Anyone Tested a Charlie Christian Pickup?

[aquin43]

Has anyone tested a Charlie Christian pickup with the long magnets, or any of the modern substitutes?

[antigua]

I've never known much about the Charlie Christian pickup, mostly because it appears that a guitar would have to be routed for it, and as a pickup/control swapping fanatic, I favor reversible mods my a wide margin. The sense I get is that it's probably similar in characteristic to an underwound P-90, with a steel bar causing significant eddy current attenuation. They've got a lot of recent attention because Lollar makes a version of them, but I have no idea how true they are to the originals.

I think in a guitar like a Tele, if it comes with import style pickups with steel poles and ceramic ceramic undermounted magnets, I think the end result will be pretty close to a Charlie Christian or a P-90, all that remains to be determined is the resonant peak, but with such acute eddy current roll off, that becomes less important too. A bigger sell is probably the aesthetics. 

Here's a demo of the Lollars in a Tele..





... hearing the pick attack, I'd bet the resonant peaks are around 3kHz, not as dull and punchy as a P-90, not as plinky as a Strat. It sounds a lot like a Tele with stock import pickups, if it were arranged with three pickups with Strat switching.

[ms]

This is a copy of a CC pickup: www.ccpickups.co.uk/about.html.  If you want to put one on a Tele, you would have to do a lot of work:  route a huge hole and put on a spruce top.  I doubt that the huge cobalt steel magnets as opposed to normal sized AlNiCo bar magnets do much to the sound, but if you pride yourself on making faithful copies, how can you call it a CC pickup copy if it does not have the correct magnets?  If you can figure out what the frequency response of the original CC pickup is, then I think you can duplicate that in a single coil pickup without either making it a non standard size or making it have the appearance of a CC.  But I think the appearance is 95% of what people want, which I think agrees with Antigua's opinion..

[aquin43]

I actually had one of the long magnet copies and built it into an archtop, but this was long before I got involved in pickup measurements.

What I remember most about it was the excessively loud B string, even with the notched pole, and the extraordinary susceptibility to magnetic hum.

I would guess that the long magnets might have a marginal effect on the linearity by reducing the rate of variation of the magnetic field with distance from the active pole but they were  made that size because it was the only way of maintaining a decently strong field above the pole with the available magnets while leaving the space above the strings clear. Earlier designs had partially closed the magnetic circuit above the strings. I think it was originally intended for steel guitars and the industry abandoned it as soon as better magnets became available.

It was, however, the pickup on Charlie Christian's guitar  so it still has an emotional pull for many jazz guitarists who think that it has a magical sound. As ms says, appearance is probably a major part of its appeal.

[b4nj0]

Within the context of this thread it is almost trivial to observe that Danny Gatton thought highly enough of the CC pickup to have one at the neck in one of his Teles, and once he had camped in the Joe Barden field, he repurposed an old CC pickup as a belt buckle, which is way cool in my view. I reckon that the CC pickup ought to be considered in a similar fashion as the P90 / P15 pickups?

P15?

e&oe ...

[ms]

Sept 7, 2020 7:56:02 GMT -5 aquin43 said:

I actually had one of the long magnet copies and built it into an archtop, but this was long before I got involved in pickup measurements.

What I remember most about it was the excessively loud B string, even with the notched pole, and the extraordinary susceptibility to magnetic hum.

I would guess that the long magnets might have a marginal effect on the linearity by reducing the rate of variation of the magnetic field with distance from the active pole but they were  made that size because it was the only way of maintaining a decently strong field above the pole with the available magnets while leaving the space above the strings clear. Earlier designs had partially closed the magnetic circuit above the strings. I think it was originally intended for steel guitars and the industry abandoned it as soon as better magnets became available.

It was, however, the pickup on Charlie Christian's guitar  so it still has an emotional pull for many jazz guitarists who think that it has a magical sound. As ms says, appearance is probably a major part of its appeal.

It would seem that the permeability of the cobalt steel magnets is very high, although I am not sure I have found info for the right material.  If so then you have the double whammy of a material with both a very weak permanent magnetic field and a very high sensitivity to stray magnetic fields.  The very large pieces attached to the steel core of the winding are a very efficient hum detector.  It probably was not as much of a problem when it was first used as today.  There was no switching equipment at the time, such as light dimmers and switching supplies, and so you just had 60 (50) Hz and low number harmonics.  The speakers then probably had not much  bass, but I bet it still required careful placement of the amp to minimize the effects of its power transformer.

[antigua]

Sept 7, 2020 10:13:13 GMT -5 b4nj0 said:

Within the context of this thread it is almost trivial to observe that Danny Gatton thought highly enough of the CC pickup to have one at the neck in one of his Teles, and once he had camped in the Joe Barden field, he repurposed an old CC pickup as a belt buckle, which is way cool in my view. I reckon that the CC pickup ought to be considered in a similar fashion as the P90 / P15 pickups?

P15?

e&oe ...

According to this diagram the original had some substantial magnets underneath, and obviously the new Lollar version must not, I'm almost positive it's essentially a P-90 with a steel bar. In either case, the steel bar factors a lot higher than the magnets underneath. 





I had to see this to believe it... 

[b4nj0]

AFAIK, Danny's belt was picked up by someone at the posthumous Accokeek garage sale, but I forget by whom. It might have been Jay Monterose- someone that would have recognised the significance (or perhaps had a hand in its making?)

I wanted to install a CC on my Heritage Sweet16- seemed like an obvious choice to me with the various booteek winders getting on the bandwagon, but it has a matching bound figured timber floating pickguard, and I've learned my lesson about gouging guitars on a whim.

Could be another case of chasing rainbows ...

e&oe ...

[stratotarts]

All the very first pickup coils had thick wire by modern standards. I wonder if the underwound aspect was somewhat compensated for by (I'm guessing here) a low resistance volume pot, maybe no tone pot? Into a very high impedance vacuum tube input. Then the amp itself probably had very low cutoff frequency for its working bandwidth. I think the simple amp tone circuit from back then was practically the same as the guitar one. A jazz player would dial it down.

[ziggystardust723]

Aquin43, & 'C.C. Lovers,
Sorry to Answer only now,
- but I'm New on this Forum..
Since the begin of the Thread,
> Nobody answered than in 1st:
- The Gibson Charlie Christian came in 1937,
= fewer latter 1932: when 1st pu 'Horse Shoe' Rickenbacher was Patented,
> so, it Used the Same Wire:
= Awg38 /Heavy-Formvar coat
(near 0,100mm diameter & 2,38 0hms/M)
- & localised on a 'Neck' side,
> not on Bridge side & on an Solid-Guitar, like the 'Frying-Pan'..
> It was wounded with a very Big Wire
= more Presence (really too much for this Place: on a 7ender Tele, from 1949 to 0urs Days: Awg43 wire is used, cause this Place don't Ask more Presence..)
> So, New replicates of this Pickup Don't Use the same big Wire:
= then, the Sound changes..
(1st P-90 in 1946 were wound with this wire, but for a few months, then: Awg42 was the 'New Std'..)
- The Grade of the Wire gives the Presence of a Pickup (& Not other),
- like the Kind of Coat gives the Character of the Sound..
- Ziggy (France, 19h05)