The now converted 01a preamp is now a RCA - NOS NIB - 6N7. The tube is metal (No!) so not much of a glow and is a dual triode with single cathode. The tubes are wired as a single triode with grids and plates paralleled.
This preamp was designed for me many years back and was originally built into a timber box as “Heavy Metal”. It had heat issues. In the better and classier chassis looks retro and business like. With Alps Blue Velvet remote pot.
I required 0.68uf output caps but had none of that value. But did have four 0.33uf Sprague orange drops. Doubled them up for a near enough 0.66uf. Had them for decades, as the tubes, so time to use them. Most 1W carbon film resistors and some metal film and wire wound. Double Pi HT filtration - 300uf total.
DC on heaters, 260V HT and 2.55V bias. All on point. Gain should be 20db with Rk un-bypassed.
Tubes are run in but the rest new so some complete burn in time required. Sounding relaxed and midrangy with voice a standout from the sound stage. Dead quiet operation with retro-Zen EL34 amp but hummed with my latest EL34 amp. Very happy so far.
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