Here is an update on development of Joseph's SET amplifiers. I have been listening to an EL34 SET amplifier in a compact chassis that uses 5 tubes (2 each EL34 as power tubes). Previously I described the very good music I received from it. Low power and very good sound - dead quiet as are all of Joseph's products.
A couple of weeks ago, Joseph brought a new SET amplifier that he wanted to listen to in my system. It had a larger chassis, 6 tubes (2 each EL34 power tubes), several transformers; it must have weighed more than 50 lbs. We listened to it for about 1 hour. It was much better than the amp I have been testing. More detail, more bass control, more air in upper frequencies; a lovely midrange.
The following week, I had shoulder surgery, so I've been laid up at home. On Friday Joseph called to ask if I wanted to listen to another amplifier, different from the first two amps. He brought me to his listening room, where I listened to his system for about an hour.
This third amplifier was in the larger chassis and used 845 power tubes with multiple transformers. More powerful bass control and better high frequencies; however, I thought that the midrange of the 845 amplifier was not as open as that of the larger (second) EL34 amplifier.
There are two SET amplifiers under development. Both are larger (and better sounding) than the sample to which I have been listening. The amp I have been testing appears to have been a prototype for the two subsequent amps. Joseph told that the peak power of the new SET amps I heard - and which may not be the final versions - are <10 watts (EL34) and <40 watts (845), respectively.
