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    Keep pre-amp tubes lit or shut down?


    Posts : 2030
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Keep pre-amp tubes lit or shut down?

    Post by deepee99 on Fri Oct 13, 2017 10:03 pm

    I power off my main amps if I so much as take the trash out or make a beer run.
    Question is, should the pre-amps be cycled the same way?
    Roy M. said of pre-amp tubes, there's only so many electrons in 'em. Makes sense.
    OTOH, I've heard and read that powering tube preamps on and off shortens the heater life, ergo the tube life.
    Be interested to know your experience and knowledge in this matter. A warmed-up pre-amp sure sounds nicer than one that's just been lit for a few minutes, But is there a cost-benefit analysis here?
    Thanks, as always,
    j beede

    Posts : 469
    Join date : 2011-02-07
    Location : California

    Re: Keep pre-amp tubes lit or shut down?

    Post by j beede on Fri Oct 13, 2017 10:44 pm

    A couple thoughts:

    -I've been running a tube preamp of some sort since 1974 and have yet to have a dual triode filament failure
    -I don't recommend leaving tube amps powered on in absentia. Same rule for soldering irons and clothes dryers. I hate "surprises" when I get home Shocked
    -A set of four always-on 12AX7 filaments dissipates about 6kW-hr per month

    Posts : 1479
    Join date : 2008-11-30

    Re: Keep pre-amp tubes lit or shut down?

    Post by tubes4hifi on Sun Oct 15, 2017 4:18 pm

    if you listen to music 2.4 hours a day (just an example) then leaving them on ALL the time of course means they are on 10x as much and wear out almost 10X faster,
    so maybe 2-3 years instead of 20-25 years of use (I'm talking preamp tubes here). Turn 'em on about half hour before serious listening, turn off when you go to bed.

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    Re: Keep pre-amp tubes lit or shut down?

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