I have a sleeve of these, and they look like they would work just fine as a preamp tube. Gain of tube 1 is 64 and 2 is 5.4.
Maybe a VA (tube1) into a CF (tube2)? Or even the other way around? One thing that is difficult about preamplification is taming the gain. Even an SRPP with the 12AU7 is too much for most amps, and you can barely click the potentiometer to 9 o'clock with an average 1V to full output amplifier.
So maybe VA using the 5.4mU section into a CF using the higher gain tube?
With the higher mU as CF, would that sacrifice the benefits of the CF lower output impedance?
I'm actually going to build a preamp for myself for once, and want to try something different:)
Thanks!
Blair