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DIRTY Power

Discussion in 'Amps and Cabs [BG]' started by ishouldbeking, Sep 12, 2008.


  1. ishouldbeking

    ishouldbeking

    Feb 5, 2007
    Hollywood, CA
    Endorsing: SIT, Eastwood, Hanson
    I don't know an awful lot about dirty power, or voltage regulators, or even power conditioners, but last night at a gig I think I came face to face with some pretty gnarly power... and it sucked.

    Actually, I survived the gig completely intact, but my band got nearly wiped out. My lead guitarist has a relatively new Valvetech Hayseed 15 (really nice sounding boutique AC-15) and as soon as he powered up for a sound check it was bad news. Squealing noises shot through the amp. He immediately unplugged his guitar and pedalboard, but the noises continued... it'd basically wail like a tortured moo-cow, so he powered down. Tried it again, same. A few times he'd power up and it'd be fine for a whole minute, but then the wailing would come back. At first we assumed one of his tubes must have blown.

    And then... our keyboarist attempts his own soundcheck. We had minimal PA support, so he was running through a very well-maintained (and TUBE-FREE) Roland JC-120. About 30 seconds in, his volume starts to cut drastically. We were able to borrow another band's Mesa combo for my lead guitarist, and we borrowed another band's bass amp for the keyboards, but it resulted in us cutting a good 15 minutes out of our 35 minute set.

    Miraculously, my Ashdown ABM 500 evo II survived completely unscathed, as did our lead singer's Peavey Classic 50.

    Does that sound like we were dealing with dirty power or is there something else we should consider? Are some amps more susceptible to fluctuations in voltage than others? And how do you deal with it, short of dropping a lot of cash on a voltage regulator?
     
  2. Rick Auricchio

    Rick Auricchio Registered Bass Offender

    It's hard to tell what happened. Could be a coincidence.

    Were both amps taking power from the same outlet? It could be loose connections inside the outlet.

    A voltage regulator like the Furman AR1215 will set you back about US$500 and 12 pounds. This unit supplies a solid, clean 120v to your equipment with incoming voltage as low as 97v. It'll also shut down if things get really bad.

    The most economical test is one of those $10 three-LED outlet testers, available at most hardware stores. Though it won't tell you about voltage, such a tester will at least warn you of missing grounds or incorrect wiring.
     
  3. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Was this a restaurant or bar with lots of refrigeration equipment and light dimmers? That's usually where you have the most problems, and there's nothing you can do about it, except decline future bookings there.
     
  4. ishouldbeking

    ishouldbeking

    Feb 5, 2007
    Hollywood, CA
    Endorsing: SIT, Eastwood, Hanson
    It was a small-ish theater... one that typically houses plays. Only in the last year have they begun hosting shows and bands. They had a pretty minimal PA setup and only a few mics available, so we assumed they may have been generally ill-equipped to handle a whole bunch of amplifiers at once, but the sound guy said he hadn't encountered this particular problem before.

    It's definitely not impossible that we just had a double whammy of amp crap-out, but it'd be nice if we could find something external to blame. ;-)

    EDIT: There was a good amount of lighting equipment, almost to the point where it seemed excessive. And whoever was running the lights didn't seem to know how or when was appropriate to use them, though it seemed more a matter of bad taste than anything else...
     
  5. ishouldbeking

    ishouldbeking

    Feb 5, 2007
    Hollywood, CA
    Endorsing: SIT, Eastwood, Hanson
    At first the amps were each connected to completely different parts of the theater, one on stage left, one on stage right (which was about 40 feet apart --the stage was really wide), so I'd assume they were on different breakers. First thing we tried was plugging into different outlets, but it didn't seem to make much difference.

    I'm sure those guys will be messing around with their amps at home as soon as they get the chance, so one way or another we'll probably figure out soon enough if the issue was the particular venue or the amp itself.
     
  6. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    That could be the source of the problems. High quality lighting gear is fine, but cheapo dimmer packs are impossible to deal with. Also, a well designed theater will have the lights powered off one 110 leg of the incoming 220 line, and dedicated stage outlets for amps on the other 110 leg.
     
  7. Rick Auricchio

    Rick Auricchio Registered Bass Offender

    Let us know what they turn up when they test the amplifiers at home.

    Nobody ever gets hit by a single-whammy, do they...
     

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