Right now my only tube piece is my phono amp which uses 6922s.
What I care about most is noise. Roger Modjeski's Tube Audio Store tests all their tubes and hand selects them. They then sell them in grades. Their Super Low Noise 6922s were embarrassingly quieter than the stock tubes from ARC. I keep the thing on continuously. The tubes are 6 years old and as far as I can tell going strong. I have a spare set of tubes just in case something happens so I will let the working tubes go as far a they can. If you have a tube unit do check Roger's site. Every tube he sent me is dead quiet. The SLN tubes are more expensive and worth every penny.
What I care about most is noise. Roger Modjeski's Tube Audio Store tests all their tubes and hand selects them. They then sell them in grades. Their Super Low Noise 6922s were embarrassingly quieter than the stock tubes from ARC. I keep the thing on continuously. The tubes are 6 years old and as far as I can tell going strong. I have a spare set of tubes just in case something happens so I will let the working tubes go as far a they can. If you have a tube unit do check Roger's site. Every tube he sent me is dead quiet. The SLN tubes are more expensive and worth every penny.