I purchased one in 1978 and had it upgraded to the QMI 300 when Quatre was purchased by them in 1980 IIRC. I ran it with Maggie II A & B's. It never blew up on me but I did hear the horror stories about it. Also, when it gave itself up to the audio ghost it liked to take the attached speakers with it. The problem has something to do with passing a 60 hz burst. They were limited to early manufactured units ann was fixed when the issue reared it's ugly head. One of the audio magazines gave it high praise and then retracked it when this issue first surfaced. It caused the company to decline and eventually to get purchased.
In 1992, I gave it away to my previous neighbor's son who was just getting interested in high end audio. Along with the QMI, I gifted him an Audionics BT2 preamp because the two seemed to have great synergy. Recently I visited with him and it was still in operation, but there was some noticeable mechanical hum coming from the transformer. It didn't pass through to the speakers and still sounded pretty good. Gain cell amps are one of those interesting designs. I will pass the repair person's name on to him so he can have it brought back to spec if it's cost effective.
L
In 1992, I gave it away to my previous neighbor's son who was just getting interested in high end audio. Along with the QMI, I gifted him an Audionics BT2 preamp because the two seemed to have great synergy. Recently I visited with him and it was still in operation, but there was some noticeable mechanical hum coming from the transformer. It didn't pass through to the speakers and still sounded pretty good. Gain cell amps are one of those interesting designs. I will pass the repair person's name on to him so he can have it brought back to spec if it's cost effective.
L