Before you say no good you would have to measure them. Sometimes after burning in they aren't matched. We then rematch them ourselves so those 2 numbers if checked could be matched properly.
"We then rematch them ourselves so those 2 numbers if checked could be matched properly." Cool, thanks for the clarification Dave. I meant that is there were both burnt in or initally measured at "39" an "60", they are enumerated based on mu (gain) rates, so would be different just to clarify.
They came from ars with those numbers. They didn't match after burning in so we just match the current up ourselves. Meaning after burn one tube was out or failed grabbed other singles we have left till we find a match.
Mine are 51 and I also ordered a spare quad set from ARS at the same rating. I'm also running my head with just 2 tubes @ 50 watts in the center position. SOUNDS KILLER!!!!