My post a few days back highlighted the work on the Stealth GM70 project as noted here: "Just a quick update on the "Stealth" project. We have a fully working single channel prototype now working on the bench. To recap this is a GM70 triode tube based project. Highlights: High voltage 850 volts DC is [...]

Progress! The "Stealth" SE amplifier project design is moving right along. This is over at my friends lab yesterday. We were proving out the output stage design and DC current feedback regulated filament supply for the GM70 tube. This is a very special design of supply it keeps constant current across the filament and is [...]