Seymour Duncan STK-1S -- Help needed

[jbforrer]

Greetings All,

I would appreciate any help on the specs of the wire and number of windings on one of these. The two coils are almost identical:

TOP: 8.37K, 2.62H, FR=9.4KHz
BOTTOM: 8.25K, 2.72H, Fr=9.4KHz
ASSAY wired out-of-phase in series: DCR=16.62K, 4,12H, FR=9.2KHz

Pictures attached.

Thanks much in advance.

JB.

[frankfalbo]

That's one of the older ones that went under a solid cover. As of 2006 they've been replaced by the Stack Plus series, but the newer ones (vs. the one in the picture) had taller magnets and went through a cover with holes.

[ShannonH]

just guessing,

Based on the readings, I'd imagine it's 44awg, and not PE, mostly due to cost. I'd try it with poly, then if you're wrong, it didn't cost as much as formvar or PE.

Peace

[David Schwab]

I had a set of those pickups once. The neck and middle had exposed poles, and the bridge had a closed cover with a blade pole. The maroon colored covers were cool.

Yes, I think it's 44AWG. I would up a similar Tele lead pickup with 43, since I didn't have any 44, and wasn't able to get the DC resistance up that high. I ended up with a very clean and bright pickup, but I wanted a bit more oomph.

The new Stack Plus pickups use an unbalanced coil design, similar to the Kinman and DiMarzio Virtual Vintage designs.

Compact hum-canceling musical ... - Google Patent Search

[jbforrer]

Thanks for all the suggestions. I'll try some #44 and give it a whirl.

Regards.

JB.

[Magnut]

I just rewound one of those. I used 43. I tried mic'ing it and got some various reads, so I went with 43. The customer was quite pleased.

The coil was so damaged that I was unable to get a super accurate count of what came off. I came close though. The rebuild came very very close.

[jbforrer]

Hi David,

The new Stack Plus pickups use an unbalanced coil design, similar to the Kinman and DiMarzio Virtual Vintage designs.

Thanks for the patent URL -- thats one more for my collection.

My STK-1S pickup was purchased in the early 80's and is still in good working condition. Apparently, they are good for neck and middle positions.

I was curious and did that frequency response plot to compare it to a something I'm more familiar. It sounds much like a Vintage Strat, except its very quiet.

I'd like to wind one myself and see how it works out.

Regards.

JB.

[Magnut]

I wanted to post a bit more but needed to check some things I had wrote down.

The pickup I did looked exactly like that one only the poles stuck up just high enough to go through a cover. The magnets go straight through the cavity into the flatwork. I think they were just under 3/16". I considered replacing the flatwork but the magnets went right through the flatwork I had which was cut for a .1875 magnet. So that means it was even smaller than about .181 . I didn't have my mic handy at the time.

The finished coils in series were 12.9k. The reading you get suggest maybe a 44awg.

Here's the only pic I can locate at the moment. There was more damage to it than you can see here. You can see the ferrous plate which was shaped just like an oblong ring between the two coils.



*Edit* Fixed the ohms reading after mistyping

[Magnut]

I got access to a comparator with a digital readout today. I had saved some of the wire I pulled off this pickup. The wire without a doubt was a 43 awg measuring an average of .0022 .

[jbforrer]

Hi Magnut,

Very useful picture, thanks for posting that.

My pickup looks a little bit different, seems like some R&D evolution when SD developed those? The protruding magnets looks a little more like the more recent dummy-coil style. Also, had a closer look for the ferrous shield plate and I dont see one on mine. Just looking at the wire on your picture, looks like #43 SPN? Very interesting, wonder why the design changed? Cost, performance, or patent issues?

Yesterday I made my own replica --- what a job.
I had an spool of #44 enamel dated 1969. Took a staggered set of taller A5 rods and regular flatwork and made a coil separator from a piece of very thin plastic. Then proceeded to wind the two coils each side of the plastic separator, much like for a Strat SC, right on the magnets. DCR per coil ended up around 6K. My tension was a bit loose so the coils are a little fat and squishy. Think with some planning, I can get 8K on there.

Performed a frequency response plot that showed my coils were not perfectly matched --- shows two distinct resonant peaks instead of the nice fat single peak the SD pickup has. If I were to do it again, I'd definately match the coils by their resonance, i.e., wind the top coil first to resonate around 9.4KHz, then the bottom one with extra wire and trim it down to match the top coil's resonance.

A lot of work, but I am happy with the way it sounds, like a Vintage Strat ... but very quiet. Please see picture attached of my prototype.

Thanks for the help.

Regards.

JB.

[David Schwab]

I'm pretty sure the ones I had didn't have the steel plate between the coils either. They actually belong to my friend, and he still has them. I'll haver to take a look next time I'm at the workshop. They are sitting in a box.

I did a variation of one of these for my Tele. I used a steel blade with two ceramic magnets on the bottom like a P-90. It worked well but I either needed 44AWG, which I didn't have, or taller bobbins.

[jbforrer]

Hi David,

Nice-looking Tele bridge. A little noise canceling pickup in disguise.

Interesting idea --- makes sense to use a blade pole instead of special A5 rods. Wonder how a fuller wind of #44 would sound with such a design. That SD set you mentioned earlier had such a blade pickup in the bridge. How does that one sound compared to the usual Strat SC bridge?

Regards.

JB.

[David Schwab]

Hi David,

Nice-looking Tele bridge. A little noise canceling pickup in disguise.

Interesting idea --- makes sense to use a blade pole instead of special A5 rods. Wonder how a fuller wind of #44 would sound with such a design.

Thanks. I'm going to make a new one at some point. Right now I have a dual rail pickup in the guitar that sounds pretty good.

That SD set you mentioned earlier had such a blade pickup in the bridge. How does that one sound compared to the usual Strat SC bridge?

Right, it was the hot stack and two vintage stacks.

I think they sounded very good. I got a great Hendrixy neck tone, and the bridge sounded like a Strat with some oomph.

I posted this clip in another thread. This was recorded on a Tascam Porta-One back in about 1987. The tape is a bit deteriorated in parts, so excuse the drops outs. But you can get an idea of the pickup used in a moderately distorted setting.

The guitar playing the melody/lead is the hot stack. The rhythm guitar is a Tele.

Drums and Wires

[jbforrer]

Hi David,

Judging from the sound clip, your stacked blade sounds like it has potential. One can hear that Hendrix tone. WiIl have to explore that idea some more.

Below is a summary of a couple of pickups from my collection that I evaluated before winding my stacked replica: The single pickup at the top of the picture is my golden standard --- a Vintage Strat, On the left are two Neo-Ferrites (re: M. Sulzer), the right displays SD STK-1S and an a dual-blade Tele bridge HB. Please also see the unloaded frequency responses of these pickups in the other picture. The colors are not the best, hopefully you will be able to get the idea why the STK-1S was of interest to me

Regards.

JB.

[ShannonH]

Who made the twin blade?