six year old 6sn7's, pushing my luck?


I retubed my Cary SLP-05 with Pope tubes about 5 years ago. I leave the preamp on pretty much all the time except when I go on vacation. That comes to about....45,000 hours. The tubes are supposed to be good for 10,000.

And...I've experienced no noticeable degradation in the sound. I heard a clicking sound once when I turned the system on after a week's time off, but I jiggled the offending tube and the sound stopped.

I've experienced tube failure and noise and rush in other systems, but this one seems to be the Energizer Bunny of tubesets.

I wish those Pope tubes were still available for a reasonable price, but Upscale now wants $275 per tube, and I need 6 -- I just cant justify 1650 to retube the preamp, but for now maybe I don't need to.

Any thoughts on this? Have you had tubes that lasted like this? Could they be degrading so slowly that I don't notice? Am I taking any chances with my equipment?

Thanks much and happy new year!

Rich
rbirke
Hi Rich

You may not THINK there is a degradation of sound but are you sure you are not maybe acclimating? it can be a subtle process and 45K hours is a LOT of hours, depending of course on the circuit and the quality of the tube itself. The only way to know for sure is to test the tubes if you can. Aside from testing trying a good set of new tubes will tell you what you need to know. I agree with Brownsfan, the Sophias are really excellent sounding tubes and worth having around if you can swing the 600.00 it will cost you. They stack up well sonically with ANY 6SN7 type I've heard.
I just put some new EH 6SN7 in my Supratek pre and they sound great. There is no need to spend a ton of money on expensive tubes IMO.
If you throw a frog in hot water; it will try to escape immediately. Raise the temp, a degree at a time, over an extended period; it will complacently remain, and boil to death(in agreement with Tubegroover). Get some NOS tubes, try them, and I'll bet there is a marked improvement. If not: you haven't lost anything! They will be put into service eventually. I've a stock of TungSol round plates, Sylvania tall bottle Ws, Sylvania and Ken-Rad 6SN7GTs for that day. Forget about newly manufactured tubes. Even your old Popes will sound better.