Schematic/Wiring Diagram Check Please

[instagvl]

Hi All! This is my first post here. I'm refinishing and customizing a '96 Epiphone SG 310 (MIK) and I want to do some fancy wiring to give me lots of tone options from a single Seymour Duncan Distortion in the bridge position. My goal is to utilize all of the pre-drilled potentiometer holes from the previous HH setup. The completed schematic shows what I have come with after lots of research, mostly on 1728.org. 


So, I think it will work like this: The switchcraft toggle switches between Position 1 - Solo Circuit that bypasses the potentiometers, Position 2 - Goes through the DPDT and SPDT switches and then the potentiometers. The DPDT provides a series/parallel wiring swap on the humbucker and the the SPDT provides a coil tap and a kill switch (though I wonder if i can have this switch between the north and south coils instead?). The Switchcraft also provides a kill switch in the middle position? Treble bleed circuit on the volume pot. 

This is my first attempt at creating an original wiring scheme. I do all my wiring work right now, and dabble in effects pedals, but I have so far only followed prepared diagrams. Thanks in advance for your knowledge and input! I'm ready to go with all my parts I just need a double check before I break out the solder!

Also, if you have suggestions, here's a blank diagram with all my parts:

[JohnH]

Hi instagvl, and welcome to GN2, and thanks for posting your scheme.

The main thing I see with it is that the old toggle switch, although it will bring you up from low volume to high volume, it does not seem to disconnect the tone pot, which might not be an issue, but it would be nice.

But I can see how, for a solo switch, a switcraft style toggle is a very good thing from an operational point of view, very easy to flick mid song, as it has been for 60 years.

Also, whats that treble bleed circuit? it looks like a series based one? I went right into these

guitarnuts2.proboards.com/thread/5317/treble-bleed-circuit

And came to the view that the best treble bleed circuit is a cap and resistor in parallel, 150k and 1nF for a 500k pot.

Ill have a think about the solo switch
J

[JohnH]

Here's one thought, and it goes against what I normally suggest, so sue me.

In this case, get rid of the treble bleed, and put the tone pot in '50's wiring' position, connected to the middle volume pot lug instead of the outer volume pot lug.

The will allow the solo switch to work better. the standard toggle is not ideal electrically for a solo switch, which normally needs two poles to fully bypass a set of pots, but, its good from an operation point of view. Doing this, with volume rolled down a bit, will seperate the tone pot from the pickup, allowing a clearer tone to be provided when you go to solo.

50s wiring makes the tone pot work somewhat inconsistently at different volume levels, but it might in this case, find you some more tones, and the LP community usually love it, and i think it might help with this solo switch thing.

[instagvl]

Thanks for the input! Im gonna solder tomorrow and see how it goes. Happy to have anymore advice between now and then. I'll update on the results as well. 

[newey]

the SPDT provides a coil tap and a kill switch (though I wonder if i can have this switch between the north and south coils instead?).

In the position where the SPDT has its upper lug connected to the center lug, you will ground one coil of the HB, thus it will give one single coil remaining.  Note that this only works when the DPDT is set to the series position; in the parallel setting, the SPDT switch does nothing.

In the other direction, it disconnects the ground entirely. The DPDT then controls series/parallel. There is no "kill switch". To have a kill switch, you need to ground the output, which you haven't done. To have the switch operate as a kill switch, the output will need to be connected to the unused lug on the switch (This assumes that it is an "on-on" switch, which is what it appears to be from the diagram.).

The center position of the switchcraft switch connects all the lugs (I believe) so it's not "off", it's always "on".  So, no kill switch there either.

To have the SPST chose between the N and S coils of the HB, you would wire the black wire to the center lug of the SPDT.  The ground then goes to one end lug; the opposite lug goes to the "hot" output.


Oh, and: Hello and Welcome to G-Nutz2!

[instagvl]

"To have the SPST chose between the N and S coils of the HB, you would wire the black wire to the center lug of the SPDT. The ground then goes to one end lug; the opposite lug goes to the "hot" output."

So, if I went this direction, would I wire this ahead of, or behind, the DPDT? Does it matter? Could you provide a little more detail, or perhaps a quick diagram? I think that the N/S coil switching is how I want to go. I can live w/o a kill switch. 


This has all been very helpful. Thanks! 

[instagvl]

Also, if it helps, here's the actual guitar with the parts installed but not wired.

[sumgai]

insty,


Hi, and to the NutzHouse!


Far be it for me to pee in someone's Cheerios so early in the morning, but then again, it is almost noon, so.....

I'm surprised that noone's pointed out the several flaws in your diagram. I do so now, at this late stage in the game, only to prevent you from tearing your hair out by the f roots as you try to troubleshoot the non-working axe.

First up, your use of Carling footswitches for the DPDT and SPDT jobs - are you certain this is what you want? I mean, those things are meant to be stomped on pretty forcefully, not by a hand but by a foot... the difference being many foot-pounds of force needed to successfully switch between the two options. There are other, more user-friendly switch options out there, you know.

Next, no matter what position your re-purposed pickup selector is sitting in, you will always have the Red-wire coil going to the two tone pots (one of them mistakenly labeled as a Volume control) when the DPDT is in parallel mode. Selecting the "blast" option will not supercede this.

Pointedly, the DPDT switch is wired correctly for your intended purpose, but the SPDT is not - you will "kill" only the red-wire coil, as the gray wire (actually white, I'm sure) is already grounded anyways... that leaves the black "hot" wire still in action, no matter which way the DPDT is set. What you have now is only a "single coil" select switch, and one that works only in series mode, not in parallel. I think you need to rethink the purpose of this switch. And for what it's worth, I think a proper kill switch does only that job. Using a three position switch could be done, but then things get all "fiddly" when you need to be quick and precise, in the middle of a performance.

Equally important, and as discussed in detail below, what if you wanted to 'kill' as part of your performance during a 'blast' solo?

As previously pointed out, the best way to "blast" is to use two poles of a switch to simultaneously disconnect the unneeded pots/switches at both ends. In effect, you're routing around those unwanted controls, just as a highway bypass goes around the outside of a city by leaving and re-entering the main highway at distant points. If that highway 'bypass' were to not re-enter somewhere along the way, then it would effectively be a dead-end spur, wouldn't it?

In closing, let me say further only that there is no such thing as "a switchcraft switch". Switchcraft is an American company that makes many, many kinds of switches, jacks, plugs, and other kinds of connector items. All three of your installed switches could have come from that company, just as they may all be from a competing company, American or otherwise.

That said, the switch we normally associate with selecting pickups in a Gibson-style guitar is actually what we call an opposing-ganged DPST. There are two poles independent of each other, but actuated by the same handle, only in opposing directions. In essence, and as usually used in a guitar for selecting pickups, this is nothing more than a SPDT with a center-both-on position. Sadly, as already noted, being one pole short means this is not a good choice for controlling a bypass or 'blast' function.

Oh, and upon re-reading the thread, I see I've "forgotten" to answer your final question. You asked about where to hook up the kill switch, as modified by newey. Basically, a kill switch should go right on the output jack. You want to kill the whole output signal, why not do so right where it leaves the guitar? By shorting (momentarily) the output from the pickups and all the controls, you ensure that nothing gets out to the amp, and as a bonus, you also ensure that there are no "open" wires that aren't grounded. That last part, the ungrounded wires, could act as an antenna, letting in all kinds of hum and other noises. We call that condition a "hanging hot", and we try to avoid it whenever possible.

Now I'm finished.   Any questions?

HTH!






sumgai

[instagvl]

Sumgai, thanks for the input! No worries about my cereal (I eat paleo anyway). This kind of feedback is what I was looking for when posting the diagram. I figured I had problems and that there were probably simpler solutions out there, or at least correct ones. I hear you on the selection of the push-button switches. I may swap to a set of toggle switches. Have to see what the 'shack has. I'm not too worried about the functionality overall, but being able to quickly see what position I am in is probably advantageous. 

You mentioned that I mislabeled the volume pot. Is that because, as wired, it would not function as a volume pot? Because I intended for it to do so.

So, knowing the functionality I am looking for (series, parallel, coil isolation, kill switch, solo "blast" circuit), could you suggest an alternate setup? The kill switch is not really needed, but I like the idea of it. Am I simply over thinking all of this? My goal from the start was to make use of the pre-drilled holes and give myself some options with a single humbucker. 

Thanks in advance for anymore advice you have for me. This has been educational.

[newey]

As sg correctly points out, your "solo blast" setting needs a DPDT switch to disconnect the pots.

Your volume pot is indeed a volume, what's throwing sg off was the same thing JohnH commented upon- the apparently series-wired treble bleed circuit. Look again at JohnH's link above, that's show you how to get the goods with the treble bleed.

So, if I went this direction, would I wire this ahead of, or behind, the DPDT? Does it matter?

Well, it's wired off of the DPDT, I don't know if you can characterize it as either ahead or behind it. I misspoke earlier when I said an On-On switch would do the trick- it won't, because then you'd always have it cut to one or the other coil, you'd have no position for the series HB.

To be able to have all three options, you need a three position switch, a SPDT On-Off-On. This would allow you to have the 3 positions select either the N coil or the S coil at either end, with the center "off" position giving you the series HB.

Follow this, redraw it, and we'll check your work.

1) The DPDT stays wired as is. The SPDT is an On-Off-On type. It will look just like your diagram, but will have a center switch position in which the center lug is disconnected from the other lugs.

2) The black wire, which is coming from the top two lugs of the DPDT, is currently wired to the upper lug of the SPDT switch. Move that wire to the center lug of the switch.

3) The ground connection, currently wired to the center, moves to either end lug of the switch, doesn't matter which one.

4) the other end lug which is the one not grounded at step 3 above, is wired to the "Hot" output (i.e., to the CW lug of the Vol. Pot

This will then give you both coils in series in the center position, N coil in one direction, S coil in the other. Your DPDT switches between Series/parallel when the SPDT switch is in the center postion, and switches between parallel and single coil (either N or S, depending)when the SPDT is not centered.

Sorry for any confusion about the required switches.

[instagvl]

Newey, thanks for the helpful info. I just got back from RS with two heavy duty ON-ON DPDT toggles. Now, based on SG's post, It sounds like perhaps I could take the footswitch DPDT and place it as the "pickup selector" switch, to act as a router between the "blast" function and the "multi-selecty V/T/Switches" function (SG said it would take a DPDT to make that happen right?). Then I can use one of the DPDT to choose between Series/Parallel and one to select between the N/S single coils? 

I'm happy to diagram out the suggestions from your post above, but as The Dude says, "New s%!$ has come to light, man."

What do you think?

Thanks!

[instagvl]

FWIW, here's the diagrams I found on 1728.org that I used when I put together the original diagram. In case they help:


Solo Circuit:


Treble Bleed


Series/Parallel/Coil Tap


Perhaps something erroneous in these has also tripped me up?

Edit: After looking these over again, the error seems to be mine on the Treble Bleed and Solo Circuits. Sloppy homework, my apologies in advance. 

[instagvl]

Hi again, I've been poking around elsewhere and I think I have a solution worked out. So, the left switch acts as a coil tap, the center as a series/parallel select, and the right as the solo switch. Parallel treble bleed between the V/T pots. Is this right? Thoughts? Thanks in advance!

[newey]

Looks good except your treble bleed should be wired across the Volume pot, from the center lug to the left hand lug.

[instagvl]

That had crossed my mind. Thanks again for all your help! I will update once I wrap up the soldering. Cheers!

[instagvl]

It works! Here's the finished product:




She screams! It's great! Thanks for all the help!

[newey]

Looks nice, instagvl! Glad you were able to get it working.

I have a soft spot for single-pickup guitars, as many of you know. Getting the maximum palette from a single HB has long been a goal of mine, and this set-up pretty near does that.

[instagvl]

Hi All, thanks again for all the assistance with the wiring. Now that I've had some time to run her through her paces and play with some big volume i'm noticing an INTENSE HIGH PITCH squealing. I've been reading around and it sounds like this is a microphonic pickup issue. I'd just like to know if this sounds right, or if there's perhaps something I'm missing. There is currently no shielding, could this be causing it (i'd think no, and shielding is normally aimed at fixing hum/RF interference, which I have no problems with)? How about the cavity in the guitar form where the neck pickup once resided? I pulled the cover off of the pickup in an attempt at a quick fix, in case it wasn't mounted properly, but it made no difference. I think I'm going to have to pull the pickup and pot it but I thought I'd check here to see if there's anything else I'm not thinking of. Something in the wiring? I don't know. Thanks in advance!

[newey]

Your analysis of the problem is correct- a microphonic pickup is a likely scenario.

With nothing electronic currently residing in the neck pickup routing, there's no possible noise source. If your thought there was that this was similar to feedback from an amplified guitar with soundhole(s), that's an acoustic feedback issue which your pickguard covering would eliminate. Also, acoustic feedback is highly directional, so you'd notice a change as you changed the position of the guitar. If this squeal doesn't vary as you move, a microphonic pickup is a better explanation.

As you note, shielding is aimed at RF hum, primarily. This doesn't sound like that, but we could certainly hypothesize some extraordinarily-noisy environment which might theoretically cause a high-pitched squeal. But this also would likely be highly directional, as 60-cycle hum is.

But before you go turning your kitchen into a waxy mess*, do some further experimentation (if you have not already done so):

1) Play this guitar through another amp
2) Play another guitar through the same amp (and cable, pedals, etc.) with which you heard the squeal.
3) Change out cables, take pedals out of the signal chain, essentially eliminate all other variables other than the guitar.
4) Take the entire rig, amp, guitar and all and move it to another room, and try it there. Make sure the electrical outlet in this other room is on a separate circuit breaker from the room in which you heard the squeal.

If you hear the squeal regardless of any of the above changes, you will have effectively eliminated environmental electrical noise as a culprit, which then heightens confidence that it's the pickup.

The sure-fire test is to substitute another pickup, but that's a lot of work. Understand that you may end up doing that anyway, as wax potting may help, but is not a cure-all for a microphonic pickup.

*Best to do this elsewhere if you can. If the kitchen is the only place, try to do it when the wife/girlfriend isn't around and use an old pot that you can throw away afterwards. There's a lot more to say about potting, as far as type of wax, etc. There are several good tutorials out on the web you can consult.

[instagvl]

Thanks for the reply. I feel confident that it's the pickup. I potted it last night using a 1-5 ratio of beeswax-paraffin. Lots of bubbles came out, which further increases my confidence that it was microphonic.

This pickup is from the early/mid-80's as best I can tell, so it probably needed it. I did notice that it was exchanging soem pretty black/gray wax with the new clean wax. Is this maybe from all the sweat/dirt/dust/grime of years of being played?

I wired it back in after it cooled and it's working through my practice amp at home. My big rig is out at the practice space so I'll have a chance to test it this afternoon during our (facebook.com/katvkmusic) run-through before a show this evening. If this doesn't fix the issue I'll be using my backup guitar, a Squier Vintage Modified Jaguar HH (which I love for the $ btw). I'll update later. Thanks again!

[newey]

Is this maybe from all the sweat/dirt/dust/grime of years of being played?

More likely a coating on the pickup winding wire that has aged its way to oblivion over three decades.

[instagvl]

OK. The potting doesn't seem to have worked. I tried a different amp and a different location. Also swapped out cables and went straight into the amp w/o the pedals. It's somewhat better, but it still pretty un-workable. Especially with the tube screamer on. I get no feedback with the same setup and my Squier '51 with a GFS Mean 90 in the bridge. Just a little bit with my Squier Jaguar with a Duncan Design JB in the bridge. Am I just not used to using a hotter pickup? Anything else worth trying? I'm thinking I may just purchase another pickup. 

[JohnH]

Is pickup still working OK though, so far as it did before? i was worried about the outcome of neweys idea about wire insulation!

And if it is acoustic related, it will vary with volume and position, and if you touch the pickup, it would change or stop.
And you should be able to do high volume but with lower gain.

If you damp the strings, does the pickup still ring?

[instagvl]

The pickup works as before. There is perhaps a small improvement. Moving around my practice space (fairly well sound-proofed 13x32' warehouse) with a 20' cable there is nowhere that the feedback won't occur, though it does seem to improve at certain areas, if only slightly. Touching the pickup makes no difference, same for damping the strings. Lowering the volume and gain do help. It will still occur at high volumes (Fender DeVille 212), but is substantially worse with the gain on, particularly with my tube screamer running.

Thanks for the input!