As with most audiophiles on these forums, my system is in a constant state of motion with minor and occasionally major tweaks and component changes. My latest addition has been a little iFi iTube2 pre/buffer. I was skeptical that it would improve the chain inserted between my Big7 with R2R and my Line Magnetic 518. Well, while the iTube2 was in my system via the AC tour, I did find it to clean things up a bit on vocals, instrumental delineation, and expansion of soundstage depth. So, I bought one of my own.
Now that I have it in the system and am settling into the sound, I have found it to ever so slightly brighten the sound, just enough that the system needs a tweak to bring back into the right balance for long-term satisfaction.
I first tried substituting the Psvane 845TII tubes in for my normal WE845 replicas. The WE845 replicas are absolutely more refined and detailed tubes, but they also shift tonal balance a touch brighter than the 845TII's. The 845TII's are a bit more sluggish, but have a denser/thicker sound that could benefit some systems. Well, I found I couldn't live without the refinement of the WE845 replica's, even though the 845TII's fixed the tonal balance issue.
So, next I decided to swap back to my Marconi U52 rectifier on the Big7, instead of the Lampi Anniversary KR 5URG I've been using. Last night, and now this morning, I think this has done just the trick! Same levels of detail and refinement as before, but with just a touch of warmth/euphony to tame a slightly slightly bright sound.
It does take some not inconsiderable up-front investment to build a tube collection with different characteristics/flavors and at a high level of resolution. But once you have that, it's a very helpful system tuning tool.
This is as opposed to say, cable swaps, which I suppose offer other options for tweaking sound signature, but which I find to have frustrations of their own in terms of system synergy.
Well, anyway, I'm just appreciating the versatility of my Big7's tube swapping options this morning and thought I'd share.