information on Brent Jesse's website (I'm only a customer) on brands , sounds etc., as well as available individual tubes and related assessments
http://www.audiotubes.com/12ax7.htm
http://www.audiotubes.com/12ax7.htm
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?