Originally Posted by SwanSong
LT1364CN LT1364CN8 DIP8 Dual and Quad 70MHz, 1000V/us Op Amps
lxr0000527 LT1364CN8 DIP8
New Burr-Brown OPA2107AP DIP-8
Precision Dual Difet(R) Operational Amplifier
2x Voshod 6ZH1P-EV
2x Mullard M8161/CV401
I think these upgrades will give me neutral and warm options to roll in and out?
I'm confused with the opamp usage more than the tubes since I've read some saying adapters needed for dual opamps replacement??
Generally, op amps are cheap, so I suggest you simply try them all to see which you like best. And if you would like to try a couple more, the MUSES02 and the LME49990 are also very good. Currently the MUSES02 is my op amp of choice, but unfortunately, it is not as cheap as the others.
The tubes you have chosen are among the best of the "traditional" tubes, but I would also suggest that you consider getting a pair of 6DT6 (RCA and Sylvania are popular) and 6HM5 (GE, EI and Sylvania - avoid the short squat tubes - get the taller tubes).
I don't have the HE-500 (my HE-300 has dynamic drivers) so I can't help you there....