I’ve spent a bit of time rolling tubes into my mid monos and I recommend that you purchase the best NOS 12ax7 and 6dj8’s you can afford. I wouldn’t waste any more money on new production tubes. Even the Psvane 12az7’s don’t sound as good as a pair of quality NOS tubes. I’ve had good luck with Brett Jesse, but there are plenty of reliable tube vendors.
For output tubes I like in this order
Mullard xf2 double getters - I came across a quad for cheap, but they aren’t worth the money.
Old production Tesla’s
Winged C’s - these are the tubes I use everyday.
Gold Lion KT77’s. Decent current production tubes.
My other suggestion is to upgrade the output caps. I have Mundorf Supremes, but I’d also recommend Audio Notes.
I know this all sounds extreme, but the amps are relatively affordable and they Respond well to better tubes - a testament to the design and construction of the amps.
For output tubes I like in this order
Mullard xf2 double getters - I came across a quad for cheap, but they aren’t worth the money.
Old production Tesla’s
Winged C’s - these are the tubes I use everyday.
Gold Lion KT77’s. Decent current production tubes.
My other suggestion is to upgrade the output caps. I have Mundorf Supremes, but I’d also recommend Audio Notes.
I know this all sounds extreme, but the amps are relatively affordable and they Respond well to better tubes - a testament to the design and construction of the amps.