Steel guitar pickup rewind....

[Possum]

Anyone have any info on this type of steel guitar pickup and some sane method of rewinding an air coil like these are. I have 2 to do, both were lacquer potted which is why they are dead I'm sure.....thanks

[Spence]

That's not an air coil. You have a cardboard bobbin there. Air coils have no bobbin. Just be careful cutting the old coil off.

[Bruce Johnson]

You could make up a core piece from balsa wood, cut with the end grain facing up. Wrap the balsa with a layer of clear packaging tape (which is very glue-resistant stuff), and fit it with the cardboard flanges. Then figure out some way of attaching the balsa core to your winder faceplate. Double-sided tape would probably do it. After winding and potting, knock the balsa out. If it's really stubborn, drill through it in a few places and chisel it out. Balsa wood is great for one-use fixturing like this

If I were doing a production run of them, I'd mold up some kind of a flexible rubber plug. It would fill up the center slot and hold everything together during the winding and potting, then just be popped out and reused.

[Possum]

...

Well it kinda is an air coil, its not wrapped around anything, the coil is naked on the interior, the guitar strings go through the coil, the plastic stuff you see there is all warped from age but is there to protect the interior of the coil. The fiber bobbins if you knocked them off it would be a true air coil. The whole thing is lacquer potted.

[David Schwab]

An air coil means there is no steel (or magnet) core in the middle of the coil. It has nothing to do with having a bobbin or not. I guess that would be called "bobbinless"?

So that pickup would be an air coil. Where are the magnets?

[Possum]

....

I call it "braless." The magnets are on the outer ends of the steel frame that encloses the whole pickup, they look like steel, maybe cobalt, dunno. Cool design but only works with the strings going thru the coil....

[Spence]

An air coil means there is no steel (or magnet) core in the middle of the coil. It has nothing to do with having a bobbin or not. I guess that would be called "bobbinless"?

So that pickup would be an air coil. Where are the magnets?

Without magnets it's not a pickup. There have to be magnets around it in the assembly.
It's clearly not bobbinless and it is therefore not an aircoil. Open up some Burns and you'll see what an aircoil is.
The thing is that this isn't helping Possum get over this problem.

[jonson]

I did a thingy like this about 20 years ago and made up a base and an upright out of plexy which I fitted to the face plate. Sprayed the whole assembly with a couple of coats of dry ptfe lubricant from my tool suppliers and jammed the top and bottom in place. I wound that with self bonding wire wetting each layer with meths(alcohol) but lacquer potting as you go should do the jobbie. It slipped straight of afterwards.

[Spence]

You can buy self bonding wire too. Here's an example of a coil wound in such a way :



and here's one that's been covered with an elastic insulator :

[David Schwab]

Without magnets it's not a pickup. There have to be magnets around it in the assembly.
It's clearly not bobbinless and it is therefore not an aircoil. Open up some Burns and you'll see what an aircoil is.
The thing is that this isn't helping Possum get over this problem.

Spence, the word "air" in air coil means there is no ferromagnetic material in the core. The core is air. Air cores have lower inductance. The old Bill Lawrence acoustic guitar pickups used air coils. The magnets were not in the middle of the coil.

Another example of an air coil pickups with self standing bonded wire are Q-Tuners:



You can se that the self standing bonded coils don't have a core, but they do have neo magnets sitting in the lower half. Most of the coil is empty.

Google "air coil" and you get the following:

Introduction to Air Cored Coils

We'll use the term 'air core coil' to describe an inductor that does not depend upon a ferromagnetic material to achieve its specified inductance

Another link:

Air Coils

I'm aware that bobbin-less coils, such as in the Burns Trisonics are often called "air coils", but that's not what an air coil is. The Burns pickup also have a steel plate under the magnet, so it's really not an air coil.

As soon as you stick a magnet in the middle of the coil, it is not an air coil. Some pickups are wound like an air coil, but they aren't. Air coils can have bobbins, but they can't have cores.

[jason lollar]

you will need to recore that, cut a piece of wood about 1/16" os so smaller than the hole in the red forbon and wrap a piece of thin cardboard arond it- over lap the seam about 1/2" and glue it. Slide it off the form. fender used cardboard before that plastic crap.
43gauge is always used on those- i dont recall if that one has 920 turns on it or not- its a really odd ball one- usually I get the trapazods in.

[Spence]

Spence, the word "air" in air coil means there is no ferromagnetic material in the core. The core is air. Air cores have lower inductance. The old Bill Lawrence acoustic guitar pickups used air coils. The magnets were not in the middle of the coil.

Another example of an air coil pickups with self standing bonded wire are Q-Tuners:



You can se that the self standing bonded coils don't have a core, but they do have neo magnets sitting in the lower half. Most of the coil is empty.

Google "air coil" and you get the following:

Introduction to Air Cored Coils



Another link:

Air Coils

I'm aware that bobbin-less coils, such as in the Burns Trisonics are often called "air coils", but that's not what an air coil is. The Burns pickup also have a steel plate under the magnet, so it's really not an air coil.

As soon as you stick a magnet in the middle of the coil, it is not an air coil. Some pickups are wound like an air coil, but they aren't. Air coils can have bobbins, but they can't have cores.

Well, here's a reply to a previous thread answered by our very own Soundmaster G regarding Burns TriSonics. Clearly he's been in touch with Adeson who in turn must be using the wrong terminology. I'll let him know:

Well Ben you've asked a question about one of the most difficult pickups to make from scratch. The original Burns Tri-Sonic pickups were an air coil with a ceramic magnet. The coils are wound on a collapsible former. Once the coil is wound to spec, the former is collapsed from the inside, and the coil is taped completely. Then its put into the cover with the magnet, and then the whole thing is epoxied so it won't be microphonic. The coil is very thin top to bottom, and there is no bobbin.

The new Burns Tri-Sonics aren't made the same, and so don't sound the same either. The only one I know of that makes the Tri-Sonics correctly is Adeson in the UK, and I have a set of his pickups. I don't have anything to pu them in yet, but I will. He uses the actual equipment from the 50's that Burns made their pickups on, and uses the same methods to make them. The pickups are very reasonably priced too. Check out his site and email him about it...he's very friendly.

http://www.adeson.co.uk/

Here's some stuff he told me about their pickups in an email.

Regarding the coils - all early European pickups (Hofner / Framus / Hoyer etc..) were built this way. The coil is wound on a removeable chassis - and then completely wrapped in a special armature winding tape (takes ages to learn this - they are ridiculously delicate!). The whole thing is pulled tight - just like lacing up your boots. The magnets are vintage ceramic (similar to Alnico 2). They have been out of production since the early seventies - I have to have them custom made - and they cost a fortune!!! The coils are then placed arround the bar magnets (the holes in the chrome top covers are purely aesthetic). The whole thing is then glued solid to prevent the brass top covers from causing howling. This is exactly how they were made 40 years ago - and they sound great!!!

Many thanks for your enquiry. Our pickups are identical re-creations of Tri-sonic pickups built between 1960-65. We use the exact build methods and original components - they are even wound on the original late 50's Burns winding machine, making them the most accurate version of this classic pickup - period!!!!! We can easily supply a hotter bridge pickup, however on Brians guitar the "hot" pickup was in the middle position. Most Red Special experts want - neck pickup approx 6.5k, middle approx 6.9k, and bridge approx 6.7k. Apparently these figures are based on Greg Fryers restoration of Brians original guitar. Regarding pots and caps, Brian's were Omeg 220k log B pots with a .022cap, although Burns originally used 500k pots in the 60's.

For the whole set of Tri-sonics from Adeson, it was less than $200 with shipping though this was about 2 years ago. Hope this info was helpful to you?

Greg

[David Schwab]

Well, here's a reply to a previous thread answered by our very own Soundmaster G regarding Burns TriSonics. Clearly he's been in touch with Adeson who in turn must be using the wrong terminology. I'll let him know:...

Yes, I know all about Adeson pickups, as I'm planning on making a Red Special this summer.

He's using the wrong terminology. The reason is air coil inductors are often wound as free standing coils, so people say they are winding air coils. But that's incorrect when it comes to pickup, unless the coils have air as the core. TriSonics are not air coils, they just don't have bobbins. They do have ferromagnetic material at the core, and a steel plate under the magnet.

So where is the air in a TriSonic? There isn't any. But it's a commonly used term for bobbin-less coils.

Possums pickup is also not an air coil, since the steel strings would be the core.

It's all about the inductance of the coil's core. Take all the screws or slugs out of a humbucker bobbin, and you have an air coil.

[Possum]

....

That QTuner pickup is truly a work of art. That guy is one of the true geniuses of pickup design, too bad he focuses on bass pickups. That pickup is just beautiful...

[David Schwab]

That QTuner pickup is truly a work of art. That guy is one of the true geniuses of pickup design, too bad he focuses on bass pickups. That pickup is just beautiful...

He makes guitar pickups too. I don't think they are as popular. They are very bright pickups. The top end extends way up. They have a good low end too, but to me the top end really stood out. Very clear sounding.

He's the guy that wrote that book on pickups, Animal Magnetism for Musicians. That's an interesting book.

I had a couple of Q-Tuners here to check out. I can't imagine how he secures everything in the mold before he pours in the epoxy. I would think the magnets would want to pull the whole thing together!