Dark Star Bass pickup info?

[Marko Ursin]

I guess the marks are just for polarity in case you want two Dark Stars. Would it even work if the magnets had front to back polarity? I made my version with magnet polarity pointing to keeper.
Marko

[David Schwab]

I guess the marks are just for polarity in case you want two Dark Stars.

I believe that is correct.

Would it even work if the magnets had front to back polarity?

I doubt it.

[bea]

Mainly i want to have more brightness without losing the deep lows. From my experiment with the PUs i already know that due to their low impedance design at least the bobbins do have the potential of a fairly low Q treble resonance - that's why i do not consider havin them rewound (in contrast to its overdamped cousin by ARTEC with its 30 k windings which will need to be rewound in order to sound well).

Enclosed a photo of the PU in its present state:


You might notice the bars of 4 mm steel between the bobbins i added. These give me a large improvement not only to more expressed deep registers but (a bit surprisingly) also more highs.
In order to further improve this i consider to replace the bars by laminated steel in order to reduce eddy currents.

This closes the gap to the dark star: the magnetic fields of the to PUs should be qualitiatively similar: magnets symmetrically from the sides and the iron between forming something like a reversed T. Most of it, the predomint direction of the eddy currents should be similar in both setups, shouldn't it?

So i think it might/should be possible to apply the same ideas to that specific feature of the two PU concepts - just let me remind to the Dark Star FAQ already quoted previously:

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 Do You think?

And, most of all: are the pole pieces of the DarkStar-PUs isolated against the magnetic core or are they in electrical contact? The latter should reduce the suppression of eddiy currents, but not completly, shouldn't it?

[David Schwab]

I rewound a real Gibson mudbucker once to about 12K. It was brighter, but not bright. It retained a lot of the sound you hear from that pickup. Maybe wound lower wound have done it, because the sidewinders I make are very bright.

The one thing about the low Z aspect of that pickup is that the having a fairly flat and high resonant peak actually makes the pickup seem less bright, because the peak is so high. If that pickup was wound with more turns of thinner wire it would bring the peak down into the range where the human ear is more sensitive and it will sound brighter.

[bea]

The resonance of that PU ist not high enough for this effect - splitting it into single coil or wiring the two coils in parallel both increases the resonant frequency and in this case also the brightness. But it decreases the output level, which is already pretty low.

My intention with this subthread is to come to a better understanding of the physical background beyond the simple model of the resonance low pass: if You understand how to model the voice of a PU you are able to modify it in a more specific way than with jus rewinding (David, i am sure that You do after listening to the soundclips of Your pickups).

Beate

[David Schwab]

I don't think you will get that pickup to sound brighter without wiring it in parallel, or rewinding it.

I wind some pickups with 40AWG, and they have a deep hollow sort of tone. The top end is there, but it very different from usual.

[mkat]

Does anyone have additional specs on these: the assembled keeper bar height, magnet dimensions, pole diameter, or any other specs not listed above?

[mkat]

Oops, sorry, just found the post I was after.

[Motoko]

Hi I'm a quest to find out Whats going on with Fred Hammond. I was dreaming of buying new American Standard P-bass and slapping on a nice Darkstar pickup.This dream started about two years ago now that I have the money for this dream to come true I can't find any new Darkstar Picks and I swear Hammond had a website with a store where you could order these pickups BRAND NEW. I had the web site bookmarked; I clicked the link and it sent me to some fake looking directory. I spent over three hours looking for answers till I ended up on this forum where you fine people were talking about this issue like you know what your talking about. So please if any one has any answers let me know.


-thank you

[nekodensha]

I know only that Hammon was inundated with orders and he had a massive waiting list.
The Hammon Engineering/DS website was real enough- had it bookmarked for quite some time.
But if the website's been taken down, it's probably not all that likely to be good news I'm afraid.

[David Schwab]

I had the web site bookmarked; I clicked the link and it sent me to some fake looking directory.

He's apparently out of business. He let the web domain lapse, so that's why you see the page you do when you get there.

I don't know Fred, but I do know that he's a full time engineer and was doing the pickups on the side. It probably got to be too much work for him as a side project.

If you go to TalkBass and search for DarkStar or Bi-Sonic pickups, you will see that a few builders, including myself, are going to have some Bi-Sonic sound alike pickups.

[Chris Turner]

I don't think you will get that pickup to sound brighter without wiring it in parallel, or rewinding it.

I wind some pickups with 40AWG, and they have a deep hollow sort of tone. The top end is there, but it very different from usual.

As an aside here, David, do you have any sound clips of the pickups you've used 40AWG on? I'm curious to hear what those sound like.

[David Schwab]

As an aside here, David, do you have any sound clips of the pickups you've used 40AWG on? I'm curious to hear what those sound like.

Yes, in this clip of my Sidewinder pickups, it starts with the bridge, and at 44 seconds in your hear the neck pickup which is wound with 40 gauge wire. At 1:05 is both pickups. The bridge is 42 gauge wire.

http://www.sgd-lutherie.com/media/sidewinder_new.mp3

[Chris Turner]

Yes, in this clip of my Sidewinder pickups, it starts with the bridge, and at 44 seconds in your hear the neck pickup which is wound with 40 gauge wire. At 1:05 is both pickups. The bridge is 42 gauge wire.

http://www.sgd-lutherie.com/media/sidewinder_new.mp3

Sounds interesting. Wonder how that would sound at the bridge...

[nekodensha]

Glad to hear you're having a go at the Bi-Sonics David, especially if Hammon is out of business. Probably a real pain to turn out in any quantity if you build to original spec- but the demand is definitely there.
Keen to hear some sound samples once you've wound something you're happy with!