Conrad Johnson PV11 tube noise


After about 2 hours of being on, my preamp will occasionally give a sustained "chirp" or sometimes a longer high pitched ringing sound, pretty basic tube noise. I typically listen at low to moderate levels, and it is therefore often audible during listening. What can I do? CJ says to use the tubes they supply, because it was designed around them, Upscale Audio says that the PV 11 is a pain with regard to retubng, and He wasnt in a hurry to sell me ANYTHING because of this. It simply cant be that this type of noise is just what you have to deal with when you want to use a tubed pre. What do you think I should do?? Has anyone used a PV 11 successfully with NOS or other non-CJ supplied tubes?? Thanks.
gthirteen
Sounds like you have a microphonic 12au7 linestage tube. I had the same problem in my pv11 a couple of years ago. I tried nos 12au7 tubes (tele,mullard,amperex) and found them pleasant sounding but lacking in "liveness" and a bit opaque when compared with the tubes supplied by c-j. I recommend sticking with them. They test and burn in their tubes, and, IMO, are quite reasonable in their pricing.
I find the tubes conrad-johnson sells to be thin and wiry sounding. These are the east german rft types. Dick Olsher says these are head and shoulders above the rest. I disagree. I own a pv11 and have mullards that sound great. Also have had good results with the yugos but they are a little on the tuby side. Whenever I experience a high pitched microphonic tube I turn the preamp off and on and this usually takes care of the problem. I have a friend with a pv11 that really likes the telefunkens and they were sold to him by upscale audio so I dont know why they werent in a hurry to sell you anything perhaps get a more knowledgable person on the phone next time you call.
Its not a tube thing.Some C-J can be picky.Try Tubeworld or vintage tube services if Upscale cant help.all 3 are pretty good sources.The Parts Connection are very good also.
I have PV10al that I have had a proble with over the years and have sent it back to Conrad Johnson but it comes and goes and I have tried about 5 sets of tubes including theirs. Good luck!