case of what happens when marketing weasels get their little paws on engineering terminology - they always mess it up. :D Mesa's Randall Smith (a fine designer) 'stretches' the "A" definition in his recent white paper talking about class A and his new Lonestar Special. He neglects to mention that the definitions are supposed to be made at the full unclipped output of the amplifier - a 'weasel' that allows 15w 2xEL84 and 30w 4xEL84 amps to be marketed as "class A". The only true A mode on that amp is the single-ended 5W setting. If the push-pull settings were truly class A the output would more likely be 10-12 watts for the pair and 20-22 for the quad, give or take. Having a tube rectifier would be irrelevant, too. Using class to market that amp is a mistake IMHO, it stands quite well on its own tonal merits. I've played it, and it's hands-down the sweetest Mesa amp I've ever played through, and one of the nicest guitar amps I've run across.

TP

jjmantele · April 30th, 2005, 11:51 AM

It's much more important to make sure you amp is Turbo Charged than Class A. Turbo is where it's at.

Boxelder · May 4th, 2005, 01:01 AM

so my badcat isn't class A?

that's too bad cause it sounds really good...

David Barnett · May 4th, 2005, 03:19 AM

Quote:

Originally Posted by cugel

what about audiophile gear?? i swear i have seen preamps advertised as class A. what does that mean?

Any preamp that is NOT class-A must have something wrong with it.

There are some true class-A audiophile amps, and also some bogus ones. You can kind of tell the true class-A amps by the huge heat sinks. If it looks like a 500W/channel amp, but is only rated for 25W, it just might really be class-A. :)

B3Nut · May 4th, 2005, 08:29 AM

SS audio (especially hi-fi) preamps often have op-amp IC's whose on-chip output transistors run class B, but that's the only place I can think of where the preamp wouldn't be class A due to the single-ended gain stages. The only place a single -ended amplifier is run in class B or (more common) class C (even longer cutoff) is in radio transmitters.

TP

Tim Swartz · May 4th, 2005, 02:54 PM

Quote:

Originally Posted by Boxelder

so my badcat isn't class A?

that's too bad cause it sounds really good...

It is not class A.

April 27th, 2005, 02:34 PM	#1 (permalink)
Paul G. Tele-Holic Join Date: Mar 2003 Location: Rhode Island Posts: 885	Is part of the hype about Class A due to the name?? I mean Class A sounds like a positive thing, you know, like Grade A, or A-OK. If it had a geeky sounding name, like "Pfletogrotic Operation" would tattood salespeople, and your know-it-all acquaintences bandy it about? P. __________________ Listen to your mother

April 27th, 2005, 04:12 PM	#5 (permalink)
Poppatwang Tele-Afflicted Join Date: Mar 2003 Location: St. Paul, MN Posts: 1,909 13 Photos	All my amps... claim to be Class A, but only 50% are. __________________ The Dieselfitters http://www.dieselfitters.com Roy Hubbs http://www.royhubbs.com

April 27th, 2005, 05:03 PM	#6 (permalink)
tombm3 Tele-Meister Join Date: Apr 2003 Location: WNY Posts: 198	Like the weatherman..... Well, the amps would be Class A at least 1/2 the time wouldn't they? About as good of a percentage as any local weatherman. :D

April 27th, 2005, 05:30 PM	#7 (permalink)
rmconner80 Tele-Meister Join Date: Jun 2003 Location: DC Posts: 247	The funniest thing is that amps can't "be" class A or A/B. Tubes operate in class A or class A/B, etc. But amps don't. So I guess you could have a class A amp even though the tubes operate in a class A/B. __________________ "A noble spirit embiggens the smallest man..." - Jebediah Springfield

April 28th, 2005, 04:39 AM	#10 (permalink)
Dust my Broom Tele-Meister Join Date: Feb 2005 Location: South Louisiana Posts: 160	Is a Bassman RI Class A? __________________ "We just played that..........didn't we?"

April 27th, 2005, 03:33 PM	#2 (permalink)
Rick S Tele-Meister Join Date: Nov 2003 Location: Tulsa, OK Posts: 494	Absolutely. When the hypemeisters found that the uninformed would easily construe class of operation as a quality rating, it all snowballed from there.

April 27th, 2005, 03:44 PM	#3 (permalink)
Daddy Elmis Tele-Holic Join Date: Jun 2004 Location: USA Posts: 961	Henceforth, I shall refer to all my amps as operating in the Pfletogrotic Paradigm :D

April 27th, 2005, 09:21 PM	#8 (permalink)
RWB TDPRI Member Join Date: May 2003 Location: Canada Posts: 19	Not to get too picky about it, but if an amp is advertised to be Class A or whatever, it's implied that the designation refers to the power amp section. All preamp tubes in ANY amp I've seen run in class A operation.

April 28th, 2005, 01:38 AM	#9 (permalink)
Tremo Banned Friend of Leo's Join Date: Mar 2003 Location: Silicon Valley, CA, USA Posts: 3,803	Yes, but as was already pointed out, 99% of the amps that are advertised as "class a" are really class ab1 amplifiers. It's all just a bunch of marketing hype to separate you from your money.

April 28th, 2005, 06:35 AM	#11 (permalink)
Paul G. Tele-Holic Join Date: Mar 2003 Location: Rhode Island Posts: 885	No, No, No. Simply put, what is meant by Class A operation is that your output section is biased so that each tube is carrying the full signal at all times. Most amps are working in Class A at very low volumes, but as soon as you turn up to "where the tone" is, not. What it has come to describe is a cathode biased amp, often running somewhat hot, and sometimes having no negative feedback. Sometimes it just describes whatever somebody is trying to sell you, 'cause it sounds good, and what do you know? Your Bassman RI does not operate in Class A. Your Dr Z does not operate in Class A. Your AC30 does not operate in Class A. Your Matchless does not operate in Class A. Your Peavey does not operate in Class A. If you have more than one output tube the odds are 95-5 that your amp is not actually operating in Class A, no matter what the guy with the cocker spaniel haircut says. Move along, nothing to see here. P. __________________ Listen to your mother

April 28th, 2005, 06:57 AM	#12 (permalink)
Smokey TDPRI Member Join Date: Mar 2003 Posts: 78	My next amp are gonna be Class A+. :D __________________ Smokey's Forums

April 28th, 2005, 11:20 AM	#13 (permalink)
Tim Swartz Tele-Afflicted Join Date: Mar 2003 Location: Michigan - Tweenst the Great Lakes Posts: 1,904	FWIW, a friend of mine has measured/tested scores of booteek and production amps; Matchless, Dr Z, tweeds, old Vox, new Vox, etc... Thus far, the only amp to be class A is the Allessandro English Coonhound, 4 EL84s producing about 15watts (about half of what a class A/B amp is capable of). FWIW, I played 2 examples of this amp and did not care for it. I much prefered the Allessandro Bloodhound which is a 2xEL34 class A/B amp. The Coonhounds were quite noisey at idle, spongey feeling and lacked touch sensivity. Is this a characteristic of a class A amp? Dunno, seeing as I've only ever played 2 (aside from SE amps). __________________

April 28th, 2005, 12:35 PM	#14 (permalink)
tomtheguitarguy Tele-Meister Join Date: Dec 2003 Location: SoCal USA Age: 42 Posts: 242	Dr. Z Well, fortunately Dr. Z doesn't advertise his amps as Class A - he just refers to them (the EL-84 powered) as self-biasing. At least that's how he advertises now - I don't recall seeing anything before, but I could be wrong. tomtheguitarguy

April 28th, 2005, 12:53 PM	#15 (permalink)
Paul G. Tele-Holic Join Date: Mar 2003 Location: Rhode Island Posts: 885	Well I have a Dr Z. I don't recall anything out of Dr Z referring to Class Aosity, but I can assure you the store I bought it from was all over it like seagulls on a dumpster. I buy amps with my ears, it's yielded me some fine sounding boxes, some of them fixed bias, some of the cathode bias, some of them with negative feedback, some without, some with tube rectifiers, some with diodes, some with ceramic speakers, some with alnicos... etc. A well-made, well-designed amp will sound great, regardless of its style. P. __________________ Listen to your mother

April 28th, 2005, 01:57 PM	#16 (permalink)
Mik Tele-Afflicted Join Date: Mar 2003 Posts: 1,416	Defending the Indefinsible Someone (mfr, retailer, player, whoever) says "Class A" guitar amp, I know, you know what he's talking about. The sound, the tubes, the design, the performance, the usual suspects amps. I just don't get all worked up about it. Mik __________________ a "motor-bike with a touch of blood in it is better than all the riding animals on earth, because of its logical extension of our faculties, and the hint, the provocations, to excess."-T.E. Lawrence

April 29th, 2005, 04:28 PM	#19 (permalink)
B3Nut TDPRI Member Join Date: Feb 2004 Posts: 56	Randall Aiken wrote an excellent "white paper" on the topic of Class A. Basically, the true definition was full plate current conduction through all 360 degrees of the waveform, at the full unclipped output of the amplifier. http://www.aikenamps.com/ClassA.htm Elsewhere on his site he debunks the AC30 class-A mythology. Not to bash the amplifier, far from it - it's a fine amplifier. But it should be regarded as a fine amplifier because of how it sounds, not because of what topology and biasing scheme it happens to use. Same goes for any amp, really...bottom line is, does she sing to ya? :D TP

April 29th, 2005, 07:28 PM	#20 (permalink)
cugel TDPRI Member Join Date: Apr 2005 Posts: 36	its funny in virtually every add for an ac30 you see it says class A. as mentioned above they aren't. that aside an ac30 is still my fave amp of all time even if it isnt top of the class. if i could only get my sfvc back from that kid i lent it too...it is (was) my only class A amp. what about audiophile gear?? i swear i have seen preamps advertised as class A. what does that mean?

April 30th, 2005, 08:34 AM	#21 (permalink)
Paul G. Tele-Holic Join Date: Mar 2003 Location: Rhode Island Posts: 885	All preamp tubes operate in Class A At least in guitar amps. It's the power section that gets the hype. The problem is, if your amp operated in true Class A, you the same (or larger) PT, the same tube complement, the same amount of electronics to make less than half the power of an AB amp. Audiophiles will pay thousands, or even tens of thousands for an 8 watt amp, you won't. 2 6L6s or EL34s would be struggling to make 25 watts in class A. You'd definitely need a fan. The funny thing is that people hear what they want. In Aspen Pitmans book he refers to "spongy Class A circuitry". Now this is a guy who must know something about amps, he must have played a few and heard even more. Class A operation is the opposite of "spongy". Because the power supply is running full-on all the time, Class A has less compression, more definition and more clarity, but we've been told an AC30 is "spongy" so that's what he hears, and attributes to imaginary Class A operation. It's a funny world. I don't get worked up about it, just amused. P. __________________ Listen to your mother

April 30th, 2005, 08:44 AM	#22 (permalink)
B3Nut TDPRI Member Join Date: Feb 2004 Posts: 56	Well, it's a classic case of what happens when marketing weasels get their little paws on engineering terminology - they always mess it up. :D Mesa's Randall Smith (a fine designer) 'stretches' the "A" definition in his recent white paper talking about class A and his new Lonestar Special. He neglects to mention that the definitions are supposed to be made at the full unclipped output of the amplifier - a 'weasel' that allows 15w 2xEL84 and 30w 4xEL84 amps to be marketed as "class A". The only true A mode on that amp is the single-ended 5W setting. If the push-pull settings were truly class A the output would more likely be 10-12 watts for the pair and 20-22 for the quad, give or take. Having a tube rectifier would be irrelevant, too. Using class to market that amp is a mistake IMHO, it stands quite well on its own tonal merits. I've played it, and it's hands-down the sweetest Mesa amp I've ever played through, and one of the nicest guitar amps I've run across. TP

April 30th, 2005, 11:51 AM	#23 (permalink)
jjmantele Tele-Holic Join Date: Aug 2003 Location: New Jersey Posts: 851	A It's much more important to make sure you amp is Turbo Charged than Class A. Turbo is where it's at. __________________ JJman If it says "Vintage" on it -it isn't.

May 4th, 2005, 01:01 AM	#24 (permalink)
Boxelder Tele-Meister Join Date: Jan 2004 Location: Omaha Nebraska Age: 36 Posts: 176 2 Photos	so my badcat isn't class A? that's too bad cause it sounds really good...

May 4th, 2005, 08:29 AM	#26 (permalink)
B3Nut TDPRI Member Join Date: Feb 2004 Posts: 56	SS audio (especially hi-fi) preamps often have op-amp IC's whose on-chip output transistors run class B, but that's the only place I can think of where the preamp wouldn't be class A due to the single-ended gain stages. The only place a single -ended amplifier is run in class B or (more common) class C (even longer cutoff) is in radio transmitters. TP