When to replace pre-amp tube?

Done!!! Thuaile, i think you are in very good shape. good luck and enjoy!

Thanks for fixing it :)

Anyone with tube equipment should keep spare tubes on hand because you never know when you can have a tube failure. If you think your tubes are getting worn you can try a new tube and see if you hear an improvement. If you don't hear an improvement your tubes are ok.

NOS tubes last much longer than new tubes. This is something else to factor in when considering cost.

08-28-11: Rrog
Anyone with tube equipment should keep spare tubes on hand because you never know when you can have a tube failure. If you think your tubes are getting worn you can try a new tube and see if you hear an improvement. If you don't hear an improvement your tubes are ok.
Rrog (Answers | This Thread)

Rrog, I agree with you. Now tell me where I can find another new MP of 60's Siemens Cca for my preamp at a REASONABLE cost? :-)