Quote Originally Posted by _JL_ View Post
Hi Justin,

Very nice tubes you have there. I own the two-box L7 DAC and I can confirm the effect of tube rolling. You may also want to roll the rectifier tube as well, yours' 6x5 or 5U4G? I found the Raytheon 6x5 much better than the Russian counterpart.

I wonder if you just plug the 6A3 into the Big7 and run it without modification? I think the 6A3 has 6 volt filament while the 45/2A3 has 2.5V so that means the 6A3 will be running with a very low filament voltage: ~2.5V vs 6V. Similar for the VT-52 which has 7V filament. This may work just fine as tubes are very resilient.

Happy listening.

Jack
Consensus is that for 6x5, the TungSol metal base is best (very hard to find), followed by RCA and Sylvania ceramic bases. All US rectis tend to beat the Russian ones too.

Regarding the L7 tube setting, the circuit auto balances itself for total wattage, so whatever combo of volts and amps that get to 4.5w max and 6.5w max will work....so I have been told.