#2
It's a different way of working, most guitarists don't need to worry about it, Mesa have a techincal explanation on their site. Generally class A/B is accepted to be ''better'' because it's more efficient.
#3
i don't think there's such a thing as class a or class a/b tubes, that refers to the type of circuit.
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Quote by K33nbl4d3
I'll have to put the Classic T models on my to-try list. Shame the finish options there are Anachronism Gold, Nuclear Waste and Aged Clown, because in principle the plaintop is right up my alley.

Quote by K33nbl4d3
Presumably because the CCF (Combined Corksniffing Forces) of MLP and Gibson forums would rise up against them, plunging the land into war.

Quote by T00DEEPBLUE
Et tu, br00tz?
#4
It's just how it's biased. The only real difference is that when biased into Class A valves can sound more musical, but realistically the only amps that run on true class A nowadays are the 5 watters and some boutique ones, so until you get to boutique level you really need not worry at all.
The Laney Thread are big and clever. No exceptions.
#5
Quote by MrCarrot
The only real difference is that when biased into Class A valves can sound more musical


I think we'd see a lot more class A amps if that was true.
#6
1) Notice the 'can'
2) And it is true, biasing into Class A will usually emphasise even order harmonics and increase harmonic distortion, even in a Push-Pull amp.

Thing is, you'll lose a LOT of wattage doing so...
The Laney Thread are big and clever. No exceptions.
#7
not to mention a lot of br00talz.
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Quote by K33nbl4d3
I'll have to put the Classic T models on my to-try list. Shame the finish options there are Anachronism Gold, Nuclear Waste and Aged Clown, because in principle the plaintop is right up my alley.

Quote by K33nbl4d3
Presumably because the CCF (Combined Corksniffing Forces) of MLP and Gibson forums would rise up against them, plunging the land into war.

Quote by T00DEEPBLUE
Et tu, br00tz?
#8
Quote by Dave_Mc
i don't think there's such a thing as class a or class a/b tubes, that refers to the type of circuit.


What he said. The Class A/AB/whatever refers to a design thing in a circuit of an amp. Class A and Class AB use the same tubes (well, can use, whatever).
Quote by Lunchbox362
This thread if fail in almost every way imaniganable.
#9
Now, what are the differences, you might ask? Well, for one, the Class AB amplifier is biased in a more non-linear portion of the characteristic curves, which means it has more distortion than a true class A amplifier. Also, the efficiency will be greater than is theoretically possible with a class A amplifier at these levels. There is a very real difference in tone and operating conditions between a true class A 10W amplifier running at say, 1W, and a 10W class AB amplifier running at 1W. Same output level, same overall power level, *but* a different class of operation, different amount of distortion, different efficiency, *and* a different tone, even though neither one of them is in cutoff for any portion of the output cycle at that low level. This is due to the bias point differences and load line differences. The differences become even more apparent when the amplifiers are run at their full undistorted output power. The true class A amplifier will have no crossover distortion, while the class AB amplifier will. The average plate current for the true class A amplifier will not change, or will change very little, from idle to full output power, while the average plate current in a class AB amplifier will increase dramatically. This will lead to "sag" in the power supply that doesn't exist in the true class A amplifier, which again results in a tonal change.


From Aiken amps. I'm not convinced that class A sounds 'better'.
#10
I based what I said from tube datasheets and them quoting different levels of harmonic distortion for Class A operation as opposed to Class AB operation. I've no idea how that translates into sound terms, but I would assume that means more warmth and slightly more thickness.
The Laney Thread are big and clever. No exceptions.
#11
The difference, to you TS, is nothing.

Nowadays, Class A is convoluted into a marketing term, like "hand wired bypass".
#12
Quote by MrCarrot
I based what I said from tube datasheets and them quoting different levels of harmonic distortion for Class A operation as opposed to Class AB operation. I've no idea how that translates into sound terms, but I would assume that means more warmth and slightly more thickness.

It translates into blowing your amp up. You can't bias your amp into class A without completely redesigning it. There's no point in comparing class A and A/B tone for the most part because you could never really get an amp design that would be switchable between the two. A lot of amps like the Valveking claim that they go from A to AB, but that's not at all what's going on- it just kind of mimics the characteristics of the classes.
Long story short: Class A vs. AB is an irrelevant and pointless argument. There are too many other variables that are much more relevant to tone.
#13
Class A/B can be turned into class A by rectifying. A/B produces AC currents (push/pull) while class A is DC.

I hope my memory serves me right.
#14
^Your memory does not serve you right. The AC signal is rectified long before it hits the power section in any amplifier.
#15
According to Mike Soldano it's possible to design an class A/B amp to sound like a class A.
Jackson KV 2, Jackson COW 7 (both in B), Jackson Demmelition V
Bogner Überschall (blue rev)
Marshall 1960B Vintage (2x V30 & 2x G12T75)
TC Electronic G Major
BBE Sonic Maximizer 422A
Weber Mass 150w
ISP ProRackG
T.Racks Dinopower
#16
Quote by Roc8995
It translates into blowing your amp up. You can't bias your amp into class A without completely redesigning it. There's no point in comparing class A and A/B tone for the most part because you could never really get an amp design that would be switchable between the two. A lot of amps like the Valveking claim that they go from A to AB, but that's not at all what's going on- it just kind of mimics the characteristics of the classes.
Long story short: Class A vs. AB is an irrelevant and pointless argument. There are too many other variables that are much more relevant to tone.
You misunderstand, 'cos I know that the bias will only be varied into Class A by an epic swing in B+, and I agree that the argument is a pointless one and impossible to effectively switch between in one amp, but my original point still stands that a Class A amp running the exact same circuitry will have a few per cent more harmonic dirt than a Class AB amp.
The Laney Thread are big and clever. No exceptions.
#17
Quote by Roc8995
^Your memory does not serve you right. The AC signal is rectified long before it hits the power section in any amplifier.


agreed.


Quote by Roc8995
Long story short: Class A vs. AB is an irrelevant and pointless argument. There are too many other variables that are much more relevant to tone.


also agreed.
I'm an idiot and I accidentally clicked the "Remove all subscriptions" button. If it seems like I'm ignoring you, I'm not, I'm just no longer subscribed to the thread. If you quote me or do the @user thing at me, hopefully it'll notify me through my notifications and I'll get back to you.
Quote by K33nbl4d3
I'll have to put the Classic T models on my to-try list. Shame the finish options there are Anachronism Gold, Nuclear Waste and Aged Clown, because in principle the plaintop is right up my alley.

Quote by K33nbl4d3
Presumably because the CCF (Combined Corksniffing Forces) of MLP and Gibson forums would rise up against them, plunging the land into war.

Quote by T00DEEPBLUE
Et tu, br00tz?