Suggestion to choose potentiometer for tube preamp

I am finishing assembling the Lite Audio LS26 tube Preamp CAT SL-1 preamplifier and I needed some help in choosing the potentiometer.
At my disposal I have:

Alps Blue 50K
Alps Black Beauty 50K

any suggestions are welcome and consider replacement :scratch2:

At the moment given that I plan to use Alps Black Beauty, is it okay as a value?
Thanks 🙂
 
Yes, the Black Beauty will do fine. I have a 100K in my Dynaco PAS3, it sounds MUCH better than the stock pot. Your 50K should work as well.

The Blue doesn't have a lot of love around here, even though it works fine in many of the older ARC preamps.