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Ampeg Portaflex 350 Problems!!!

Discussion in 'Amps and Cabs [BG]' started by Stickbone, Dec 4, 2017.

  1. Stickbone


    Dec 7, 2015
    I played a gig Saturday and had to use my PF350 (never used it before for a gig but use it all the time for practicing by myself) because my SVT3 Pro was out getting biased. Played perfectly for a three song sound check, left the amp turned on but not plugged in to my bass. The first song of the gig my 350 started cutting out intermittently (every 5 to 15 seconds for a note or two) and come back in. I didn't have a backup close and played the rest of the gig that way, it never stopped cutting out. I'm at a loss for finding if this happened to anyone else and I've searched a lot of threads on TB and Google. Anyone have a similar problem and where do I need to look. I visually inspected the PCB and everything looks good, no burn marks, no burnt smell or ozone smell, at a loss for what it could be. Has anyone run into similar problems? Thanx!
  2. Stumbo

    Stumbo Guest

    Feb 11, 2008
    Cable problem?
    Wisebass likes this.
  3. Stickbone


    Dec 7, 2015
    No, swapped from using my line6 gt10 to cables and got the same results. Also changed the battery in my Jaguar bass.
  4. Bim1959


    Apr 15, 2009
    Naples Florida
    Sales and electronic tech/piano tech: England Music Center - Clinton IA - now closed
    Speaker cable problem?
  5. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    Low line power at the gig can cause this. The power sags at some venues, especially if too many amps and lighting are plugged into the same circuit.

    So can excessive heat. The amp need air to circulate around it. Avoid putting it against a wall or restricting airflow around the vents.

    What’s odd is that it kept dropping out as opposed to a shutdown that takes a few minutes for the amp to recover. That makes you think perhaps an intermittent contact. It could be the connection at the cabinet.

    If you were pushing the bass EQ, that stresses the amp much like high volume levels.

    No signs of damage is good. Reseating all the connectors inside the amp could help.
  6. Stickbone


    Dec 7, 2015
    Thanks, trying to duplicate the problem and not having any luck, which is probably good luck. I switched the cable from the Line6 receiver, but am still using my 1/4" to Speakon going from amp to speaker that I made myself and it's a heavy duty cable done correctly.
    Last edited: Dec 4, 2017
    beans-on-toast likes this.
  7. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    Sometimes the weight of a heavy duty cable can cause an intermittent contact in a jack. As a test, try lifting it at the jack end to releave any stress due to the weight.
  8. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    I should have said this earlier. Patch an instrument cable from the effect send to the effect return. If there is oxidation on the jacks, it can interrupt signal flow. Using the patch cable bypasses any oxidation on the jack shunts (switches).
  9. Turn down your gain a bit, crank up the master a bit.
  10. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

    Apr 13, 2021

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