I'm stumped, help me ID these Seymour Duncan pickups.

[commonplayer]

Just picked up a late 70s Fender P bass and was surprised to see that the pickups had been swapped out to something I had never seen before. They're Seymour Duncan's with three tiny switches on one of the pickups, and they must be active because someone also did a battery route on the back of the bass.

Anyone ever seen these before? They sound great btw!

 

[bholder]

I've seen them before, long while back, though. Someone here will certainly chime in with the details...

 

[MIMike]

Yes, they are active and I have a set of J-Bass pickups. Seymour Duncan wrote something on these a while back and this is what he said about the switches and their functions:

Originally posted by Seymour Duncan FAQ
Functions of switches on old-style "Active EQ" bass pickups
We stopped making the switch pickups ("Active EQ") in the mid-'90s. We replaced them with the Pro-Active series.
The little rocker switches on the Active EQ pickups change the sound. Switch #1 shifts the coil resonance. On a Jazz Bass neck pickup and a P Bass pickup, the resonance moves downward from 22 KHz to 6.4 KHz. On a Jazz Bass bridge pickup, it move downwards from 17 KHz to 4.9 KHz. The effect is to give a more focused sound with a harder attack. Switch #2 gives a broad band bass boost of 4 dB for the Jazz Bass neck and P Bass pickups, and 5 dB for the Jazz Bass bridge. The switches can be a very effective tool for changing the tonal "character" of your instrument.

He only addresses two of the switches in the above post, and I think it’s possible that a later version only had two.

 

[sunbeast]

They were Seymour Duncan's original version "Active EQ" pickups. I have a few PJ sets of these and one J set. They are great pickups with probably a lot of fluff for most people (probably you'll find one or two settings that you stick with, like me)- capable of the most "hi-fi" open bright (and potentially thin depending on your strings and EQ!) sound or warming up with different switch selections. I've never really heard anything like them. They are also very low-noise and don't seem to require shielding in the instruments I've used them in. Some of the brighter settings are pretty extreme, but you can hone in on some great cutting peaks with other settings. They work really well IME with filter-type preamps (ala Alembic/Wal) when you use one of the peakier settings as you can retain some more brightness than with more traditional pickups used with a filter pre turned down into the mids.

The above description applies to the later dual-switch versions, but these early 3-switch ones dedicated all three switches to the resonant frequency selection.
Here is a thread where someone posted pictures of the manual that originally came with these showing the pickup response curves with different settings: https://www.talkbass.com/threads/seymour-duncan-active-eq-pickups-info.1074884/