Wiring Passive Humbuckers as Balanced-out?

ElRay

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A lot of modelers have at least one balanced input. If you've got passive humbuckers, you can wire-up the two coils as balanced-out. Has anybody tried this? I'm assuming it would sound basically parallel-ish.

What's rattling around in the brain bucket is to wire-up the two humbuckers to a 4-Pole On-On and then to a stereo XLR jack into the two balanced inputs on the modeler and then the modeler can handle the neck/bridge/blend switching. The On-On switch will then be able to toggle between Neck/Bridge and Inner/Outer.
 

Wiltonauer

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The common point between the two coils would be ground. A balanced input is differential, so would it really be any different in series mode, otherwise? But recording the two phases on different tracks?
 

Lemonbaby

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The common point between the two coils would be ground. A balanced input is differential, so would it really be any different in series mode, otherwise? But recording the two phases on different tracks?
As you said, it's just not gonna sound like a humbucker to begin with.

The easiest solution would be wiring the output of each PU to one line of a stereo output. Modelers usually expect stereo signals on two inputs (XLR or 6.3mm), so this signal needs to be split once it leaves the guitar. That particular guitar will only work in the modeler setup, obviously.

Long story short, sounds like a solution to a non existing problem.
 

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Is the balanced input stupid-low impedance? That might make it a no-go with most conventional passive pickups.
 

ElRay

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The common point between the two coils would be ground. A balanced input is differential, so would it really be any different in series mode, otherwise? But recording the two phases on different tracks?
It would be differential, so one "pick-up" would go to to Balanced-In-1 and the other "pick-up" would go to "Balanced-In-2"
 
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It would be differential, so one "pick-up" would go to to Balanced-In-1 and the other "pick-up" would go to "Balanced-In-2"

... a few questions...
1 - Lets say a pickup IS 1 single coil... how many of these do you have in said guitar (a 2 humbucker guitar will have 4 single coils...obviously).
2 - I'm curious to understand if what you want is to control pickup switching via a outboard gear or just to see how things sound "balanced"...?

... if the first option on the second question, I'd suggest to find one of the following systems:
1 - Ernie Ball Music Man GAME CHANGER guitars
2 - I know that the website guitarelectronics had a contraption that could allocate any kind of combination to a switch from any pickup configuration. One would connect the pickups directly into the contraption's main board and then select the desired combo for each switch position... something in the way of what Ernie Ball Music Man did with the GAME CHANGER guitars... so much that it led to court trials and these products lust vanished from the face of the Earth... but if you find anything like that in the used webz... maybe give it a go?

Besides that, and regarding "balanced" wiring of humbuckers, I have no idea nor how to help you...
 

bostjan

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I'm lost here.

Balanced output:
1. Hot
2. Neutral
3. Ground

Unbalanced output shucks the neutral and ground together.

If you want to wire your pickups for balanced output, you'd have to wire hot to hot and keep the neutral and ground wires separate in your control cavity, then wire neutral to neutral and ground to ground. That doesn't really give you any additional wiring options or anything unless you couple it with a stereo output, which is something totally different, but you could do stereo balanced or unbalanced.

And I would highly recommend NOT using balanced wiring on your guitar unless you add some sort of way to idiot-proof it. Since, if you plug into an old tube amp or whatever with shitty wiring, and it's not properly balanced, your ground becomes floating and your neutral becomes potentially hot, meaning that your body becomes the likely short-circuit path from high voltage to ground. In other words, you could be more likely to receive dangerous or even lethal shocks.

Otherwise, though, you could, of course, rewire your guitar to be stereo unbalanced, with two outputs and a common ground, and that would not only be safe and potentially offer you some cool wiring options that you could control in post, but it's already sort of a thing.
 

ElRay

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I figure a little bit of "How I got here" might be in order:
  1. I've always been an "small amounts of overkill are almost always good" person
  2. We have a Roland JC-40, which has a stereo effects return
  3. We have a Partscaster with a piezo-bridge
  4. I've been having fun with the mag/piezo stereo-out
  5. The a Presonus 68c has two "smart" dual 1/4"-unbalanced/XLR-balanced inputs
  6. I'm liking using the pedalboard/scene change options in the "Stompless piStomp MOD Dwarf Clone" to do pick-up selecting/blending
  7. I found a stereo (5-pin) XLR jack in my parts box that I don't recall purchasing and have no idea how it got there
  8. I started thinking about my undergrad days when we'd use balanced sensors whenever possible to boost signal input and reduce noise (I know that with two coils of a humbucker, I won't get anything more than the two coils in series.)
  9. Realization that this guitar will likely never be played anywhere but in-house, or at the least, connected to an audio interface.
  10. Curiosity about what I could do with parallel chains, high-pass/low-pass filtering (trying to get the tighter bass from the bridge and and the warmer treble from the neck), and other audio mad-scientist tinkerring
As for fool-proofing (really fool-resistant, fools are too ingenious), the intent was to use the XLR stereo jack and a XLR-stereo to dual-XLR-mono cable. This experiment will not be connected to anything but and audio interface or a DI setup. I might/should add some caps to deal with the potential for phantom power to be turned on.

As I'm typing this, there's a chance I'll actually be making noise worse, because I'd be adding DC-blocking caps that weren't previously needed and I'll technically be introducing a "ground loop". In the guitar and through the cable, both channels have the same neutral, but in the audio interface, they'll be routed as if they were two independent signal generators.

It's a curiosity. I'll likely go stereo unbalanced, because that's how the Partscaster is wired.
 

Wiltonauer

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I'm lost here.

Balanced output:
1. Hot
2. Neutral
3. Ground

Unbalanced output shucks the neutral and ground together.
The unbalanced output certainly does that in most cases, but the “Neutral” on a truly balanced output is anything but. In general, it’s an inverted version of the “Hot” output. They each carry a signal that is hot compared to the ground reference. A more common notation is something like Hot(+) and Hot(-). For every millivolt Hot(+) goes positive above ground, Hot(-) goes that far negative below ground, and vice versa. The balanced input on the other end responds to the difference between the two hot signals, rather than depending on either of the two signals referenced to ground. That is how they get higher signal levels and common-mode noise rejection out of balanced lines.

Used to be some cheap gear would just ground the Hot(-) and forego the extra cost of differential inputs and outputs, making it not truly balanced at all.
 

bostjan

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The unbalanced output certainly does that in most cases, but the “Neutral” on a truly balanced output is anything but. In general, it’s an inverted version of the “Hot” output. They each carry a signal that is hot compared to the ground reference. A more common notation is something like Hot(+) and Hot(-). For every millivolt Hot(+) goes positive above ground, Hot(-) goes that far negative below ground, and vice versa. The balanced input on the other end responds to the difference between the two hot signals, rather than depending on either of the two signals referenced to ground. That is how they get higher signal levels and common-mode noise rejection out of balanced lines.

Used to be some cheap gear would just ground the Hot(-) and forego the extra cost of differential inputs and outputs, making it not truly balanced at all.
Ok. I understand. Thanks. I do think everything else I said still applies, though, no?

I figure a little bit of "How I got here" might be in order:
  1. I've always been an "small amounts of overkill are almost always good" person
  2. We have a Roland JC-40, which has a stereo effects return
  3. We have a Partscaster with a piezo-bridge
  4. I've been having fun with the mag/piezo stereo-out
  5. The a Presonus 68c has two "smart" dual 1/4"-unbalanced/XLR-balanced inputs
  6. I'm liking using the pedalboard/scene change options in the "Stompless piStomp MOD Dwarf Clone" to do pick-up selecting/blending
  7. I found a stereo (5-pin) XLR jack in my parts box that I don't recall purchasing and have no idea how it got there
  8. I started thinking about my undergrad days when we'd use balanced sensors whenever possible to boost signal input and reduce noise (I know that with two coils of a humbucker, I won't get anything more than the two coils in series.)
  9. Realization that this guitar will likely never be played anywhere but in-house, or at the least, connected to an audio interface.
  10. Curiosity about what I could do with parallel chains, high-pass/low-pass filtering (trying to get the tighter bass from the bridge and and the warmer treble from the neck), and other audio mad-scientist tinkerring
As for fool-proofing (really fool-resistant, fools are too ingenious), the intent was to use the XLR stereo jack and a XLR-stereo to dual-XLR-mono cable. This experiment will not be connected to anything but and audio interface or a DI setup. I might/should add some caps to deal with the potential for phantom power to be turned on.

As I'm typing this, there's a chance I'll actually be making noise worse, because I'd be adding DC-blocking caps that weren't previously needed and I'll technically be introducing a "ground loop". In the guitar and through the cable, both channels have the same neutral, but in the audio interface, they'll be routed as if they were two independent signal generators.

It's a curiosity. I'll likely go stereo unbalanced, because that's how the Partscaster is wired.
Are we talking unbalanced stereo or balanced mono here?

Using an XLR output ought to pretty much do the trick, since XLR is a balanced format. The capacitorrs will block DC current, but, if they are in series, I suppose they would charge up when you phantom power them, which could still be dangerous. The phantom power won't probably supply enough current to be dangerous, but the capacitors might. If the phantom power supplies DC potential between the hot and cold without capacitors, it should be okay as long as everything is grounded properly in the guitar, i.e. nothing "grounded" is accidentally actually cold.

I'm intrigued, though. I may not understand what exactly you are trying to do, but a guitar with a balanced XLR out could be a really nifty thing.
 

ElRay

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Are we talking unbalanced stereo or balanced mono here?
Two channels of balanced mono:
Code:
 ---------- Hot(+)
/
\
/           <- Traditional "North" Coil
\
/
>---------- Neutral
\
/
\          <- Traditional "South" Coil
/
\
 ---------- Hot(-)
So, with the 4PDT in the "up" position, Channel-1 would be the Neck Pick-up, and Channel-2 would be the Bridge Pick-up. In the "down" position, Channel-1 would be the inner coils, and Channel-2 would be the outer coils (maybe visa-versa).
 

bostjan

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Two channels of balanced mono:
Code:
 ---------- Hot(+)
/
\
/           <- Traditional "North" Coil
\
/
>---------- Neutral
\
/
\          <- Traditional "South" Coil
/
\
 ---------- Hot(-)
So, with the 4PDT in the "up" position, Channel-1 would be the Neck Pick-up, and Channel-2 would be the Bridge Pick-up. In the "down" position, Channel-1 would be the inner coils, and Channel-2 would be the outer coils (maybe visa-versa).
I've gone stupid and I still don't understand.

You have 4+1 conductors for the pickup: 1. Start of N coil, 2. End of N coil, 3. Start of S coil, 4. End of S coil, and 5. Ground. Ground is easy, right? Pin X from the XLR goes to ground and to all of the shielding. Then solder 1 N start to pin L and 3 S start to pin R and finally the ends of both coils to ground. That way everything is differentially balanced as it is supposed to be, right? Then your audio interface's differential amplifier will reject the noise and combine the signals. It should sound much like a humbucker wired in series, but I suppose there might be some very subtle differences.

If you want two coils from two different pickups, you need the start of the N coil of one pickup and the start of the S coil of the other pickup, but then, unless the coils are the same impedance, which I think we can assume that they are not, it's not a balanced signal, right? So you'd need to run one of the coils through a little transformer to match the impedance of the two coils, but then, are the signals even perfectly out of phase? Erm, I guess I don't know- but maybe it's all close enough to assume it'll work...

As for phantom power, I'd be careful. Like I said, if you drop a capacitor in series with each signal line, and you accidentally phantom power them, those capacitors will charge up slowly. They won't ruin your pickups at least, but you could potentially have 96 volts at your fingertips if you touch the two hot lines together whilst grounded. A safer way would be to use an isolating transformer between the pickup and the output jack. That would block DC from getting to the pickups and you could also chose one that gives you a hotter output if desired, kind of like how an alumitone pickup works...

If you simply run stereo XLR such that each pickup is wired to its own output, it should be easy peasy. The switching part of this is either over my head or else it's kind of janky.

EDIT: Thinking about this a little more, I bet that a guitar pickup would clip the hell out of a differential input amplifier, so the output transformer is probably a little more necessary than for just blocking DC. This whole idea is intriguing enough that I'd much like to try it as soon as possible.

If anyone wants to use a volume and tone control, you'd have to go with dual pots to keep the settings identical for the output from each pickup but also isolated from the other signal. That would significantly complicate the control cavity. Maybe that's the main reason why this hasn't really been done. But if you delete the tone knob and did a single pickup output or used a 2-way switch, I think it'd be simple enough for anyone to manage. I have a bunch of little transformers lying around, so I might play with that a little when I have time. But, unfortunately, with it being the holiday season, I don't see myself having time to do any of this stuff this weekend or likely anytime this month...
 
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bostjan

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Or am I needlessly overcomplicating this? Maybe all you need to do is float the pickups instead of grounding them and then send the hot to L and "neutral" to R and the separate ground with all of the shielding to X. xlr.jpg

Not sure which transformer to use though.
 

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Ok, I'm obsessed with this idea now. There's got to be a reason why nobody offers this system anymore, but, the more I think about it, the more I wonder why not. For high gain tones, there are reasons why this ought to be the hot ticket - less susceptibility to EMF, hotter sounding output, etc. There just has to be a catch. Maybe I'll buy some TRS output jacks and maybe a little audio transformer after payday and go ahead and make some time to solder one into one of my less commonly necessary guitars, with a floating pickup configuration.

You know Lace Alumitones? So, what if you rolled with the idea of a low-Z pickup, but instead of an output matching transformer, you wired it with a balanced output. On paper, something like that ought to be the ideal configuration for high gain and low noise. Personally, I don't really feel like spending $120 on a lace pickup just to potentially ruin it by disassembling the output transformer, but I feel like the idea is simple enough that anyone with a thin enough sheet of copper or even heavy duty aluminum foil and a couple of magnets could pull this off. Maybe there is still a Thanksgiving tin hiding out in my recycling container.
 

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@bostjan You're getting a little carried away with this phantom power stuff, don't you? This solution will anyway need a custom cable that can't be used for another purpose.
 

bostjan

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@bostjan You're getting a little carried away with this phantom power stuff, don't you? This solution will anyway need a custom cable that can't be used for another purpose.
Howso? All I said was don't use any DC-blocking capacitors, which might make it more dangerous, and that the transformer that you'd need probably anyway would block any DC from the pickups.
 

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I know it's been nearly a month since the original post and it seems like interest in this topic has waned, but I finally pulled the trigger on the stuff I need to try this out. I'm going with a 1300:8 transformer and an XLR out. I'll update this weekend. If I love it, I'll do the treatment on a few different guitars. If I hate it, it'll only do one and probably switch it back after I've decided. I bought enough hardware to do 5 guitars, not because I'm optimistic, but, oddly, because it was cheaper to buy 5 XLR jacks than just one (same brand).

It might make more sense to go with TRS 1/4" cables, but I've had some bad luck with cheap TRS jacks in the past, so I think XLR will be more robust.

Totally off topic, but I have a 14-EDO guitar that I really want to redo with alumitones and new hardware, which I've only ever used for recording. I'll try on another guitar first, and then, if I like it, that one will be #2, particularly because it's so damned noisy and all of the old hardware on it is kind of rusty.
 


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