Tube Amp, Preamp upgrades -- what did you do that improved your units?

Yes on the .27uf combo from Audience or Sonicap. Both should be a step up. I am basing this on the parts quality used throughout the amp which are modest. Someone is making the QS caps, but I am fairly certain they are not quite up to the Audience XO level of quality.
Yes on the 47uf preamp caps. I added the bypass idea which is a no brainer and will yield sonic improvement. Look up the dimensions of this Mundorf cap and be sure they will fit. Just make sure. I bet they do, but……

I swapped out Gold Lion 6SN7's for NOS Ken-Rad's in an amp and got more bass definition and depth, which I liked in my system. The Gold Lions might be smoother on higher frequencies.  Not cheap on a per-tube basis, but no big deal in the overall allotment of audio funds.

@grannyring Thank you. I'll communicate with my tech on this. The additional bypass cap is not something I anticipated and we'll discuss. 

Do grannyring's suggestions, these may be end game pieces for you then. While I've not yet tried the ODAM, I will drop them in my phono pre in a bit. Reportedly right up there in sound quality with best, and their relatively smaller size vs. film caps makes them better, easier fit. Other parts he mentioned I've heard or modded with, all good. I'm using the Airlock for all my diy power cords, better than Duelund here.

I'm using combo of silver litz and Duelund copper internal wire, Duelund silver bypass cap on power supply in my custom 300b monoblocks. Flavor wise, wonderful timbre, extension on top, controlled bass. I know the silver internal wire and Duelund silver bypass has much to do with attainment of this sound quality. I'd presume the ODAM with Airlock silver would be avenue for you.


I'm not sure all techs will take on custom work, many frown on customer spec'd parts substitution. Don't want the liability if you're not happy with sound and/or don't trust you're substitutions are correct for circuit.

I'm not sure all techs will take on custom work, many frown on customer spec'd parts substitution. Don't want the liability if you're not happy with sound and/or don't trust you're substitutions are correct for circuit.

I'll need to confer with him. Doing caps with exact value matches and not much else would be a decent upgrade and would minimize risk. The preamppot seems very doable We'll find a happy consensus, I'm sure.