Hot acoustic gigs, low pickup output - wisdom needed, please

Discussion in 'Acoustic Heaven' started by CC Ryan, Sep 5, 2017.

  1. CC Ryan

    CC Ryan Tele-Meister

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    I've been playing acoustic gigs with a high-end guitar, fitted with what I assume is a piezo pickup under the saddle (no controls, just a socket where the end pin usually goes).

    I did one outdoor gig in extreme heat (southern California) and the signal level quickly dropped to almost nothing. First thought: change the battery. No difference.

    Tried everything back at home, plugged into an Acoustasonic. All working fine. Did more gigs (in cooler circumstances), the system still held up. Until last weekend.

    Another hot outdoor one, and the level took another dive. Changed the battery anyway, but the one I took out was still strong. There are no other problems, no intermittent noises, no cutting out or crackles. And when it's working, it sounds great. Naturally, I do my best to keep myself and the guitar in the shade during outdoor gigs.

    Has anyone else ever experienced the same problem? If so, how did you fix it?
     
  2. clintj

    clintj Friend of Leo's

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    I haven't had those issues using a straight up passive pickup - the K&K Mini - through a DI box.

    That's interesting, though. We use 9V batteries in stomp boxes regularly, and they usually are rock solid reliable. Maybe something in the circuitry is going belly up at high temps? Unless someone has some deeper insight, I might also suggest carrying a small condenser mic as a backup for emergency use. Sorry if this isn't the most helpful answer. It's hard to make an educated guess over the internet.
     
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  3. CC Ryan

    CC Ryan Tele-Meister

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    Clint J, thank you so much. You directed my attention to the battery more than to the wiring and I think that might be the key to the whole conundrum. Perhaps the high temperatures cause the battery to under-perform.

    And I like the idea of a condenser mic as an emergency backup. Small and relatively cheap. Thanks again.
     
  4. Hexabuzz

    Hexabuzz Friend of Leo's

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    It's an easy enough theory to test in a controlled environment - do you have a room that gets direct sun, and gets really warm? Put the guitar in its case in the sunlight (so it's not getting the direct rays), but it's getting up in temp to what you encounter at a gig.

    I'd let this happen slowly, and let it cool back down slowly as well, but it might recreate the problem.
     
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  5. CC Ryan

    CC Ryan Tele-Meister

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    Or I could put a battery in direct sunlight and then stick it in a stomp box and see how it works.
     
  6. CC Ryan

    CC Ryan Tele-Meister

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    just been doing some "research" on batteries. Apparently, alkalines can "operate without significant degradation in high temperatures" - according to a Gizmodo article.
     
  7. Dacious

    Dacious Doctor of Teleocity

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    Maybe your connection on the guitar is loose or corroded. Resistance increases with heat and the preamp will warm up itself. Maybe tension on the spring contacts in the battery holder has loosened off and they need retensioning?
     
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  8. CC Ryan

    CC Ryan Tele-Meister

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    Dacious, interesting point. I was hoping that might not be the case, since there seems to be no crackling or sound cutting in/out. And I was hoping not to go to the repair shop, but it looks like that's going to be wisest course of action.
     
  9. Hexabuzz

    Hexabuzz Friend of Leo's

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    It could be the circuit itself that's being compromised by the heating of the surrounding material of the guitar. If the battery is in the guitar (instead of the stomp box) you could easily verify whether the culprit is the battery or the guitar - you could also immediately pop in a room temp battery, and if the pickup isn't working, you know it's the electronics themselves that are failing in the heat.

    You didn't mention what kind of guitar/pickup you're using.
     
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  10. Musekatcher

    Musekatcher Friend of Leo's

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    battery current increases with temperature, so that's not it. Its less likely to be thermally related, unless your guitar is getting really hot, in which case I'd be worried about glue and joints coming apart. Are you toting your own amp or sound system?
     
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  11. noname_dragon

    noname_dragon Tele-Holic

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    I'm assuming you are singing too. No drop out on your vocal mic? In that case maybe your P.A. amp is overheating and causing volume drop off? Run a fan in that case.
     
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  12. CC Ryan

    CC Ryan Tele-Meister

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    Hexabuzz, the battery is in the guitar, but it's not so easy to pop in a room-temp replacement. It means having to loosen the strings and then bring them back up to tune. The guitar is an early Collings. Don't know what the electric system is (didn't buy the guitar new), but assume it's pretty decent to be in such a great guitar.

    Musekatcher, going into the PA via a Fishman preamp (no problems with that). The rest of the PA works fine; the other half of the duo (who plays a Breedlove) has no problems either.

    Noname_dragon, Yep, singing too, but using a vocal mic and that's all cool. Well, as cool as my vocals ever get.
     
  13. cnlbb

    cnlbb Tele-Afflicted

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    On a limb, but there's a chance that the temperature messed with the piezo itself. Under saddle, pickups can drop in output if the physical connection between the saddle and piezo isn't just right (spent hours trying to balance string output once before realizing that the saddle slot wasn't flat). A cheap plastic bridge (not saying you have one) could possibly snug up weirdly in high temps and not rest on the piezo right.

    Anyways... it's a long shot, but just one more possibility to consider. Also, I like it when problems can solved with bone or wood rather than wires and solder.
     
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  14. Dacious

    Dacious Doctor of Teleocity

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    I'm still plumping for loose/dirty contact on the battery box. Seen that with effects loop jacks which work for a while then fade out (could be the other thing - jack-plug on guitar where you plug cable in), especially if it has a switch incorporated to turn the internal preamp on/off.
     
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  15. CC Ryan

    CC Ryan Tele-Meister

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    Musekatcher, you also said it was less likely to be thermally related. In which case, it's coincidental that it was a really hot day on the two occasions where the output dropped. Which is scary, because then it could happen any time.

    Cnibb, after learning that it probably isn't battery, my thoughts also turned to the piezo pickup. That's beyond my technical knowledge, so it's going to have to be a trip to the repair shop, I reckon.
     
  16. Dacious

    Dacious Doctor of Teleocity

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    Unlikely to be the piezo under the saddle, if it broke you'd get low output 100% of the time. Given its got a battery powered preamp connections are a prime candidate. Also - what batteries are you using? Not rechargeable?
     
  17. CC Ryan

    CC Ryan Tele-Meister

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    Using disposable Duracell alkaline 9-volt batteries (PP3).

    Whenever I've done a battery swap, I've checked the wires for any obviously visible issues. They look pretty clean to me, but I'm no expert.

    And if it was a wiring/connection issue, wouldn't the sound be on/off intermittently instead of just going weak?
     
  18. Dacious

    Dacious Doctor of Teleocity

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    Not if signal related. You can get a borderline weak signal that reduces as temp rises.
     
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  19. Musekatcher

    Musekatcher Friend of Leo's

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    Guitars, pickups, batteries and all just aren't that delicate to be upset by weather conditions, short of being drenched or something. Sounds like your battery is draining quickly and dropping voltage? I've had defective onboard pre-amps that sucked a battery down before finishing a set. I've also got pre-amps that suck batteries down between gigs.

    Or something else is going on - for instance, why are you running a Fishman pre-amp, if you have an active pre-amp in your guitar? I don't think I've ever "doubled" pre-amps like that? You only need one or the other to match impedances to amps and PA's. Maybe having both is pulling your battery down prematurely? I googled, but didn't get anything about actives being incompatible with pre-amps. Interesting that I've not come across this scenario before - an active pickup in front of a pre-amp....
     
  20. CC Ryan

    CC Ryan Tele-Meister

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    Thanks for your musings, Musekatcher. The Fishman is a preamp/DI box (the Platinum Pro). It has an onboard tuner, mute and boost functions, EQ, phase/notch, and a compressor. Fantastic thing, gives me more control over the sound going to the PA. I use a power supply for it.

    The last battery I pulled out of the guitar was still strong. I'm still thinking the basic problem is heat-related because the two occasions when it happened occurred during outside gigs on super-hot days. Other gigs between these two events had everything working as it should.

    Intermittent problems are always more annoying than a predictable issue, aren't they?
     
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