Does anyone makes an bladed air-coil?

[RoadToNever]

Basically I'm looking for something similar to an old Lawrence acoustic guitar pickup for my bass which accepts guitar size pickups.

Adeson?

...?

[David King]

There seem to be plenty of new "Bill Lawrence" acoustic guitar pickups for sale. I counted at least 4 models.

I don't get the concept of a bladed air-coil, isn't that a contradiction in term? Could you refer us to a patent of something?

That Adeson Deco model is a beaut, never heard of those before. There's a couple of sound clips on the site so maybe that tells you something.

[RoadToNever]

There seem to be plenty of new "Bill Lawrence" acoustic guitar pickups for sale. I counted at least 4 models.

I own an old one with the cursive Lawrence logo printed on. These come up on eBay every now and then. I'm sure if you took the guts out and mounted them in a standard pickup housing you would have an awesome pickup.

Posting an excerpt from Guitar Electronics for Musicians:
...As the Lawrence brochure says about the FT145: A medium impedance extended range pickup for the steel string flat-top guitar (6 and 12 string) matches most high or low impedance amplifiers. Two coaxial synchron wound hum bucking air coils with a high flux alnico-8 magnet in the center translate every vibration ofthe strings into an audio signal. You can get brilliant highs, mellow midrange, clean responsive bass. The use of synchron winding helps to produce balanced outputs and this together with shielding results in quiet noise factors. The use of air coils, which are wire coils without an iron or magnet load in the center of them, results in a lowering of impedance and this allows trebles to be passed easier. However, it also results in lower induction and output.

[Lovelock]

Blades & aircores are not contradictory:
Lawrence also had a single coil sized unit, I forgot it's name ( L???.) It had a single blade, and was a sidewinder with air cores.
They were intended for guitar, and they probably fell out of favour to guitarists because they where too hifi sounding.
But it was an awesome bass pickup! They have a beautifull clarity about them.
Several Anno Galama (dutch luthier in 70's and early 80's) basses have them as pickups.
Wish they would still be available. Maybe something for David Schwab to delve into?

[Mike Sulzer]

Blades & aircores are not contradictory:
Lawrence also had a single coil sized unit, I forgot it's name ( L???.) It had a single blade, and was a sidewinder with air cores.
They were intended for guitar, and they probably fell out of favour to guitarists because they where too hifi sounding.
But it was an awesome bass pickup! They have a beautifull clarity about them.
Several Anno Galama (dutch luthier in 70's and early 80's) basses have them as pickups.
Wish they would still be available. Maybe something for David Schwab to delve into?

Really? A sidewinder with a steel blade that guides the flux down from the strings, and then just air to guide it through the sidewinder coils? That seems like an unlikely way to make a successful pickup.

[big_teee]

We need Pictures, I don't have a clue and I don't have a mental visual!

Rock On!
Terry

[David Schwab]

Blades & aircores are not contradictory:
Lawrence also had a single coil sized unit, I forgot it's name ( L???.) It had a single blade, and was a sidewinder with air cores.

...Maybe something for David Schwab to delve into?

The L-250? I have three of them. You can actually see inside them because they are encapsulated with clear polyester resin, and not black epoxy. They have black felt stuck on the bottom.

They are sidewinders, but they are not air coils. There is a blade that passes through each coil, and connects to the string facing blade, like an inverted T. The magnets are on the outside of the two coils facing the core-blade. I'l see which of my pickups had the black felt missing from the bottom (I removed it) and try and take a picture.

I remember the air coil pickups. I believe they are also sidewinders, but with air cores, and the alnico magnet as a blade in between.

Sidewinders are interesting pickups. I just finished a new set for bass, which I'm happy with.

New Sidewinders 9-25-10

The hard part was squeezing them into a Jazz Bass cover! But I got a working bridge pickup: (warning, intonation is way out!)

Jazz Sidewinder (with half rounds) test 2

[David King]

I'd think that the air-coils i.e. a very large gap between the coils and the armature would cause them to be darker sounding not bright. I hope we can find a patent diagram or that David will post some closeups

David are you using neo bars inside those coils? They sound really nice, the Jazz sounds even brighter with the 1/2 wounds. Wery q-tuner-esque.

[RoadToNever]

Nice clips, Dave! Mighty full sound out of a bridge PU if I ever heard one.

I suspected the single-blade discussed is not an air-coil like the acoustic pickup. Mine reads 7 KOhm and has a big mid boost around 500Hz-ish. I initially liked it over a low output L500 for the smooth highs of a single-coil but the mid boost wasn't complimentary to my bass and accentuated anomalous tone shifts as I went up and down the neck. Now the L500 is back in duty with a more agreeable tonality.

Googling about air-coils yeilded nothing more than Bill Lawrence and Alembic using such designs. A discussion on a vintage guitar forum talked about 70s Gibson Ripper bases having air-coils, I couldn't verify this with any other source, though. I have to mention how much I like the tones of those bases. Does Greg Lake ring a bell? Check out the clips on flyguitars.com if you like bright yet full bass tones. If anyone would offer something like those pickups in an EMG HB housing for less than 80 USD I'd be all over them.

Getting back on topic, I guess it would make sense that that sidewinder air-coil design is uncommon as it's not efficient in terms of output. Still I wonder if it would be feasible with modern ND or Cobalt magnets.

Here's some clips of the Lawrence acoustic pickup temporarily mounted on an electric bass. Sorry about the occasional buzzing from the string hitting the pickup, but doesn't it sound nice?
all my silencer.mp3 - File Shared from Box.net - Free Online File Storage
jazzy silencer.mp3 - File Shared from Box.net - Free Online File Storage

EDIT: Forgot about Q-Tuner. They're air-coils.

[Lovelock]

Yep, I was wrong about the air cores, the pickups I was talking about where probably something like the L220 & L250's Must have gotten some things mixed up.
Nice pickups Dave!

[David Schwab]

I'd think that the air-coils i.e. a very large gap between the coils and the armature would cause them to be darker sounding not bright. I hope we can find a patent diagram or that David will post some closeups

The air coils are lower inductance. Higher inductance usually gives you a warmer tone.

I don't have any of the Lawrence air coil pickups, but I do have some old L-250s. They are not air cores, but they are sidewinders.

David are you using neo bars inside those coils? They sound really nice, the Jazz sounds even brighter with the 1/2 wounds. Wery q-tuner-esque.

Thanks. No, they are ceramic magnets. I tried neos and they were too harsh sounding. I might try them again with a few alterations to the design. I keep tweaking things.

Yeah, the Jazz pickup is very bright. I'm assuming that's because it's narrower. It was hard fitting that pickup in the jazz cover.

[David Schwab]

Here's some clips of the Lawrence acoustic pickup temporarily mounted on an electric bass. Sorry about the occasional buzzing from the string hitting the pickup, but doesn't it sound nice?
all my silencer.mp3 - File Shared from Box.net - Free Online File Storage
jazzy silencer.mp3 - File Shared from Box.net - Free Online File Storage

That sounds good.

EDIT: Forgot about Q-Tuner. They're air-coils.

Technically, yes, since the only thing in the coil is the neo magnet. But they do have the steel poles. My understanding of the Lawrence aircoil was it didn't have any steel in it.

My sidewinders are also technically air coils.

[Rick Turner]

You could almost call coils wound on ceramic magnets "air core"...no metal in there.

[David Schwab]

You could almost call coils wound on ceramic magnets "air core"...no metal in there.

Exactly. That's why I said my sidewinders are also technically air coils. Neos are the same way... they have the permeability of air.

Sometimes you need some steel in there though.

[Mike Sulzer]

You could almost call coils wound on ceramic magnets "air core"...no metal in there.

Ceramic materials can gave relative permeability of up to several thousand, higher than steel. The material used for ceramic magnets is different than that used for cores that are not permanently magnetic (See Ferrite (magnet) - Wikipedia, the free encyclopedia). Not at all like air, although not all ceramic magnets use identical materials, so it can vary.

Hard ferrites

In contrast, permanent ferrite magnets are made of hard ferrites, which have a high coercivity and high remanence after magnetization. These are composed of iron and barium or strontium oxides. In a magnetically saturated state they conduct magnetic flux well and have a high magnetic permeability. This enables these so-called ceramic magnets to store stronger magnetic fields than iron itself. They are cheap, and are widely used in household products such as refrigerator magnets. The maximum magnetic field B is about 0.35 tesla and the magnetic field strength H is about 30 to 160 kiloampere turns per meter (400 to 2000 oersteds).[3] The density of ferrite magnets is about 5g/cm3