Instrument Separation and Tone

[Universe Man]

I was just wondering about a couple of upgrades. I am considering doing the speedball upgrade, and I was wondering if I should expect an increase in instrument separation, which seems to be a weaker aspect of the non upgraded unit I have. I was also wondering if anyone can recommend something like alternative tubes or capacitors (not too expensive) that could make the sound slightly darker.

[Paul Birkeland]

I would definitely expect you to hear better separation with the Speedball.  Some of the tubey distortion produced by the 12AU7 is reduced by replacing the 22.1K plate loading resistors, and that will likely accomplish what you're looking for.