George Benson Fender Amps

[Justin Thomas]

I read that many years ago on the old Ampage site. Don't remember who from, originally. It's then when I learned the difference between "works" an thd "works well."

I've also heard the theory that part of the reason AU & AT7s sound "bad" in AX7 circuits is vuz they're not optimized for the same circuits. Then there's all the data sheets, where the AT &AU are mentioned as "function" tubes, specifically phase inverters or drivers, & AX & AY are listed as voltage amplifiers in audio amps. But I'm sure that someone could build a good-sounding amp out of nothing but AU7s they ganked from an old Hammond...

Justin

[Chuck H]

But I'm sure that someone could build a good-sounding amp out of nothing but AU7s they ganked from an old Hammond...

I had a small tub of au7's pulled from an old Conn organ. I had planned to build a 3W self split amp just for them. I even had it all drawn up. As time passed and I found occasion to use a couple of them I found that many were aged enough that I had to really pick through them to find a good one. So I never got around to building the little amp.

I had another idea to run a bunch of them in a power amp (miller capacitance be damned) just as a lark to see how much power I could get from, say, four in parallel (eight triodes) per side in a push pull circuit (total eight tubes). At three watts per triode (subtract for the real world) I thought maybe fifteen watts. Again, since most of them weren't that good I scrapped that notion too.

As it is I'm using them for reverb drivers with good success. I just pick through them when I need one and cull the ones that don't make the cut. I have maybe twenty left. Of which maybe five are actually ok.