Hi,

Given its been a bit quiet on here, I thought I would post some of DIY
output.

Here is a link to some pictures of the GM70 amp that I have been working
on for the past eight months.

http://www.lurcher.org/nick/images/gm70/

Circuit is a C3g Pentode voltage amplifier with VR tube screen
regulator, then 300b driver to 1:1 amorphous interstage to GM70 grid.
Output TX 7k amorphous. Driver and 300b supply, series regulator using
6080, ecl82 and 0d3 (Steve Bench inspired). TJ-Meshplate 300b, running
330v @ 55ma. Copper plate GM70 running 1020v @ 110ma.

All transformers by Automatic Electric Europe.

Rough specs, -3dB points (5w into 8ohm) 18Hz, 52kHz. 3% distortion
reached at 42w into 8 ohm.

It was designed to drive a set of large panel electrostatics, but I have
been using the breadboard version driving a pair of Yamaha NS1000's. My
normal 94dB/W speakers are slightly overpowered for them :-).

I can't take too much pride in them, as their owner did the construction
and I did the design and internal build. But I am still very pleased how
they have come out.

--
Nick