(05-22-2018, 05:56 AM)slider313 Wrote: I usually find hum after warm up to be tube related. Have you tried a couple of different 6SN7's?
Yes, and maybe not. I have swapped a number of different tubes. But it's not like I've kept records, and I have been chasing after a number of different issues. So it's a good reminder to go back and revisit the possibility. Also, one has to remember that my stock of tubes are all early production, from only a few manufacturers, so there is the possibility that they just all suck in this spot of the circuit.