class A operation

[Nightburst]

I think I prefer class A over A/B as I found out just a minute ago.
The tone is just way more crunchy,creamy warmer and complex.

I've read that operating an amp on class A is very hard on the tubes, my question is: how hard is this on the tubes exactly?
And how does it differ from class A/B operation?

 

[Hellion]

Re: class A operation

I'm sure this will come under fire, but I've always equated Class A amps analagous to a diesel engine. High RPM, lots of torque; ie High plate voltage, lots of response. I'm not sure there's a lot of difference if any in time between retubes. Obviously they wear out, but as to how long between, I'm not sure. I like the sound of Class A amps a lot, but I've always been able to get the same response from A/B (at least the response that I was looking for).

 

[seafoamer]

Re: class A operation

I like operating class A amps under the influence of class B substances.

 

[Curly]

Re: class A operation

you might check Aiken amps tech info. He has some good info on class A operation.

 

[Nightburst]

Re: class A operation

I'm sure this will come under fire, but I've always equated Class A amps analagous to a diesel engine. High RPM, lots of torque; ie High plate voltage, lots of response. I'm not sure there's a lot of difference if any in time between retubes. Obviously they wear out, but as to how long between, I'm not sure. I like the sound of Class A amps a lot, but I've always been able to get the same response from A/B (at least the response that I was looking for).

Interesting, but I don't think high RPM with diesel engines is correct.

I notice it on the clean channel the most, class A is much fuller sounding.

I like operating class A amps under the influence of class B substances.

Lol, as a matter of fact I opened a bottle of class B Bourbon last night. Very smooth. :13:

Thanks Curly, that's a good read, very technical!

I'd love to hear some personal experiences here as well.

 

[Kent S.]

Re: class A operation

IIRC Class A conducts the signal for the full cycle of the wave, start to finish, where as class B conducts for half the wave ... most class B's are quite true as they tend to conduct a tad over. Class A tends to run a bit hotter than Class B, you get more headroom with class B then class A. I haven't really seen that it shorten tube life dramatically or anything, but I would ventilate more with A. You don't get the power with class A that you can get with Class B, and you get greater dynamics with B and more compression and more even ordered harmonics with A ... they do run hotter though, but i don't realy think it's anything to be concerned about, does it shorten the life of the tube? Yeah, how much so percentage wise ...eh, couldn't really say maybe if a calss B lasts 100%, then maybe a class A would be 90~80%, but that's only a real rough guess mind you.

 

[aleclee]

Re: class A operation

AFA tube life goes, the tube's output current is max at idle. Basically, at any volume in class A operation the tube is working like a class AB tube at max output.