Has "Class-A" marketing always been around?

Is the marketing of "Class-A" as a decision feature on guitar amps relatively new?

My understanding is that a Fender Champ is a Class-A amp, but that was sold as a basic practice amp. Did the marketing of the Champ list Class-A as an important feature?

The more professional amps, Fender Deluxe & Twin, Marshall 50w & 100w, and Vox 30w are not Class-A so it wouldn't be a feature there. So during the era of growing power and full stacks was anyone shopping for Class-A?

I've only been looking at amps for three years so I don't have any historical perspective. How far back do you guys remember so much discussion regarding Class-A/AB?

I don't know if it was part of their actual marketing, but Vox AC30 amps were long referred to as being Class A amps (which they aren't). When folks started making Vox-derived amp designs, the "Class A" thing started gaining traction.

Cheers, Tim

I don't know if it was part of their actual marketing, but Vox AC30 amps were long referred to as being Class A amps (which they aren't). When folks started making Vox-derived amp designs, the "Class A" thing started gaining traction.

Cheers, Tim

I'd say it even got to the point of EL84 power tubes = Class A operation as a given. I've seen many examples of amps like Blues Jrs or Peavey Classic 30s being described as Class A even after the manufacturers have categorically stated they are not.

People are making the mistake of equating Class A, A/B, B etc as a sonic grading system. It is not. It is the physical operation of the amp - like a car or motorcycle engine can be 2-stroke, 4-stroke, diesel or run on natural gas.

All single power tube audio amps are class A, because if they aren't you would get horrendous (not pleasant) distortion as they shut off and turn on - that's if it even starts amplifying. Play your guitar and wiggle the lead in the input of an amp to see what it would be like. Class A simply means all the tubes amplify all the time. Think of turning a handdrill or eggbeater. You have to keep cranking 100% of the time, through 360 deg. rotation of the handle or it will stop.

Some sorts of radio-frequency amps do shut on and off. They are not audio amps, but signal processors. That is class B - it means the tube turns on and off partway a sinewave 360 deg. cycle. You would not listen to audio through this.

Class A/B simply means the tubes on one side of the output transformer provide power for approx 50% or 180 degrees of the cycle. The other half of the tubes on the other side of the output transformer provide the other half of the necessary power. They shut off and turn on in a synchronised way to retain the continuity of the single sine wave (sound) being amplified.

Think of each side as the pedals of a bicycle - when one side is being pushed down to turn the wheel, the other side is coasting up doing no work. When the left pedal gets to the bottom and you can no longer push through it, the right pedal takes over as it moves forward and downwards. You can keep trying to apply pressure through the pedal moving backwards and up, but it is very hard and inefficient use of your energy.

The bicycle is the sine wave representing a sound. That is class A/B operation and it is more efficient for multi-tube amps than class A, where all the tubes work all the time - even when it is not efficient to do so. As a result more power is consumed in class A and the tubes work harder and burn more energy as heat because they are always passing current, not shutting on and off.

Here are some good Wiki articles with some little diagrams that help explain this:

Class A (http://en.wikipedia.org/wiki/Class_A_amplifier#Class_A)

Class B and A/B (http://en.wikipedia.org/wiki/Class_B_amplifier#Class_B_and_AB)

Class A/B simply means the tubes on one side of the output transformer provide power for approx 50% or 180 degrees of the cycle. The other half of the tubes on the other side of the output transformer provide the other half of the necessary power. They shut off and turn on in a synchronised way to retain the continuity of the single sine wave (sound) being amplified.


My understanding is that if the tube is only handling 50% of the waveform, that constitutes Class B, which has the weakness of excessive 'crossover distortion' or distortion from the waveform switching from one tube to the other at the 0 (or crossover) point. Class AB is a hybrid of Class A and Class B in which each power tube handles more than 50%, but not 100% of the waveform, eliminating crossover distortion, but not working the tube as hard as it would in a purely Class A configuration.

Admittedly, my understanding may be flawed, but that's what I was taught.

You are right. That's why I said 'approx' 50%. To avoid distortion each side of the amp might have to keep amplifying for 60-70% of the signal, or 230-270 degrees of the wave producing a significant overlap, partly because to minimise distortion they don't just start or stop, it is more like a gradual transition between full power and none, with an overlap between sides.

I'm not really thinking of the particular merits or engineering issues of Class-A/AB. I'm just asking more about manufactures retail sales promotion of amps. I'm wondering if amp brochures of the 60s, 70s, 80s touted Class-A as a desired feature like the current marketing.

I'm not really thinking of the particular merits or engineering issues of Class-A/AB. I'm just asking more about manufactures retail sales promotion of amps. I'm wondering if amp brochures of the 60s, 70s, 80s touted Class-A as a desired feature like the current marketing.

I don't recall anything like that in the marketing of the day.

It was more about what kind of eye-catching ad could be produced, or maybe who was endorsing the amp.

Vox benefited more from the Beatles than anything else. Fender benefited because it was everywhere. Marshall thanks to Jimi and others.

Etc.

No, they didn't. The average player didn't care or didn't understand. As Tex said, you just saw 'Fender' or 'Marshall' or 'Vox' and that's all.

If you did find a referrence to class of operation it was buried somewhere deep in the specs literature and often not even then.

They just 'were'. Remember, a Champ was a low dollar practice amp - the equivalent then of a Squier 15. It wouldn't have got many column inches of advertising compared to a Twin Reverb. And Fender, Marshall et al mostly sold by showing who used their stuff, same as today.

It was more about what kind of eye-catching ad could be produced, or maybe who was endorsing the amp.
Etc.

Click on the first photo on the page for a better look (http://web.mac.com/georgevw/Less_Than_Meets_The_Ear/Photos.html#grid)

Who doesn't want to play like Moe? (This was a Fender endorsement shot from '64 or '65)

Who doesn't want to play like Moe? (This was a Fender endorsement shot from '64 or '65)
Quiet, lame brains! I'm rehearsing.

Excellent.

Bob Arbogast

Click on the first photo on the page for a better look (http://web.mac.com/georgevw/Less_Than_Meets_The_Ear/Photos.html#grid)

Who doesn't want to play like Moe? (This was a Fender endorsement shot from '64 or '65)

Hey...I wouldn't mind having some of those off-the-wall guitars.

Did you notice that the weird "Gibson" is actually a Guild?

Tex, thanks for the heads up. Fixed.

From what I recollect class A was first reduced to a mere buzzword in the early '90s, when a particular company gained substantial success with a handwired (another buzzword, but these amps truely are) beefed up Vox AC30ish amp. This was right at the start of what a few years later became a boutique amp explosion. These were the amp dejour for several years and were the amp which all others were compared, so other companies borrowed the buzzword...and the lie just proliferated.

Yeah, that's the way I remember it, too. At least I wasn't aware of the term "Class A" until about 1992 or so...

Cheers, Tim

They weren't advertised as "class A" back in the day (prior to transistors) because there wasn't any reason to... if you were running a tube amp, it was pretty much gonna work that way.

I don't know for sure when it got to be a "big deal," but I remember "class A" being a buzzword back around the early to mid '80s in home stereo equipment.

The early 90's was when Class A became a marketing buzzword. I believe for a few years before that, there were a few companies claiming "Vox-like chime" due to the use of EL-84's (Bedrock and Seymour Duncan, as I recall). Then Matchless came on the scene and quicker than you could say tremolo/vibrato, suddenly Class A/cathode biasing became forever muddied.

I think the "Class A" marketing thing didn't really become a big thing (or a thing at all) until some time after the mid nineties. That as far as I can tell is when exchanging information on the internets became popular.
I don't remember giving any thought to things like amp class, tone woods, or even fret board radius, before "now".
It wouldn't surprise me to find out that people in the marketing devisions of the companies we buy from read through our post looking for the right buzz words to use to sell us stuff.

Just my 2 cents.

My Palomino V32 has the Class A plaque on the front :rolleyes:

I think it's Crate's way of cashing in on it's Matchless/Vox like circuit

About 10 years ago Americans "discovered" the Vox AC30, and Matchless started marketing their interpretation.

Trying to differentiate between their amps and Fender/Marshall/Ampeg the "Class A" malarky was born.

As recently as last month there was a profile of some new amp maker in Vintage Guitar Magazine. He proudly talked about his knowledge, experience and skills, then talked about his Class A, 20 watt, 2xEL84 amp, and his Class A, 40 watt, 4xEL84 other amp.

Now the only way 2xEL84 will yield 20W in Class A is if you place the amp in a nuclear reactor on the planet Mars. So, he is either not that good an engineer, or he is selling a 10W amp as a 20W amp, or he is selling a Class AB amp as a Class A amp.

Now, I'm sure it sounds great, but I don't like being lied to, or being mislead, or "experts" who are anything but, so...

P.

My Palomino V32 has the Class A plaque on the front :rolleyes:

I think it's Crate's way of cashing in on it's Matchless/Vox like circuit

It all boils down to the marketeers. If you were buying a product you knew nothing about and one was labeled "Class A" and the other "Class A/B" which would you chose based solely on that? This is the whole premise of the lie.

I really don't care if the V32 is Class A or not. It sounds darn good and better than the Valveking and Blues Junior to me.

Personally, I dig the stooges ad. :grin:

No, they didn't. The average player didn't care or didn't understand. As Tex said, you just saw 'Fender' or 'Marshall' or 'Vox' and that's all.

If you did find a referrence to class of operation it was buried somewhere deep in the specs literature and often not even then.

They just 'were'. Remember, a Champ was a low dollar practice amp - the equivalent then of a Squier 15. It wouldn't have got many column inches of advertising compared to a Twin Reverb. And Fender, Marshall et al mostly sold by showing who used their stuff, same as today.

+1

This is absolutely the way I remember it, in the 70's anyway. As you say, most players didn't care or know either way.

Likewise, we didn't care about:

Tubes, tonewoods, nitro v. poly, or the density of bridges.

I just don't remember any conversation or fretting over any of those things. The stuff gear-wise that players used to concern themselves with were speakers (JBL's and Celestions were the hot iems), and getting Humbuckers rewound (boutique pups were just hitting the market and were out of reach for most people). Effects pedals were a big deal.

Musicmaster Bass amps were considered junk and no one played a guitar through them, and Champs weren't taken too seriously either. At that time I would play club dates or even high school dances at different times through a Twin, Blonde Bassman, or 50w Marshall half stack.

That's how I remember it...granted the 70's are a little blurry to me now :oops: .

It all boils down to the marketeers. If you were buying a product you knew nothing about and one was labeled "Class A" and the other "Class A/B" which would you chose based solely on that? This is the whole premise of the lie.

That's the way I see it as well. They are taking advantage of the non-technical guys who don't know any better. I'd say they've been pretty successful, look at all the guys who today are completely fooled by this nonsense.

From what I recollect class A was first reduced to a mere buzzword in the early '90s, when a particular company gained substantial success with a handwired (another buzzword, but these amps truely are) beefed up Vox AC30ish amp. This was right at the start of what a few years later became a boutique amp explosion. These were the amp dejour for several years and were the amp which all others were compared, so other companies borrowed the buzzword...and the lie just proliferated.

Again we agree. I think we have Brian May to thank for starting it, then Matchless to thank for perpetuating it and taking it to the next level. After that, every BS artist jumped on the bandwagon, and that's where we are today.

It's a bit like DCX's 'that thing got a Hemi in it?' ad line. The new 'Hemis' are hemi in name only, as hemispherical cylinder heads have been discredited amongst racers, serious tuners and vehicle manufacturers for decades.

But people buy it as a marketing buzzword because of the old legendary 426 Hemi of the sixties and the success of Hemi-derived motors in Top Fuel and other motorsport.

I have to add, if anyone has overstated the Class A hype, it's Randall Smith.

The Maverick, and Blue Angel date back well over a decade and say "Pure Class A' on the front, as do the newer still in production Lone Star Specials.

Having said that, I gig a Blue Angel and love it. I like the Mesa build quality, customer service, tone, and their pricing policy. Everybody pays the same price. Period.

Hartley Peavey swore he'd never outsource, but now Peavey Valvekings, Windsors, Bandits, ect. are made in China.

Fender builds a lot of amps in Mexico.

Randall Smith spent a lot of time explaining how his push/pull amps are Class A (you can read it at Mesa.com, it's several pages), but at least every Boogie you buy is built in U.S.A., holds a good resale, and can take a beating.

It's a bit like DCX's 'that thing got a Hemi in it?' ad line. The new 'Hemis' are hemi in name only, as hemispherical cylinder heads have been discredited amongst racers, serious tuners and vehicle manufacturers for decades.

But people buy it as a marketing buzzword because of the old legendary 426 Hemi of the sixties and the success of Hemi-derived motors in Top Fuel and other motorsport.

Shocking - I made the same exact reference in a Class A thread here, roughly a week ago.

Actually, (off topic, sorry) many racers still swear by a true hemispherical design, and Porsche use one in the 911/930/etc. until they went to a watercooled design. But like Class A (back on topic, again, slightly), a true Hemi design requires a lot of iron (or lots of heat treated metals of other sorts), and it's fundamental design makes it impossible to make it more efficient (no 4 valves per cylinder, or other generally superior designs).

What I want to know now is how can I get a Hemi in my amp, and a Class A engine in my car? I'm guessing that both will have to be powered by cold fusion.

It's a bit like DCX's 'that thing got a Hemi in it?' ad line. The new 'Hemis' are hemi in name only, as hemispherical cylinder heads have been discredited amongst racers, serious tuners and vehicle manufacturers for decades.

But people buy it as a marketing buzzword because of the old legendary 426 Hemi of the sixties and the success of Hemi-derived motors in Top Fuel and other motorsport.

True hemispherical heads have been discredited? Huh? I thought they were the most efficient, best breathing, best volumetric efficiency and most resistant to detonation.

The next best thing was supposed to be the pent-roof design, which allows for the 3 and 4 valve arrangements.

OHC and 4 valves per cylinder dates back to the 1930s. Look at the V12 Allisons and Merlins.

I have to add, if anyone has overstated the Class A hype, it's Randall Smith.

...

Hartley Peavey swore he'd never outsource, but now Peavey Valvekings, Windsors, Bandits, ect. are made in China.

...

Randall Smith spent a lot of time explaining how his push/pull amps are Class A (you can read it at Mesa.com, it's several pages), but at least every Boogie you buy is built in U.S.A., holds a good resale, and can take a beating.

I also own several of the Mesa "Pure Class A" amps (Subway Rocket, Subway Blues, the 20/20 power amp, the MkIV which has a Class A mode), and just based on the output values claimed it appears that they can't really be Class A, but it doesn't bother me. They sound great, they're very reliable.

I also have a THD Univalve which is definitely Class A, and while it also sounds great, I never plug into it and think "Oh, wow, there's something very different about this amp..." It's just a great sounding low-wattage amp that you can plug almost any preamp or power tube into to sample different flavors.

At this point, I don't really worry too much about the insides of amps--class A, whether the effects loop and reverb are tube driven, carbon comp resistors, etc. I look at the output (since I'm not really interested in anything over 40W or so), what knobs are on the front, and then I plug in and play. If it sounds great, I don't care, and vice versa. Amps are systems and greater than the sum of the parts, so I'm not going to obsess over parts of them in isolation. Amp designers chose components and make design decisions based on everything that comes before and after, and trying to second guess them as even an experienced player can lead to a lot of tail chasing.

I used to work with a guy who used to race for Lotus and Porsche professionally, and at one point he picked up a used 911 that had been fiddled with by the previous owner. He said he ended up taking out all the mods because he determined that each "advantage" gained in a single area hurt the overall driveability of the car. I've know terminal gear tweakers who bought something they liked, and then in short order started swapping and modding. The first mod would fix one thing, but then reveal or cause another problem, which necessitated a second mod, and a third one, until finally they sold the thing with all the mods detailed and all the original parts included. And then the process started again with the next amp!

A side note regarding Peavey never outsourcing: PRS was also set up to go into the Asian outsource business sometime back in the 90's and bailed late in the process because Paul said he just couldn't do that when his name was on it. People change their minds.

To risk taking things too off-htread. Hemi heads were the answer to power when the best tech was large displacement cast iron motors and OHV, one big intake and exhaust with more primitive casting technology. The wide included valve angle and straight shot into the combustion chamber with big valves provides good volumetric efficiency at high RPM and wide throttle openings.

A hemi-head has a great flame-front - until you stick the corresponding domed piston in it, then it's dreadful. And the piston has to be thick for strength (heavy), so it weighs a ton which means the rod has to be stronger and the counterweights on the crank weigh a ton. So it is slow to accelerate it's own mass.

The biggest issue - the convoluted flame front caused by the large hollow in the combustion chamber and the resulting piston hump to maintain a high compression ratio. Needs a lot of ignition advance (bad on todays low-octane fuel). Spends a lot of time heating the engine up, wasting thermodynamic energy or btus.

The old Hemi with hemispherical heads
http://www.offroaders.com/tech/images/hemi-head-3.jpg

It was state of the art once - not today.

The new 'Hemi' with flat top piston and small included valve angle - actually technically a wedge like the GM Powertrains LS1
http://www.dragracingonline.com/technical/images/hemi1.jpg

Today imrpoved casting tech, porting knowledge, multivalve and in particular precision valve control from DOHC lobe bearing on valvestem is state-of-the art. This is what F1, the worlds supercars, Grand Prix Motorcycles etc use. The matching piston top is almost flat, with some valve eyelids in it. In practice it is a shallow ellipse or dish-shape.

If they can use anything they like in racing, and they don't use hemi heads (and neither do DCX, their new motors use near-carbon copies of GM heads ) it should tell you they aren't the S-O-A anymore. Not to deny their heritage, but like pushrods Flatheads, Small Block Chevs etc etc they've been surpassed.

Having said that, I love old Hemis, and the 5.7 pushrod OHV LS1 in my Holden Monaro!http://marks.4t.com/VY/monaroiii.jpg

To risk taking things too off-htread.

Risky, but yeah.

At this point in technological development, you can't beat a multivalve OHC setup. Sure, it's been around since the 30's, but now you have tight tolerances, lightweight metals, electronic fuel injection, variable valve timing, etc.

While there hasn't been anything ground breaking with Class AB (that I know of), it's the equivalent of modern engine head design, IMO.

Even lawnmowers are all going 4 stroke, electric start, fuel injected, etc. They were probably the last Class A equivalent.

At least some guitarists aren't suckers for the Class A fish bait, in part because of these threads. They just have to watch out for all of the other doo doo that many amp vendors are pushing down their throats.