Kjl1065, I really don’t see a need to purchase EL34 power tubes from Brent. I’ve gotten tubes from him in the past and everything worked out well but you’re gonna pay very high prices for the tubes. I have several tubes testers in my home so I’ve been able to buy tubes off many site at reasonable prices and test and match them. When it comes to 8 power tubes, it makes sense to buy them new on the many website available including eBay. I’ve purchased many new tubes off eBay with fine results. You opened this topic mentioning you presently have Sovtek EL34’s in your amp. If it was me, I would leave the Sovtek’s in. This is coming from someone that owns a ton of tubes. I personally don’t like Sovtek. In comparison to other tubes, I’ve found them lacking a little in openness and fleshing out the music in an immediate way. But recently I setup a headphone system in my house and didn’t quite like the balance of tone I was getting from the system so I began rolling some tubes and I started with one of the small input tubes on the headphone tube amp. Well I had some really great tubes in my collection, Telefunken, Amperex, RCA black plate, GE, Tungsol, Raytheon etc. The tube I settle on that gave me the sound I preferred the best hands down was a Sovtek and I don’t like Sovteks but for the synergy, it was the one I liked the best. Many of the more popular tubes I tried did sound clearer, and more detailed with greater resolution than the Sovtek but the Sovtek gave me the perfect balance of what my headphone system needed. So even though I’m not a fan of Sovtek tubes, I would keep yours in your amp and tweak around them. If you really feel like you want something different, there are a lot of really good new EL34 tubes available. I wouldn’t bother with anything vintage since you need 8. Sometimes people buy the best (clearest) sounding item and it’s not a good match for their system. So I wouldn’t bother be careful trying to buy the best EL34 tube.