EMG pickup distortion

nenehubert · #1 10-17-2006, 02:19 AM

Hey all,

I'm having problems with my pickup replacements in my warwick thumb. I replaced the MEC J pickups with The stock EMG Js. They have been in my bass for about 8 months, and i'm having problems with battery drain; Something must be grounding out. That could be the source of distortion in the pickup, but i'm clueless as to why i'm getting lots of audible distortion while i'm playing. The distortion from the pickups has just recently started. Could it be a solder connetion i made? Should i de-solder everything and just try it again? I have a gig thursday and i would like to have this problem dealt with.

Thanks in advance,
Rene

azzyrazzy · #2 10-17-2006, 02:23 AM

I have also experienced emg-distortion, but only when the battery is getting weak, and I play hard. When I put in a new battery, all distortion is gone. Don't know if that helps...

sunbeast · #3 10-17-2006, 02:33 AM

When I used EMGs in the past, the only times I ever had problems with distortion are when the battery was low or when they were overdriving the preamp of my amplifier. If you don't have a padded input for active pickups on your amp, your preamplifier might not be able to take the large output that EMGs put out- try cutting the volume on your bass and see if that helps.

As far as the battery drain- does your bass have a stereo output jack? You need to have a stereo output jack in order to correctly install EMGs (or any battery powered circuit), or the battery will be draining all the time and not just when a cord is plugged into the jack. The wire that attaches to the output jack directly from the battery should hook to the 3rd stereo terminal, so when a plug is inserted it makes a circuit with ground. Any distortion caused by bad soldering would probably have something to do with the battery connections as well (at least thats the first place I would look). Lastly, does your bass have 25K pots? EMGs are specified to only use their pickups with 25K pots (I think thats the value I remember...)- if they are another value then the pickups may not function correctly.
Karl

nenehubert · #4 10-17-2006, 03:31 AM

I've had the EMG pickups in my bass for at least 8 months. Just recently i've noticed distortion while playing with a full or weak battery. I'm not sure what a stereo output is, but i do know the pot configuration is this:

4-string: 2 active MEC Jazz pick-ups.
5-string: 2 active MEC Jazz pick-ups.
6-string: 2 active MEC soapbar pick-ups.

All Thumb Bolt-on basses come with an onboard active preamp.

Push/Pull Volume Control (Part #M84500 - 500K)*
Pick-up Pan Control (Part #M85252 – 25K)
Stacked Tone Control (Part #M85110 – 2 X 100K)

(This is from the warwick owners manual)

The battery drain has only been a problem since installing the EMGs. Didn't have to fool with the battery at all it was just plug and play with the de-soldering of the old pickup wires.

ldervish · #5 10-17-2006, 05:04 AM

Do you still have the MECs? Or a friend with a spare active J you could swap in to eliminate either the pup or the circuit? At the least you would have a functioning axe for your gig.

AFAIK distortion is caused by too much or too little signal, in your case the latter seems right. And it's possible a "cold" solder joint could do it, less likely is something internal to the pup.

**BFISHER1970** · #6 10-17-2006, 05:53 AM

I had the same problem with one of my old corvettes. Try some contact cleaner on your pots. That's what the problem was on mine. The volume pot was dirty.

MNbassist · #7 10-17-2006, 04:47 PM

If you are using an equalizer you should wire up an 18 volt system, its not hard just get another 9volt connection and wire the ground to the hot and the hot to the ground, then follow the same connections to the output jack

nenehubert · #8 10-17-2006, 05:25 PM

ok, so the distortion is either from the internal pre-amp or the pickups. I have the original MEC pickups and the EMG pre-amp that i didn't install. I was just using the MEC pre-amp. I need to run a test and switch out the pups and if that doesn't work then the pre-amp. Obviously, both pre-amps are active. Think this will help me find the verdict?

Evidently, the pack of batteries i bought, it was a pack of 6, weren't fully charged. So i'm back from the store with some new batteries and the distortion seems to be gone. The only problem i'm still going to have is battery drain. It seems there's a short from where the battery + & - go to the circuit board. Should i replace this? Will this help?