Burn in: What do you do??

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Nolatone Ampworks, Sep 12, 2008.

  1. Nolatone Ampworks

    Nolatone Ampworks Silver Supporting Member

    Messages:
    2,736
    Joined:
    Jun 4, 2006
    Location:
    Flowery Branch, GA
    Mainly geared toward those who build amps...

    When you burn in your amps, do you just switch them on and out of standby for a period of time or do you put signal through them?
     
  2. brad347

    brad347 Member

    Messages:
    4,813
    Joined:
    Feb 8, 2006
    Location:
    Brooklyn, NY
    This will be a thread worth watching.

    I'm about to build my second amp. The first one, I just broke it in the old fashioned way-- by playing it.

    This one I'm going to try some different stuff. I have an old pair of worn-out russian 6L6s and some cheap Sovtek preamp tubes I'll put in, and then leave it on in "play" mode for 72 hours.

    Then I'll take it down to the basement with an old moog synthesizer, plug the synth in, set the LFO to sweep the filter resonance and modulation, tape a few keys down, and let it do its chaotic, whooshy madness (which would amount to a bunch of frequency sweeps from very low to very high) for another 10 hours or so.

    Then I'll put the "real" tubes in and have at it the old-timey way, with a guitar. I figure that will give me a jump-start on break-in/burn-in of speakers, caps, etc.
     
  3. SatelliteAmps

    SatelliteAmps Member

    Messages:
    6,185
    Joined:
    Oct 19, 2007
    Location:
    Normal Heights, Calif
    Burning in tubes has to be done with working voltages on the tubes. That means not on standby. I prefer running a signal as well.
     
  4. Nolatone Ampworks

    Nolatone Ampworks Silver Supporting Member

    Messages:
    2,736
    Joined:
    Jun 4, 2006
    Location:
    Flowery Branch, GA
    Hey Adam, what duration do you use? Do you do the complete burn in with tubes the amp ships with or do you use other tubes for part of the burn in to save life on the new ones?

    Thanks,

    Paul
     
  5. RussB

    RussB low rent hobbyist Silver Supporting Member

    Messages:
    11,071
    Joined:
    Jul 3, 2004
    Location:
    CT
    I run a signal through them for about an hour, set at the verge of clipping. I switch the frequency around just for fun. I start at 1k with guitar amps. Then I re-check bias and voltages, and have a listen to the amp.

    I do this to every amp I build, service and/or replace tubes in. (which isn't many!)

    I run a fan on the dummy load, it get's quite hot!
     
  6. SatelliteAmps

    SatelliteAmps Member

    Messages:
    6,185
    Joined:
    Oct 19, 2007
    Location:
    Normal Heights, Calif
    Burning in time is done with all the parts in the amp that will be sold in the amp. I never burn in new amps with old tubes. The biggest failure is in the tubes so there is no reason not to use the new ones.
     
  7. brad347

    brad347 Member

    Messages:
    4,813
    Joined:
    Feb 8, 2006
    Location:
    Brooklyn, NY
    Many capacitors have ~60 hours recommended burn-in time. That's the reason I will use old tubes to get some hours on the caps and make sure there are no malfunctions before I put the good tubes in.

    I recognize that some people dispute "capacitor burn-in" as a concept, and that's fine-- no need to open that can of worms for the hundredth time-- but many boutique-y cap manufacturers do recommend a certain number of hours (Sozo, Jupiter, et al) so that would be "a reason" for burning in for a period of 60-75 hours with old tubes, then burning in for another 5 or so with the 'real' tubes.

    Looking/waiting for failures might be called "testing," in my opinion. "Burning in" I consider as operating the amp for awhile to allow everything to stabilize. Semantics maybe.
     
  8. WesKuhnley

    WesKuhnley Member

    Messages:
    2,241
    Joined:
    Mar 9, 2007
    Location:
    Minneapolis/St Paul
    I only burn amps in to make sure I don't have any crib-death components in the amp. I don't buy the cap break in ********, and as long as the amp isn't going to die in the customer's hands, I'm more than happy to let them break the speaker and tubes in (the only components in my opinion who's performance changes permanently over time).
     
  9. RussB

    RussB low rent hobbyist Silver Supporting Member

    Messages:
    11,071
    Joined:
    Jul 3, 2004
    Location:
    CT
    :NUTS

    Are you saying you're going to burn in your amp for 60 hours? You read too much internet babble, Brad.
     
  10. brad347

    brad347 Member

    Messages:
    4,813
    Joined:
    Feb 8, 2006
    Location:
    Brooklyn, NY
    If you think my decision is based on "internet babble," that's fine, but don't you think it's just a touch disrespectful to comment in that manner? I don't mean any harm, but really guys!

    To answer your question, yes I intend on burning my amplifier for over 60 hours. Why? Because 1) the manufactuer of the components suggested it, and 2) I don't see what harm it could do.

    Many people choose not to believe that capacitors can break in, and that's fine. There is actually empirical evidence backed up by some very interesting tests (complete with scope traces) that I have presented in other threads before that demonstrate a change in a capacitor's behavior over the initial several hours.

    Last time I linked to the test-- which I found interesting and convincing-- some people seemed very interested in denigrating the results, almost as if they had a vested interest in not believing it.

    That's fine, I really have no profit to make from proving it one way or the other. Everyone is entitled to believe whatever they're convinced of.

    But certainly we can have a discussion about it without being disrespectful to one another? Right? Maybe I'm being too sensitive, but both of your guys' posts were downright insulting to me.
     
    Last edited: Sep 13, 2008
  11. WesKuhnley

    WesKuhnley Member

    Messages:
    2,241
    Joined:
    Mar 9, 2007
    Location:
    Minneapolis/St Paul
    I don't think anyone here is trying to insult you brad. If in fact you'd like to listen to your amp getting pounded by an oscillator for 60 hours, that's fine too. Regarding your aforementioned "empirical evidence", someone posting a picture of a scope screen without accurately describing test methods, or adhering to scientific test principals during said "test" is hardly evidence of any kind. It's your business whether or not you prefer to believe marketing mojo BS, but don't suggest that I would have any variety of commercial interest in proving this "theory" wrong.
     
  12. brad347

    brad347 Member

    Messages:
    4,813
    Joined:
    Feb 8, 2006
    Location:
    Brooklyn, NY
    I suggested nothing of the sort.

    How would you have done the test differently? As I recall, he detailed exactly how he performed the test. Seems pretty definitive to me. Here is the link, in case you or anyone else would like to have another look:

    http://www.diyaudio.com/forums/showthread.php?threadid=81355

    Many of the salient details are later in the discussion, by the way.


    At any rate, I'm not sure how capacitor break-in is "mojo marketing BS."

    If I were selling capacitors, I would see no potential for profit in telling my customers they actually had to wait for 60 hours before my capacitors sounded good.

    In any case, you continue to phrase your statements in an argumentative and insulting manner. I'm not really one to be hurt by things like that, but it does seem rather impolite. Don't you think?

    At any rate, I specifically requested that we not open this can of worms. This thread is about something else. If you wish to continue this discussion/call me stupid further, that's fine, but please dig up the old thread about this subject! Thank you.
     
  13. WesKuhnley

    WesKuhnley Member

    Messages:
    2,241
    Joined:
    Mar 9, 2007
    Location:
    Minneapolis/St Paul
    Again, sorry if you're insulted by my comments, no offense was intended.

    On a purely logical basis, I'm not sure how you can read that thread and come up with the conclusions that you do. There are a SLEW of other explanations for what is shown in those pictures. Read post 22, poster actually describes a scientific test that could be done to determine the facts in the matter. It doesn't surprise me that the discussion didn't continue after that...

    I'm not asserting that it make sense to market component "break-in" in this manner, in fact, I wonder how it could be beneficial to do so. But then again, guitar players and hi-fi nuts are not always the most technically minded people on the planet and maybe this works on that level. Again, just my humble opinion.
     
  14. mooreamps

    mooreamps Senior Member

    Messages:
    377
    Joined:
    Nov 8, 2007
    Location:
    Sunnyvale, Ca.
    We do an 8 hour burn in ; inside a small Thermotron chamber ; 0 to 50 C. Then let it cook at ambient overnight. We used to run the chamber overnight, until we got the PG@E bill. "What was I thinking" !!!!



    -g
     
  15. RussB

    RussB low rent hobbyist Silver Supporting Member

    Messages:
    11,071
    Joined:
    Jul 3, 2004
    Location:
    CT
    Brad,

    I appologize if you feelings were hurt. No malice was intended.

    60+ hours of burn-in is a long time. How are you going to go about it? Would it be better to have music as a signal, rather than the drone of a signal generator? Do you have a dummy load, or do you plan to run it through speakers?
     
  16. brad347

    brad347 Member

    Messages:
    4,813
    Joined:
    Feb 8, 2006
    Location:
    Brooklyn, NY
    I plan to run it through speakers. Part of why I'm doing it is to get a jump-start on breaking in the speakers. I do realize 60 hours is a long time. That's why the majority of it will be with inconsequential tubes. I won't have signal running through it that whole time. I don't really see why leaving it on for a few days with old, worthless tubes will be a problem. Any amp that couldn't stand up to that, I probably wouldn't want to rely on as a professional instrument, anyway.
     
  17. RussB

    RussB low rent hobbyist Silver Supporting Member

    Messages:
    11,071
    Joined:
    Jul 3, 2004
    Location:
    CT
    To each their own, I rekon. Me I just go ahead and play the heck out my personal builds :)

    Do you feel that just having the amp on with no signal will break in the tone/coupling caps?
     
  18. brad347

    brad347 Member

    Messages:
    4,813
    Joined:
    Feb 8, 2006
    Location:
    Brooklyn, NY
  19. teleamp

    teleamp Senior Member

    Messages:
    3,508
    Joined:
    Aug 22, 2006
    Location:
    Central Texas
    +1, this weeds out the weak tubes, plus the new tubes benefit from the burn in as well.
     
  20. WesKuhnley

    WesKuhnley Member

    Messages:
    2,241
    Joined:
    Mar 9, 2007
    Location:
    Minneapolis/St Paul
    What else would break them in? There is no DC in a tone-stack, so signal is the only possible electrical impulse these caps will ever see.

    I really would love to see a scientific test on the subject, maybe when I'm not so freaking busy I'll design one and publish the results.
     

Share This Page