#1
Hello all, I have just finished installing an SPC and a PA-2 in my Fender Strat. I'm running 3 Lace Sensors, a 250K volume pot, a 250K tone pot (with a .01uf cap) and the SPC in the 2nd tone pot position. I have the setup wired as per the instructions in the PA-2 install guide under "PA-2 on the output with an EQ circuit." The only difference is my electronics are star grounded.

So plugged in, everything works fine. My problem is that at certain points of the volume and tone knob positioning I get this bizarre oscillation/feedback noise. With the tone knob at 0 or 10, it occurs at all volumes. With the tone knob in between those points somewhere (like 5), it occurs only when the volume knob is between 7 and 8. The rest of the time, there is no noise. The guitar is completely hum free. The oscillation/feedback noise is a constant tone. It changes pitch with slight adjustments of the knobs as long as they are still in a position that causes the tone to be present. The tone occurs regardless of whether the PA-2 is switched on or off and regardless of how much the SPC is dialed in. I'll add that the noise is only present when the battery is plugged in. When the battery is unplugged, I cannot get the guitar to make the noise anymore.

I've searched the net for hours trying to find an answer and I can't find anything. Any help is GREATLY appreciated!!
#2
Could this have something to do with the fact that the PA-2 changes the output impedance to low-impedance in both switch positions?
#3
Firstly, don't self bump. It had only been an hour. Use the Edit Button.

Getting no sound out with the battery unplugged is supposed to happen.

As for the rest, if you put them in yourself, did you double check your lay out and wiring? I always keep the layout and a highlighter beside when I wire things. When I make a connection I highlight it. Then after I go back over everything and dot my connections with a pen. Once everything is marked twice, I call it a day and hope that it works.

For this, what I would do, is remove the PA2 and the SPC from the circuit, so it will just be the 5way switch, the MV and the MT. Make sure that works. Then add in the SPC. Make sure that works. Then add in the PA2. Make sure it works.
#4
Thanks for the response. Perhaps you misunderstood my problem. Everything works, so it's not a question of the components not working. It is a question of strange oscillation/feedback being introduced into the signal at varying tone and volume settings. The wiring is exactly like the schematic EMG provides.
#5
Quote by defdwight
Thanks for the response. Perhaps you misunderstood my problem. Everything works, so it's not a question of the components not working. It is a question of strange oscillation/feedback being introduced into the signal at varying tone and volume settings. The wiring is exactly like the schematic EMG provides.


Exactly. This way you isolate where the sound is coming from...
#6
Is there anyone with direct experience installing these EMG components on a passive pickup setup that could offer some insight? This appears to be an issue with parasitic oscillation from the 9 volt power source. The strange thing is the occurence at the varying volume and tone settings. With all due respect, PainIsPower's suggested troubleshooting is not the way to go here. There's no way to chase down parasitic oscillation in that manner. Additionally, EMG's site has little to no troubleshooting info. Any further insight is appreciated!
#7
I've had the same problem. Installed it in 3 different guitars and it did the same thing in each. I do know one thing... its the SPC thats causing it all. when its engaged, tap on it and you'll know what I mean. Sent it to EMG, said it was fine, but replaced it anyway, and guess what.... the SAME thing happened. So now I'm going to try and get my money back from the place I ordered it from, which I'm not sure I'll get it. Who knows... maybe they got a bad batch, but wait.... this is Feb of 2011.... your post is in 2009. hmmmm
Last edited by jlsatkins at Feb 18, 2011,