EMG PA-2 wiring

DocNrock

Senior member
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4,295
So the EMG website is not helpful with this, and neither is Google.  For those who aren't familiar with it, the PA-2 is an on-board preamp powered by a 9v battery.  The wiring diagram that comes with the PA-2 says that it can be used with passive pups, but the only wiring diagrams included are for their active pups.  Nowhere on their website is a diagram for wiring with passive pups. 

Sooo, I can read simple schematics.  I basically wired a body as I normally would, and put the PA-2 between the volume pot output and the output jack. 

Here is my question:  when wiring EMG active pups, the bridge is not included in the grounding circuit.  Should I connect one of the grounds from the PA-2 to the rest of the guitar ground circuit, or not?  If so, should I ground the bridge?
 

blue313

Senior member
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2,824
I just did a KFK set (81-85 + PA-2) last week.  The PA-2 ground does go to the common ground that all the electronics share, but you don't need to ground the bridge with EMG Actives.   

http://www.emginc.com/downloads/wiringdiagrams/EMG-KFKset.pdf


With passives I'd ground the PA-2 as well. I don't have the complete schematic (including the pinouts on the chips) but I wouldn't want any open circuits.
 

DocNrock

Senior member
Messages
4,295
blue313 said:
I just did a KFK set (81-85 + PA-2) last week.  The PA-2 ground does go to the common ground that all the electronics share, but you don't need to ground the bridge with EMG Actives.   

http://www.emginc.com/downloads/wiringdiagrams/EMG-KFKset.pdf


With passives I'd ground the PA-2 as well. I don't have the complete schematic (including the pinouts on the chips) but I wouldn't want any open circuits.

Right, but here is where I get confused:  do I ground the PA-2 to the main ground circuit?  If so, do I also ground the bridge, as is NOT done with the EMG active pups?  Or, do I ground the bridge to the passive circuit as is usually done and NOT ground the PA-2 to the passive circuit?

I e-mailed tech support at EMG 2 weeks ago and never got a reply.  A google search was useless, as was the EMG website.
 
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8,318
DocNrock said:
blue313 said:
I just did a KFK set (81-85 + PA-2) last week.  The PA-2 ground does go to the common ground that all the electronics share, but you don't need to ground the bridge with EMG Actives.   

http://www.emginc.com/downloads/wiringdiagrams/EMG-KFKset.pdf


With passives I'd ground the PA-2 as well. I don't have the complete schematic (including the pinouts on the chips) but I wouldn't want any open circuits.

Right, but here is where I get confused:  do I ground the PA-2 to the main ground circuit?  If so, do I also ground the bridge, as is NOT done with the EMG active pups?  Or, do I ground the bridge to the passive circuit as is usually done and NOT ground the PA-2 to the passive circuit?

I e-mailed tech support at EMG 2 weeks ago and never got a reply.  A google search was useless, as was the EMG website.

My $.02 is to ground everything.  On EMG systems the strings are not grounded because the pickup is internally shielded, but you're not using EMG pickups, so ground it.  If you don't ground the PA-2 to the passive circuit, it will not work.  The negative terminal of the battery is connected to the third prong of the stereo jack.  The chord, when plugged in, completes the circuit, thus grounding it.  Regardless if it's passive or active, it's still grounded, just not the strings with EMG active pickups.  Ground is ground.
 

DocNrock

Senior member
Messages
4,295
Super Turbo Deluxe Custom said:
DocNrock said:
blue313 said:
I just did a KFK set (81-85 + PA-2) last week.  The PA-2 ground does go to the common ground that all the electronics share, but you don't need to ground the bridge with EMG Actives.   

http://www.emginc.com/downloads/wiringdiagrams/EMG-KFKset.pdf


With passives I'd ground the PA-2 as well. I don't have the complete schematic (including the pinouts on the chips) but I wouldn't want any open circuits.

Right, but here is where I get confused:  do I ground the PA-2 to the main ground circuit?  If so, do I also ground the bridge, as is NOT done with the EMG active pups?  Or, do I ground the bridge to the passive circuit as is usually done and NOT ground the PA-2 to the passive circuit?

I e-mailed tech support at EMG 2 weeks ago and never got a reply.  A google search was useless, as was the EMG website.

My $.02 is to ground everything.  On EMG systems the strings are not grounded because the pickup is internally shielded, but you're not using EMG pickups, so ground it.  If you don't ground the PA-2 to the passive circuit, it will not work.  The negative terminal of the battery is connected to the third prong of the stereo jack.  The chord, when plugged in, completes the circuit, thus grounding it.  Regardless if it's passive or active, it's still grounded, just not the strings with EMG active pickups.  Ground is ground.

OK, that helps.  I'll ground the bridge and the PA-2 to the main passive circuit and see what happens.  The stereo jack is wired as you stated.  Thanks!
 
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