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Jazz Bass feedback?

Discussion in 'Pickups & Electronics [BG]' started by Blues Bass 2, Jul 11, 2005.


  1. Does anybody else get feedback when approaching your amp from the front at gigs when your amp is still turned up.I get a high pitched squeal if I don't turn down my bass volume when I want to adjust the Eq.on my amp.I use a 5 string Essex Jazz now and remember in the 70's my Ash/Maple 76 jazz did the same thing.Is it the single coils?
     
  2. JPJ

    JPJ

    Apr 21, 2001
    Chicago, IL
    I used to have that same problem when I was still gigging with my '77 jazz. It could potentially be several things, although it shouldn't be single coil pickups "in general". There are a LOT of people who use singlecoils that don't have that problem! ;)

    First, it could be the specific pickups in your bass (is there anyone who has more info on a microphonic pickup creating a feedback loop)? It might also be the use of a high-end driver/tweeter in your cab or cabs. I experimented with things when I was having this problem, and when I turned off the tweeter, the problem largely went away. Also, in my scenario, I was running my rig with a lot of tube distortion at pretty high output levels, so right there, I was introducing a lot of upper harmonic distortion into the picture.

    Nevertheless, after retiring my '77, I'm still using a jazz with singlecoils, am still using a cab with a horn tweeter, and am still using tube distortion at relatively high volume levels (although sometimes without the tweet and sometimes willout the distortion). Nevertheless, the problem has been completely eliminated.

    If I had to guess, I'd say that the bass/pickups were at the root of my problem several years ago, and I would guess that the same might be true in your case, based on the limited amount of information we have to go on. Is the SX jazz the only bass you own? Can you experiment with another bass/friend's bass while keeping all other elements constant? Approach it scientifically and see what you can eliminate from the equation. ;) :bassist:
     
  3. dave251

    dave251 Wendler Instruments

    Feb 5, 2004
    Lawrence, KS
    Soiunds to me like the pickups are microphonic...the coil wire is vibrating against either the bobbin it's wound on, or the magnets if it's a real Fender pickup. Fender has never been consistent about potting the coils in wax.

    We used paraffin while I was an engineer at Peavey. Get one of those "potpourri pots" from Wal mart...you know, the ones you throw herbs in...or you can use a crock pot...DON:T melt the wax over an open flame, such as a gas stove. Parafin is HIGHLY FLAMMABLE, and moreso the hotter it gets...that's why I highly recommend the potpouri pot...it heats to exactly the right temp.

    You'll need enough paraffin to cover the pickup once it's melted. A pound should do it, although the pup will only soak up less than an ounce worth. Remove the pickup from the bass, and the cover from the pickup...be VERY CAREFUL to not break any wires or the pickup is toast.

    Anyway, melt the parafin...about 145 degress if my memory serves, and drop the coil in for about 15 minutes...pulll it out and let it cool about halfway, and wipe the excess wax from it. Should cure the problem. I'm sure there's a source on the net that will show you how to do this...not complicated, although if you're a klutz it's pretty easy to destroy an unprotected pickup coil. You'll have to be the judge of that one.
     
  4. JPJ

    JPJ

    Apr 21, 2001
    Chicago, IL
    Fenders from the '70s are pretty famous for their microphonic pickups....unfortunatley. :( I always suspected that was my problem, but I just ended up retiring the bass.
     
  5. Thanks for the replys. My other bass right now is an 80's Guild Pilot 5 with EMGs so of course it doesn't feed back.I've had two American Peavey Millenium 5s,a 97 American Jazz Deluxe and a Cirrus the past five years and none of them have fed back and all of them had humbuckers.I play through a RBI/Crown with an Eden 210 XLT and yes I use the horn.My rig when I had my 76 Jazz was an SVT head through a Cerwin Vega B-36 which was a folded horn with an 18" speaker,not exactly something you would expect to feed back on the high end.

    I think sometime I might try the wax treatment on my pickups.I can deal with turning my bass down when coming up to my amp if I think about it beforehand but it is a hassle when trying to change EQ.This is why I got rid of my 76 Jazz years ago.Before the Jazz I used a Ric 4003 for 8 years and never had this problem with it's single coils.I thought about changing the pickups to something different but the SX five string pickups are smaller than most and the string spacing is very narrow for a five string.Also the tone of the stock pickups is why I use the SX for my main bass over the Guild with EMGs,it just has a more open sound and better dynamics.Mostly I was just trying to see if it was a common thing for Jazz single coils.Sounds like the wax is the answer.Thanks for everyones input.