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Topic: B6 horseshoe pickups |
Robert Corwin
From:
Philadelphia, Pennsylvania, USA
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Posted 28 Sep 2005 6:23 am |
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I'm in need of a basic education in horsehoe pickups. Seeing the wiring diagram reminds me that sometimes the expertise of this group is a bit over my head. I'd love it if you folks could give the "horseshoe pickups for dummies" treatment.
I have several pre war B6's, and the output varies quite a bit between them. When my '59 tele pooped out, Lindy Fralin had me take a reading, then send the pickups in for him to rewind. (actually, I had one pickup rewound, then realized that made the output of the two unbalanced, so he did the second one as well.)
I hear of having the B6 horseshoes remagnatized, but haven't heard of the coils being rewound. Can you tell me the roles of the coils and magnets in the B6? How do I know which needs attention? I honestly don't remember how I measured the tele. How does one measure to see if the B6 coil and shoes are up to specs?
If you care to include a basic primer explaining wiring, tone controls, pots, capacitors etc., that would be icing on the cake.
always grateful,
Robert |
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Rick Aiello
From:
Berryville, VA USA
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Posted 28 Sep 2005 7:10 am
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Basically the bobbin is very similar to any conventional pickup ... a coil of copper wire wound around a bobbin.
The difference is ... the pole pieces are simply steel slugs ... not magnets.
The magnetic field is produced by the two horseshoe magnets ... which are opposing ... i.e. The (N) pole of one faces the (N) pole of the other ... and visa versa.
This sets up a situation where the magnetic lines of force make their "loop" ...
Via the bottom flange of the magnet ... up through the pole piece ... through the tiny "air gap" ... and then into the upper flange of the magnet ... back thru and around to the bottom flange ....
The problem with this configuration is that the opposing poles set up a degaussing situation ... and the two magnets start degaussing each other the moment they are set.
They remain "functional" for a very long time ... but after 20 years or so ... the flux density that they produce is far from what it was ...
I haven't seen a set yet that didn't enjoy a good "jolt" ...
The earliest magnets seemed to have the (N) poles on top ... but most post wars have (S) up ...
When I remag or build a pair ... I always make the (N)s up ... doesn't matter ... just a "nod of acknowledgement" to George Beauchamp ... 
As far as the bobbin ... the wire is thin as a hair and after time ... corrosion can set in ... causing partial or complete shorts.
Some shorted bobbins are still functional ... but "lack" output and some frequency response ...
Then a rewind is in order ...
Most coils have a DC resistance between 1.5K ohms and 2.5K ohms ... because of the larger diameter wire that was used.
A rewind with #42 ... should read around 6 K ohm.
Overwound Rickys sound like crap (again, in my opinion) ... I have bought Rickys that had been rewound by someone ... and I had to sendd them to Jason Lollar to be "re-rewound".
I just included some pot/cap info on that wiring thread.
Hope this helps ...
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Aiello's House of Gauss
My wife and I don't think alike. She donates money to the homeless and I donate money to the topless! ... R. Dangerfield
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Rick Aiello
From:
Berryville, VA USA
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Posted 28 Sep 2005 7:34 am
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| Quote: |
| How does one measure to see if the B6 coil and shoes are up to specs? |
Sorry ...
A multimeter can be used to check DC resistance ... just set the volume and tone wide open ... plug in the cord ... and touch one probe to the "tip" and the other probe to the "sleeve" of 1/4" plug (thats good enough to give you an idea if it's compromised).
As far as checking the magnets ... you need a gaussmeter ... and they are $$$.
Suffice it to say ... if they haven't been "zapped" in the last 30 yrs ... they are due ...
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Aiello's House of Gauss
My wife and I don't think alike. She donates money to the homeless and I donate money to the topless! ... R. Dangerfield
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Robert Corwin
From:
Philadelphia, Pennsylvania, USA
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Posted 28 Sep 2005 9:18 am
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Thanks Rick, this is really helpful. I'm so impressed with the responses on the forum, and the thoughtful responses off-line.
Interestingly, the oldest of my B6's seem to have the highest numbers. My new 7 string, #C69, one knob, chrome, takes the high ohm prize at 2.198k ohms. And my favorite, #C2164, chrome, opposite side arrow knobs, very sweet, but good output, is the lowest, at 1.165k ohms.
So I'm assuming that the coils on all of these are fine, since the one that's out of the range you mentioned sounds great.
The one exception is a white plate, which has no output and reads 100.8k. The pots were scratchy, so I took a reading inside where all the wires meet. Same reading. How can I tell if the problem is the pots, the capacitor, or the pickup?
As for the shoes, would you recommend doing them all, not mess with the ones that sound good, or what? Rick, I've seen in the past that you were doing these for free for Forum members, with a donation to the Forum. Are you still doing this? Is it a pain to do more of them, or do you do a batch, and it's just as easy to do several at once? Also, it was mentioned that the shoes should be de-magnatized befor being re-chromed. Is this true?
Thanks so much for lettting me pick your brains.
Robert |
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Rick Aiello
From:
Berryville, VA USA
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Posted 28 Sep 2005 10:12 am
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| Quote: |
| which has no output and reads 100.8k. |
Sounds like the coil is bad ... you could run the leads straight to the jack (bypass the vol/tone) and see if you get signal ...
If not ... a rewind is in order.
Jason Lollar is the best ... don't know if he's taking rewinds now (he's really swamped these days) ... give him a holler at info@lollarguitars.com ... www.lollarguitars.com ... if it's bad & he'll either do it or recommend someone.
| Quote: |
| As for the shoes, would you recommend doing them all, not mess with the ones that sound good, or what? |
Some folks don't want to remag theirs ... afraid that it will affect the tone they have grown to like ... a personal choice.
My personal opinion ... is that when Iona, McIntire ... even Jerry Byrd ... was recording with Rickys ...
The magnets were much stronger when these guys were playin' ... than the same guitar's magnets would be today ...
To each his own though ...
| Quote: |
| Rick, I've seen in the past that you were doing these for free for Forum members, with a donation to the Forum. Are you still doing this? Is it a pain to do more of them, or do you do a batch, and it's just as easy to do several at once? |
I don't charge for the service ... some folks do donate to b0b ...
So my recommendations for "juicin' up" Ricky, Fender, Supro, etc., magnets ... isn't driven by profit ... just tryin' to help folks (and the SGF) out.
It's no biggie ... I have fixtures for each of the above magnet types ... I just throw them on my electromagnet and hit the switch ... 0.03 seconds is all it takes ...
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| Also, it was mentioned that the shoes should be de-magnatized befor being re-chromed. Is this true? |
You can plate magnetized "live" magnets ... I do it all the time (out of necessity) ...
BUT it's much easier to plate degaussed magnets ... doesn't pick up ferromagnetic junk in the tanks that way.
I can't use the language here, that pours outta my mouth when I pull an MRI or H-Shoe outta the tank ... to find one nickel speck that has attached itself to the dead center of the magnet ... then built up a wad of plating.
Or even worse ... when the nickel electrode itself gets pulled onto the piece ... 
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Aiello's House of Gauss
My wife and I don't think alike. She donates money to the homeless and I donate money to the topless! ... R. Dangerfield
[This message was edited by Rick Aiello on 28 September 2005 at 11:41 AM.] |
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Robert Corwin
From:
Philadelphia, Pennsylvania, USA
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Posted 28 Sep 2005 11:53 am
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I hope someone besides me is learning from this. I'm sure getting an education and a half. I suspect this will be useful to have in the archives.
I've pulled the pickup apart, and can't believe what a delicate, fine wire goes from the coil to the lead. Can't believe it's held up for 70 years!
- Sounds like I need to take apart the solder joints on the jack to disconnect the leads and get a reading? Just want to make sure before I do anything stupid.
- How does one go about degaussing the magnet before re-plating? Is that a House of Gauss job, too?
- Bob Stone has mentioned the person who plated his chrome. I know his job involved crafting new plates. For a simpler job, maybe cleaning up a few dings, should I fill it myself and bring it to someone locally, or should I be asking for recommendations for this?
- Can I tell anything about the strength of the magnets by comparing how strongly they are attacted to each other, or is that just not a useful test?
- Rick, please let me know where I should send the magnets, and how I can pay you for return postage.
thanks again- |
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Rick Aiello
From:
Berryville, VA USA
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Posted 28 Sep 2005 12:46 pm
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| Quote: |
| 've pulled the pickup apart, and can't believe what a delicate, fine wire goes from the coil to the lead. Can't believe it's held up for 70 years! |
That bare ground leading to the grounding "ring/screw" .. grounding the bobbin, magnets and mounting plate ... is often the trouble spot ... be careful around it.
| Quote: |
| Sounds like I need to take apart the solder joints on the jack to disconnect the leads and get a reading? Just want to make sure before I do anything stupid |
You don't have to disconnect to take a DC resistance reading.
But if you are trying to bypass the pots to see what kinda signal the pup itself is puttin' out ... by wiring straight to the jack ... you are gonna have to cut.
Chances are ... it's bad ... so you will have to cut anyway.
| Quote: |
| How does one go about degaussing the magnet before re-plating? Is that a House of Gauss job, too? |
Well its tough to get them totally degaussed ...
A degausser would do a nice job ... but they are $$$ ...
You could tape the two opposing magnets together ... and set them aside for awhile ... but that won't kill 'em completely.
I guess the best way is to buy a small neodymium-iron-boron magnet ... wrap it with some terry cloth so it won't latch on and scratch the crap outta the horseshoes ... and rub it all around in a random pattern ...
You will still have some domains aligned ... but most will be cancelling ... certainly good enough for a "chrome job" ...
| Quote: |
| Bob Stone has mentioned the person who plated his chrome. I know his job involved crafting new plates. For a simpler job, maybe cleaning up a few dings, should I fill it myself and bring it to someone locally, or should I be asking for recommendations for this? |
The more prep work a commercial plater has to do ... the more he'll charge ...
But if you are talking about the horseshoes themselves ... thats a serious job ... that cobalt steel is super hard and brittle ...
I have heard of folks snapping them in half ... with their bare hands ... trying to "even up" the top flanges.
I've redone a few badly rusted/pitted horseshoes ... it was a very time consuming job ... not alot of fun.
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| Can I tell anything about the strength of the magnets by comparing how strongly they are attacted to each other, or is that just not a useful test? |
Pull tests are not terribly reliable ... unless they are done individually using a a series of "gradient" weights ... like in a physics lab.
But things like surface area contact ... can make the results misleading.
| Quote: |
| Rick, please let me know where I should send the magnets, and how I can pay you for return postage. |
Email on the way ...
Back to my Dustpans ... just comin' up for a break ...
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Aiello's House of Gauss
My wife and I don't think alike. She donates money to the homeless and I donate money to the topless! ... R. Dangerfield
[This message was edited by Rick Aiello on 28 September 2005 at 02:02 PM.] |
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