need schematic for hum cancelling jazz bass pickups

[Mike Sulzer]

Mikes's argument does not fail. It is exact for the square coils and approximate for the round ones.

It's not a line input, it's a Hi-Z guitar input. I was in error about the input impedance, it's 1M. Not sure what I was thinking... The line inputs are 20k.




Mike's argument fails because you can clearly hear that multiple smaller coils sound very different from that much wire on two large coils. The coils are in close proximity only in a very small area, and even then they don't touch. There's about 1/16" between them on their sides.

[Mike Sulzer]

Mike, I can only think you are being difficult on purpose because I know you are not dense.

I am not the one being difficult here. I simply took your description of your test as written, as did Steve. With the input impedance so low, both series and parallel would have very similar responses because the R/L time constants are the same. (Both R and L change by a factor of four.)

Let's assume that the differences between the sounds of the two tests are due to the series/parallel difference as you say, and not resulting from a problem with the test. I agree that parallel does in general sound brighter (into high impedance), but you do have to be careful. Parallel can sound less bright if the resonant frequency moves too high (outside of the range of the instrument/amp). This is something I have observed, and SD has commented on it in the Q/A on his web page (if it is still there).

So your test shows something that is obvious. So what? It does nothing towards proving what you want to show: that individual coils connected in series are significantly brighter than a similar single large coil. I guess you realize that, but given your description of the test, how was anyone else supposed to know what you were or were not tyring to prove with it?

[David Schwab]

It does nothing towards proving what you want to show: that individual coils connected in series are significantly brighter than a similar single large coil.

The input impedance was 1M. The test was not to show the difference between series and parallel. The test was to show how bright eight coils wired in series would be.

Mike, how many pickups have you played through in your life? Did you ever play though a pickup wound to 20K? There aren't too many of them. A P bass is 11K, and they are darker than this. How about a Duncan JB?

Anyone with any experience trying pickups has a rough idea what a 20K pickup would sound like based on previous experience. We all know that pickup makers list the DC resistance to give people a relative idea of what the pickup sounds like.

[Mike Sulzer]

So if one does not accept that he is listening to an unexpectedly bright 20K pickup when it was mounted on an unfamiliar instrument, recorded on an unfamiliar system under unknown conditions, and compared to nothing, then it means that he does not play using 20K pickups.

You are certainly right about one thing. Verifying or disproving your claim requires constructing the pickups and doing the tests.

I will report back sometime in the future!

The input impedance was 1M. The test was not to show the difference between series and parallel. The test was to show how bright eight coils wired in series would be.

Mike, how many pickups have you played through in your life? Did you ever play though a pickup wound to 20K? There aren't too many of them. A P bass is 11K, and they are darker than this. How about a Duncan JB?

Anyone with any experience trying pickups has a rough idea what a 20K pickup would sound like based on previous experience. We all know that pickup makers list the DC resistance to give people a relative idea of what the pickup sounds like.

[David Schwab]

Mike, why not go wind some pickups and THEN get back to us.

And in the end, no one cares.

[David King]

Hey! I care.. -sort of.

[Guitarist]

Hi guys,

Just saw this timely thread.

Today I plugged in my Aria Cat Bass comparing it my humcancelling guitars and it is the noisiest: hum and hash. No shielding on the leads or cavity routes! But has great tone though.

It has both PUP configs, J and P. I'm studies the copper slug treatment above...but don't yet "get" it. I do have copper tape though and have shielded and star grounded many elec. but never a bass.

[David Schwab]

Hey! I care.. -sort of.

My point is that no matter how much Mike says it's wrong, the pickups show otherwise.

Since a known length of wire has a known resistance, this is roughly the same amount of wire as on a Gibson mudbucker, regardless as to the differences in each pickup.

And as someone who has unwound a mudbucker to 12k, I can attest that doing so improved the high end response in exactly the way you would expect.

[David Schwab]

Hi guys,

Just saw this timely thread.

Today I plugged in my Aria Cat Bass comparing it my humcancelling guitars and it is the noisiest: hum and hash. No shielding on the leads or cavity routes! But has great tone though.

It has both PUP configs, J and P. I'm studies the copper slug treatment above...but don't yet "get" it. I do have copper tape though and have shielded and star grounded many elec. but never a bass.

The P shouldn't be humming.

[Steve Conner]

Don't the mudbucker pickups have a huge steel core, though?
The Wal pickup just has eight little screws.

[David Schwab]

Don't the mudbucker pickups have a huge steel core, though?
The Wal pickup just has eight little screws.

Huge? No. It has a 1/16" thick piece of steel that runs through both coils. I wouldn't call that huge. If it were 1/4" I would call it huge.

Even then it's easy to wind a bright pickup with a thick core. I used to do it all the time:

I don't use those cores anymore though.

Now take the Bi-Centenial Thunderbird pickup (designed by Bill Lawrence). It has the same 1/16" piece of steel. The TBird pickup is bright like a single coil. The mudbucker is not. The mudbucker even has 4 ceramic magnets, while the Tbird has one alnico magnet. The difference between them is how much wire is wound on the mudbucker. The designers of the mudbucker knew what they were doing when they wanted a pickup that sounded like the pedals on a pipe organ. Anyone who winds pickups knows that as you increase the amount of wire on the pickup, the tone will have more low end, and less high end, and the resonant peak will get lower. If you want a bright pickup, don't wind it to hot. If you want mud, over wind it.

'76 Tbird



Two other pickups built like the mudbucker, and also designed by Bill Lawrence are the Gibson L9-S Ripper bass pickup, and the Lawrence L-250 strat pickups. They also use the 1/16" thick blade running through the two coils, and sound very bright. Once again it's because they are not very hot. The Ripper is 6.25k. The T-Bird pickup is 6.5k (43AWG wire).

I make sidewinders, and some of them have have had an 1/8" steel core. Once again they are very bright like a Ric pickup. So I think it's safe to say the affect of the core on the high frequencies in these pickups is less than expected.

Here's the core of a Gibson mudbucker. You can see how much wire I unwound off that bobbin. I took it down to 12k and it opened the tone up a lot. it was still darker than a Ripper pickup, but that's to be expected from a 12K pickup.





Also on the Wal pickup the pole screws are threaded through two rather large keepers. The keepers do influence the tone. Marco made some with no keepers and then one with laminated keepers, and he reported the pickup with the keepers had more low end.

Here's the Wal pickup from the side with the poles raised all the way up:



Now if one wants to take measurements to see the affects of these variations, I'm all for that. But you have to have the pickups in hand, and not just sit and speculate. That over simplifies things IMO.

Maybe I'm going to have to spend some of my tax return on an Extech 380193.

[Steve Conner]

Thanks for the pics, Dave!

Anyone who winds pickups knows that as you increase the amount of wire on the pickup, the tone will have more low end, and less high end, and the resonant peak will get lower. If you want a bright pickup, don't wind it to hot. If you want mud, over wind it.

I think we all agree on that. What we are debating is essentially, if you unwound all of the wire off a Mudbucker and wound it onto the eight Wal coils in series, would the resulting pickup sound brighter than the Mudbucker did?

Assuming it would all fit of course. If it wouldn't, the comparison doesn't really make sense, and the answer is something like "Multiple coil pickups sound brighter because the extra bobbin material leaves less room for wire."

[David Schwab]

Thanks for the pics, Dave!

Ypu're welcome. I take photos of everything. It's a good way to document stuff along with writing down measurements, etc.

I think we all agree on that. What we are debating is essentially, if you unwound all of the wire off a Mudbucker and wound it onto the eight Wal coils in series, would the resulting pickup sound brighter than the Mudbucker did?

Yes, it would. And we know this because the Wal pickup with all coils in series is 20K. So we know that's the same amount of wire as on the mudbucker because we know what the resistance is per foot on 42AWG wire.

Also, I'm trying out stuff all the time. When I started working on the Wal pickups I decided to try the approach with other pickups. So it's simple enough to make a platform for a pickup with the same poles and all, and just swap bobbins. There's always that trade off of output vs. high frequency response, so one of the things I have tried is dividing up the the coil into smaller coils. And that works. It's been used for a long time now in quite a few pickups. Even Gibson had a 4 coil replacement for the mudbucker.

Here's the Gibson EB-4L pickup:

Assuming it would all fit of course. If it wouldn't, the comparison doesn't really make sense, and the answer is something like "Multiple coil pickups sound brighter because the extra bobbin material leaves less room for wire."

It does based on the final resistance of the two pickups. At 1.6Ω per foot, we are dealing with about 12,500 feet or wire!

[Mike Sulzer]

That Gibson EB-4L does not look as though it has nearly as much wire as a mudbucker. You need to show that it does to use it as part of your proof.

[David Schwab]

That Gibson EB-4L does not look as though it has nearly as much wire as a mudbucker.

Ya think? The question is; why wold they make the pickup with four coils and not two? Do you think they were just bored? I mean they had to actually tool up for that pickup. They must have felt their was a need for it.

And looky here... another one:

You need to show that it does to use it as part of your proof.

No, actually I don't have to do anything. You are the one saying that when you connect the coils in series that it's equivalent to one big coil. Prove it.

I'm busy making pickups Mike. I don't have to prove anything to you. If you don't think they sound different, fine. Others who make them will disagree however.