This build is to replace a single stage valve preamp with a
jFet buffer\driver stage. This allows a simple
valve preamp to drive low impedance loads. The frontend is a 12AU7 plate
follower with moderate gain and the back-end a Pass inspired B1 buffer. The
buffer stage uses two jFet with one acting as a constant current source. Either
stage could be used by itself but together you get the better of two worlds. I called this preamp "Parley".
The enclosure is a 2U 19”, black stippled rackable. Four
modules: 250VHT\12VDC reg, 18VDC for buffer stage and the valve preamp section.
There are three selectable inputs on the rear and with Alps Blue Velvet pot and
4oz solid brass knob the build is stylish and good sounding. It also
compliments my tube and chip amp, “Number 9” which is in a similar enclosure
and from both the front and back look the same.
