Stacked Humbucker Modification

[heugel]

Read this in an old guitar book called "Getting Great Guitar Sounds" my Michael Ross, about Eric Johnson's live guitar tone (circa 1988):

"Johnson's '54 Stratocaster sports a DiMarzio HS-2 stacked pickup in the bridge position. He has disconnected one of the coils leaving him with a true single coil. He maintains that this coil is fuller sounding than a stock pickup and the extra coil still helps eliminate some of the noise."

Does that sound right? For some reason, this complicated techno-wizardry is too much for my primative mind to comprehend.

[lovekraft]

You're not alone! Other than shielding the back of the pickup (if it's grounded), if that coil is disconnected, it's contributing nothing electronic to the sound.

[Jester700]

Read this in an old guitar book called "Getting Great Guitar Sounds" my Michael Ross, about Eric Johnson's live guitar tone (circa 1988):

"Johnson's '54 Stratocaster sports a DiMarzio HS-2 stacked pickup in the bridge position. He has disconnected one of the coils leaving him with a true single coil. He maintains that this coil is fuller sounding than a stock pickup and the extra coil still helps eliminate some of the noise."

Does that sound right? For some reason, this complicated techno-wizardry is too much for my primative mind to comprehend.

It's mostly right. I had one of these temporarily wired so I could instantly A/B what he's talking about. In that pickup, only the top coil really senses the string & generates signal, since the magnet poles don't pass through the bottom coil and there's a metal shield between the halves. When you switch to only one coil, you get more output and a fuller sound because the pickup isn't loaded down by the extra coil (which adds resistance but no signal). Of course, you lose the humbucking effect, too.

If he meant that it was fuller than a stock STRAT pup, yeah, maybe. I'm pretty sure it uses 43AWG wire instead of the strat's 42, which will roll off some highs; it's also wound a bit hotter - around 8k compared to 6k for a typical strat.

As for reducing the noise when the bottom half is out of the circuit, I don't buy it. I couldn't A/B that aspect, because you have to physically remove the pickup to remove the bottom coil. Since I only use the middle pup in combinations, I permanently removed the bottom coil (when combined with other coils, you can still get a humbucking effect). I didn't notice any difference after doing this, but human auditory memory is short. But then, so is Eric Johnson's. I don't know of any magnetic theory that would suggest what he describes, but I'm no pro, either.

Incidentally, I like this pup a lot. Ibanez's C2 is the same thing, and you can often get them cheap on eBay...

[Southpa]

Maybe the mass of the other, unused coil helps the grounding. Even if the "hot" side is disconnected the magnetic flux effect with the strings is still active. So that unused signal is going to ground instead of to the amp. The coils are still arranged on opposite poles and the hum cancelling effect is still active.

I have an old Seymour Duncan Hotstack in my strat. Its a large bar magnet, 4-wire setup in the bridge position. I just might experiment a bit.

Edited September 20, 2004 by Southpa

[Jester700]

Maybe the mass of the other, unused coil helps the grounding. Even if the "hot" side is disconnected the magnetic flux effect with the strings is still active. So that unused signal is going to ground instead of to the amp. The coils are still arranged on opposite poles and the hum cancelling effect is still active.

I have an old Seymour Duncan Hotstack in my strat. Its a large bar magnet, 4-wire setup in the bridge position. I just might experiment a bit.

There is little flux with regard to the strings due to the plate between the "dummy coil" and the magnetic poles and strings. But there could be some; I dunno how to measure it. In this design, the dummy coil isn't intended to have ANY interaction with the magnets; only to supply an out of phase signal of pure noise. Again, there could be some, but it's incidental.

The dummy coil was originally a series connection, so you couldn't disconnect just one side. But if it were rewired as a parallel connection, you could send one lead to ground, but that's not how a bucker works in the first place; the idea is to phase cancel the noise - that means the dummy coil needs to be in the signal path.

If you play around, I'd be interested in what you find. But does the Duncan have magnets that go through both coils? Is there a plate separating the coils? Because if these factors are different than the DiMarzio, the results are likely to be as well.

[lovekraft]

If he meant that it was fuller than a stock STRAT pup, yeah, maybe.  I'm pretty sure it uses 43AWG wire instead of the strat's 42, which will roll off some highs; it's also wound a bit hotter - around 8k compared to 6k for a typical strat.

Now there's a statement I can get behind whole-heartedly. A heavier, overwound pickup is definitely going to sound "fuller" (ie, more midrange) than a stock Strat pickup, with or without a dummy coil. It's that disconnected dummy coil having any effect on the pickup's sound that I have a problem with, unless it adds mass and lowers the frequency of any physical sympathetic vibrations in the pickup mounts. Of course, we are talking about a human being who, after having played loud music for most of his adult life, claims he can hear the minute differences in discharge levels of cheap zinc-carbon batteries in his distortion pedals.

Southpa, I'll be interested to see if your experiments yield any audible results.