[TKonrad.NOLA]

this is the first piece of equipment that I have ever own with a tube in it.  I have read that changing out the stock russian tube would make a significant difference.  What tube would you suggest I try?  Its a 6922 tube.

[Tyson]

The usual suspects - Amperex and Siemens are about the best you can get (sometimes labeled as 6dj8), with GE and Philips being a slight step down, but still far better than the Sovtek russian tubes.