Back in 1970'Th I used to be a student of an Institute of Automated Control Systems and Radio Electronic, TIASUR. Audio was my passion, I played in a rock group, and designed for it amps, guitar effects, synthesizer, mixers, etc... I thought when I graduated in 1981 that I know precisely what is needed to get the best audio reproduction, that tubes were obsolete, transistors were the best. My last audio amplifier then delivered 200W per channel, I thought that it was perfect, and nothing better can be done...
...until in 2002 in a small high-end store in Walnut Creek, California I dropped my jaw when heard as if a real Diana Krall playing and singing. The amp was single ended with 211 output triodes, something like 10W per channel, and very inefficient Magnepan speakers, huge like doors. It was not loud, but soo reeeal, I got goosebumps, and sphincters almost unleashed!
Since then I started again, with vacuum tubes, trying to get as real as possible sound reproduction. I had my day job in software development industry, but could not shake off the desire to make my own high end equipment. My previous experience with tone shaping for rock group appeared handy, instead of creating audible musical distortions I felt and knew what is needed to make distortions as if to disappear. And now since my job is my passion, I am eager to bring to the market what I finally earned to do: affordable equipment of high end quality of sound reproduction.
In short, Back in 1980 I designed what I though was the best amplifier. It was 200W per channel fully complementary ultrafast wideband opamp.
In 2004, after hearing in 2002 real high end for the first time in my life, I designed 100W per channel push-pull amp with military output tubes.
In 2009 I designed 100W per channel hybrid amp with augmented SiC source followers loaded on modulated CCS,
and finally in 2018 come to 6W per channel single ended amplifier, with regulated power and 3 nested feedback loops.
Well; I forgot to mention that I did not jump from 100W per channel transformerless hybrid amp directly to 6W per channel amp. Between them were 5W per channel triode class A2 amp without feedbacks, and 45W per channel single ended class A2 pentode amp with 3 nested feedback loops, similar to current 6W per channel amp, but much more expensive, and consuming half a kilowatt of electricity constantly. While I love my 45W per channel amp with military transmitting output tubes, it consumes more than half of kilowatt electricity, and I found it impractical, since high end quality speakers with 92 dB/W/M and better sensitivity are widely available, and 6W per channel amp is quite adequate, and many of NOS and current production tubes are available for such amps.