You're in the wrong forum -- the ST-40 is a tube amp! [Moderator: You may want to transfer this thread to the Tubes forum.]

That said, the ST-40 was the first kit I ever built (c. 1996?) and the first tube amp I ever heard. At the time, I'd never soldered and didn't know a capacitor from a resistor, so it was quite a learning experience. You're right, it's an excellent amp. I still have, use and love mine. It's really a shame that that kit went out of production when the old Parts Connection went out of business.

Unfortunately, I can't help you. I built mine bone stock, as they say (I think there was an upgrade package, which I did incorporate when I built it), and haven't touched it since.

I think what you want to do is convert the EL-34s from pentode to triode operation. Perhaps the people at http://www.partsconnexion.com , the de facto (not legal) successor to the old Parts Connection, have retained the know-how to give you guidance. Have you tried contacting them? If they do have advice, please post it here. I'd be interested. Good luck!

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