Hi,

So, what are the advatages/disadvantages of using a tube like a 12AU7 in the poweramp section of an amplifier? I've noticed smaller amps like the Revelation Serena and Retroman Retroplex (I think the Stephenson Stagehog?) do this. They will have a typical 12AX7 preamp section and then follow it with a poweramp section of 12AU7.

What can you tell me about this? Is this a bad idea? I'm really green on this type of technical stuff and need some help on the issue. I'm going between a Retroman Retroplex and a Gries 5, very different amps. One is blacface, single-ended, and follows a typical Champ style circuit. The other is voiced Marshall, 1/2 watt, and uses a 12AU7 as poweramp section.

This is for home use only I should say. What do you think?

Thanks.

Are you wanting the amp for clean home use or are you expecting to push it into distortion? The difference in those circuits is powerstage wattage/headroom. If you are going for clean with pedals for dirt, I'd get the Gries. If you want to push the amp into overdrive at home, I'd get the smaller one.


D

quote:

Originally posted by dk_ace:
Are you wanting the amp for clean home use or are you expecting to push it into distortion? The difference in those circuits is powerstage wattage/headroom. If you are going for clean with pedals for dirt, I'd get the Gries. If you want to push the amp into overdrive at home, I'd get the smaller one.
D

Either one would probably work for me, clean/pedals (Gries) or poweramp distortion (Retroman), I was just curious whether there were inherent flaws in such an amplifier design. I guess this just invites a philosophical discussion of what constitutes a "preamp" or "poweramp" tube and why. I personally don't know. I mean, I know Emery Sound uses tubes that were originally meant for car radios in the Microbaby, so is it any different using "preamp" tubes as "power" tubes? Aren't tubes just tubes or not? Enlightenment here would be good for me...figured you guys could help.

Thanks.

I'm no expert, but I wouldn't imagine there would be any inherent flaws as long as the circuit was designed properly. The Zvex nanoamp uses tiny little tubes and it will power a 4X12 cab. I think the designation between power tubes and preamp tubes just comes from their traditional uses in bigger amps. I think what those designers are trying to do is to get a big Marshall amp sound by running the tubes in a push-pull arrangement. This sound is different from the normal Class A low wattage amp sound.

Thanks guys...I appreciate the help a lot. I know these are two very different amplifiers. The Gries is very traditional I know, save for the master volume etc., I just wasn't sure about the other one.