Back to Passive J: My first wiring diagram!

[chapito]

Hi Guys,
This is my first mod. Ive been reading up for the past couple months in prep for this build. I’m wiring up my 74 Jazz V/B/T with:

Fralin Split Js (+5%),
series/parallel (push-pull pot),
ungrounded Blend pot,
2 switchable caps (push-pull pot),
killswitch (basically a “quick-mute")

I’ve put together the following diagram from an amalgam of other diagrams. (Thanks, you amazing group of TBers!!) I’d like to get your advice/feedback in general, and specifically…

I'm running the tone into the volume (instead of after the vol). I’d like to keep the wiring as minimal as possible, can I wire the tone pot to the blend pot (see diagram—dotted line) or does it have to go direct to the volume pot?

and I should be grounding the Vol pot to the casing, right? (not shown on diagram)

[line6man]

Your capacitance switch and killswitch are overcomplicated. You should only be using one pole to minimize switch pop, and the possibility of failure.

The tone control already is wired to the blend pot.

[SGD Lutherie]

Right, keep the one side of both caps grounded, or you will get pops. Use a SPDT switch, or one half of the DPDT.

The kill switch should be shorting the output to ground, not leaving it open, or you will likely get hum when you have the signal muted.

[chapito]

Hi line6man,
long time reader first time poster…

will do on the cap/kill switches. —so the caps can terminate on to the casing for ground. cool.

sorry for the misleading question about the tone lead. I’m still trying to figure out the best route for the tone lead. I originally wired the tone to the vol pot but noticed it could go to the blend (dotted line). Are there any negative implications to wiring via the blend pot vs. direct to vol pot?

[SGD Lutherie]

The tone control should connect the amp side of the volume control. That will prevent the change in volume from affecting he tone control.

[chapito]

Originally Posted by SGD Lutherie

Right, keep the one side of both caps grounded, or you will get pops. Use a SPDT switch, or one half of the DPDT.

The kill switch should be shorting the output to ground, not leaving it open, or you will likely get hum when you have the signal muted.

Hi SGD Lutherie
Thanks. so would I take the
Vol out (center lug) to killswitch
killswitch “push” to output (single throw)
killswitch “pull” to ground (single throw)

[line6man]

Originally Posted by chapito

Hi line6man,
long time reader first time poster…

will do on the cap/kill switches. —so the caps can terminate on to the casing for ground. cool.

sorry for the misleading question about the tone lead. I’m still trying to figure out the best route for the tone lead. I originally wired the tone to the vol pot but noticed it could go to the blend (dotted line). Are there any negative implications to wiring via the blend pot vs. direct to vol pot?

There is not a difference. Electrically, both methods are the same, unless you were considering wiring the tone pot to the output of the volume pot, in which case, the capacitor would see a variable impedance as the volume is adjusted.

There are many ways to physically wire what is electrically identical. If it is easier to run the tone pot to the blend than to the volume, you can do that.

[SGD Lutherie]

Originally Posted by chapito

Hi SGD Lutherie
Thanks. so would I take the
Vol out (center lug) to killswitch
killswitch “push” to output (single throw)
killswitch “pull” to ground (single throw)

Look at the Duncan diagram. The tone control should attach to the output of the volume control. Not on the blend pot (input) side.

The kill switch is wrong. It should be grounding the output, not disconnecting the volume pot.

I Googled and found this. Something like this will work fine. It can be a momentary switch or a latching type. If you are using a switch just to mute the signal, I'd just turn down the volume control.

[chapito]

thanks for clearing that up. I’d like to keep the control plate as clean as possible so its nice to know I can run a short lead.

I noticed the Basslines™ diagram above shows the output to the Tone center lug, whereas other diagrams on TB (where the tone is before the Vol) show the cap at the center lug.

I’m curious, are the tone leads correct?

[line6man]

Originally Posted by chapito

thanks for clearing that up. I’d like to keep the control plate as clean as possible so its nice to know I can run a short lead.

I noticed the Basslines™ diagram above shows the output to the Tone center lug, whereas other diagrams on TB (where the tone is before the Vol) show the cap at the center lug.

I’m curious, are the tone leads correct?

Again, it makes no difference. Neither the capacitor nor the pot have any polarity in the circuit.

[chapito]

Originally Posted by SGD Lutherie

Look at the Duncan diagram. The tone control should attach to the output of the volume control. Not on the blend pot (input) side.

The kill switch is wrong. It should be grounding the output, not disconnecting the volume pot.

I Googled and found this. Something like this will work fine. It can be a momentary switch or a latching type. If you are using a switch just to mute the signal, I'd just turn down the volume control.

So, I would wire the spdt to connect the tip to the ground of the jack basically isolating the rest of the jack from the rest of the control plate.


I wanted to try the tone-before-vol after reading a post by walterw. He described the concept,

with the V/BL/T, the tone can be wired to the input to the volume along with the pickups. this allows both the volume and the tone to remain consistent in their behavior no matter where the other is set.

combine this with a linear volume and the "unloaded blend" thing, and you've got way smoother control of volume, tone and blend.

I tried to draw it up. I’m sure I misunderstood something.


Killswitch:
I want the mute for stage and pit work where the FOH has a DI, that way when Im switching instruments—I can keep the same vol, quickly switch and avoid any string noise in the stand. Sometimes i just use a stomp box tuner, but I always think it would be nice to have one on board.

[chapito]

Originally Posted by line6man

Again, it makes no difference. Neither the capacitor nor the pot have any polarity in the circuit.

ah ha! Im learning~

[SGD Lutherie]

Originally Posted by chapito

Killswitch:
I want the mute for stage and pit work where the FOH has a DI, that way when Im switching instruments—I can keep the same vol, quickly switch and avoid any string noise in the stand. Sometimes i just use a stomp box tuner, but I always think it would be nice to have one on board.

Look at your kill switch wiring, and the image I posted. You are switching he output. Just leave it attached and switch it to ground.




Make sure you wire the blend up the right way. You need to measure the resistance between the center and the two outside terminals to determine which side goes to hot, and even though you aren't grounding the blend, you have to have the right side left floating.

What you want to look for is the side with a resistance close to zero is the hot, and the side with closed to the full resistance of the pot is the ground side, assuming you use an M/N taper pot.


Like this:


But you have to check, because they are all different. This was for a Bourns blend pot.

I never play with my volume on less than 10. I only use my volume control to mute the bass. The FOH sound guy is expecting the level to be the way it was when he did a sound check.

[chapito]

strike three with the killswitch!
I have to laugh at myself, wired the switch every which way but right! Thanks for the visual, I get it now.

I actually used that blend example from a previous post to test it! Thanks for the heads up!


Hey, Happy New Year everybody!

[SGD Lutherie]

I'd still wire the tone control to the volume pot. If you have ever wired up a few blend controls you will find they are very cramped. You do not want to add any extra wires. There's no point in wiring the tone to the blend pot since the same wire from the blend goes to the volume pot.

Seymour also did it that way for a reason. Trust us, we have been wiring stuff for a while now.

[chapito]

opps forgot the tone lead. (thank god Im not a surgeon)
thanks!