How does pickup pole diameter affect tone?

[sidd_laroy]

Well sometimes the pole pieces are just steel with the magnets attached underneath. So there can be "identical magnets but different pole pieces"]

+1

 

[mongo2]

It makes sense about the old days and blowing speakers.

One reason they blew the more delicate older style speakers becuause of the attack transient I mentioned earlier. Today's drivers are much more robust.

 

[SGD Lutherie]

Hey David, what effect does the magnet have when it's above or below the coil?

Like on these:

If it's on top it's closer to the strings. Most of the time the magnet or pole runs though the pickup. If you think about a Fender type pickup with rod magnets, the poles are on either end, and the middle of the magnet is magnetically dead.

Some designs like the Kay were probably mostly for looks.

 

[GlennW]

If it's on top it's closer to the strings.

I may have asked the wrong question.

I read somewhere that guitar pickups (HB's, P-90s) with adjustable poles sounded better with the screws down, as opposed to raised to follow the fretboard radius. I thought something was said the magnetic field changing, not sure.

But, it might have had something to do with the distance of the coil from the strings instead. The Kay/DeArmond has a bar magnet which sticks up above the coil; the Mustang pickup has a large portion of the magnets below the coil.

This might this be a better way to ask the question. With the string-to-magnet distance the same, would there be a difference in sound with the Mustang pickup mounted rightside up and upside down? One way the coil is closer to the strings, the other way the coil is further from the strings; but, in both cases the magnets are the same distance from the strings.

 

[SGD Lutherie]

I may have asked the wrong question.

I read somewhere that guitar pickups (HB's, P-90s) with adjustable poles sounded better with the screws down, as opposed to raised to follow the fretboard radius. I thought something was said the magnetic field changing, not sure.

But, it might have had something to do with the distance of the coil from the strings instead. The Kay/DeArmond has a bar magnet which sticks up above the coil; the Mustang pickup has a large portion of the magnets below the coil.

With the screws down the coil is closer to the strings. it sounds fuller that way. It's brighter and thinner with the screws up.

I think the Kay pickup was done just to have the thin bar sticking though the pickguard. I'm not sure it's the best way to do things.

With the Mustang, it could be they wanted stronger magnets? I don't know. That's actually the first time I saw the bottom on one of those. The old Ric toasters also had the magnets sticking out the back of the pickup. You can't have alnico rods too short or they demagnetize after a while. Leo was always trying new pickup ideas. That was a passion of his according to George Fullerton.

This might this be a better way to ask the question. With the string-to-magnet distance the same, would there be a difference in sound with the Mustang pickup mounted rightside up and upside down? One way the coil is closer to the strings, the other way the coil is further from the strings; but, in both cases the magnets are the same distance from the strings.

I'd want to keep the coil closer to the strings. If you take a stacked humbucker, and listen to the bottom coil, they don't get very much output, and sound kind of dull.

 

[mongo2]

This might this be a better way to ask the question. With the string-to-magnet distance the same, would there be a difference in sound with the Mustang pickup mounted rightside up and upside down? One way the coil is closer to the strings, the other way the coil is further from the strings; but, in both cases the magnets are the same distance from the strings.

Here's an interesting factoid (I think so anyway): On the Mustang RI the pickup poles are flush to both sides of the bobbin and wider than the originals.

I think the RI pickups sound punchier and fuller...more alive than the originals.

I know that doesn't answer your question about the coil proximity but I've never tried it. Give it a try and let us know what happens.

 

[GlennW]

With the screws down the coil is closer to the strings. it sounds fuller that way. It's brighter and thinner with the screws up.

Thanks, David. That's what I'd forgotten; it has to do with the coil rather than the magnetic field.

 

[GlennW]

Here's an interesting factoid (I think so anyway): On the Mustang RI the pickup poles are flush to both sides of the bobbin and wider than the originals.

I think the RI pickups sound punchier and fuller...more alive than the originals.

I know that doesn't answer your question about the coil proximity but I've never tried it. Give it a try and let us know what happens.

I've been trying to learn a little about those. It also seems like the older ones were wound hotter. Someone on ebay sells new Mustang RI pickups, and I believe he says they're 8.74K; the older ones I've seen specs on are within .5 either way of 10K (with the longer magnets).

 

[mongo2]

I've been trying to learn a little about those. It also seems like the older ones were wound hotter. Someone on ebay sells new Mustang RI pickups, and I believe he says they're 8.74K; the older ones I've seen specs on are within .5 either way of 10K (with the longer magnets).

My B-34 uses the same pickups as the original Mustang.

 

[GlennW]

My B-34 uses the same pickups as the original Mustang.

Early '80s? They're nice looking basses.

 

[PilbaraBass]

My theory is that with a single narrow polepiece/mag-field a vibrating string can approach or maybe exit the magnetic field during it's excursion causing the induced electric field in the pickup windings to collapse some and then be re-established when the string re-enters the mag field.

To me the resultant dynamics of the tone are more compressed/limited sounding in that situation.

Wider mag fields can prevent that.

Actually, you're pretty spot on… a wider pole piece is a more-aggressive, more responsive instrument…not necessarily a good thing (as compression is often desired in a bass sound)…but if you're trying to make your jazz bass sound more like stingray, you're on the right track.