• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Valve buffer for Purify module

My, those nuTubes are kind of pricey and very specialized. So I’m not sure why everyone wouldn’t just go with a simple 9-pin dual triode which almost grow on trees. The 12au7 is best for low voltage use, being able to run off the amps power rails. You really don’t neec a pcb for this, just a place to mount a socket and then solder up a few parts. And I’m pretty sure there are lots of ready to go options on eBay too.

I’ve had harsh sounding set ups myself and ended up replacing speakers, amps and sources as needed - maybe I should’ve tried a no-gain cathode follower tube buffer. For modest gain there are many pre amp options too such as Salas simple 6v6 based common cathode stage.