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previous: Brutus Yes in general I'd say that you are... -- 10/5/2004 2:01 AM

Re: What tube amp to build next?

10/6/2004 7:28 AM
Greg Simon	Re: What tube amp to build next? Hi Brutus. When I said Class A wasn't really Class A, I was only referring to the examples you mentioned, such as the AC30. That amp and others that people commonly point to as being 'Class A' aren't. We all know that single ended stuff is Class A, but I would tend to say after reading Randall Aiken's paper about it that the only way an push-pull amp could be considered as being Class A would be if it was that way throughout it's operation. So the voltages have to be lower for that to even be a possibility. I remember that it even alludes to that somewhere in the Radiotron Handbook, but don't ask me to find it again. That book is too damn big and technical! I think biasing to one end or the other doesn't alter the fact that your amp is still going to be Class AB for part of the cycle, depending on what the volume is. That means it isn't Class A from what I've been able to ascertain by reading Randall Aiken's paper and others. Greg

10/6/2004 7:28 AM

Greg Simon

Re: What tube amp to build next?

Hi Brutus. When I said Class A wasn't really Class A, I was only referring to the examples you mentioned, such as the AC30. That amp and others that people commonly point to as being 'Class A' aren't. We all know that single ended stuff is Class A, but I would tend to say after reading Randall Aiken's paper about it that the only way an push-pull amp could be considered as being Class A would be if it was that way throughout it's operation. So the voltages have to be lower for that to even be a possibility. I remember that it even alludes to that somewhere in the Radiotron Handbook, but don't ask me to find it again. That book is too damn big and technical!
I think biasing to one end or the other doesn't alter the fact that your amp is still going to be Class AB for part of the cycle, depending on what the volume is. That means it isn't Class A from what I've been able to ascertain by reading Randall Aiken's paper and others.
Greg