Crackling when raising pole pieces on DiMarzio* Model P

[Riff Ranger]

This isn’t so much a problem I need solved as a mystery I want demystified. The instrument worked fine before tonight’s tinkering and does again having reversed my actions.

Chasing slightly more output from this beast, I just tried raising the pole pieces of the pickup one full turn of a 3/32” hex key each. I may have gained a bit of output in so doing, but I gained enough static-ish crackling when digging in (most noticeably on the big string, a .125 tuned to B0) to render the instrument unusable. When I turned each pole piece back a full turn of the hex key, it sounded exactly as it did before, so harm done; but I would like to know what happened, as I presume they made the pole pieces adjustable on purpose.

As you might have guessed, this Electra X700JB came out of the Matsumoku factory in Japan in the early 1980s. I believe it has its stock pickup, which I did have swapped out and back in once, and if it’s not a DiMarzio Model P it’s a very convincing clone. I have the pickup height as high as possible while retaining string-to-string balance, but the gap remains about 5/32” on each string when fretted at the 20th fret.

Thank you in advance for any insight into what I’ve observed; bonus points if you can help me lose the crackling while getting those pole pieces up a bit, but it’s no big deal to make slight adjustments on my pedals or amplifiers.

 

[toddsterbassist]

They can sometimes pick up static electricity. Try rubbing a sheet of the static cling things you throw in the drier over the pickup and see if that solves it.

 

[two fingers]

My guess is that the strings are touching the magnets when you pluck certain notes. I would try lowering the magnets back to where they were and bumping up your gain if you need more from the bass.

Those are already pretty hot pickups. Sometimes more isn't better.

 

[Riff Ranger]

They can sometimes pick up static electricity. Try rubbing a sheet of the static cling things you throw in the drier over the pickup and see if that solves it.

That sounds bonkers, but if you can’t trust someone WHO SPELLS “LOSE” CORRECTLY then who can you trust? You do the world a service with that status, and it has not gone unnoticed

 

[Riff Ranger]

My guess is that the strings are touching the magnets when you pluck certain notes. I would try lowering the magnets back to where they were and bumping up your gain if you need more from the bass.

Those are already pretty hot pickups. Sometimes more isn't better.

I suspect you’re right, and I could check on that later today (original post should read “no harm done,” and I see no danger in trying it again to confirm).

Yes, it’s entirely possible I’m just getting greedy. I was very happy with the instrument before raising the pole pieces and as you say it’s a fairly hot pickup anyway; but I have played and owned hotter (my Peavey Furies, and the nearest thing I have to seller’s remorse, which would be selling this one’s cousin, a Westone Spectrum GT, the hottest passive bass I remember playing, though I haven’t played anything with a mudbucker in decades). As I recall, you know how it is to want a hot passive bass

The thing is I’m trying to match outputs between my basses, and that’s largely how I use the onboard preamps in all the other ones I use regularly. And this one’s so close to where I have my active basses. Matched output between instruments is a nice-to-have, not a must-have; as we’ve both said, my amps and pedals have gain knobs.

If what I hear does indeed come from the strings making contact with the pole pieces, I wonder why I don’t get that with my newer Yamahas (BB734A and 735A), where I have that gap down around 3/32” and even less tension on the big strings (which I consider a feature rather than a bug for my purposes).

 

[two fingers]

I suspect you’re right, and I could check on that later today (original post should read “no harm done,” and I see no danger in trying it again to confirm).

Yes, it’s entirely possible I’m just getting greedy. I was very happy with the instrument before raising the pole pieces and as you say it’s a fairly hot pickup anyway; but I have played and owned hotter (my Peavey Furies, and the nearest thing I have to seller’s remorse, which would be selling this one’s cousin, a Westone Spectrum GT, the hottest passive bass I remember playing, though I haven’t played anything with a mudbucker in decades). As I recall, you know how it is to want a hot passive bass

The thing is I’m trying to match outputs between my basses, and that’s largely how I use the onboard preamps in all the other ones I use regularly. And this one’s so close to where I have my active basses. Matched output between instruments is a nice-to-have, not a must-have; as we’ve both said, my amps and pedals have gain knobs.

If what I hear does indeed come from the strings making contact with the pole pieces, I wonder why I don’t get that with my newer Yamahas (BB734A and 735A), where I have that gap down around 3/32” and even less tension on the big strings (which I consider a feature rather than a bug for my purposes).

I absolutely get it! But what you're doing is kind of like raising the pole pieces on G&L MFD buckers. They're "hot enough" without that. (That's what I'm thinking of installing in that bass I was asking about in that thread a few months back, by the way.)

 

[Riff Ranger]

I do still mean to look into the suggestions here, but I got busy today working with a new drummer who sings and writes! I just might get to record and perform actual songs with this bass! It has been way too long.

 

[StayLow]

Those pickups do have static issues at times.

Is your fingertip touching the poles? Try it and see if the static manifests.

Raising /lowering the pickup is good for changing output or tone.

Raising/ lowering poles is good for string-to-string balance.

 

[SulzerType2]

5/32” Seems way too high. 4.5 mm, for those in civilised parts of the world, FYI.

I've never liked the feel of adjusting the poles in a Model P. I think it's a gimmick.

 

[Riff Ranger]

Raising /lowering the pickup is good for changing output or tone.

Raising/ lowering poles is good for string-to-string balance.

I've never liked the feel of adjusting the poles in a Model P. I think it's a gimmick.

Putting these bits together makes sense; it seems the adjustable pole pieces allow for fine adjustment of output, but not big changes, and probably aren’t terribly useful on a split coil where you can more easily adjust the relative heights and angles of the pickup halves (I imagine adjustable pole pieces do come in handy on the Model J).

 

[Riff Ranger]

5/32” Seems way too high. 4.5 mm, for those in civilised parts of the world, FYI.

Way too high?! I know Fender’s factory recommendations are just that—what Fender recommends for their instruments with stock electronics—but even so, I thought 5/32” was fairly typical; most of my instruments measure around that or even a bit less.

As for the “civilised” comment, you’ve managed to find at least one pair of sympathetic ears in the United States with that one The logic of the metric system resonated with me when I learned it in elementary school (yes, it is taught here ) and I really learned to love it and speak it as a park ranger at Redwood National Park, where one in nine summer visitors spoke German as their first language; nearly all of them spoke English very well, but they certainly didn’t speak Imperial units! My co-workers would often call me over to “translate” into metric I think those of us who work on imported musical instruments or automobiles necessarily learn to work in millimeters at least, but km and kg and °C will get you a lot of blank looks around here.

 

[Riff Ranger]

My guess is that the strings are touching the magnets when you pluck certain notes.

Is your fingertip touching the poles? Try it and see if the static manifests.

Upon further investigation, I don’t think this is causing the crackling/static/whatever. Deliberately hammering on the strings and even just pressing them to the pole pieces didn’t produce anything like what I was hearing playing just a bit heavy-handed-ly with the pole pieces raised above the covers. Touching the pole pieces with my fingertips produces no dramatic results here either (though it generates a loud buzz with my Yamahas; go figure). I may have to look into the static cling things mentioned above.

 

[StayLow]

If the bass has a plastic pick guard or other plastics you may be touching while playing, rub those too with the dryer sheet. Downside is it’s not the best feeling stuff, and may be unhealthy for those with a habit of putting fingers or picks in the mouth. Those dryer sheets aren’t necessarily toxic, but not delicious either… so I’ve heard.

To check the poles for certain, play something that results in static then place a piece of tape over the poles and play the same thing. Any difference? It’s less a touching-to-test thing and more a rubbing-while-playing static-causing thing.

Yes, the adjustable poles are much more useful on a J pickup and that feature was one of many reasons the Model P and Model J pickups were - and still are - such a popular mod, to the point some might argue a “real” 70’s Fender has those installed. If anyone from Fender is reading this and running out of reissue ideas, take note.

 

[SulzerType2]

I'm thinking too high because the magnetic pull from a Model P must be quite strong? I've found they need backed off a little versus lower output pickups.

 

[LetItGrowTone]

The Model P's magnets aren't unusually strong.
But I find the highs can be harsh if the pickup is too close to the strings, maybe for some other reason.

 

[brianrost]

My guess is that the strings are touching the magnets when you pluck certain notes.

I had that problem on a BC Rich with Model Ps that I owned in the 1980s. Lowering the polepieces got rid of the noise.

 

[two fingers]

Upon further investigation, I don’t think this is causing the crackling/static/whatever. Deliberately hammering on the strings and even just pressing them to the pole pieces didn’t produce anything like what I was hearing playing just a bit heavy-handed-ly with the pole pieces raised above the covers. Touching the pole pieces with my fingertips produces no dramatic results here either (though it generates a loud buzz with my Yamahas; go figure). I may have to look into the static cling things mentioned above.

Your fingertips won't make a sound on magnets. Touch the strings to the pole pieces with your amp cranked and it'll sound like a rifle going off.

 

[Riff Ranger]

Your fingertips won't make a sound on magnets. Touch the strings to the pole pieces with your amp cranked and it'll sound like a rifle going off.

Yeah, I can definitely get that out of it. Bad enough through headphones this was more of the note disappearing, replaced with crackle. I’ll see if it still does it (any better way to share a quick clip than a link to SoundCloud?), and if I have any dryer sheets around. No pickguard on this one, so no plastic issues from that.

 

[StayLow]

… this was more of the note disappearing, replaced with crackle…

Oh. My suggestions are based on a crackle / static sound in addition to the notes sounding not instead of notes sounding.

Maybe you affected an intermittent short somehow.

It’d be helpful to hear sound samples.

 

[Riff Ranger]

It’d be helpful to hear sound samples.

Is there a better way to share a quick clip than a link to SoundCloud?