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Ampeg VR issue...

Discussion in 'Amps and Cabs [BG]' started by scotttaylorbass, Apr 19, 2009.

  1. I was playing a gig last night and my 3 month old Ampeg VR head suddenly goes into stand by mode! After the band finish the song bass-less, the amp came back on. We tried another song and half way thru in went into stand by mode again. I tried putting the head on the floor, thinking that maybe I had a loose switch and the vibrations from the cabenit was shaking it loose, but no, it did it again! I finally just went direct into the soundboard to finish the gig, but have no idea why my amp is acting this way! Has anyone else had this problem?
  2. JimmyM


    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    A ton of people. There was a major thread about it on here a couple weeks ago. There's an unnecessary relay in it that prevents you from turning it out of standby before it's warmed up that needs to be bypassed because it shuts down when the voltage gets to 112v or lower. Hopefully Jerrold Tiers or Johnk_10 will chime in later with more details, but they both say bypassing the startup relay will fix it. I would think a tech would do it for you for his regularly hourly bench charge. Doesn't seem like there's much to it.
  3. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    yep, silly relay.

    You can use the Johnk10 modification, which is 2 pieces of wire and 3 insulated "faston" terminals. (Basically hardware store stuff)

    There are pictures he took of the mod in a recent thread..... search is your friend
  4. Thanks Jimmy & Jerrold!!
    I thought it was a defect in my Amp!! I tried searching the threads for info last night...Lemme go look harder!!!
  5. johnk_10

    johnk_10 vintage bass nut Supporting Member Commercial User

    Feb 16, 2008
    Thousand Oaks, CA
    John K Custom Basses
  6. FFTT


    Mar 15, 2009
    Always Always check the stage outlet voltage any place you play.
    In some cases you may need your own isolation transformer because
    the power in some old buildings is so poor.

    Glad to hear you guys found a good work around for the relay, but still what
    a hassle!
  7. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    In what way would an isolation transformer help the situation? If the AC going in is low the voltage coming out will be low too. What is required is voltage correction.

  8. FFTT


    Mar 15, 2009
    Well that's where checking outlets before you start helps.

    In the past we've had to run extension chords direct from the panel,
    providing we had enough to work with.
    Our sound man was pretty handy at this stuff and built a special
    sub panel for the band for just this problem.
    Not sure if the term isolation transformer is correct, but he used
    something in that box to protect the band's equipment.

    This usually only happened once at those clubs and then we'd
    recommend an electrician before the next booking.

    When your band makes the club bunches of money as we did, the club
    owner will usually work with you to get things right.

    Part of our booking agreement was that the club be able to provide us
    with no less than 2 dedicated 20 amp circuits with nominal 120 volts.
    Otherwise our equipment would pull too much load.

    In some cases the local electric company would be called in to
    check the secondary supply side for a failing transformer or loose
    connection in the meter base.
    That cost the club nothing.
  9. Does the SVT -CL have this same problem? I heard of this problem before, but my friend told me it was the classic that breaks and to get the VR instead, so I think he might of had them switched.
  10. johnk_10

    johnk_10 vintage bass nut Supporting Member Commercial User

    Feb 16, 2008
    Thousand Oaks, CA
    John K Custom Basses
    IMO, once the relay delay circuit is bypassed, i think that the VR is the superior amp of the two.
  11. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Not really..... and in the CL the relay actually HAS a function, so it's better not bypassed.

    But they are different units..... not same sound-wise
  12. mikepaulhamus


    Jun 26, 2011
    my ampeg svt vr does this with generators too even if the volts read 115 on the tester actually won't even come out of standbye at certain gigs, I made a 10 gauge extention cord for some gigs and it does run at those clubs now but some other won't work. will this bypass hurt the tubes and transformers if it is running down around 90-100 volts my teck says it will and if a tube goes down it won't protect the amp and longer
  13. Bassmec


    May 9, 2008
    Ipswich UK
    Proprietor Springvale Studios
    No so many a bass tracks have been recorded using a big tube amp and
    a Variac on the mains to lower the output before distortion, It's a known alternative to variable power soaking of the output stage.:bassist:
    PS. Not tried this with a new fangeled auto bias amp though. Can't see why it would cause any issues, as it's only comparing voltages across resistors?.

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