Ampeg portaflex question?!

Discussion in 'Amps [BG]' started by The Thunder, Jan 19, 2014.


  1. The Thunder

    The Thunder

    Joined:
    Mar 9, 2011
    I was trying to help out a friend of mine with some major buzzing issues he was having with portaflex 210 cab he's using the pf-500 to power it. It's starts buzzing pretty bad when you crank up the volume. We noticed the back of the cab says it's a 8 ohm cab but when you look at both the speakers they say their both 16 ohms and of course the pf-500 is a 8 ohm head. So we are wonder how is it possible for a 8 ohm head to have enough power to use two 16 ohm speakers and why the cab say its a 8 ohm cab but has two 16 ohm speakers? Can someone help clarify this please
  2. Jim Carr

    Jim Carr Dr. Jim Gold Supporting Member

    Joined:
    Jan 21, 2006
    Location:
    Denton, TX or Kailua, HI
    Two 16 ohm drivers = 8 ohm load. The buzzing? Sounds like distortion to me.
  3. SuperK

    SuperK Supporting Member

    Joined:
    Sep 12, 2012
    Location:
    San Jose, CA
    Is he using any pedals? If so try running straight in without the pedals and see If the buzzing stops. Also try plugging it into a different power outlet. And yes 16/2=8.
  4. beans-on-toast

    beans-on-toast

    Joined:
    Aug 7, 2008
    Yes the two 16Ω speaker are wired in parallel yielding an 8Ω impedance. So this is correct and the amp is a match for the cabinet.

    As for the buzzing, you have to determine if it is distortion or a mechanical vibration in the cab.

    Assuming it is mechanical, move the cab into a different room. See if there is still buzzing. Sometime it is something in the room that is buzzing and not the cab. If you clearly hear that it is something in the cab, apply pressure in different places -- the grille corners, the lid, the casters, the back plate, the speaker from the inside, the latches, etc. Remove the front grille, see if that helps. You have to take one thing at a time and test it and see.
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  6. pie_man_25

    pie_man_25

    Joined:
    Jun 28, 2007
    Location:
    Windsor, ON.
    you're probably hearing the speakers start to fart out/run out of excursion/distort, that's probably the buzzing, at least if it sounds like a sort of farting sound. If it sounds like rattling, then something has come loose. Also, the cabinet is 8 ohms because the two woofers are wired in parallel - this means that the impedance of the woofers is halved assuming that they are of the same impedance, if they're both 16 ohms - which they are - then logically the total impedance is 8 ohms.
  7. The Thunder

    The Thunder

    Joined:
    Mar 9, 2011
    We took the grill off and saw that there is a wrinkle/crease in the cone. Can that distort the sound that much?
  8. JimmyM

    JimmyM Supporting Member

    Joined:
    Apr 11, 2005
    Location:
    Apopka, FL
    Disclosures:
    Endorsing: Ampeg Amps, EMG Pickups
    Yes. Unfortunately, that means the end of your speaker. You can have it reconed or you can get another one from Ampeg, but it's toast.

    It's caused by cranking too loud, BTW. If you REALLY want to be loud, he should have two of them.
  9. beans-on-toast

    beans-on-toast

    Joined:
    Aug 7, 2008
    Yes. A crease can be caused by pushing the speaker beyond its limit -- called over excursion. At lower volumes you don't hear any effect, at higher volumes it get pretty distorted. The fix is to recone or replace the speaker.

    If you are pushing the cab hard enough to do that you should consider getting an additional cabinet. Dialing back your lows so that you are not pushing the speaker so hard can help prevent this from occurring.

    Jimmy is a faster typer than me!
  10. pie_man_25

    pie_man_25

    Joined:
    Jun 28, 2007
    Location:
    Windsor, ON.
    As much as I like Ampeg, especially now that I own some of it, they might charge an arm and a leg for new speakers, check to see if it's covered under the warranty. If it isn't, you could try modelling various speakers (preferably Eminence ones) on WinISD to see which ones would make a good "drop in" replacement. I'm getting ahead of things though, if Ampeg is cool with giving you new drivers for free (or not too expensive considering various factors), I'd grab at them, and pick up a second cab as well.
  11. The Thunder

    The Thunder

    Joined:
    Mar 9, 2011
    Has anyone tired the glue over the crease trick? I saw were people say it works. Is it worth a shot since I'll have to recone or replace the speaker anyway?
  12. JimmyM

    JimmyM Supporting Member

    Joined:
    Apr 11, 2005
    Location:
    Apopka, FL
    Disclosures:
    Endorsing: Ampeg Amps, EMG Pickups
    I agree. Give it a shot. At this point you have nothing to lose. BTW, got no idea what Ampeg charges for those speakers, but usually replacement speakers are pretty reasonable.
  13. beans-on-toast

    beans-on-toast

    Joined:
    Aug 7, 2008
    It wouldn't hurt. It would be a good idea to address why it occurred. You need to consider an additional cab or dialing the low end back on the one that you are using.

    Creases can often be found in segments around the cone. So other positions around your cone from where the crease is may have a weak spot that you just don't see now. If you fix one area, the problem could develop somewhere else with time if the damage is done.

    Check out this video showing cone crease from Celestion:
  14. Bravo Del Sur

    Bravo Del Sur

    Joined:
    Apr 19, 2014
    Location:
    Costa Rica
    Well, well...... Sorry to tell you that but it's not your cabinet, I have a PF-500 connected with a PF-115HE, cabinet is good but the amp is just SH*T, I bought my gear a year and a half ago and it started to loose power and there was that distrotion sound,one night during a gig, it lost 80 % of its power, sounded like a active bass with low battery but I have a passive bass.... so !I live in Costa Rica, I contact the store where I bought it and they honor warranty for only 6 months... I turned myself to Ampeg and those guys are telling me that the Ampeg products sold outside North America dont have any warranty. Desperate I phoned a local amplifier repairman , he said that it is a faulty diode or something like that, he told me also that it is " class D " electronics that means, cheap price all integrated circuits , hard to repair, delivers a lot of power for a low price but does'nt hold the road for long......In short I got robbed, All products of Ampeg, Crate, Mackie, tapco sold outside north America are'nt garantied....it's a ripoff stay away from that Junk !!!

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