Can someone tell me what's wrong with this circuit? (Pickups out of phase)

[Tumshie]

So, I've had this second-hand C64 custom build for a year now. When I got it home, I found out that the pickups were out of phase, and the original front toaster was microphonic, so I replaced it with an alnico six-slugger (make unknown) with a Gibson braided ground. The problem is, with both pickups fully on, they are most definitely out of phase: a thin, reedy tone, devoid of low end. Turning either volume pot back, no matter how minuscule an amount, sees the other pickup roar into Life, I've tried swapping the wires on the horseshoe, but then of course I'll get a grounding issue. I even tried sending the horseshoe chassis ground direct to ground, and swap the wires, but to no avail. I'm truly at a loss. The bass rarely gets played because of this.

[Tumshie]

Anyone? Any input at all?

[Helmholtz]

I guess you are speaking of a Rickenbaker 4001 bass?
Maybe it's possible to reverse the coil wires of one of the PUs before the coax, i.e. at the PU end of the coax?


This forum might have good info: https://www.rickresource.com/forum/v...c.php?t=394104
Seems out-of-phase PUs are not unusual with the 4001.

[TomCarlos]

I hope this helps....

So what we do not know (or maybe you do) is the proper wiring of the replacement pickup. How many wires come off the pickup? Is the wiring between the bobbins correct? By some chance, did you install a pickup backwards?

I might do the following... One pickup at a time.... bypass the volume, tone and switch. Take each pickup directly to the output. Make sure each pickup working properly. I guess you can also take DC resistance readings for each pickup. Once you have a nice loud output on each pickup, then and only then I would follow a standard wiring diagram. And even then, I would wire up some pickup at a time, making sure you know Pickup 1 is working once wired and you can then go onto Pickup 2.

[The Dude]

......Maybe it's possible to reverse the coil wires of one of the PUs before the coax, i.e. at the PU end of the coax?......

^^^^^^ That!

[Tumshie]

I hope this helps....

So what we do not know (or maybe you do) is the proper wiring of the replacement pickup. How many wires come off the pickup? Is the wiring between the bobbins correct? By some chance, did you install a pickup backwards?

I might do the following... One pickup at a time.... bypass the volume, tone and switch. Take each pickup directly to the output. Make sure each pickup working properly. I guess you can also take DC resistance readings for each pickup. Once you have a nice loud output on each pickup, then and only then I would follow a standard wiring diagram. And even then, I would wire up some pickup at a time, making sure you know Pickup 1 is working once wired and you can then go onto Pickup 2.

Well, given that both the original (microphonic) toaster and the replacement one are, when wired correctly, out of phase, is it possible it's the horsie that's at fault?

Both the horsie and the replacement pickup work as per, until both volumes are at 100%

Anyway, attached is a photo of the original pickup. Like the replacement, it's a two-wire job, except the can is soldered to the ground wire internally. I'll pull the replacement later on today, but I am extremely nervous about damaging the wires inside.

[TomCarlos]

Both the horsie and the replacement pickup work as per, until both volumes are at 100%

And you have checked the pots to make sure they are clean and operating correctly over the full range? Maybe you can undo one end of the pots and check for continuity over the full range.

[Tumshie]

And you have checked the pots to make sure they are clean and operating correctly over the full range? Maybe you can undo one end of the pots and check for continuity over the full range.

The pots are fine, lad.

Anyway, I opened up the replacement pup and decided to have go. It's a cheap pup, so I wasn't too bothered if it got damaged. As expected, something went wrong at unsoldering the wires on the bobbin. I managed to get one off without dislodging the copper wire, but on the other terminal, the copper wire disappeared back into itself, and I could not, for the life of me, find the end. SO, I decided to leave that for the time being, and opened up the original. That was much easier to deal with. and the bass sounds as it should now. So this must surely prove that the Rick horsie is incorrectly wired.

Thanks to all who inputted.