Thanks for asking. I-60 is a solid state integrated amplifier designed by local audio engineer Sol Samet. It was finalized Christmas 2014 but he has it back for some improvments. Sol is full of new ideas and he applies them to his existing amps. It is very conservatively rated, with 300VA toroid, it can make >120W>4ohms both channels driven at 20kHz all day. It can kick the living crap out of large full range speakers with <2ohm impedance dips. It has beautiful, clean, incisive, precise high frequency and tonal accuracy. It has very strong damping at all frequencies so it sounds ultra confident and powerful, like a "large amp" sounds at low power output. Output stage bias is low, so it runs fairly cool in normal use. It uses the amplifier chassis as heat sink. Careful temperature compensation makes it sound the same hot or cold. Sol says that using his old HP distortion analyzer the amp replicates his signal generator. There is no visible crossing distortion at full power, 4ohms, 20kHz.
It has always been an all discreet design, but last year it was changed from 3 stage amp to a 4 stage amp with separate preamp and power amp in the same box. The preamp uses an opamp. I was skeptical, but it was a big step forward, and clarity was dramatically improved.
At this time, he is trying different bipolar output transistors, temperature compensation, and tweaking local decoupling caps. I am looking forward to hearing the next iteration. I have had the prototype in my posession several times for long periods, using many different speakers over the years. I have heard it evolve dramatically since 2007 when I first heard it. I tried to order one last year on the previous version, but Sol is too busy and the build is too complicated for P2P. So eventually there will be PCB and either kit or production version.
I would like to say that will be soon, but both of us find it difficult to devote the necessary time to the project. Meantime it just keeps getting better. Sol always brings his latest amplifiers to our G2Gs, so you might hear it and talk tech with him at one of those. He is not active on any audio forums, but I can relay any specific technical questions to him which I can't answer.
There is also an I-15 (which I own,) and an I-30. I also own a LM1875 based current source amp designed by Sol, called C25.
Jason, you probably have heard the I-60 at one of my meets. The prototype is a plain aluminum par-metal amplifier case 3x16x12.
