Need help choosing replacement tubes for my 211 SET

@testpilot Old post, but it is worth a shot: My preamp has a bundle of 6SN7 Electro Harmonix and someone recommended Sylvania 6SN7 as a replacement. Do you have an opinion?

Not sure the tubes are the problem. Sit tight and see what else might be the problem. Tubes generally last a very long time.

Before you invest in changing out the 211 tubes, swap out the 6SN7 driver tubes first as they have a significant impact on the sound of the amp

I think that you first try to determine if all the tubes are getting tired or if just certain pairs or a single pair. My experience is the greatest benefit comes from replacing the smaller driver tubes in the amp. Determine which tubes most directly handle the incoming signal and these are most likely the most critical. Old stock 211s are almost impossible to find at a reasonable price so look for old stock with the other tubes in this amp. If you are using 6SN7s then you have many good old stock tubes to choose from and much is available online about the best in this family. If you buy a pair of the very best 6SN7s I think that you will experience a significant improvement over the stock current production tubes. It would be good to know what tubes this amp uses. Hope this helps.