Pretend Gibby pup and build idea

[sniper]

my precious extra pre-wound Bird coils (never mention them to Carlo!!!) actually fit the P90 dog ear no hole covers i ordered. a little careful work with some sandpaper on a table top and they will be on thier way to Curt. they are almost too big to fit but there is a little leeway to slim them down a bit. they keep wanting to "buckle" up and i am holding them down in this pic.

they are bigger than a Melodymaker coil (they will not even come close to fitting into a Melodymaker cover!) with 2 3/16" blade length openings. can anyone say "4 glued in shallow false pole pieces"?

this might change the priority of my next project design.

hmmm, double cut LP Maho body, check. black ABM lock down bridge, check. black Gibby tuners, check. rosewood fretboard, check. bunches of other crap to make a bass, almost enough.

[Psycho Bass Guy]

can anyone say "4 glued in shallow false pole pieces"?

Rather than glue, I think you ought to try using a clothes-snap crimper and use 'female' snaps to fake the polepieces.

[dadagoboi]

You could also cut the heads off pup adjustment screws and glue THEM on the covers.

What specific Thunderbird were those coils from?  They look very different from all the various I've seen.  Vintage mags are 2 1/2" long.  60s bird pup bobbins are the same width and height (around 1/2") as git humbucker bobbins, only longer.

You could epoxy just about any 35 series soapbar in the p-90.  Steve and I peeled a cover off a Duncan when he was here.  It easily fits in one of his covers.

The problem I see with the dog ear P90 covers and non adjustable pole pieces is adjusting pup height since they are usually just screwed to the top of the instrument.  But it could be done with a cover shaped body route and the usual spring or foam setup under the pup.  Go for it!

[drbassman]

I like the look without the pole pieces.  As for adjusting up or down, I'd cut 1/16" footplates out of ebony to make risers, as needed.

[sniper]

What specific Thunderbird were those coils from?  They look very different from all the various I've seen.  

i think they are "Firebird" coils actually or maybe some left over Epi stuff. i bought them from the guy i bought my first neck from. the neck he got in an old warehouse inventory lot sale in Kalamazoo and i used it in my first design. it was his guess as to what they really are.

Rather than glue, I think you ought to try using a clothes-snap crimper and use 'female' snaps to fake the polepieces.

i like that idea and will mull it over, thanks.

[SGD Lutherie]

they are bigger than a Melodymaker coil (they will not even come close to fitting into a Melodymaker cover!) with 2 3/16" blade length openings. can anyone say "4 glued in shallow false pole pieces"?

You don't need fake pole pieces. Just use some real steel screws. You would need a keeper bar threaded for the screws, and then you could use a bar magnet under the pickup like on a regular humbucker.

But blade poles are much better than round poles.

Those bobbins look like these:

HUMBUCKER BLADE PICKUP BOBBIN BLACK

http://www.mojotone.com/guitar-parts/pickup-parts-bobbins-flatwork-humbucker/Mojotone-Humbucker-Blade-Pickup-Bobbin-Black



I use them for 4-string bass humbuckers, as well as guitars.

[Dave W]

Welcome, David.

Just curious, besides eliminating string alignment issues, do you think there are other reasons that make blade poles better?

[ThunderBucker]

Not to speak for David, but certainly for guitar, it is pretty easy to bend a string right off a fender .187" pole, esp in the neck position. This is probably less of an issue for bass.

I also suspect, tho haven't tested the idea, that you can get similar output levels between a more uniform, lower strength field and a more powerful but point-source-like field.  If that is true, the lower strength field will reduce string pull (which can cause wolf tones and poor sustain).

Richenbacker's early work with lap steels had him develop pickups with an upper pole piece (strings go *thru* the pickup), thus magnetic pull was equal up and down, balancing out.  This helped with sustain, a big deal for lap players.

I suspect the the big Ric bass pup is similar, can anyone confirm?

[Dave W]

Not to speak for David, but certainly for guitar, it is pretty easy to bend a string right off a fender .187" pole, esp in the neck position. This is probably less of an issue for bass.

I also suspect, tho haven't tested the idea, that you can get similar output levels between a more uniform, lower strength field and a more powerful but point-source-like field.  If that is true, the lower strength field will reduce string pull (which can cause wolf tones and poor sustain).

Richenbacker's early work with lap steels had him develop pickups with an upper pole piece (strings go *thru* the pickup), thus magnetic pull was equal up and down, balancing out.  This helped with sustain, a big deal for lap players.

I suspect the the big Ric bass pup is similar, can anyone confirm?

I meant other than string bending, that falls under string alignment issues.

The big Rick bass pickup is just a conventional steel polepiece pickup with an extra large ceramic magnet beneath. The cover is just a chromed plastic handrest that looks somewhat like the top half of the old horseshoe magnet.

[the mojo hobo]

The current Rickenbacker bridge pickup is as Dave describes it, but the first horseshoe bass pickups were based on the lap steel pickup with magnetized shoes. The current re-issue horseshoes have metal shoes that are not magnetized. With bass horseshoes being impossible to get hold of, I have heard of lap steel pickups being converted to bass use.

[SGD Lutherie]

Welcome, David.

Just curious, besides eliminating string alignment issues, do you think there are other reasons that make blade poles better?

Sorry for the long delay... I wasn't getting notification when there were replies...

Round poles often form hot spots under strings. if you use strong magnets, you can get a lot of string pull and warbling. Blades tend to spread out the field more evenly, and you can use a very thin blade, say like 1/16" of an inch. If you used a pole that small (like on the old Ripper pickups) you will quickly bend the string away from the pole.

Leo Fender had a good idea when he started using a pole on either side of the string. I started with that arrangement on my pickups, and quickly went to blades, and as you said which also eliminate string alignment issues, which is important when you make replacement pickups.

[Dave W]

Thanks for the explanation.

[drbassman]

I always thought blades made way more sense than poles.  But I'm not very electronics savvy!

[SGD Lutherie]

I always thought blades made way more sense than poles.  But I'm not very electronics savvy!

They are sensitive, but they also have less magnetic force over them than poles, assuming they are charged from a bar magnet like a typical humbucker. That's my experience anyway.

[eb2]

I haven't been overly particular about pups - they either sound good or bad to me.  The sound I have liked the most over all these years was an old Gretsch Supertron bass pup. The guitar Supertron used several thin sections stuck together to make a blade, while the bass version was one big thick blade.  It recorded wonderfully, and sounded fine live.  I always attributed that to the blade design. It sounded really even all the way across, and was punchy low and high.

My least favorite has been the DiMarzio p-bass with the allen screws.  It is a hot pup, but has that grating overtone.  But I believe the open top Allen screws were selected for the way they react to the strings vs a regular screw.