Transferring impedance from Strat to P-bass

[GlennW]

If you have a Strat pickup that measures X Kohms and you want to make a similar pickup in P-bass configuration should the separate individual coils of the P-bass pickup be X Kohms or 1/2 X Kohms (all other things being equal)?

[Magnetosaure]

Like in a classic Humbucker, the total resistance is the addition of the 2 coils, serie law. So yes, to get the equivalent DC resistance of a Strat pickup for a P-bass PU, you have to wind each bobbin so you can reach more or less 1/2 of the total resistance you want to acheive. Just find the right number of turns.

But once again, is DC resitance a good way to look at pickups?..

[GlennW]

Thanks. That's what I thought, but wasn't sure because with a guitar HB each string gets picked up by both coils.

[GlennW]

Are you sure? After thinking about it some more it seems like both halves of the P-bass pickup should be the about same as the Strat pickup because of the coil cross section. And when you consider the two extra outside 180 degree turns on the bass pickup stuff changes even more.

Maybe coil cross sectional area would be a better way?

I might use the put too much on and peel off until you like it approach on one half; then measure it; and wind the other half to match.

[GlennW]

Anyone else?

[David Schwab]

You can get them to come out the same DC resistance, but it wont sound exactly like the Strat pickup, because the coil is a different size and shape.

But give it a try. I'd start off making each coil about half a strat pickup. Maybe a little more.

I had a Vox stereo Phantom XII with three split pickups. They were originally wired up for stereo, with the top three courses and bottom three course going to separate outputs.

It wasn't very useful that way, and the sound was weak, so I wired them up like P-bass pickups, in series, and they became nice sounding hum canceling pickups. Sounded like single coils. Not like a Strat, but then they never would anyway.

[GlennW]

Thanks David. There are a few extra variables...more magnets, bigger magnets. I was trying to get an idea of where to begin.

After reading about the pickups you mentioned my plan to just try 1/2 probably wouldn't be a good idea since it would likely sound different when inseries with the other half. I think I'll start around 5K each and work my way down.

[Peter Naglitsch]

Don’t use DC resistance as a measurement for this. Use a turn counter and wire the two parts of the pickup to the same turn count as an ordinary strat pickup and wire them in series. That way you will also end up with a DC resistance that is similar to an ordinary strat pup. The law of series resistance is Rtot=R1+R2+R3+ +Rn (n is the last resistance in the “row”).

At the same time I got another idea. The only time I have heard sound clips from a split strat style pickup they suffered from the same slight dullness/lack of top end that traditional HBs have (Pls don’t get me wrong, I like HBs). A HB with the coils in parallel have more “luster” than one with the coils in series and are much more “SC-sounding” while still retaining the humbucking ability. So a suggestion would be to wind the two parts hotter and wire them in parallel. So why wind the parts hotter? A HB with the coils in parallel has a lesser output. And as the law of parallel DC resistance is 1/Rtot=1/R1+1/R2+1/R3+…+1/Rn over wound halves will bring the DC resistance closer to a “real” SC

[David Schwab]

Don’t use DC resistance as a measurement for this. Use a turn counter and wire the two parts of the pickup to the same turn count as an ordinary strat pickup and wire them in series. That way you will also end up with a DC resistance that is similar to an ordinary strat pup. The law of series resistance is Rtot=R1+R2+R3+ +Rn (n is the last resistance in the “row”).

I agree here. I never wind to DC resistance anymore. But I do write it down when I'm done.

The only time I have heard sound clips from a split strat style pickup they suffered from the same slight dullness/lack of top end that traditional HBs have (Pls don’t get me wrong, I like HBs).

They shouldn't because none of the strings are picked up by both coils. On traditional HB's, the distance between coils is larger than the upper harmonics, so they tend to get canceled out, as they are picked up by both coils pretty much the same. The lower frequencies are picked up in a kind of differential pattern... the string is up over one coil while it's down over the other.

Each coil on split humbuckers only pick up one string. So they really are single coils. But since you have a bit more area to wind, you have the potential to wind a darker sounding pickup.

Split coil bass pickups, like the DiMarzio Model J, sound just like the single coil versions.

A HB with the coils in parallel have more “luster” than one with the coils in series and are much more “SC-sounding” while still retaining the humbucking ability.

And that goes back to the idea of winding too much wire on a split single coil.

I actually think the small side-by-side humbuckers, like the Duncan rails, sound pretty good if you don't over wind them. I wind some pretty bright humbuckers. Parallel wiring is good for that if you want the "luster". Both coils are contributing to the output, unlike a stacked pickup.

I'm not sure why I said to over wind them... but I'll use the defense that I only had 3 hours sleep!

[Peter Naglitsch]

They shouldn't because none of the strings are picked up by both coils. On traditional HB's, the distance between coils is larger than the upper harmonics, so they tend to get canceled out, as they are picked up by both coils pretty much the same. The lower frequencies are picked up in a kind of differential pattern... the string is up over one coil while it's down over the other.

You are probably right David. As I stated I have only heard ”split SCs” once, and not live, only as a sound clip. So the sound clip I heard might have been a bad example.

But then an interesting question, because I have lately become quite interesting in making a split SC, maybe because the last split SC thread we had here. What would be best: wire the coils in parallel or in series? OK, I know, wind the damn coils and test it... and then report back to us.

[David Schwab]

You are probably right David. As I stated I have only heard ”split SCs” once, and not live, only as a sound clip. So the sound clip I heard might have been a bad example.

There aren't that many split coil guitar pickups on the market, and the problem as I see it is trying to fit the thing in a Strat size cover. You end up with an overlap issue. Look at a P-bass pickup. The coils don't just stop as they do on split coil strat pickups (Or Jazz bass). The Vox guitar I used to own had small soapbar size pickups. I bet P-90 size covers would work great. KInd of like a Wide Range humbucker, but with real split coils.

Or you do like the Duck Bucker, and have full width coils, but with half the magnets/poles.

Another issue is phasing. You get a drop out as you bend a string across the two halves. I guess this isn't as much of an issue on bass... people don't usually bend their D string that far. On the 12 string Vox, I wasn't doing much bending either.

I've never played any split coil Strat pickups.

But then an interesting question, because I have lately become quite interesting in making a split SC, maybe because the last split SC thread we had here. What would be best: wire the coils in parallel or in series? OK, I know, wind the damn coils and test it... and then report back to us.

Well it depends on how much wire you have on it and the sound you are after. Think about a regular humbucker... in series you get a fuller tone, and parallel is brighter. An 8K series humbucker is 2K in parallel. You can do both of course. I used to have series/parallel switches on a lot of my instruments. It's nice to have access to both. Personally I find parallel too thin on bass to use al the time. EMG P pickups are wired in parallel (I think all EMGs are in parallel) and when I used those, I often wanted to hear thicker mids.

But... it all depends on how you wind the pickup. Obviously if you wind very hot coils, parallel will sound more "normal". That might be useful if you want to increase the inductance for a certain tone.

I don't have as much experience winding guitar pickups as the others here who have figured out a lot of ways to get different tones from very similar designs. Last year I made a pickup for a 9 string guitar. It was the size of a 5 string bass pickup! The owner of the guitar plays in a metal band, so he wanted a high output pickup, but with got high end and definition.

Obviously with coils that wide I had no reference point to work from, so I just went by the seat of my pants and wound what I thought would get the tone I had in my head based on other pickups I've owned.

It had a very interesting tone, and wasn't muddy at all in the top end. The big surprise was the tone in parallel. It had a very "Stratty" snarly tone. Reminded me of Jeff Beck.

So my long winded point was, having an option for series/parallel is very useful for over wound pickups. For something like a PAF, it gives a passible single coil type vibe.

Here's two examples of the 9-string pickup. (excuse the sloppy playing.. the pickup was suspended over the strings on little blocks... )

Series

Parallel

[Zhangliqun]

Just the positioning of the two coils will change the sound too. They can't be directly in a line, they have to be offset a bit like the P-bass pickup, or like those G&L pickups. So at least one coil will be sitting under slightly different harmonic node than a regular Strat pu.

Doesn't mean it will sound bad, might even sound better, just not exactly the same.

[GlennW]

Thanks for the further input.

I came to a realization about my original question. Those pickups are two different animals. I will be trying the parallel when I get to it. And I think I'd be better off waiting until I build the speaker cabinet - no sense in hunting down a sound only to lose it because of changing the amp setup.