Help! Picking up AM Radio When Volume Maxed

ynot12

ynot12

Supporting Member
Mar 7, 2012
2,688
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Wellington, FL
#1
Hi guys, I'm using a Darkglass Tone Capsule and just swapped out EMG GZRs for M&V Atlas pickups. It sounds SOOO GOOD.

However, when my volume get close to 100% I pickup an AM radio station. I've checked all of the obvious solder joints, but I can't figure out what's going on. Any thoughts?

I live right by a big radio tower (presumably the station I'm picking up) and this has popped up with other basses in the past, which were fine when played elsewhere.
 
#2
Shielding! You need shielding.

Get some copper foil with conductive adhesive backing. Shield anything near anything that's got wires in it. Try to make sure that there's as much shielding surrounding everything in your bass. Try to make sure that you don't have any circular grounds that could act as an antennae.
 
#3
O
honeyiscool said:
Shielding! You need shielding.

Get some copper foil with conductive adhesive backing. Shield anything near anything that's got wires in it. Try to make sure that there's as much shielding surrounding everything in your bass. Try to make sure that you don't have any circular grounds that could act as an antennae.
Click to expand...

Thanks for the response. I should have taken some pics first. It's shielded and it was working perfectly fine with the EMG Geezer pickups. When I swapped them in with the Atlas pickup the issue surfaced. Here's some pics so everyone can see what we're working with here.

Is it possible the volume pot is going bad?

79512F64-02B4-439B-B27F-15987E555FDA_zpsgfzc0exn.jpg


I had this cavity all nice and clean looking, but I screwed it up during the pickup swap. I'll get back and clean it up once i get everything working 100%.

593967C5-E79C-4B75-9EF9-A5FB7FCB7602_zpsbvbg4gsf.jpg
 
#5
ynot12 said:
Hi guys, I'm using a Darkglass Tone Capsule and just swapped out EMG GZRs for M&V Atlas pickups. It sounds SOOO GOOD.

However, when my volume get close to 100% I pickup an AM radio station. I've checked all of the obvious solder joints, but I can't figure out what's going on. Any thoughts?

I live right by a big radio tower (presumably the station I'm picking up) and this has popped up with other basses in the past, which were fine when played elsewhere.
Click to expand...

Did you ever get a resolution? Curious, as I had this happen with two separate TC circuits, (along with some other unwanted behavior)...unfortunately, all the problems shunned me away from the TC as a result.
 
#6
Nice neat setup, my guess is that pickup is acting as an antenna, and the preamp could be helping, even with shielding in the pickup cavity, it probably would still do that, as the sides, and tops of the pickup would still be exposed...one thing to try..if you haven't already..the other piece of gear that can pickup radio is a guitar cable, if you haven't, see if it's better with a different cable. I've seen the problem more with clear bright sounding pickups, than with darker sounding pickups.
 
#8
One thing about EMG is that they have impeccable build quality. I would bet they internally shield the Geezers in a way which those Atlas do not.
 
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#9
Growlmonkee said:
Nice neat setup, my guess is that pickup is acting as an antenna, and the preamp could be helping, even with shielding in the pickup cavity, it probably would still do that, as the sides, and tops of the pickup would still be exposed...one thing to try..if you haven't already..the other piece of gear that can pickup radio is a guitar cable, if you haven't, see if it's better with a different cable. I've seen the problem more with clear bright sounding pickups, than with darker sounding pickups.
Click to expand...

I would look at trying a different (or very short) cable also. There have been cases of hi-fi amps picking up radio signals in the speaker cables. The RF had no problem running back into some previous stage of the amp where it was detected by a diode or transistor junction.

So it may not be the pickup or preamp that is picking up the RF, it may just be the preamp that is detecting a signal picked up by the cable. Possibly a ferrite bead (choke) on the cable may help.

-
 
#10
Thanks for the replies, everyone. It turned out to be a simple fix. I just connected the shielding in the pickup route to the control cavity with a little wire and no more radio. Super simple and dead quiet now.

I did the same thing on a recent build that included the new Atlas H.O. (high output) pickups and they are also dead quiet.

Killer sounding pickups, too! You all should try them.
 
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