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PF500 trouble after two+years

Discussion in 'Amps and Cabs [BG]' started by Orpheus55, Jun 18, 2014.

  1. I powered up my Ampeg PF500 today and all looked normal, but I got no sound. Checked everything: cords, inputs, etc., nothing. I turned it off and then on again. Nothing. Then I waited a few more minutes, turned it on--and it was fine! Tried again a few hours later and the same thing happened. Took two "start-ups" and it worked fine. I haven't had any trouble in the over two years since I bought it, though I know all about the threads claiming otherwise. I'm sure I am out of warranty, so I guess I have to go amp hunting.
  2. High Camp

    High Camp

    Oct 3, 2013
    Well, for the PF series you get a two year warranty for the electronics, so just maybe, you're in time!
  3. will33


    May 22, 2006

    Check the specifics of your warranty.

    If it is out of warranty, use the effects loop to isolate the problem to pre or power section.

    I think you can get replacement circuit boards, which are fairly easy to change out.
  4. seamonkey


    Aug 6, 2004
    It is probably mechanical, the power switch, or the power cord connection
    But if you want a new amp, there are some good choices.
    Look for one with a longer warranty, it is an indicator of how much the manufacturer believes in their own quality.
  5. All the lights and fan come on; Ampeg service has no advice, and I am out of warranty. I certainly got a lot of use out of it, but will ask around to find someone who can fix it. It's odd though that it suddenly starts working the third time or so I turn it on. Meanwhile, my old SWR workingpro 12 is going back into service.
  6. will33


    May 22, 2006
    If you're handy, jumper around the power switch so the amp turns on when you plug it in. Unplug it to shut it off.

    If it works good that way---> bad power switch.

    Caveat: this works on "regular" amps. If yours has some "soft start" procedure or other sort of self-regulated start up procedure built in it, it might not.
  7. He already told us it turns on. Not the switch.
  8. will33


    May 22, 2006
    Ah...nevermind then.
  9. Luvie


    Oct 23, 2012
    Houston, TX
    Just a few silly ideas to rule things out:

    Try the other speaker output you;re not using (speak on or 1/4 inch);

    Try cycling the mute button several times in case that might be the issue (either the switch or circuit);

    See of there's sound coming from the headphone jack.

    Also, if you have another amp, seek if you can use the pre-amp out on the PF-500 into the other amp to see whether the pre-amp works; then use the pre-amp out from the other amp into the power amp in on the PF-500 to see if the power amp works.
  10. wave rider

    wave rider

    Jan 5, 2005
    If you bought it new with a credit card, your card may extend the warranty. Worth checking...

  11. I did try the headphones, and they worked. I also tried another jack--I tried with both speakon cable and thick 1/4 jacks. Somehow, today the thing worked without a problem. Now, I did use the AC cord from my SWR (they're next to each other), and when I went back to the original PF500 cord (looks the same to me) everything worked fine in every configuration possible. I was getting power all along, so who knows? I ran it hard through practice, tried it again four times, and it seems OK now. I did also try the mute switch on and off (which I never use), so maybe that was part of the initial problem--if there really was one! Weird. Thinking of getting a Hartke LH500 for backup; heavy and old-school, but a class A amp. Just wish it had speakon connectors.
  12. will33


    May 22, 2006
    It is entirely possible the mute switch just got dirty/intermittent a little if you never use it. Same goes for effects loop jacks or any other control that never gets used, leading to dirty contacts, break in the signal path, scratchy pots, etc.

    Here's hoping.

    As for the Hartke, I wouldn't dismiss any amp just due to 1/4" jacks. Yeah, speakons are technically "better", but they get oversold/hyped up a lot. The increased contact area really doesn't matter until you get over 500 watts, and the lowly 1/4" has been making beautiful music for 100 years or so.:)

    Though, if you are running problem free, there may be nothing at all wrong with your amp. Just typical dirty contacts which are no fault of the amp at all, just a routine part of regular use/maintenance.
  13. Rockin Mike

    Rockin Mike

    May 27, 2011
    If Ampeg cares about their reputation they should be motivated to help you even if it is a little out of warranty. Considering the number of reports of problems with the PF-500 this may get you some results.

    Eden customer service went way above and beyond to help me when my amp failed a little bit out of warranty. Judging by the number of Eden problem threads on here they may have finally got their quality control stuff together.
  14. okcrum

    okcrum in your chest

    Oct 5, 2009
    Verde Valley, AZ
    RIP Dark Horse strings
    I think you're right about the contacts. Jostling them all and then testing makes it hard to tell which contact it was, but the switches seem more prone to getting oxidized than the jacks. There was another recent thread here where a DI switch was dirty, and mechanically they are the same design as the front panel switches.

    The limiting value for 1/4" use for speakers is around 10 amps, depending on plug and jack condition. For comparison, an XLR is rated for 15 amps and a speakon is rated for 40 amps. These are all continuous current ratings. So you wouldn't use 1/4" above 400 watts at 4 ohms, 800 watts at 8 ohms, and 200 watts at 2 ohms - all continuous ratings. MI use is usually 50% higher rating.
    Last edited: Jun 20, 2014
  15. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Speak-Ons are used to comply with safety regulations also, especially with touch-proof requirements of the E.U. On amps that used a bridged output stage (many class D amps use this config.) It's usually not the current limits until you get into the bigger amps.

    Another reason they are used is to prevent short circuiting when plugging and unplugging, mostly an issue at the load end.
    okcrum likes this.
  16. shoot-r


    May 26, 2007

    I can tell you from my experience with Loud/Ampeg and my burnt out PF-500's.....(one was still in warranty, one wasn't.)
    When their product is out of warranty..........your on your own.

    On the same note as you, I had a problem with a slightly out of warranty G.K. MB2-500 head.
    G.K. didn't just say "sorry" as did Loud in a e-mail reply, G.K. repaired it at a very reasonable price and it was repaired and back to me in the time they promised.
    I even got a e-mail from Bob G. checking to make sure everything was fine..........
  17. Punkpolock


    Feb 11, 2013
    I've been using my PF500 with the 15" cabinet for two years now and the head crapped out on me this week. It will turn on and work fine for about ten minutes of playing, then the sound drops out and the fault light comes on. If I turn it off and turn it back on- it will work again for a minute...
    I have enjoyed the tone and ease of moving this setup around for the past couple of years, but I'm really pissed the problem has come right after the warranty expired!
    Has anyone had luck getting this head repaired? I'm hoping for a low cost repair but leaning towards selling the thing and moving to Markbass ASAP.
  18. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    One possible problem with your amp is that it has a build up of dust inside. This makes the amp overheat and fault out. It could be that it needs a cleaning, the jacks and connectors cleaned with deoxit.

    Many people don't do this but it's a good idea to have a gigging amp checked out at least once a year, whether or not it is under warranty. Hindsight is great, but it is also a good idea to have the amp checked out a couple of months before the warranty expires in case there are any pending issues.
    bftbassman and Garret Graves like this.
  19. Punkpolock


    Feb 11, 2013
    Sounds like good advice, sure wish I would have done that before the warranty expired!
    Hopefully it will be something simple and easily remedied like a good cleaning.
    I did open the head up and look for obvious loose wires or solder joints everything looks clean and connected (not a lot of dust).
    Perhaps I'll blow it out and try cleaning the jacks as suggested.
  20. Sorry about that. It probably won't be repairable unfortunately. The cost will nearly equal the retail price of a new one. Get a GK next time

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