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!


Showing 1 response by larryi

I would NOT leave the linestage on all of the time. That will shorten the life of the tubes as well as other components (heat shortens the life of capacitors and resistors).

Your Cary has tube rectification which provides a soft start turn on of the tubes. There is no benefit, in terms of preserving tube life, to leaving the gear on all of the time. There is also a small risk of fire from leaving gear on unattended.

Small signal tubes, like the 6sn7 can last quite a long time, provided that they are run well below specified maximum parameters. It appears, from your experience, that that is the case with your Cary linestage. Still, with valuable tubes, it makes little sense to use them up heating your room--they are NOT making new tubes that are comparable to some of the better 6sn7s of yesterday.