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Best Way To Maximize Preamp Tube Life?

I would love to learn how to best maximize tube life. Tubes have a limited lifespan, of course. So when you're not listening for a time, is it best to shut everything off to preserve the "hours" left on the tube's life? OR does the act of powering off/on itself shorten tube length as well? If so, by how much? Something like "powering off/on costs 3 hrs of tube life, so taking a music break of less than 3 hours, better to just leave it powered on." Or 1 hr, or 10 minutes, 6 hours, etc? Where is the tradeoff point?

In my system FYI, I am running a Don Sachs preamp with 4 6SN7s and 1 6BY5 rectifier.  Don says the preamp is only running the tubes at 40% of their rating. I would greatly appreciate some input from people with tube knowledge. Thanks in advance!
sid-hoff-frenchman

Showing 2 responses by oldhvymec

oldhvymec
5,101 posts
 
Just don’t use them, they will last forever..

Read ON..

Kind of like running tubes in a MM or MC phono circuits but you use neither and use and external phono pre amp..

Pull the valves.. It won’t hurt a thing. Save them for when you need new ones.. I’ve done it for years with Macs.. New and old.. Pull the phono section you are NOT using and leave the one you are. Either or but quit burning up valves..

Do you know how many perfectly good Telefunken and RCA prime 12AX7 have just been BURNT UP? Me neither, a BUNCH is a good guess though. :-)

If people new.. now they do...

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Off topic a bit OP I’ll erase it if you want..

Here is a cool one, I can bias up 4, 8 or 12 valves on my V12R Cary. Just depends how LOUD or LOW I want to go..

4 valves total of 6V6 is @ 15 - 20 watts total (2 valves per side).
OR 12 valves of KT88 or 90s at 200 + watts. (6 per side) 100 + watts per side at 8 ohms.

I can get an easy 90db from just 4 valves (about 10 watts per rail or channel) and small planars.. I get a little tube breakup if I REALLY crank it.. Ribbons or small planars aren’t to fond of a goofy wave pattern, you do need to be aware of that..

I bias cool and really get the watts UP, if I’m cranking it. I bias HOT for late night low volume listening.. Nuggets for ALL to share.. They all save valve life and save a few quid to boot.. Electric bills and valve cost...

Regards
oldhvymec
5,101 posts
 
Pulling tubes and running a circuit without all them in there is absolutely the WRONG thing to do unless you know exactly how the circuit is designed. You can destroy a filament supply (or a tube in it), or overwork a B+ (high voltage) supply if the circuit is designed to have all the tubes in it. I have rebuilt well over 500 pieces of vintage tube gear.

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That's why you preface it with Mcintosh, What's WRONG is telling people it's WRONG..  I've yet to work on any Mac valve amp that you couldn't plug and test voltages without valves, add the valves in the circuits and keep on testing.. NO LOAD either, I've NEVER had a problem..

I guess I'm lucky, or maybe ol Mike Samra was right.. I don't know a better tech on Vintage gear anywhere, and MAYBE one Mac tech but he retired. He was a great repairman BUT he wouldn't rebuild Mac gear only repair..

I'm sure Terry Dewick was wrong, TOO.

BOTH guy helped me a few times

BOTH recommended pulling valves.. I wonder who's right?
Hmmm?

OR continue to BURN up perfectly good valve for NO GOOD reason, other than the warm glow at night.

You only get a given number of power ups and a given number of hours. It's all down hill from the first day you flip the switch.. Like I said I have close to NEW Telefunken valve pulls from MM and MC phone section in Macs that are 60+ years old.. C11,20,22,2500, PULL THEM...

You can drive around with your head lights on all the time too.. :-)

Regards
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