Bartolini bass pickup 5 stirngs Gary willis model spec

[cenizasblancas]

Hi i`m Juan Motta from Uruguay and i`m new in this staff! I`ll want to build this particular model of pickup or similar but i`dont know the resistence, magnets, inductance,size,turns, is a humbuker no? If someone knows some about this pickup of similar, let my know because i`ll want to make a stewart mac donald buy.

thanks a lot

Juan

[David King]

Hi Juan,

I don't know all the details but the pickup has 5 coils like the Bartolini 9W-5J except it's for much narrower string spacing. On the 9W5J there's a laminated iron core that looks like a rake with one coil on each prong. There's a long ceramic magnet that charges all the coils the same way. The coils alternate CW and CCW with the three CW coils measuring about 970 Ohms and the two CCW coils measuring around 1450 Ohms. Each coil is wound on it's own plastic bobbin and all the coils are connected to a PC board that sits opposite the magnet. There are three copper plated iron plates on top of the three coils that have the lower number of winds to bring their signal up to parity with the 2 larger coils. All 5 coils are connected in series for about 6K DCR. The wire looks finer than 42 I'd guess it's 43 but I haven't measured it yet.
I think the GW pickups are brighter than the 9Ws so they probably have fewer turns or a slightly different core structure. The GW pickups are impossible to find short of buying a GW bass. I used to get them from Gary but he hasn't been able to get them himself for years. Bartolini wouldn't sell them to me and I wouldn't know who to ask at Ibanez.

[David Schwab]

David, I'm assuming you opened one up. Have you taken any photos? I'd love to see the inside of that.

I have an old Hi-A pickup that I don't use any more, and I'm trying to get past the sentimental attachment and dissect it. I've had it since 1976.

[big_teee]

David, I'm assuming you opened one up. Have you taken any photos? I'd love to see the inside of that.

I have an old Hi-A pickup that I don't use any more, and I'm trying to get past the sentimental attachment and dissect it. I've had it since 1976.

It's hard to Sacrifice an Old Friend, or Eat the Prize Pig!
B_T

[David Schwab]

It's hard to Sacrifice an Old Friend, or Eat the Prize Pig!
B_T

Yeah, I got it as a High School graduation gift! I had broken the bridge pickup in my Rick trying to see if I could rewind it! So this was the replacement.



The other thing is it's a humbucker, and not one of the multi coil pickups. So while it will have the flat steel tops, it won't be as funky as the others ones:

[cenizasblancas]

Thanks for the information but iīm begininer and i can understand all the técnical description of David King because my language is spanish and i canīt find world like "prong" "rake" and i think is much complicated for my to build this than buying a kit for 5 string bass pickup. Maybe i can use some part and build it myself.

Thanks

Juan

[David King]

Hi Juan, I'll try to post some photos of the pickup I have taken apart but you are right this this is not a beginner's pickup. I could not replicate it in my shop even if I wanted to.
A rake is a rastrillo in Spanish, imagine a horizontal crossbar with 5 vertical sticks.
Figure 5a in the patent illustration that David Schwab posted above is a good illustration.

[cenizasblancas]

Ahh i understand now, i looked this world in the dictionary but i can`t find any "rasrillo" in the pickup ja ja, i think you are saying about the base of the pickup and the 5 coils no? i think now iīm understanding better... it takeīs my some time to undersand the inglish world in spanish....
If i`ll build this pickups, for my is not a problem if they sound diferent i`m not looking for the "exact" replica, i like the sound of this particular "type" of pickup.
Well i wainting for the photos

Thanks again

Juan Motta

[David King]

9W5*70-S

Here are the photos, I apologize if you can't make much out of them but the entire pickup is encapsulated in black epoxy.

[cenizasblancas]

hoo!!!! Thanks for the pictures i want to ask you about you have writed "The coils alternate CW and CCW with the three CW coils measuring about 970 Ohms and the two CCW coils measuring around 1450 Ohms" what is alternate cw y ccw? and what are the three cw coil and how are conected with the other part of the pickup?

[David King]

Juan,

Actually I doubt that it makes any difference but CW stands for "clockwise" and CCW stands for counter-clockwise. I bet all the coils are actually wound in the same direction but are simply wired out of phase for every other string. All the coils are in series to make the longest possible coil.

If each coil has two ends, a "head" and a "tail", they would be connected like this:
head–––tail-tail–––head-head–––tail-tail–––head-head–––tail
(where "–––" represents a coil).

[cenizasblancas]

Now i understand, and what are the dimension of the ceramic magnet? what are the dimension of the 5 coils and the rake? (i canīt find the rake in the picture,sorry)

[marku52]

Wow, that is one complicated pickup. Does it really do anything magical for all that effort?

[big_teee]

Does it use a Ceramic bar magnet at the bottom?
T

[David King]

Terry,
Yes the ceramic magnet is at the bottom on one side of a thin steel vertical plate that runs the whole length of the pickup (.050 x .250 x 3.375" approx).
On the other side of that steel plate from the magnet are spot welded 5 vertical steel posts (at first I thought they were laminated steel but they aren't, they are .125" x .250" x .625 tall.
Over those posts are fitted the plastic bobbins which seem to be extremely thin about .020" or less all around. These bobbins are about .375 tall x .50" wide x .375 across.
On the tops of the three low-turns coils are copper-plated steel plates that measure .031" x .275" x .475"
All measurements made by eye so give or take a couple thou...

Marku, there is nothing magical but they are very efficient pickups with low string pull and very low material costs. The frequency response is quite flat. We are talking maybe a few grams of copper at most compared to the 2-3 oz for a typical pickup.

Juan, the ceramic (probably C8) magnet is .25 x .25 (6.3 mm^2) and 3.375 long or so