I don't think I ever got a good answer to my question as to which set of tubes in my pre-amp have the most effect on the sound output. My VAC uses 2 12AU7s (input I believe) and 2 12AX7s for the output-gain.

When I took ownership of this pre, the previous owner had 4 12AX7s in it, which will play but not correctly. One could also use 4 12AU7s but again without good results.

I had several pairs (triplets) of Sovtek 12ax7lps and wxt+ from my previous Sound Valves 101i so I used a set of those along with purchasing a set of JJ Tesla ECC82s. I think they were under $15 a piece.

I recently had some AX7s go bad and am looking to replace them but still have questions.

Is it always best to have both sets of matching quality-price range and MFG?

Would I be best off leaving the AU7s alone and focusing on the AX7s? The PSVane tubes have a pretty good rep so far but I don't want to spend $200 right now.

So I'm trying to decide do I go with 1 set of PSVane 12AX7s or get a set of each JJ Tesla Gold Pin or similar keeping my budget somewhere near $100?