Dark Star Bass pickup info?

[David Schwab]

I've had a few DS in my hands. From Fred's site
"Other improvements include using thinner and better insulated steel laminations in the bobbin core. I was able to put 8 laminations instead of 5 in the same space. This is to better reduce eddy currents and hysteresis loss which can limit high frequency."

What material would you use if you tried to make a similar sounding pickup? Do the adjustable pole pieces make difference to the sound compared to just solid laminated core? I remember reading that DS has 42 wire and 6,5kOhm resistance.
I'm planning to try to make a pickup with DS-like core, magnets and coil shape but without adjustable poles or chrome cover. Any help with core material would be nice. For magnets C5 or A5 blocks were used. From Fred's site again

"The red DeArmond Starfire you see in the website photo has ceramic V magnets instead of alnico V. Originaly I had 2 mags in the neck DS and 2 in the bridge DS. The pull was so strong at the neck (normal pole piece height) that the flux did stop the string literally! It stopped the string and left these awfull harmonic overtones....bletch! I ended up taking one bar mag out of that DS and the bass sounds fine now. The alnicos don't have that problem. In fact you're going to notice INCREASED sustain due to the iron content of the DS. The 8 steel laminations saturate and release the energy slowly. This is what gives the DS it's unique sound."
Marko

You know I read that, and couldn't figure out where the laminations would be? I mean the pickup has steel poles, so where's the core?

Then I saw this picture on his site:



So I guess the poles pass through those keeper bars?

If you go to the sound clips page; Fred mentions:

The first track heard "Short and Fat", was using a stock Dark Star pickup with its 1/4" tall coil. The second track "Tall and Skinny" was also a Dark Star but with a modified bobbin having a coil height of 3/8". The number of winds in the coils is the same and the DC resistance measures to within 50 ohms of each other at approximately 6.3K DCR.

Another interesting fact is from Rick Turner:

Owsley "Bear" Stanley had already discovered that the pickups could be hot rodded by adding a second magnet, and so the sound was born. Ron further improved things by building transistorized emitter followers onto the pickups, thus creating what were probably the first active pickups (yes, 1969).

So the second magnet was not in the original Hagstrom pickups.

Where;s Rick when we need him?

[David Schwab]

The plot thickens . . . the mystery continues . . .

As a pickup manufacturer, if you were to go about making something like a Dark Star, where would you start? I would think the chrome bezel would be the trickiest part, yes?

Chesh

You can make a pickup that sounds like a DarkStar/Bi-sonic. The chrome bezel looks cool, but you don't need it, unless you just want that look.

[Marko Ursin]

You know I read that, and couldn't figure out where the laminations would be? I mean the pickup has steel poles, so where's the core?

Then I saw this picture on his site:

Thanks for the pic David! I didn't remember that one. I was planning to make the core with laminated pieces side by side but this pic changes my plans. The poles pass thru the laminated core.

So where do I find bigger than usual hb A5 or C5 magnets? How do I cut ceramic magnet? With diamond tile cutter or what? I've planned a kind of a fixture for my tile cutter for cutting the magnet if diamond is the way to go.
Marko

[Marko Ursin]

I have measured a Dark Star I have on loan.
-core W8xL60xD5,
-poles 6x28
-coil height 7
-magnets W14xL55xD5,5
-coil outside W18,3xL69,5, tape included
-6kOhm

All measured in mm.
Marko

[bea]

You can make a pickup that sounds like a DarkStar/Bi-sonic. The chrome bezel looks cool, but you don't need it, unless you just want that look.

Do You think it is possible to dark-starify a mudbucker, notably the 1.2 k-variant epiphone uses? I actually consider refining the modifications i have applied to the Epi Mudbucker (adding some iron and two alnico magnets). How could that be done?

THX

Beate

[David King]

Back from summer. I have some detailed photos of DS pickups if anyone still wants to see them.
I see that Fred was using Wonder Solder from Kimber, that stuff is crazy expensive but I love it.
I heard a while back that Dan Lakin sold the US division of Lakland basses to the folks from Hanson pickups, that might explain the absence of DarkStars on the current models.
Cutting alnico is a pain, I grind it dry with a brown grinding stone, but don't breath the dust! Cobalt is bad for you. I think Shea at Magnetic Hold would be a much better option for custom bar sizes.
The DSs weigh a ton, putting two of them in a bass is a lot of extra weight to have around your neck, I like them but they are a little brighter than I need them to be, I'd bump the turns count up by 20% and try a thinner pair of magnets.

[David Schwab]

Do You think it is possible to dark-starify a mudbucker, notably the 1.2 k-variant epiphone uses? I actually consider refining the modifications i have applied to the Epi Mudbucker (adding some iron and two alnico magnets). How could that be done?

What are you trying to do to the tone of the Epi pickup?

[David Schwab]

Back from summer. I have some detailed photos of DS pickups if anyone still wants to see them.

I'd like to see them.

[bea]

I'd like to have a deeper sound and at the same time have more treble (and of course more output).

Yesterday i played it against an old gibson EB-3 (with a defect, only the mudbucker with the varitone was usable) and against the "low cost" variant of the Gibson SG bass (mhmm, way too expensive for that quality - my modified epiphone is fully competitive...).

Yes, i succeeded in getting it deeper, bassier - a lot. It comes pretty close to the old sidewinder, and it still has a lot more treble than that. But not enough.

I am aware that i can operate the two coils in parallel to increase the pickup resonance, but that would reduce the output too much - the bridge pickup is already a lot louder.

Anyway: i have heared soundclips of the dark stars - and these come closest to my ideas.

[belwar]

Dave,

Can you tell me what the heck this wonder solder is? Why do you like it?

[David King]

Dave,

Can you tell me what the heck this wonder solder is? Why do you like it?

Belwar, it's just eutectic solder 63/37 but the Kimber Kable stuff is just amazingly nice to solder with, price is $50/lb (of course it's *audiophile*). I get mine through a former Kimber dealer who knows the rep. I can send you a sample if you'd like to try it.

[David King]

photos

here are some small images

[David King]

The photo of the back side shows the magnets both marked N for North presumably. It raises a question as to how they are magnetized. Could they be magnetized through the thickness i.e. front to back?

[big_teee]

Does the main Pole pieces go through a wooden Strip?
The Pickup Sure is Large, When compared to the size of the Bobbin.
A lot of Mechanism just to be able to adjust up and down a little bit.
B_T

[David King]

Terry, the copper colored keeper is laminated steel. I don't know if all the laminations are copper plated or just that outer one to prevent rust. The laminated steel is there to prevent eddy currents, copper plating doesn't seem like the best choice under the circumstances but perhaps it's just the cheapest way to get electrical iron sheet-stock?