Tony Iommi humbuckers

[Dr. Guitar]

Anyone have some details on these? A co-worker gave me one of his and asked me to make it sound good. They are epoxy potted, so no chance of a reasonable rewind. Mostly I'm wondering if I pry the external magnet off the back, if it will sound better.

[David Schwab]

I'm guessing that's the only magnet?

What doesn't he like about them? I weaker magnet will make them darker, and I'm guessing that are dark already.

[Dr. Guitar]

You need to hear them to know what I'm talking about. They have a weird almost out of phase sound that only sounds good with tons of distortion. From what I have read, they have bot a ceramic, and alnico magnet in them.

[NightWinder]

Originally Posted by Dr. Guitar

You need to hear them to know what I'm talking about. They have a weird almost out of phase sound that only sounds good with tons of distortion. From what I have read, they have bot a ceramic, and alnico magnet in them.

Got any pictures? I'm wondering if its a spin off the original "birch" design.

[David Schwab]

Originally Posted by NightWinder

Got any pictures? I'm wondering if its a spin off the original "birch" design.

I think they are supposed to be a copy of the John Diggins pickup.

This is what they say about them:

Using a totally unique design, this is the first signature pickup made by Gibson. With its closed cover it's built to pack a real punch, with blistering mids, razor-sharp highs and balanced low-end. The "patent-applied-for" magnet configuration and special wire winding ensure maximized sustain, while the wax and epoxy potting protects against unwanted feedback. Four conductor wiring permits any desired wiring combination.

Anyone know the patent application number?

From Iommi's site:

The Story of the Gibson Tony Iommi Signature Pick-up
by Mike Clement

Throughout the history of Black Sabbath there are (so far) three guitars that have been, in succession, Tony's main instrument. These were a) the original red Gibson SG; b) the black John Birch SG; and c) the maroon Jay Dee SG. All have had custom made pick-ups, the first two by John Birch and the third by John Diggins (Jay Dee).

In the early days of Sabbath, a recurrent obstacle to Tony's quest for improvements and modifications was the inflexibility of the established manufacturing companies to entertain any form of customer feedback. Examples of this in Tony's case include; increasing the number of frets to 24 to allow a two octave span, electrically shielding the control cavity, the provision of very light strings and experimentation with pick-ups. It was due to these frustrations that Tony linked up with John Birch, the undoubted father of the British custom guitar. John's interests covered guitar electronics as well as guitar construction so most of Tony's concerns were addressed.

A pick-up is basically a magnet with a coil of wire wrapped around it. When a metal string vibrates within the field produced by the magnet, a varying voltage analogous to the sonic vibrations of the string is induced in the wire wrappings. While that sounds nice and simple, the actual characteristics of the sound that is produced are a complex interaction of a whole host of variables affecting the shape and strength of the magnetic field and the nature of the coil of wire. These include the magnet material, its alignment, its position, the number of turns of wire, its thickness, its insulation, its material, its electrical resistance etc. etc. almost ad infinitum.

It is obvious that experimentation is of primary importance regarding pick-up design and this just what John Birch was able to do. Further down the line John Diggins was able to do the same when he produced the pick-ups that went into the Jay Dee SG. The down side to this however, is that due to the hand-made nature of these devices coming out of small workshops, it is sometimes difficult to make exact replicas once a successful pick-up has been made.

This does then lead to a degree of nervousness regarding the well being of these unique pick-ups (and the unique guitars that they sit in!!), and a dread of what to do if the unthinkable were to happen.

While Tony and I were visiting the 1996 Frankfurt Music Fair, we met up with J.T. Riboloff, at the time the resident Gibson R&D genius. J.T. had built a guitar for Tony 4 years previously, a black SG with Floyd Rose vibrato. The quality of this guitar had always impressed Tony (especially as it had been built in 72 hours!!) and although the two had spoken on the phone they hadn't met. An immediate rapport developed, (J.T. is a fine player, and left handed) and the conversation quickly turned to pick-ups. In the course of the visit to the Gibson stand we met Rick Gembar (general manager of the Gibson Custom Shop Division), Jim Goulomb (general manager of the Gibson Strings & Accessories Division) and Scott Johnson (of Strings & Accessories). All were immediately very keen to start forging new links between Tony and Gibson. (Jim and Scott have since both left Gibson).

Very soon after our return to the UK, Scott Johnson made contact to suggest the development of a Gibson Tony Iommi Signature pick-up. This was a first for Gibson, never having made a signature pick-up before. This quickly led to numerous phone calls between J.T. in Nashville, Scott Johnson in Chicago and myself in South Wales. It was decided that the pick-up would be a standard humbucker size to allow retro-fitting and the sound would be based on the bridge pick-up in the Jay Dee SG. This pick-up is not only quite different in size, but it is sealed in epoxy resin as an anti-feedback measure, which also renders it impossible to disassemble without destroying it (see above regarding the worries over one-off experimental devices, John Diggins himself couldn't remember how he had made it!!). This fitted in though with the idea of the project as it was not the intention to directly copy the Jay Dee device, but analyse the aspects of it that Tony liked in order to produce a pick-up that would completely satisfy him and also be practical for mass production.

This meant that J.T. would have to examine the pick-up at his lab in Nashville. To send the guitar or the pick-up over to the US unaccompanied was far too risky an option, so I was lucky enough to be flown, courtesy of Gibson Strings and Accessories, over to Nashville for a few days in June 1996 with the Jay Dee SG. What followed was the most determined electrical detective work I have ever seen! J.T. just lives guitars. With his encyclopaedic knowledge up pick-ups, he started taking measurements, listened and quickly worked out that there were very unusual goings-on within the Jay Dee that gave it the smooth power with a hint of phase cancellation. I have just enough electrical knowledge to understand what J.T. talks about (e.g. “well Mike, the inductance is the motor of the pick-up, and the resistance is its brake”), so to watch and listen to him at work was a great pleasure. Once he had worked out the way to go, which is a radical break from traditional pick-up design, it was a question of experimenting. He worked constantly, pausing only for the occasional cigarette break, to eat or to take me back to the hotel.

He set up the coil winding machines to wind different numbers of turns of different gauges of wire, tried different magnets, milled the pole pieces to different sizes. Coil winders are not like computers, doubling their speed every 3 months, so all this took a lot of time! At the end of the week we had about a half dozen pick-ups to take back to the UK for Tony to try out.

J.T. put together an SG from unfinished parts so that Tony could try the pick-ups out in a Gibson. I got back to the UK, headed up to Birmingham and that was it! The unit was given Tony's full approval. In January 1997, Tony went over to the NAMM show in Anaheim, California for the launch, and the pick-up got its first 'blooding' on the extremely successful Black Sabbath reunion / Ozzfest tour that summer, loaded into another SG that J.T. built. They also feature in the two SGs (one black and one red) that the Gibson Custom Shop built for Tony in late 1997, as prototypes for Tony Iommi special Custom Shop model. These two guitars are still the main live instruments Tony plays. The pick-up is still in production and available in silver, gold or black covers. It has been used in the Custom Shop models, the factory Iommi SG and most recently in the very well received Epiphone Iommi SG.

I don't think you can alter them. Better to sell them and get different pickups.

[Possum]

JT's name is the key, I think this is the patent?
5792973

[David Schwab]

Originally Posted by Possum

JT's name is the key, I think this is the patent?
5792973

Eureka! I do believe that is it.

Wow... very odd.

[Possum]

Yeah, it'll take me a week to read it and look at all the little numbers and read all the lawyer talk, but it is one weird ass pickup design, worth studying.....

[Sweetfinger]

I am guessing that the original Diggins design (specifically the complex magnetic fields that provide the slight phase cancellation) was a happy accident, and that the Gibson version is essentially, a reworking of that design.

This looks to me like a pickup that was envisioned, then possibly modified in an attempt to get an even string response with no dropout on bends. The slight phase cancellation was likely a fortunate, but unintended side effect, that now, almost 30 years later, Gibson has patented.

If J.D. was really that brilliant at pickup design, i.e. conciously manipulating the magnetic field orientations within a pickup to affect tonal response, you'd think that he'd at least kinda remember something about constructing the originals. IMO, it seems that he probably threw a bunch of things together and that's the one that stuck.

Interesting, though, 'cause it really doesn't look like what you'd expect under the cover, does it?

any more pundits care to comment?

[Possum]

If you read the patent there is no claim of phase cancellation nor any explanation of how the magnets affect anything, disappointing. Its hard to tell where the magnets actually sit, it looks like the top small magnet sits above the coils and the two longer ones that sit on top of eachother are below the coils and the blades contact both? Could have had a better drawing or more detailed drawing of assembly. I'm not so sure the bottom two magnets are even needed, I bet at least the second one up from the bottom could be eliminated with no change in tone. Where is the phase cancellation happening? steel blades will always spread the magnetic flux out to its ends, yet we have these magnets seemingly trying to force the flux inwards or some weird thing. Its obvious that they don't even know whats going on in that design because there's no real mention of what forces are doing what :-) To me it would seem the smaller alnico II magnet at the top would just add more metal and thus tone down the treble response, all the magnets are oriented in the same direction. This is a weirdy.....

[David Schwab]

He does seem to say in column 3, paragraph 30, that the upper small magnet causes a "reduction in harsh frequency peaks".

At 55 he says "So that the magnet 26 has the desired effect of creating a smoother tonality than is obtained without it, the magnet 26 has a length of about one-third the length of one of the blade-type pole pieces 20."

He also states that the upper magnet should be Alnico 2, while the bottom magnets are Alnico 5 and Ceramic 8.

But, yeah, why exactly? I can't imagine what the stepped sizes of the magnets would do.

This is not the first design to manipulate the magnetic field to get a desired tonal response. Take a look at the two Bartolini patents (3983777, 3983778). He uses planar flat topped pole pieces to get a low flat field. Another interesting one is from jazz guitarist Attila Zoller (3588311) where he uses the orientation of the magnets to shape the field (he called it a bi-directional flux pattern).

I think the various Don Lace designs also manipulate the shape of the field with those magnet guides and "fingers".

They said in that article that JD didn't remember what he did. I'm surprised they didn't try to X-Ray or MRI the thing. I think JT just messed around with magnets until he got something interesting! (as with all good inventors... Look at Edison and the diode tube, and even the phonograph... happy accidents often based on hunches)

The John Birch pickups sound like they have fairly odd construction also.

I think this is where "modern" pickups are in a rut. Fender and Gibson designs are pretty normal. You don't see the odd things like DeArmond/Rowe, Rickenbacker, Hagstrom, et al, did anymore.

The new Bartolini "classic bass" series claim to have CNC machined blades. It makes me wonder what's so different about them that they need to be machined that way. Maybe they are like his original designs.

I've been exploring magnet placement and pole shapes. I think that's where new ideas are yet to be discovered using the traditional wire and magnet pickups, as opposed to the lo-Z current designs.

I have some weird ideas I'm going to be trying out.

[Dr. Guitar]

I already gave the pickup back. Trust me, they have their own sound, and unless you're in a Sabbath tribute band. probably not what you are looking for. I've installed 2 sets of these, and heard them OEM in a few other guitars. From looking at the bottom, I believe the most exposed magnet is an alnico. Beyond that, it's all epoxy.

[Possum]

I think this "phasing" thing is bullshit really, WHAT phasing? You have two blade poles sensing the strings right? OK now add a thick piece of metal to bridge a section between the two blades. You've added extra sensing area and you've added more metal mass creating more eddy currents. I think if you have a dual blade humbucker you could add a small section of alnco II magnet like they do in that design and it would have the identical effect. The stacking of two different kinds of magnets on the bottom must have been done to copy the original without much thought to whether it actually does anything or not. The alnico down there vs the ceramic again is going to load down the treble response so that counts. They probably DID Xray it to see what was going on why else would they have come up with such a strange idea?

[NightWinder]

Can anyone post a link....I totally can't find the damn thing!!

[NightWinder]

http://patimg2.uspto.gov/.piw?Docid=...iew+first+page

[Possum]

go here:
http://www.pat2pdf.org/
paste in the patent number then when it grabs the pdf it will show up in a blue link, click that to download to pdf

[NightWinder]

Thanks. That was a but better reading. C8 and A2 are sitting on top of eachother in the same direction to the poles- Seems like it would weaken over time..Both are stated as being Northsame to the Blades so sitting on top of eachother Like that could contribute to the overall Phase issue? Fun stuff : )

[kevinT]

wow, this pickup design is interesting.

I have Tony's Star Licks Lead guitar series instructional video from the 80s. He has a really compressed tone. To me, it's almost wierd sounding.

Did it mention the DCR anywhere?.....i didn't see it....or am i just blind.

[Possum]

No it doesn't have the DCR but it does have the turn count in 44 guage wire, yeah that WOULD sound compressed, I think they were wound fairly hot, and with blades that would really do that....

[salvarsan]

Originally Posted by NightWinder

Can anyone post a link....I totally can't find the damn thing!!

Most of the pickup patents are hosted in the Pickupedia in a sortable list.
http://www.pickupedia.info/Patents

The links go to a local copy of the patent.

Sometimes, it helps to sort on the "Assignee" column
so you can see who has been busy at the patent office.

-drh

[NightWinder]

Originally Posted by Possum

No it doesn't have the DCR but it does have the turn count in 44 guage wire, yeah that WOULD sound compressed, I think they were wound fairly hot, and with blades that would really do that....

6,900 turns 44= 8.8k estimate. safe to say 9k per bobbin. Also depends on the stretch or tension. Probably between 17.8k and 18k