I'm looking for a new amp in the £300-400 (\$600-800) and have been particularly interested in the peavey valveking. one thing they make a lot of fuss about is the texture control that can be switched from a class A to an A/B.

What does that actually mean in terms of sound? where do the class types come from?
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Nothing really in terms of sound.

In terms of the classes, its relatively complicated, but essentially it means that the voltage at the plate is constant whether your are playing or not when in Class A, though in Class AB the voltage is always changing IIRC
if it makes no difference to the sound then why bother having the feature, and why does every review make such a MASSIVE thing about it?

still a bit confused as to how the voltage thing works... :s surely if you keep a constant voltage accross the plates you won't get any signal => no sound?
i'm taking an engineering degree so you can get as complicated as you like in your answer i'd be really intereste dto know
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Quote by doive
if it makes no difference to the sound then why bother having the feature, and why does every review make such a MASSIVE thing about it?

still a bit confused as to how the voltage thing works... :s surely if you keep a constant voltage accross the plates you won't get any signal => no sound?
i'm taking an engineering degree so you can get as complicated as you like in your answer i'd be really intereste dto know

IMHO The "texture" control is just there to move units, though I'm sure some will disagree.

As far voltage across the plates is concerned, I wrote that down wrong. What I meant was the negative bias on the grid. For so-called Class A operation, the entire bias supply can be eliminated (saving a lot of expense) and a simple resistor connected between ground and the power tubes can serve for biasing. Essentially Class A means that the grid bias and alternating grid voltages are such that plate current in a tube flows at all times. I'm not technically proficient to tell why exactly this works, so I'll let Randall Smith explain it:

http://www.mesaboogie.com/US/Smith/ClassA-WebVersion.htm