The lastest is that yesterday I put together the first prototype board just back from the PC card house and installed it in a prototype chassis.
The board works perfectly, only one minor bugger, I got the polarity marked backwards on two small bias supply capacitors, requires only a fix to the silkscreen printing on the board.
Anyway, the new full ground plain shielded board works perfectly, even better than expected. The noise level from the amplifier is VERY low, about 2 mV peak to peak broad band, with either open or shorted inputs. The stability on high frequency square waves is excellent too, better transient response and linearity than ever. There must be something good about the low impedance ground plain and laying it out so that the charge current ground path from the first supply cap is isolated completely from the board ground.
Musically, its a winner, hard to describe, none of the mud or rounding of a typical tube amplifier, and of course no solid state glare or grain either. It sounds much more powerful than its approximate 30 watt per channel rating, doing a darn good job of driving a set of 85 dB efficient Salk Veracity HT3 speakers.
Next step is to fit a set of Magnequest output transformers that are supposed to ship to us this week, then if all goes well do a go for production.
Price, have not figured that out yet completely. Likely somewhere between $1500 and $1800 for a factory wired unit. Kits will have a several month wait as I will have to write and debug a complete new build manual.
You will like it when you hear it.
Frank Van Alstine
