Help! EMG Wiring Trouble!

[ManRay]

Hi,

I just wired up an EMG 35P4 active pickup in my bass that already has a passive Nordstand Music Man pickup in it. I wired each pickup to its own volume and tone control and then fed both to the tip of my output jack. I thought that this would give me independent level control over both pickups, but instead my passive volume acts as a master volume over both!

As it stands I can hear the music man pup, both pups or none, but I can't play the EMG by itself. Any suggestions or guidance is greatly appreciated.

Thanks,
Mr.

[David Schwab]

It sounds liek you have the passive tone control wired for a single pickup bass. Check the passive volume pot to see how the hot and pickup leads are wired. You want the pickup lead soldered to the wiper lug (center) and the output to the outside lug, the way a Jazz bass is wired. If you wire it so the hot is to the wiper it will act as a master volume.



The the following in mind when mixing active pickups and passive:

Can I mix EMG’s with passive pickups?

It is possible to mix EMG’s with passive pickups. There are three possible wiring configurations; one is better than the other two.
Use the high impedance (250K-500K) volume and tone controls. The problem is that the high impedance controls act more like a switch to the EMG’s. The passive pickups, however, will work fine.

If you have a guitar with two pickups and two volume pots, with a three-way switch, there is another alternative. Use the 25K pots for the EMG, and the 250K pots for the passive pickup. This way you can use one or the other with no adverse affects, but with the switch in the middle position the passive pickup will have reduced gain and response. Use the low-impedance (25K) volume and tone controls provided with the EMG’s. The problem here is that the passive pickups will suffer a reduction in gain and loss of high frequency response.

This is the best alternative. Install an EMG-PA-2 on the passive pickups. There are two benefi ts to doing this. With the trimpot on the PA-2, you can adjust the gain of the passive pickups to match the EMG’s. The PA-2 acts as an impedance matching device so you can use the low-impedance EMG controls (25K) without affecting the tone of the passive pickups. You will also be able to use other EMG accessory circuits such as the SPC, RPC, EXB, EXG, etc. For this application, we recommend ordering the PA-2 without the switch for easy installation on the inside of a guitar.

[Wilder Amplification]

Hi,

I just wired up an EMG 35P4 active pickup in my bass that already has a passive Nordstand Music Man pickup in it. I wired each pickup to its own volume and tone control and then fed both to the tip of my output jack. I thought that this would give me independent level control over both pickups, but instead my passive volume acts as a master volume over both!

As it stands I can hear the music man pup, both pups or none, but I can't play the EMG by itself. Any suggestions or guidance is greatly appreciated.

Thanks,
Mr.

Did you hook the pickup outputs to the CENTER leg of their respective pots, then join the outer legs opposite the ground together and send them to the output jack? Or do you have the center legs of each pot joined together and going to the output jack? If you have it hooked up the 2nd way that would definitely cause one to act as a master over the other.

[ManRay]

Output level mismatch...

Ok,

I think that I have the whole issue sorted out now. You both seemed to have my problem pretty locked down. Now I am faced with a bit of an issue with the impedance mismatch of the two pickups. The EMG being WAY louder than the passive Music Man. I noticed that your quote from the EMG website shows that I can fix the problem with the addition of a boost circuit, but space is at a premium in my cramped control cavity at the moment.

This bass has been begging to go active for a minute now and I think I am gonna stop tip-toeing around it. Thanks again for helping me sort out the problem.

All the best,
Mr.

[Wilder Amplification]

Ok,

I think that I have the whole issue sorted out now. You both seemed to have my problem pretty locked down. Now I am faced with a bit of an issue with the impedance mismatch of the two pickups. The EMG being WAY louder than the passive Music Man. I noticed that your quote from the EMG website shows that I can fix the problem with the addition of a boost circuit, but space is at a premium in my cramped control cavity at the moment.

This bass has been begging to go active for a minute now and I think I am gonna stop tip-toeing around it. Thanks again for helping me sort out the problem.

All the best,
Mr.

And that will happen when mixing active and passive pickups. The active one has a built in preamp that boosts the pickup's output well and above what a passive pickup can put out on its own, hence why the active pickup is louder than the passive.

That's why they're called "active pickups"...they have an active preamp built in...which is what requires the battery.