Rod Magnet Bridge P/U Project

[big_teee]

I've been wanting to experiment with a H sized double bobbin rod magnet bridge pickup.
I have a lefty strat with HSS setup, I currently have a regular PAF style pickup at the bridge.
There is a switch mounted to split the pickup.
I want to make a pickup that when split sounds more like a traditional SC at the bridge.
Looking for that Quack tone in position 2, when the bridge P/U is split.
I will post some pictures along the way.
I'm thinking about two coils with 4/2 A3/A5 rod magnet configurafion wound in the 6-6.5k range.
I will make the bobbin height around .435-.450", like a regular strat pickup.
If you have any ideas before I start, or while we are in progress please post your comments here.
T

[jack briggs]

I did one last year for a client that thought he wanted that - double rod magnet poled HB wound to about 9K with 42PE. Ended up so damned bright it would run a Tele slam out of town! I ended up taking the rod mags out and pressing 1018 studs and using a bar magnet.

Did another one recently with rod mags in one coil and slugs in the other, a bar magnet underneath. This one sounds really good! The key was the charge on the rod mags - keep it LOW. Otherwise it may be too bright for your tastes - especially with the tall coils (I used standard HB bobbins.)

Best of luck with it!


cheers,

[big_teee]

Thanks!
Was that 9k total, or 9k per bobbin?
I made one about 5 years ago and it was 15-16k total.
It had A5s, and it was too everything, mainly too aggressive.
I thought if I dialed it back and use A3s and only A5s on the E & A.
T

[cbarrow7625]

Since you asked......I've recently acquired a profound interest to learn everything I can about pickup making, forgive me if this it too "boring" a question only a wide eyed book learner like me may ask.....

Can anyone think of a clever, reasonably simple method to mechanically modify the magnetic flux lines to also be more "single coil like"?

Flip an electrical switch for the standard split bucker, then move a mechanical piece or " switch" to modify the flux lines.

Bucking magnets? Shorting bars? Magic & voodoo?

[Jim Darr]

T,

I experimented with this same concept several times, the most recent being a few years ago. I used fiber flat work this try, strat height between the flats. One coil was wound to 5,000 turns, the other coil was wound to 8300 turns with a tap at 5,000. I wired it so I had std type HB configuration using the 5,000 turn tap and a SC at 8300 turns was like a std strat.

Worked great as an SC, but was too bright for a HB. Then tried to de-Gauss the magnets down and it helped with the shrillness, but still not the sound I wanted. This was with A5s. Then I was going to try it with A3s as I thought this would mellow the HB sound a bit but never got around to it. I believe the concept is completely viable and may work best with an induced magnet on the 5,000 turn bobbin. I need to find some time to experiment a little more to truly find a formula that yields excellent results.

Keep us posted on your project.

Jim

[cbarrow7625]

After my previous post, i sat down to continue reading Helmuth Lemme's book and happened upon a, perhaps, obvious variable to take into account.

To summarize his thought on p. 135: HOW a pickup is switched from humbuckimg mode to single coil may ( likely) effect the amplitude at resonance. Simply shorting the second coil (typical) results in that coil acting as a short-circuit winding, resulting in a lower amplitude at resonance than would occur by leaving the second coil open. I.e., Moving the ground connection from the "bottom" of the humbucker to the venter tap as opposed to simply shorting the center tap in addition to the (typical) static HB ground.

As a pro audio loudspeaker design engineer for more than a decade, I couldn't help but immediately recognize the parallel application of a demodulation (shorting) ring in a loudspeaker driver. Different application / result but based on the same principa . Funny how that "obvious" parallel had escaped me for so long. *Dope Slap*

If the humbucker mode is too bright, as Jim mentioned, a small value cap and/or resistor across one and/or both coils could help reduce and/or shift the resonant frequency in HB mode and be switched out in SC mode.

(Is that too many and/or's for one sentence and/or statement?).

[Jim Darr]

If the humbucker mode is too bright, as Jim mentioned, a small value cap and/or resistor across one and/or both coils could help reduce and/or shift the resonant frequency in HB mode...

Yes, you could use a simple passive "Low-Pass Circuit" filter to roll off some highs HB mode. It is an interesting idea.

[big_teee]

Thanks guys, I see I'm not the only one that's been thinking about this.
On this prototype, I'm going to use some 53mm humbucker cut a part tops and bottoms, left over from another project.
If I get it perfected, I'll probably try one made from flatwork.
After hearing about all the brightness issues, I may make the bobbins a little shorter between the flats.
The A3 magnets not overly charged should help on the shrillness.
In split mode, I'm going to use the coil closest to the neck, or normally known as the slug coil.
TBC
T

[Alberto]

I've made some as well! I use a standard sized strat pickup (6k nearly) alongside a humbucker bobbin (4k) with 0.187 rod magnets (they fit perfectly). To me, they sound exaclty like a strat pickup in split mode and have nice and warmer sound in humbucking mode. I use them with 250k pots.

Here is how it looks with and without cover

I should have some samples somewhere...

[big_teee]

That sounds good, and is a nice looking pickup.
I'm going to start with the data below.
It will be a work in progress, and starting with prototype parts.
Now I need to get off my Recliner, and getter done!
T

[big_teee]

I finally got back on this project.
The pickup was part of the rewiring of my old lefty import test strat.
I built the pickup like below, I used sawed apart humbucker bobbins.
Went with standard .435" spacing between the flats.
Wound one bobbin 8500, and the near bridge bobbin 8300.
One bobbin measures 6.4k, and the other 6.25k.
When split it sounds like a regular strat single coil which the PAF type did not.
It has good quack in position 2 & 4.
In humbucker mode it still sounds Like a Strat, but with more balls, and really drives an amp and distorts well.
By using the A3 rods on the treble bobbin, and 4/2 A3/A5, on the split bobbin it still has nice warmth, with strong bass strings, and sounds like a strat.
It's just a beater import test guitar, but I like it.
IMO the Rod Humbucker in a strat, with a split switch is the best of both worlds.
Give it a try.
T

[big_teee]

After putting the pickup through its paces for a few days?
It is a very versatile pickup, and has many more tonal options over the standard PAF type pickup I had in it.
Sounds great humbucker or split.
The only thing I would possibly do different, is use shorter magnets, and shorten the bobbins from .435" down to .400" or so.
I would still wind the coils 8500, and 8300 turns.
Shortening between the flats, would fatten up the tone a little more.
It is good as it is, but I think that would make it even better.
I would stick with the all A3s on one coil and a 4/2 A3/A5 combination, on the other coil.
Pleasantly surprised how good it sounds in bucker mode, but still has that woody stratty sound.
It has that great position 2 Quack tone I was after, and what I built it for, in split mode.
In bucker mode it really drives an amp, and covers the bridge rock pickup requirements of a humbucker.
The Prototype, IMO was a huge success, and covers the tones I was after.
T

[Alberto]

Same impression here with my version of rod magnets humbucker. I used A5 magnets because it was meant for the neck position, but it seems like the overall feeling is the same.

[big_teee]

I've made a lot of neck pickups with A5s.
Now when I make them for myself, I usually use A3/A5, with the A5s on E & A.
IMO the A3s have a warmer tone on the high strings.
I've also quit buying .187s, I like the the .195 and larger.
Whatever you like and what works for the player!
Rock On,
T

[Alberto]

I made a new project with a rod magnets humbucker. A customer asked me for a "tele" set with:
- one humbucker made out of a tele neck pickup and a strat pickup side by side;
- tapped tele bridge pickup to match the output of the neck pickup.
It also has the most intricate guitar wiring I've ever made! The customer agrees that a space shuttle dashboard may not have so many options With two push-pull pots and a 4-way switch you can select the tele neck alone, the strat neck alone, tele and strat in serial or parallel humbucking mode, neck humbucker AND bridge pickup in parallel or serial mode. When the neck is in full humbucking mode (serial or parallel) the hotter lead of the bridge is always selected.

Here are some pictures taken yesterday while testing the whole thing. It works