Guild / Hagstrom Bi-Sonic Specs

[Jim Darr]

Does anybody know the coil height on the original 60's /Hagstrom Bi-Sonic?

[Jim Darr]

Does anybody know, or have an educated guess???????

[big_teee]

I found this.
http://curtisnovak.com/pickups/repairs/Hag-Bisonic/
Not sure how it all fits in there.
You might contact novak, he might shed some light?
T

[Jim Darr]

Thanks T,

I am aware of the work Curtis has done reproducing and repairing the Bi-Sonic. Very impressive. I haven't run across any detailed specs for the original pickup other than general design/construction images. I am looking for coil geometry information.

I actually played a very early Guild Starfire Single pickup bass while in college. It had the very rare smaller pickup (also believe made by Hagstrom) before the Bi-Sonic was standard. It was a great bass and I regret letting it go. Actually saw the same one for sale online about 6 years ago....brought back many found memories. I was happy to see it was still playable and in pretty good shape.

Anyway, thanks for the suggestion T.

Jim

[big_teee]

Maybe you can answer some of my curiosities about the bio-sonic pickup.
Is the coil on a bobbin, or is it a loose coil that is wound then placed in the pickup?
I can't tell anything about the coil itself in the pickup pictures.
Looks old and antiquated to me.
T

[Jim Darr]

T,

DISCLAIMER --- I am not an expert on these obscure pickups.

In fact, I have very limited knowledge and direct experience with them as a winder. I do greatly admire their unique sound and have been thinking about coming up with a similar sounding version that doesn’t have as big a “footprint” as the originals. Hence my query about the coil.

So, take anything I say on the Bi-Sonic with a big grain of salt!!!

The original had opposing bar magnets (think P-90) that charged a multi-layer (think transformer iron design) keeper bar. The keeper bar had iron core poles that adjusted up & down with the adjacent height screw(s). The keeper bar and strings poles were grounded via the height adjust traveler plate. The bar magnets appear thicker than modern day HB bars and perhaps are more like the thickness of vintage Filter-trons.

I read at one point that some of the pickups may have had only had one magnet (I have not confirmed this or have seen any evidence supporting this).

Even though they were advertised as “humbucking” they were really a single coil design.

My best guess is that coil form is injection molded and that the magnet wire was wound directly on the bobbin core (again think again P-90 design and some Hofner designs).

Modern-day Guild replicas state they use an A2 magnet and are 6.4K Ohms.

Its design concept may have been inspired by the DeArmond-Rowe Dynasonic 2000 of the late 50s and early 60s.

These vintage pickups sound fantastic IMO and are very rare. Hope this info helps.

Anyway, my 2 cents.

Jim

[big_teee]

I'm with you and think there should be a easier way to accomplish a similar sound.
The two opposing magnet concept, works well, and gives a bright sound.
I experimented with bass pickups for a couple of years, and bobbin height means a lot.
Taller is brighter, pickup placement for bass is important.
I ended up liking the round multi-coil tall bobbin pickups.
The downside to multicoils, is lots of labor, and higher cost to make.
GL, in your endeavor.
T

[David King]

Didn't Fred Hammond try to reproduce this with his Darkstart pickups? He had to discontinue the line because they were costing him too much time and trouble to make but i have a set photos of those from all sides if that would help anything.

[Jim Darr]

Didn't Fred Hammond try to reproduce this with his Darkstart pickups? He had to discontinue the line because they were costing him too much time and trouble to make but i have a set photos of those from all sides if that would help anything.

Yes he did the DarkStar. Thanks, any pictures would be helpful. Either post here or PM. Thanks again

[David Schwab]

I had this in my notes for a darkStar:

• Core W8mm xL60mm xmD5mm,
• Poles 6mm x 28mm
• Coil height 7mm
• Magnets W14mm x L55mm x D5,5mm
• Coil outside W18mm, 3mm x L69,5mm, tape included
• 6kOhm

The keeper bar is not a transformer core. It's just stamped out of multiple thin pieces of steel.

[Jim Darr]

I had this in my notes for a darkStar:

• Core W8mm xL60mm xmD5mm,
• Poles 6mm x 28mm
• Coil height 7mm
• Magnets W14mm x L55mm x D5,5mm
• Coil outside W18mm, 3mm x L69,5mm, tape included
• 6kOhm

The keeper bar is not a transformer core. It's just stamped out of multiple thin pieces of steel.

Thanks David!!!

[David King]

Here are the Darkstar photos. Hopefully they will appear as everything looks right with the upload.

[David King]

Someone needs to help me getting these to appear in the post because I'm clueless.

[big_teee]

Here's the great looking pictures from David King.
I couldn't attach them either, until I converted them to a different file type.
T

[David King]

Thanks Terry,
Interesting that the filesize increased by an order of magnitude (magnetude?).