Nash JM Wiring

[jc808]

I have a Nash JM that is one of my fave guitars. But I have gone through several pickup changes on this guitar, just trying to find a config that works for me.

Every set of pickups I've tried have sounded quieter/duller than what I've expected. Even moving to 500k pots hasn't helped.

I finally splashed out for a set of Seymour Custom Shop '59 pickups. They're humbuckers that magically look like regular JM single coils and are drop-in replacements.

These have been especially disappointing because I have a set of '59s in a Tele style guitar that are perfect.

I'm starting to wonder if the unconventional "rhythm circuit" might be the culprit? Even when it's bypassed, the signal makes a round trip up there if I'm not mistaken. For those who don't know, Nash makes their rhythm circuit as more of a "preset" selector.

Before I go in for major surgery there, I wanted to check and see if I might be on the right track. I don't mind bypassing that circuit if it means restoring some "oomph" to this guitar. Just hate to do all that work for nothing.

[andy_tchp]

Nah. The neck pickup output only makes a 'round trip' via two terminals on a switch - It is already bypassed with the switch in the lead circuit position.

Though no idea what the 'preset selector' Nash implements is without seeing a diagram/explanation of what it actually does.

Jazzmasters are traditionally equipped with 1Meg pots, have you tried these? They shift the resonant peak up when compared with 500K or 250K and certainly aren't 'dull' when combined with single coil Jazzmaster pickups (often shrillness/harshness is a complaint, though it depends on which pickups/signal chain/amps are being used).

[jc808]

Nah. The neck pickup output only makes a 'round trip' via two terminals on a switch - It is already bypassed with the switch in the lead circuit position.

Though no idea what the 'preset selector' Nash implements is without seeing a diagram/explanation of what it actually does.

Jazzmasters are traditionally equipped with 1Meg pots, have you tried these? They shift the resonant peak up when compared with 500K or 250K and certainly aren't 'dull' when combined with single coil Jazzmaster pickups (often shrillness/harshness is a complaint, though it depends on which pickups/signal chain/amps are being used).

Right, that's on a traditional rhythm circuit. The Nash circuit works like this; you set the upper bout vol/tone where you want them, and flipping the switch up engages that "preset". It works across the bridge/middle/neck positions.

I've had JMs in the past with 1meg pots. They were a bit much for me. I like treble, but yikes.

[timtam]

Nah. The neck pickup output only makes a 'round trip' via two terminals on a switch - It is already bypassed with the switch in the lead circuit position.

Though no idea what the 'preset selector' Nash implements is without seeing a diagram/explanation of what it actually does.

Jazzmasters are traditionally equipped with 1Meg pots, have you tried these? They shift the resonant peak up when compared with 500K or 250K and certainly aren't 'dull' when combined with single coil Jazzmaster pickups (often shrillness/harshness is a complaint, though it depends on which pickups/signal chain/amps are being used).

Right, that's on a traditional rhythm circuit. The Nash circuit works like this; you set the upper bout vol/tone where you want them, and flipping the switch up engages that "preset". It works across the bridge/middle/neck positions.

I've had JMs in the past with 1meg pots. They were a bit much for me. I like treble, but yikes.

I haven't checked a Nash circuit directly, but wiring a JM like that - so that the rhythm circuit works on all pickups (instead of the just the neck) - does not change the route taken by the pickup signals when the rhythm circuit is not engaged - diagram below. I can't think of any way of wiring that which would involve a 'round circuit'. The standard JM circuit sends only the neck pickup to the lead/rhythm switch. The circuit below sends the output of the toggle switch there instead. But either way, when the lead/rhythm switch is OFF, no pickup signals go through the rhythm circuit. A gut shot of the Nash looks to be wired as in my diagram below ...
viewtopic.php?t=98811&start=60#p1394975



But if you suspect a wiring problem - either inherent or a fault - you could test-wire one or each pickup direct to the lead circuit volume pot. And if the problem is still there, wire the pickup direct to the output jack (admittedly then you won't have the pots' effect on lowering the Q factor (treble emphasis) of the pickup resonant peak* ... that effect is less on a regular JM because of the 1meg pots, but might convince you that changing your Nash's 500k to 1meg pots would send it more in the sonic direction you want). BTW I assume you've tried different downstream signal chains (eg the problem is not just something like a cable with very high capacitance, the pedal board, or the amp) ?
* http://www.buildyourguitar.com/resources/lemme/

[jc808]

Nah. The neck pickup output only makes a 'round trip' via two terminals on a switch - It is already bypassed with the switch in the lead circuit position.

Though no idea what the 'preset selector' Nash implements is without seeing a diagram/explanation of what it actually does.

Jazzmasters are traditionally equipped with 1Meg pots, have you tried these? They shift the resonant peak up when compared with 500K or 250K and certainly aren't 'dull' when combined with single coil Jazzmaster pickups (often shrillness/harshness is a complaint, though it depends on which pickups/signal chain/amps are being used).

Right, that's on a traditional rhythm circuit. The Nash circuit works like this; you set the upper bout vol/tone where you want them, and flipping the switch up engages that "preset". It works across the bridge/middle/neck positions.

I've had JMs in the past with 1meg pots. They were a bit much for me. I like treble, but yikes.

I haven't checked a Nash circuit directly, but wiring a JM like that - so that the rhythm circuit works on all pickups (instead of the just the neck) - does not change the route taken by the pickup signals when the rhythm circuit is not engaged - diagram below. I can't think of any way of wiring that which would involve a 'round circuit'. The standard JM circuit sends only the neck pickup to the lead/rhythm switch. The circuit below sends the output of the toggle switch there instead. But either way, when the lead/rhythm switch is OFF, no pickup signals go through the rhythm circuit. A gut shot of the Nash looks to be wired as in my diagram below ...
viewtopic.php?t=98811&start=60#p1394975





But if you suspect a wiring problem - either inherent or a fault - you could test-wire one or each pickup direct to the lead circuit volume pot. And if the problem is still there, wire the pickup direct to the output jack (admittedly then you won't have the pots' effect on lowering the Q factor (treble emphasis) of the pickup resonant peak* ... that effect is less on a regular JM because of the 1meg pots, but might convince you that changing your Nash's 500k to 1meg pots would send it more in the sonic direction you want). BTW I assume you've tried different downstream signal chains (eg the problem is not just something like a cable with very high capacitance, the pedal board, or the amp) ?
* http://www.buildyourguitar.com/resources/lemme/

Thanks for all that.

I also sent this question to Nash. They replied pretty quickly: "Hi jc808, the pickups first go to the two way toggle switch, so I believe the circuit that is not selected should be fully bypassed. Hope that helps! -Taylor "

Not a resounding confirmation, but it does coincide with the diagram you sent and what I'm seeing in the guitar.

I'll try a 1 meg pot. I've never had to go that high with humbuckers, but first time for everything I guess.

Thanks again!