Selecting a volume pot for specific output impedance

[Jphillips]

I'm building a power amplifier to match with the Smash preamp and I'm trying to select the correct volume pot. The Smash preamp lists it's output impedance as 1.6K, and states that it works with any amps that have an input impedance of 10K or more.  Am I correct that the general rule is 10:1, which would put the volume pot around 16k? Assuming this is the case, would 20k pot be a good choice, or would it be better to be up around 50k to be safe? I know in general the expectation is to go as low as possible, and while the Smash may "work" with a 10K input impedance, I was wondering what is optimal. In general, what's the best way to go about matching these?

[Paul Birkeland]

Can you describe the power amplifier you're building?  To some degree, what follows the pot at the input of an amplifier may also dictate the value range of the pot.

[Jphillips]

It's for a Tubelab SSE http://tubelab.com/designs/tubelab-sse/schematic/ a single-ended amp running (in my case ) KT88s.

[Paul Birkeland]

50K seems like a decent compromise there.

[Jphillips]

Great, thanks. That's what the default recommendation is as well. Out of curiosity, what other factors did you consider? I'm still learning how all of these pieces fit together so any other insight would be much appreciated.

[Paul Birkeland]

The Tubelab board and the Stereomour I have similar Miller capacitance.  Stereomour I was OK with 100K, but I think the Stereomour II is a little nicer on the top with some reduction in the first stage Mlller capacitance due to a minor design change, so it's more just based on experience that 50K ought to be a good place to be. 

Alternatively, you could estimate the miller capacitance and worst case scenario impedance driving that with the pot at 50% of resistance in its rotation, then see how bad it actually is.