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Maintenance and cost of maintaining a tube amp?

Discussion in 'Amps and Cabs [BG]' started by BIGEJ2, Apr 29, 2015.

  1. BIGEJ2

    BIGEJ2 Supporting Member

    Jul 29, 2009
    Happy Valley, PA
    So here's the situation. I have been gassing for a new Ampeg B-15N since they were released in 2012/2013. The amp will be for recording / home studio use only. Normal use will be about 1-3 hours a day, 5 days a week. I usually play for an hour, collect my thoughts for an hour or so then play for another 2 hours. It will be in standby during the in-between time.

    I know there is no way to determine how long tubes will last. Under the conditions above, how long should they last? And, how much does it cost to have them replaced, including cost of tubes and tech time?

    Thanks in advance. Any info and experiences are appreciated.
  2. You are thinking about buying an enormously expensive reissue amp, and are worried about the cost of a few tubes?

    Find an older one, pair it with a decent 115, and use $2,000 you saved to re tube it as often as you want.
  3. The_Janitor


    Jun 30, 2012
    Madison, Wi
    ^ pretty much this.

    I can't imagine that a full retube of a B15N is going to cost much at all - it's only 15W. If it's only used for occasional use at home or in the studio you should expect years of life out of the tubes.
    Kukulkan61 likes this.
  4. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    Tubes can last for a long time. At the same time things can happen. Many vintage B-15's still have their original tubes.

    There are two versions of the reissue B-15. Some have 6SL7GC tubes like the vintage ones and others have 12AX7 tubes. The all have a 5AR4 rectifier and two 6L6GC power tubes.

    They don't publish tube life data. There was the RCA 5691 red base tube. This was a long life 6SL7 tube that was rated for 10,000 hours under continuous commercial use. Based on the numbers, if you had one of those tubes, at three hours a day, five days a week, it would last 13 years. In intermittent service they last even longer. Now a big but. The life of a tube is also based on how hard you push them. With at-home/recording volume levels regular tubes can last more years than you need to worry about.

    Buy the amp, get a spare set of tubes. Enjoy it.
    LowEndWooly and SirMjac28 like this.
  5. coreyfyfe

    coreyfyfe Supporting Member

    Nov 19, 2007
    boston, ma
    At that use rate I'd say a new set of well matched 6L6GC's once a year would keep you running smooth. You could probably go every other year or longer without issue. The only thing I'd say is don't leave it in standby for an hour.

    If you only run it in the 25W/cathode biased mode (instead of the 30W/fixed bias mode) it will never have to see a tech for biasing as long as the cap/resistor are good so you'd only have to buy the tubes. A well matched pair of modern production 6L6GCs should cost about $40-50. I've tried a pair of these tung-sol reissues in my 65 B15 and they were nice, sounded fairly comparable to a set of side-getter GE tubes and the set of RCA tubes it's running now. I believe the fixed bias on these amps is non-adjustable, but even if you had a tech retube and check the bias it should run you under $100.

    If you were ever in a position where you needed to be spending $100/year to retube/bias a B15 for the use you describe I'd be really surprised, but it would be worth it IMO. Great sounding amps.
  6. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Replace tubes when they go bad on you. This could be tomorrow, or it could be years from now. But don't do full retubes unless you like spending money on nothing.
  7. BIGEJ2

    BIGEJ2 Supporting Member

    Jul 29, 2009
    Happy Valley, PA
    Thank you @coreyfyfe. This is the kind of information I was looking for. I read stories of people spending upwards of $300 to re-tube on SVT's and didn't want to get into that territory.

    Concerning standby - is it better better run the amp for an hour, put it in standby for an hour and then run it for two more hours or completely shut it off in between?

    And to replace a tube or two. Is this something an everyday Joe can do, or is taking it to a tech the best way to go?
  8. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Unscrew the tube cage, pull the old one out, pop the new one in, put the tube cage back on. Technically, when you replace power tubes, you should replace both with a matching set and have it re-biased, but I own a B-15N and I usually skip the re-biasing and I've yet to have a problem when replacing power tubes. But the other tubes are plug and play and you don't need to worry about biasing as they bias themselves.
    kaba7a likes this.
  9. BIGEJ2

    BIGEJ2 Supporting Member

    Jul 29, 2009
    Happy Valley, PA
    Thanks JimmyM, appreciate it.
  10. 10cc


    Oct 28, 2013
    Don't even worry about this
  11. Mark Reccord

    Mark Reccord Supporting Member

    A B15 has 6 tubes while an SVT has 14 and 6550s are way more costly than 6l6s, so the cost of retubing a B15 would be incidental compared to that of an SVT.

    Turn it off (or just leave it on) in between. There's no good reason to put it in standby at any time other than when you first power it up.
  12. At this point I'm not really adding anything, but I've got some old pepco amps with %100 original tubes in them, they've got to be fifty years old by now. They're used fairly intermittently though, even under regular use, you shouldn't be paying too much for tubes, maybe a hundred bucks every few years.
    chaosMK likes this.
  13. The B15 has a pair of 6L6's. So maybe $40 in tubes to retube the power section. (plus tech time).
  14. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    If you are leaving the amp without playing for an hour I would shut it off. If you are recording, I'd leave it on to keep it consistent. An amp takes time to warm up and reach a steady state.
  15. BurningSkies

    BurningSkies CRAZY BALDHEAD Supporting Member

    Feb 20, 2005
    Syracuse NY
    Endorsing artist: Dingwall Guitars
    In the over two decades I've had my Twin it's visited the shop twice. Once to have work done when I first got it, and once to have a decent tech undo what the first did.
  16. I'll make this short. Your car/truck/motorcycle is MUCH more expensive and requires much more attention than the amp ever will.
  17. I am Soma

    I am Soma Supporting Member

    Jan 2, 2013
    that is why i love my 100t. tells me if the tubes are good, if one goes bad, and does the rebiasing for me. that ampeg is awesome too though.
    Moosehead1966 likes this.
  18. BurningSkies

    BurningSkies CRAZY BALDHEAD Supporting Member

    Feb 20, 2005
    Syracuse NY
    Endorsing artist: Dingwall Guitars
    To my knowledge my 65 Vibrochamp has never been serviced. It probably could use new caps, at this point...given they're 50 years and running. It has had different tubes over the years, but I'm not convinced that people often switch tubes out of paranoia and wishful thinking rather than actual need.
  19. Sputnik Monroe

    Sputnik Monroe

    Feb 11, 2014
    After a 47 year run with the original tubes and caps a total overhaul on my 68 Sunn 200s was only 400.00 and that's with new KT 88s installed ...
  20. Yep that is my point. Even if you re-capped and re-tubed at three to four hundred it would be a drop in the ocean compared to the tens of thousands you spent on personal transportation over the same period.
    SamJ, beans-on-toast and BurningSkies like this.

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