I’ve been developing an all-tube rotary-knob DJ console for the soundsystem at Berlinetta Brewing. One idea I decided to experiment with was building the 4 channels of phono pre amps as little plug-in modules, similar to theatre soundsystems of the 1940s and 50s. This would, in theory, allow me to make just 5 of the modules and have “zero downtime” if/when a channel failed. Anyhow, I made one as a demo, and man what a pain in the ass! The device you see above and below uses the classic RCA circuit from their receiving tube manual RC20 plus an additional 6c4 cathode-follower output stage, all built in a tiny grey Hammond box. All i/o and power (300vdc B+, 7vDC heaters) are on an 8-pin Jones for maximum “fake historical authenticity.” It worked out fine, sounds great, very low noise floor, but it’s just too fussy working in that tiny 4x2x2 inch box I will probably end up going with a different solution. Still an interesting possibility though…
