Circlotron amps are terrible. You should sell them to me really cheap. That will save you headaches and Keep your conscience clear.

I think the Atma-Sphere OTLs use a variation on the circlotron design. No idea how the EVs sound though. If they're not cheap, you could almost certainly build something better for less

Roscoe

Okay, clarification here. Roscoe and I were both assuming that this was an OTL design. Not the case; there is an output transformer. The advantage in this circuit may lie in that the output tubes are functioning in cathode follower mode. Cathode followers have very low distortion compared to grounded grid or grounded cathode designs (think degenerative feedback across the cathode resistor). That's the good news. The bad news is that the gain of a transformer coupled output stage in cathode follower mode is going to be way less than unity.

So the demand for gain falls on the input stages. That gain needs to be very large and controlling the distortion there is another problem. Broskie has written on it extensively, I'd read up. Dave Berning has an opinion on the CF output stage as well. Maybe he'll chip in here.....

Personally, at $2k, I'd pass on them. Not even close. If it was an OTL design, I'd have to hear them, because I'm thinking wholesale rebuild with modern parts.

I think collector value and non-DIY users would be interested in this. As for a DIY guy, I COMPLETELY agree with Roscoe....Do It YOURSELF for lots less and a better finished product!!

Stuart