Diagnosing My P

[velorush]

Finally got to plug in the new (to me) Cruisebass last night and discovered what I initially posted as needing a pickup adjustment was in fact a problematic P-Bass pickup.

The P pickup has far less output compared to the jazz pickup (I would think if anything the opposite would be the case).

If I tap on the P pickup cover it is quite loud compared to tapping on the jazz cover - tapping on the P polepieces with a screwdriver, however, yields softer 'clicks' than the of the jazz.

I didn't have time to really get into full diagnosis mode, but could it be shorted across the coils? Wouldn't be something simple like the volume pot, would it (actually, the control seems to work fine, taper-wise)?

[AdmiralB]

I know absolutely nothing about P-bass pickups. My assumption was based on construction of a guitar humbucker, where the coils are reverse wound/reverse polarity from each other. If the P construction is the same, the polarity, as well as the direction of the coil wire, would be reversed. I'll do some Googling.

P construction is probably the same. What I'm saying is that I don't think in this case it really matters; the reverse polarity isn't important since none of the 'information' is heard by both coils.

Having said that, assembling it as though it was a standard guitar humbucker is probably safest.

[velorush]

Resurrecting this thread (as I only now was able to get to this): I disconnected the P pickup from its pot and connected it to the J pickup pot (disconnecting the J pickup). Results the same. I reflowed solder for the P pickup ground - all things remained the same.

Best I figure, I've got something going on in the P pickup that I can't figure out. Magnet orientation seems to be fine; DC resistance seems within spec... Think I'm going to see if I can find a replacement DiMarzio.

[Ethan]

The Model P that Dimarzio makes is really nice, and not too expensive. I might buy a Will Power P pickup from them for my newer bass.

[velorush]

The Model P that Dimarzio makes is really nice, and not too expensive. I might buy a Will Power P pickup from them for my newer bass.

That's funny, I was just on the DiMarzio page looking at the Model P (DP122) - introduced in 1977, DC Resistance of 11.54 kΩ. I'm guessing that (or a form of that) is what is in the bass now. Not very expensive either (like $60).

If I can get some time this weekend I'm going to try fiddling with the magnets and checking connections one last time. If I don't get any different results I think I'll order one of these.

[velorush]

Finally got some more time to work on this, checking magnet orientations and the like. I dug into the high string coil and discovered the magnets were not same-pole-facing (I've got to think P-90!), so I flipped one of them so that they were properly oriented, put it all back together and now the high string pickup coil has great output, but the low string output has dropped to similar to what I had prior on the low string coil.

Additionally, when blended with the bridge pickup I can tell they are out of phase.

The plan, then, is this: flip both magnets on the high string coil (to get them in phase with the bridge pickup), then check the orientation of the magnets on the low string coil and make adjustments... back in a bit.

If this fixes it, this may be helpful for someone with a similar problem down the road.

[carfish7]

Man, I think you have suffered enough with this troublesome beast. Plus, it is all beat up and not very mint or pristine.

The best solution here is to sell it to me cheap and buy that CAR one at GC. Yeah, that's the ticket. You'll feel SO much better after this move.

Trust me!

[velorush]

AACK! Now the low coil is working (sounds fantastic!) but the high coil is not... This is beginning to appear to be a problem from my old course in Logic and Sets!

Checking orientation and polarity of the high coil - and not even touching the low coil.

I put a set of larger strings on that I had laying around - the E and A strings sound thunderous and piano-like!

ETA for Chris: I WILL whip this thing!

[carfish7]

AACK! Now the low coil is working (sounds fantastic!) but the high coil is not... This is beginning to appear to be a problem from my old course in Logic and Sets!

Checking orientation and polarity of the high coil - and not even touching the low coil.

I put a set of larger strings on that I had laying around - the E and A strings sound thunderous and piano-like!

ETA for Chris: I WILL whip this thing!

It is inhabited by demons obviously. Step away. I'll save you!

[velorush]

YES!

IT'S ALIVE!

FFR: all magnets should carry the same orientation as the J pickup, each magnet should repel when facing its paired magnet (remember someone's P-90 analogy).

Man, oh, man does this thing sound fabulous!

I'm thinking what must have happened is someone popped the hood to have a look and one of the magnets on the high side dropped. They stuck it back in without thinking or considering orientation and, viola! Non-functioning pickup (or half a pickup). I did the same thing (since the pickup wasn't working right when I received it) and put the magnet back in with the wrong orientation.

Oh this is great!

I gotta go and re-edit my WTB thread as now all I need for this is the Cruisebass truss rod cover!

[carfish7]

I still fear for your soul......

But congrats!

[veatch]

Very cool! Glad you got it running!

[crunchee]

Good to hear that your P is nice and clear now.