Thanks for that. I am using a modified (mainly Blackgate caps) YS Audio pre into a Rogue Stereo 90 power amp on the electrostatic panels of my bi amped Martin Logan Vantage speakers and an Acurus A250 on the base units. The pre came with Phillips Mini Watt 12ax7s which I replaced with Tungsram and then matched RCA NOS 12ax7s which made a hell of a difference. I would replace with RCAs again if I could find someone selling them at an acceptable price
pre amp tubes
Are 12AX7 and 12AU7 tubes interchangeable in preamps and if so what are the differences. Any suggestions for not overly expensive tubes? I have used RCA nos and Tungram before but can I do better?