Sub-miniature tube preamp

[Blurry blur]

Low output impedance sounds good to me and maybe it's not needed but I faintly remember something about these vintage orange amps "sound" having alot to do with cathode followers...but I could definitely be wrong there.

Danger of Frying expensive music equipment is not in my plan for this project.

Here's the circuit I "borrowd" from

[fryingpan]

How did you choose those values? (They're wrong  ).

Wrong how??

It NEEDS an output coupling capacitor or what comes next may smoke. It IS over-complicated-- direct coupling can work.

Direct coupling can work (probably will work) but a 100k cathode resistor is probably a bit oversized for a 10k impedance (a very plausible power amp). It may not matter, depending on input sensitivity, but I would make it smaller. Also, the top resistor needs to be worked out for proper bootstrapping. (Which you won't need if you directly couple).

Output cap, hm, a 10u capacitor would be more than fine if you don't want it to have any impact on the low frequencies (which should have been dealt with prior to the last stage anyway).

[Blurry blur]

Ok thank this should help

[PRR]

a 10k impedance (a very plausible power amp).

You have a long memory.

You don't want to plan to drive 10K with little triodes, without checking the available data.
https://frank.pocnet.net/sheets/137/6/6021.pdf   page 6
The guys trying to sell this tube to happy designers suggest DC loading 47K or up, with AC loading 100k or more. As cathode follower you can do 100K 100K and 100V supply, 8Vrms out. But the proposed use is in an FX loop where signals are lower and impedances higher.

[fryingpan]

Dunno about that. My old bass amp, for instance, had a 33k input impedance into the FX return. I am assuming the OP wants to use a tube preamp into a solid state amp, presumably a combo maybe.