Dual Humbucker Experimentation Build

[autieblesam]

The plan for this build is to pack in features in a nice aesthetic package. My goal is to have a sort of jack-of-all-trades type guitar with the tradeoff that switching between configurations is relatively slow, i.e. this guitar is not meant for live performance, but is more suitable for just exploring differences in configurations as well as having more tonal range for recording and/or planning live performance. The ability to experiment is the main key for this one.

Starting with the body and neck:


Most of the decisions here are of course primarily aesthetic. I love the look of the black/brown/yellow finish on the mahogany. I am considering requesting custom finish on the neck, though I'm still on the fence on whether I want to match the black outside of the burst on the body, or the yellow inside.

The Jazzmaster is my favorite among the available body styles, but is also a functional decision as Warmoth offers both the blade and toggle switch on this guitar. These are essential for the electronics configuration:

Pickups

• Bridge: Seymour Duncan JB Standard - gold
• Neck: Lollar Imperial Standard - gold
• Black metal humbucker mounting ring

Switches

• Oak Grigsby 4P5T Super Switch
  • Position 1 (closer to neck): both pickups in series
  • Position 2: neck pickup in parallel; bridge pickup in series
  • Position 3: both pickups in parallel
  • Position 4: neck pickup in series; bridge pickup in parallel
  • Position 5: both pickups in series (Outside positions identical since I'm unable to find a viable 4P4T switch)
• Switchcraft 3-way toggle in standard configuration (bridge active; both active; neck active) - gold

Potentiometers

• 3x 500K concentric pots
  • Pot 1: top pot bridge tone; bottom pot neck tone
  • Pot 2: top pot neck volume; bottom pot neck pan
  • Pot 3: top pot bridge volume; bottom pot bridge pan
• 3x modern upper concentric knob - gold
• 3x moddern lower concentric knob - gold

Jack

• Pure Tone 1/4" output jack, stereo - gold
• Electrosocket jackplate - gold

Shielding

• Body routing: StewMac conductive shielding paint
• Routing covers: adhesive copper foil

String Hardware

• String ferules: gold
• Bridge: Gotoh Tune-O-Matic - gold
• Tuning pegs: Schaller M6 Locking Guitar Tuners, 6-In-Line Set, left - gold
• String retainers: barrel-style, pair - gold

Other

• Neck plate: gold
• Strap buttons: Schaller S-locks - gold

I don't have a wiring diagram, but the gist of the wiring is as follows, in order of where the wiring goes starting from the pickups (note for anyone new to wiring: I am using hot and output interchangeable and don't feel like editing everything to stay consistent):

• 4P5T super switch
  • The key to this one is that there are two wires per pickup that change connection based on whether they are in series or in parallel:
    • north end connects to south end in series
    • north end connects to ground in parallel
    • south end connects to north end in series
    • south end connects to output in parallel
    • north start always connects to output
    • south start always connects to ground
  • A mutual ground can be used, but each pickup will need its own hot to drive the stereo functionality
• 3-way toggle
  • Rudimentary wiring where position 1 connects neck to output, position 2 both, and position 3 bridge. The key to this one is that the two output lugs must stay separate to divide the pickup channels for stereo
• 500K concentric pot wired for tone
  • Each pickup gets its own tone knob with standard wiring: lug 1 is input hot, lug 2 is output hot, lug 3 connects to ground over 0.22µF capacitor
• 500K concentric pots for volume and pan (these will have identical wirings for neck and bridge)
  • Top pot: wired for volume over standard wiring: lug 1 is input hot, lug 2 is output hot, lug 3 shorts to ground. Both volume pots will be wired with a Kinman treble bleed circuit, but I haven't worked out the capacitor and resistor specs yet.
  • Bottom pot: wired for left/right channel pan: lug 1 left/mono channel hot to tip lug on jack; lug 2 input hot from volume; lug 3 right channel hot to ring lug on jack. Both left/mono channels will connect from each pan pot to tip lug, as will right channel to ring lug

I haven't decided if I want to work out trying to run one pickup in reverse—I need to look up if this will have the expected affect if the stereo output were to be run to a balanced TRS input.

I'm open to any feedback, especially from anyone who has experience configuring pan pots or if anyone happens to spot an incompatibility I've overlooked.

 

[JohnnyHardtail]

I have some comment about your electronics choice:
1) The Lollar imperial neck is quite low output as it has Alnico 2 magnet and it is very vintage sounding. I think a Duncan '59 would match better with the JB. Otherwise If you are after a premium-priced pickup have a look at Bare Knuckles. IMO they are probably more sutiable than the Lollar imperial if you are looking for rock oriented tones.
2) If it was me, I would definitely avoid the concentric pots. They feel very clumsy and difficult to use, but maybe it's just me!

 

[autieblesam]

I have some comment about your electronics choice:
1) The Lollar imperial neck is quite low output as it has Alnico 2 magnet and it is very vintage sounding. I think a Duncan '59 would match better with the JB. Otherwise If you are after a premium-priced pickup have a look at Bare Knuckles. IMO they are probably more sutiable than the Lollar imperial if you are looking for rock oriented tones.
2) If it was me, I would definitely avoid the concentric pots. They feel very clumsy and difficult to use, but maybe it's just me!

1) Thanks for the heads up. I was looking at sound samples for the imperials and liked that they had a very mild tone; I thought it might be a good complement to the surprisingly-mild-for-a-bridge-pickup JB. I could just raise the imperial closer to the strings, but it sounds like that might not work out as well as I'd hope. (Just to add, I was looking more at the clean sounds from the pickups over various types of distortion.) I'm not married to the pickups and will probably adjust. First steps will be acquiring the body and neck.
2) I anticipated this; this is part of what makes this guitar better suited to practice/experimentation over live performance—I expect the large feature set to make for some configuration changes that require more attention and may interrupt playing.

 

[Scab Pickens]

Keep in mind you will need long shaft pots for a rear route. I learned this the hard way. Long shaft concentric pots can be difficult, if not impossible, to find.

 

[autieblesam]

Keep in mind you will need long shaft pots for a rear route. I learned this the hard way. Long shaft concentric pots can be difficult, if not impossible, to find.

This is still an open concern—the only concentric pots that are both 500K that I've been able to find are the ones offered by Warmoth with 9.5mm depth on the threads. Do you happen to know the thickness of the hole on a rear-route?

Maybe I should just do top-route. The only thing I'd sacrifice would be the 24-fret extension:

 

[Scab Pickens]

This is still an open concern—the only concentric pots that are both 500K that I've been able to find are the ones offered by Warmoth with 9.5mm depth on the threads. Do you happen to know the thickness of the hole on a rear-route?

I don't know the exact thickness. Pots are installed already on the bodies I have (Diamondback and Tele), so can't measure. I do know that I was planning to use concentric pots on my (still in progress) rear route Tele and the ones from Warmoth will definitely not work. Saving them for a future project, I guess (2HB Floyd Hybrid Strat, perhaps ). Long shaft concentric pots might be available, I don't know. I gave up searching and moved on.

Maybe I should just do top-route. The only thing I'd sacrifice would be the 24-fret extension:

If you are stuck on the concentric pot idea, that might be your best option. You can still do a 24 fret neck as long as you are not planning on using a super thick pickguard ...

Number of Frets

Default Description

warmoth.com

 

[JohnnyHardtail]

I would consider other body styles and wood combinations. A solid mahogany jazzmaster is likely to weigh around 5 1/4 lb or more. I don’t know if the weight is a concern. I think the use of pickguard is an advantage for an “experimentation build” because it is possible change the control layout if you replace the pickguard.

As for pickups it’s not easy to find humbuckers that work well in alternate wiring configurations such as coil split or parrallel. The JB is a moderately high output pickup with strong mids so it would normally help to find a stronger neck pick to pair it with. The lollar imperial may be a good choice if you like clear and polite clean tones, although it was brighter than I anticipated. I personally wouldn’t match it with a JB. One thing I found with the Lollar imperial neck humbucker, is the slug coil is underwound compared to the screw coil. So if you want to use coil split wiring, it is better to select the screw coil IMO. I’m not sure if parrallel wiring would be successful due to the aspect of unbalanced coils.

 

[autieblesam]

If you are stuck on the concentric pot idea, that might be your best option. You can still do a 24 fret neck as long as you are not planning on using a super thick pickguard ...

Number of Frets

Default Description

warmoth.com

Warmoth states the 24-fret neck extension requires the neck pickup rout to be moved down the body a bit. This is not an option on the Jazzmaster pickguard or top-rout body, and this is routing visible enough that I would not be comfortable trying to perform this modification myself.

I would consider other body styles and wood combinations. A solid mahogany jazzmaster is likely to weigh around 5 1/4 lb or more. I don’t know if the weight is a concern. I think the use of pickguard is an advantage for an “experimentation build” because it is possible change the control layout if you replace the pickguard.

As for pickups it’s not easy to find humbuckers that work well in alternate wiring configurations such as coil split or parrallel. The JB is a moderately high output pickup with strong mids so it would normally help to find a stronger neck pick to pair it with. The lollar imperial may be a good choice if you like clear and polite clean tones, although it was brighter than I anticipated. I personally wouldn’t match it with a JB. One thing I found with the Lollar imperial neck humbucker, is the slug coil is underwound compared to the screw coil. So if you want to use coil split wiring, it is better to select the screw coil IMO. I’m not sure if parrallel wiring would be successful due to the aspect of unbalanced coils.

I'm not too worried about weight—for the most part, I'm not going to be moving a whole lot while playing and most of the initial use this guitar will see is going to be sit-down practice. That said, regarding your next point, I think I'm modifying my plan a bit in a way that makes the soloist body a viable option, which it looks like is a body style more people here tend to go mahogany with?

This information on the pickups is great. Pickups are the area where I'm still learning about and it seems there's a lot more complication to alternate wiring on these than I'd thought. I think maybe I should dial this plan back a bit to something more simple.

As far as the pickup type, I think I'm going to go with Alnico 2 pickups. The imperials have the best sound to my ears based on the provided samples, and I recently learned that the signature sound I prefer from specific GnR performances (most notably Slash's performance of the Godfather theme) are all done on Alnico 2 pickups. I also want something I can practice more classical and potentially even jazz genres on, as I suspect I'll be playing a lot of these genres when trying to refine technique—rock and metal are great and all, but I feel like they can seem more forgiving to unrefined technique during practice.

I'm avoiding coil-splitting specifically as I don't want to try to work out optimizing a mix of 250k and 500k pots.

 

[JohnnyHardtail]

There are a lot of Duncan humbuckers with Alnico 2 magnets. I used the APH-1 humbuckers and I liked both neck and bridge versions in a Strat, but ironically not in a set as they were intended. The bridge version is low wound, and it tends to be bright. So I used it with a 250k volume control, then later with two 500k controls and a 510k parrallel load resistor to smooth the top end brightness.

There are many others from Duncan that I have not tried including: APH-2 slash, Pearly gates, Antiquity, Seth Lover ‘55, Green Magic. Most of them will be relatively low output. The one I’m most interested to try is the Green Magic bridge pickup as it seems to be wound a bit hotter. I’m less sure about the Green Magic neck pickup because it is designed to be out of phase with other humbuckers unless you deliberately reverse the polarity by reversing connection or flipping the magnet polarity.

 

[kevin_guitars]

My 2 cents here is to do a rear route for the ability to make lots of alligator clip leads to test some of these experimental tones before committing with the solder and putting the pickguard on. A wiring scheme as complex as yours is somewhat of a nightmare to troubleshoot and dial in/tweak if it means having to remove strings and pickguard every time you want to do so. A rear route may mean some compromise/challenges to what types of pots based on length and diameter but it sure makes a difference if you can test your wiring with plucking real notes on a string vs. tapping the pickup with a screwdriver to listen for a 'click'

 

[Scab Pickens]

Warmoth states the 24-fret neck extension requires the neck pickup rout to be moved down the body a bit. This is not an option on the Jazzmaster pickguard or top-rout body, and this is routing visible enough that I would not be comfortable trying to perform this modification myself.

Sorry about that. I didn't realize the 24 fret option wasn't available on top route Jazzmasters. Should have done my research before posting.

 

[autieblesam]

Sorry about that. I didn't realize the 24 fret option wasn't available on top route Jazzmasters. Should have done my research before posting.

Nah, it's all good. That's what these forums are for, right? Crowdsourcing compatibility saves money and headache.

My 2 cents here is to do a rear route for the ability to make lots of alligator clip leads to test some of these experimental tones before committing with the solder and putting the pickguard on. A wiring scheme as complex as yours is somewhat of a nightmare to troubleshoot and dial in/tweak if it means having to remove strings and pickguard every time you want to do so. A rear route may mean some compromise/challenges to what types of pots based on length and diameter but it sure makes a difference if you can test your wiring with plucking real notes on a string vs. tapping the pickup with a screwdriver to listen for a 'click'

I think I can accomplish most of my testing with a second 1/4" jack. I can test my pots by running audio signal in one end and out the other to make sure they're doing what I expect (I can include the 3-way toggle since I'll have a pot set for each pickup, but I could also do this with 2 stereo jacks). Then once I get everything together, the remaining failure points are my 5-way switch and my pickups. I don't expect the much higher output of a pre-amped audio signal going through the pots to cause any damage (these are the same kind of pots that you use to adjust your pre-amp volume and tone in a standard guitar amplifier, though the wire gauge may be a little low for it), but I can run the audio through at a very low volume just to be safe. I also don't know how much signal would be enough to blow the capacitor.

That said, I think JohnnyHardtail makes some pretty strong points that this wiring scheme is a bit ambitious for a first-time build. I think I'm going to dial it back to standard LP-style wiring with more minor tweaks to tone and treble bleed over trying to do fancy stuff with pickup wiring. Jury's out on if I still want to try the stereo wiring; I'll have to see if I can find an example of 6 pots on a guitar and if it looks okay, but I can custom-drill the holes and plan for the ability to add a blade switch and two more pots after the fact.

That is to say, I think ultimately, I'm now working on a build that's not this one. I'll revisit this concept in the future, but right now, it's more important to me that I just get an upgrade over the cheap Carlo Robelli strat copy that I have on hand (the cost of servicing to make it playable at this point is at least 5x more than the guitar would be worth afterwards).

Thanks, everyone.

 

[autieblesam]

Something I found that might be interesting for anybody trying to do a pan setup similar to this:

• https://www.amazon.com/dp/B01KWJ1WNC/ - 250K
• https://www.amazon.com/dp/B01KWIX18C/ - 500K

The proper way to do a pan pot is with a balance-blend pot. CTS makes these in 250K and 500k with a linear taper and a center detent (perceivable bump at the center point when rotating). This will allow you to send signal to ground when panned away from that input, effectively muting that channel and preventing any bleed between left and right channels. I suspect I will be perfectly happy with the wiring scheme I outline in a previous reply, but for anyone who wants to completely eliminate that bleed, this is the way to go.

The required dual-pole setup to accomplish this will mean you probably can't find these in a concentric setup (or if they exist, they may not fit in your control cavity).

 

[xld]

2) If it was me, I would definitely avoid the concentric pots. They feel very clumsy and difficult to use, but maybe it's just me!

Absolutely! I couldn’t get them out of my build fast enough…