EMG active pup specs

[mkat]

Yeah, it looks a little heavy, but I think it's the wax. Larger diameter does give lower resistance.

This is what the guy wrote. He's from Poland so his English was a bit spotty. I forgot he wrote specs... What would .06 mm be in AWG?

0.0635mm or there abouts is 42 AWG. So, if you take account of the tolerance (lets say -5%) it's roughly 0.06mm (0.06033mm).

[Joe Gwinn]

Joe - this is the second time I've heard the term "Wolf tone" to describe something other than the most deformed 5th in Just temperment.

Obviously they're different things... but I don't understand the mechanism of the wolf tone you're referring to... is it a sharpening of the fundamental due to magnetic pull? Does it alter the harmonics of the string... effectively creating a magnetic bessel curve by tightening the string only along a certain portion of its length? Wow... this is reminding me of work I've done with Shakuhachi bore shaping... (japanese end blown flute)

The extra pull, especially if nonlinear, moves the harmonics into increasingly non-harmonic frequency relationships. The ear is very sensitive to this. There are a number of names for various kinds and perhaps degrees of this: wolf tones and stratitis come to mind.

[Joe Gwinn]

This is what the guy wrote. He's from Poland so his English was a bit spotty. I forgot he wrote specs... What would .06 mm be in AWG?

It's #42, as mkat reported. Having a buffer right next to the coil eliminates the capacitance of the cable from guitar to amp, and will raise the resonant frequency to something exceeding 7,000 Hz. This would have the effect of making the response quite flat for guitars. As would winding 5,000 turns versus 10,000 turns, as inductance varies as the square of turns count.

[mjmiller]

Right - I used to make end blown flutes from bamboo, and there are a couple of techniques I used to alter the bore profile in different ways. slipping a beveled choke into the barrel is equivalent to this pull for the neck and mid pickups and tapering the bore at the embouchure end is the equivalent of the bridge pickup. This is necessary to bring the second register into tune - with a straight bore, it's naturally a tad flat. I experimented extensively with bore shaping (I'll spare you the details) and I can confirm that it has a huge effect on tone. I realized a lot more connections after having posted that... I do that a lot - I post about something, and the process of writing my thoughts gets me thinking more, and more clearly, and then I realize that I'm totally wrong about something I said, or I asnwer my own question, or something totaly different. Damn brain...
I like the term stratitis - is that from strat players who move their pickups too close to the strings? I used to be guilty of that, but now the pups are way down near the pickguard - I find I prefer the tone (I play cleanly a lot more these days)

Great freakin thread, guys. Tons of cool info - food for thought - and it's cleared up a number of misconceptions I had

Michael Miller

[erikbojerik]

Yes, you can see the SMD's in the last photo. I'm actually surprised the op amp isn't one.

Ah, right you are. Ditto my initial reaction upon seeing the op amp...which your guy in Poland could probably ID by cutting through what looks like a bit of a rubber coating.

[David Schwab]

Ah, right you are. Ditto my initial reaction upon seeing the op amp...which your guy in Poland could probably ID by cutting through what looks like a bit of a rubber coating.

I don't think it has a rubber coating... it just looks funny from having been in epoxy.

I see they use a LF442 dual low power JFET input op amp for their tone control circuits. I'd bet the IC in the pickup is similar.

[sumitagarwal]

Looks like a fairly normal humbucker with a alnico magnet, twin blades, and a bunch of wire on the bobbins.

The one thing about EMG's is they use a differential input to the buffer and run each coil separately. They also use the buffer to mismatch the response of the coils, and probably some EQ also.

Sorry to revive a dead thread, but two interesting things here that I have questions about:

1) Are you sure its alnico? Everyone says 81's have ceramics, while the 85's have alnico.

2) If I'm understanding this right, are you saying that 81's are actually wired in parallel instead of in series like a standard humbucker? I guess that would make sense if they're aiming for more clarity, and parallel is lower output than series but with their preamp they don't need to worry about that.

Also, do you think the coils might have a differing number of windings, like a Seymour Duncan Pearly Gates? Even if the EMG doesn't, I guess they're doing a similar thing through the electronics anyway.

EDIT: whoops, what an embarrassing mistake to make on a first post. I didn't notice there was a second page to the thread. So I guess it is indeed ceramic, and by that wiring diagram (op- ^^^^^^ ^^^^^^ op+) looks like it is in series instead of parallel.

So much for my Sherlock ambitions...

[David Schwab]

Sorry to revive a dead thread, but two interesting things here that I have questions about:

1) Are you sure its alnico? Everyone says 81's have ceramics, while the 85's have alnico.

I was going by what was written in the description that came with the photos. EMG says it's a ceramic magnet.

The EMG-81 has the familiar U-shaped humbucking structure but replaces the pole pieces with steel bars and a smaller ceramic magnet.

2) If I'm understanding this right, are you saying that 81's are actually wired in parallel instead of in series like a standard humbucker? I guess that would make sense if they're aiming for more clarity, and parallel is lower output than series but with their preamp they don't need to worry about that.

It's not wired in series, but it's not really parallel either. It's wired in a differential mode. So it's like just one coil, as far as the impedance. The output of the two coils is summed together, but they do not interact the way passive parallel coils do, so the DC resistance is not halved.

The common connection of the coils goes to ground, and the hot connection of each goes to the (+) and (-) inputs of the op amp.

Also, do you think the coils might have a differing number of windings, like a Seymour Duncan Pearly Gates? Even if the EMG doesn't, I guess they're doing a similar thing through the electronics anyway.

I have no idea. They might though, because they said the 58 was too noisy, so they changed it and it became the 85. The 58 was a really nice pickup.

So I guess it is indeed ceramic, and by that wiring diagram (op- ^^^^^^ ^^^^^^ op+) looks like it is in series instead of parallel.

It looks that way because the ASCII graphic became misformatted. The connection between the two coils is grounded.

Here's some more interesting "I wonder what's in there" pictures...

Notice the brass screen for shielding. I guess that would make that a Faraday Cage. That's a boatload of wire on those coils! They seem to wind all their bobbins until full. The larger the coil, the more wire they wind on it.

It's fun taking things apart!

[sumitagarwal]

Awesome post, man. Seriously interesting stuff here and good clarifications.

I guess EMG is sort of like two single-coils being used simultaneously... almost as if you took output from each coil and ran them separately to two identical amps. Really weird, and really cool. Nothing like it (or even possible?!) in the passive world. I wonder how they wire their "81 in a passive box" EMG H4. Not that I've heard it.

Thanks for replying to such an old and dead thread. Built-in Faraday cage? Great idea! I'm having more respect for EMG than before.

I've created a 'Partscaster' hot-rodded baritone Tele and I'm thinking about EMG's Telecaster actives. On their website they even say something like "undoubtedly the best pickup EMG makes"!

And thanks for replying (in such detail!) to such an old thread. You're the man!

P.S. Anybody else surprised that EMG doesn't try to make a 81/85 in single-coil size? I'm sure Strat and Tele players would eat that up, and that ESP players would try to stick two of them in their humbucker slot! I guess it would be pretty tough trying to stick all those windings into so little space...

[David Schwab]

Awesome post, man. Seriously interesting stuff here and good clarifications.

I guess EMG is sort of like two single-coils being used simultaneously... almost as if you took output from each coil and ran them separately to two identical amps. Really weird, and really cool. Nothing like it (or even possible?!) in the passive world. I wonder how they wire their "81 in a passive box" EMG H4. Not that I've heard it.

Any time you mix two pickups passively you have one loading down the other. Even if you buffer the output. The way around that is to buffer each pickup first, and then mix them together.

I think the passive pickups are wired up like regular passive pickups... they have 4 conductor wiring and all. I haven't heard any good reviews on them. I suspect they are taking the same parts as the actives and just leaving out the preamp.

Built-in Faraday cage? Great idea! I'm having more respect for EMG than before.

Alembic do the same thing, only they use braided copper mesh, like you find on coaxial audio cables.

I've created a 'Partscaster' hot-rodded baritone Tele and I'm thinking about EMG's Telecaster actives. On their website they even say something like "undoubtedly the best pickup EMG makes"!

That's just the Tele neck pickup... that's the one they think is their best pickup. I think it's very odd to not be able to make them all sound the same. As I pointed out, they wind more wire on larger coil forms, so their 6 string bass pickup has a higher DC resistance than the 4 string pickup, and each one has a different resonant peak. I think that's dumb myself.

The rhythm pickup (EMG-FT) is undoubtedly the best pickup we make. All the elements are in the right proportion; magnet choice, coil size, amount of turns, and good luck have given the EMG-FT the sweetest sound of any EMG.

They made some custom strat pickups for a guitarist who's name escapes me at the moment, with tele neck pickups in the strat size case.

And thanks for replying (in such detail!) to such an old thread. You're the man!

I'm interested on how things work... that's how I started fixing guitars... because I take everything apart, and then have to figure out how to put it back together!

Seymour Duncan used to unwind pickups to learn how they are wound. I'm not looking to copy EMG pickups, but I'm curious to know what's in them. Someone else took the 81 apart, and I had an old SA sitting around for a while in my pickup box that I wasn't using. It was cosmetically disfigured, so I figured what the heck! I was hoping to keep the coils intact, but that's very hard to do.

P.S. Anybody else surprised that EMG doesn't try to make a 81/85 in single-coil size? I'm sure Strat and Tele players would eat that up, and that ESP players would try to stick two of them in their humbucker slot! I guess it would be pretty tough trying to stick all those windings into so little space...

They are slow to come out with new models. They just came out with a P-90 size pickup not too long ago.

There are a lot of single coil size humbuckers on he market already... but they are all passive.

I think the one disadvantage of the differential wiring is some of the pickups, like the P bass replacement, sound too thin. Series wiring gives a nice fat bottom.

[sumitagarwal]

Nice to find people with a real passion for this stuff... let me know when you open up mass production! I'll be watchin for ya.

I'm trying to wrap my head around what would be the closest passive equivalent to the EMG active humbucker wiring... maybe it would be hotly overwound dual coils wired in parallel? Still quite different, but maybe.

[sumitagarwal]

In a related question, about parallel/series/differential wiring: does anyone happen to know how hum-canceling 'single coil stacks' are wired? I have the Seymour Duncan Vintage Stacks and I'm wondering if they get the humbucking by added a bottom coil in parallel or in series.

[David Schwab]

In a related question, about parallel/series/differential wiring: does anyone happen to know how hum-canceling 'single coil stacks' are wired? I have the Seymour Duncan Vintage Stacks and I'm wondering if they get the humbucking by added a bottom coil in parallel or in series.

I'm pretty sure they are in series. You can only do series or parallel with passive pickups. The differential thing is part of the op amp's wiring.

The older Duncan stacks are covered by this patent from 1985: 4524667

Now they state they have a "new patent applied for design", so they might have changed things. Kevin Beller, Duncan's chief designer got this patent in 2007: 7166793, which might be the same pickup. It's an advancement on the DiMarzio/Kinman style stack with magnet shields and added loads in the bottom coil.

I used to have some Duncan stacks, and I thought they sounded pretty good. I've installed a few DiMarzio Virtual Vintage Pro stacks lately... they have alnico II magnets and are supposed to sound like p-90's. They sound very good. It seems this is the direction to go in with stacked pickups.

The EMG SA seems to have an alnico bar magnet running though both coils, which is similar to the original Duncan patent. I haven't gotten to the bottom coil yet, so I don't know what's in there.

I made a Tele lead stack with a steel blade running through both coils, and two magnets on the bottom of the blade like a P-90. Even though I would it pretty hot, it's very bright. This must be why some stacks have a lot of wire on them, to try and warm them up. But the real issue is phase cancelation. My pickup gets a good vintage Tele tone, but that wasn't what I was going for!

[sumitagarwal]

Really cool insights... I'm interested in talking about the EMG SA's more, and also about maybe the (discontinued?) EMG-S4 passives.

But first about the Dimarzio and Duncan stacks: I'm really interested in the Dimarzio Virtual Hot T (seems to match some specs on my beloved Duncan Alnico II Humbucker well, the A2 magnet and the T/M/B ratings). How would you compare your experience between the Duncan and Dimarzio stacks? I find the Duncan Vintage Stack really interesting, but a bit harsh for my tastes. I've noticed all my favorite pickups in my other guitars are Alnico II or III.

[bajaman]

Hi David S
i know this is an old thread but did you ever discover if the alnico magnet went right through the two coils of the SA you disected?
I wound some stacked coil pickups way back in the late 70s (inspired by Seymour Duncan's stacks) with the two coils in series using AWG 44 plain enamel and approximately 8000 turns on each coil which I then connected in series out of phase. I found them to be a bit thin sounding due to the bass cancellation caused by inductive coupling of the two out of phase coils.
The Kinman, Belcher and Stich designs appear to have addressed this bass rolloff but the EMG SA appears to be the same construction as my early stacked coil pickups. Perhaps the differential preamp design has some built in bass compensation?? Do you have any further details on the SA preamp design - component values etc?? ( I have seen the EMG 81 preamp design)
Or do EMG SA pickups sound a bit thin on the bottom end as well??
Cheers and thanks for the info - I only discovered this forum recently!
So glad I did
bajaman