Been wanting a single 12 pin tube amp for a long time to use as a tube tester. Since finding a single tube 12 pin amp is almost unobtainium, the only one I know of is the Maco 75. Yeah, I know I have a Maco Super 75, but it is a 2 tuber, plus the Maco 75's run about 1kv on the plate. A M-2057 may handle that, but the rest of the tubes won't. So, I got this Palomar 90A on Epay. I had this in mind with it from the start. Lots of room, and simple enough design, pretty easy to convert to a single tube. I did see why many don't like this amp though. Tubes are cooking as soon as you turn the amp on. No cut off bias, and no disconnecting the HV or screen during standby. You turn it on, tube(s) are drawing power. As said in the video, the Palomar 300A which is considered a very well made amp, cuts off the tubes in 2 places, the HV and with the bias. The Palomar 350Z only does it with the Bias, and this amp doesn't do it at all. Meaning it could let the smoke out even in standby. Anyway, since I plan on using it as a Tube Tester, I don't care much about that. May mod it one day if I got some extra time, but not today. With a hot tube, does 60 dead key, 75 rms swing and 150 peak swing. Thats pretty freakn good from 1 tube. However going thru my pile, some do..... and some don't. Funny how even a good mutual conductance tube tester like my Sencore or B+K will show good, put the proof is in the pudding. No fooling this 'Tube Tester'. Not for sale, as I need it to go thru my scrap pile of 12 pin tubes.
