Wired my First Jazzmaster Today

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Bradley-Jazz
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Re: Wired my First Jazzmaster Today

Post by Bradley-Jazz » Thu Oct 08, 2020 11:54 am

The bracket is probably too big to get hot enough to get a good solder joint. Connecting to the back of the pot is easier. Bolting each pot to the bracket makes electrical contact so you only need to put the ground wire to one of the pots.
Stop me if you think you've heard this one before....

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j mascis
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Re: Wired my First Jazzmaster Today

Post by j mascis » Thu Oct 08, 2020 12:07 pm

Bradley-Jazz wrote:
Thu Oct 08, 2020 11:54 am
The bracket is probably too big to get hot enough to get a good solder joint. Connecting to the back of the pot is easier. Bolting each pot to the bracket makes electrical contact so you only need to put the ground wire to one of the pots.
Ah thanks. I thought someone said earlier not to ground to them.
So two issues I made the thread about are good now, but now on the rhythm circuit the volume and tone both control volume. i.e. if I turn the tone down, the volume goes down. This was maybe true before but got lost with the other issues. It seems to be the last issue. This rhythm circuit is giving me fits. Double checked the wiring, and it looks right. It has to be something with the ground. I have a black ground wire coming out of the far right volume pot lug and it grounds to the bracket. In that same lug the cap is in there. Is that wrong?

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Re: Wired my First Jazzmaster Today

Post by Bradley-Jazz » Thu Oct 08, 2020 1:16 pm

I have a black ground wire coming out of the far right volume pot lug and it grounds to the bracket. In that same lug the cap is in there. Is that wrong?
That sounds fine, as long as the bracket is grounded (via the physical connection to the pot body, then back to the lead circuit pot). Check continuity with a meter from there to the sleeve of the output jack.
the rhythm circuit the volume and tone both control volume
This thread seems to been that very issue: https://www.tdpri.com/threads/jazzmaste ... me.664136/

This is getting beyond my knowledge, but the suggestions seem to be that one of the tone pot lugs is accidentally grounded, or (more likely?) that using the 1M pot for tone means that the cap is not now big enough in value, so too wide a spectrum of the signal is grounded when you turn down the tone, effectively dropping the volume. So, check wiring on the tone pot and if in accordance with the diagram, try higher value caps...?
Stop me if you think you've heard this one before....

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Re: Wired my First Jazzmaster Today

Post by j mascis » Thu Oct 08, 2020 1:28 pm

Bradley-Jazz wrote:
Thu Oct 08, 2020 1:16 pm
I have a black ground wire coming out of the far right volume pot lug and it grounds to the bracket. In that same lug the cap is in there. Is that wrong?
That sounds fine, as long as the bracket is grounded (via the physical connection to the pot body, then back to the lead circuit pot). Check continuity with a meter from there to the sleeve of the output jack.
the rhythm circuit the volume and tone both control volume
This thread seems to been that very issue: https://www.tdpri.com/threads/jazzmaste ... me.664136/

This is getting beyond my knowledge, but the suggestions seem to be that one of the tone pot lugs is accidentally grounded, or (more likely?) that using the 1M pot for tone means that the cap is not now big enough in value, so too wide a spectrum of the signal is grounded when you turn down the tone, effectively dropping the volume. So, check wiring on the tone pot and if in accordance with the diagram, try higher value caps...?
Thanks. I used a higher .047 cap in there figuring it would have to be higher, but looking through my caps it's the highest value I have. They suggest .068. Darn.

The wiring on the tone pot looks correct. On the multi-meter, the tone pot in the rhythm circuit shows a ground to the jack/input. So does the volume pot in the rhythm circuit. Both also have continuity.

So does this eliminate the issue down to cap value?

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Re: Wired my First Jazzmaster Today

Post by Bradley-Jazz » Thu Oct 08, 2020 1:38 pm

So does this eliminate the issue down to cap value?
Well its very hard to say for sure, but looks that way. You can link caps in parallel (if you have the physical space) to increase the effective value - so do you have a .022 you can put in parallel with the .047?

https://www.allaboutcircuits.com/textbo ... apacitors/
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Re: Wired my First Jazzmaster Today

Post by j mascis » Thu Oct 08, 2020 1:40 pm

Bradley-Jazz wrote:
Thu Oct 08, 2020 1:38 pm
So does this eliminate the issue down to cap value?
Well its very hard to say for sure, but looks that way. You can link caps in parallel (if you have the physical space) to increase the effective value - so do you have a .022 you can put in parallel with the .047?

https://www.allaboutcircuits.com/textbo ... apacitors/
Ah! yes I do have a bunch of .022s. I will try that. Does it matter if they're different voltages?
How do you actually connect them, solder?

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Re: Wired my First Jazzmaster Today

Post by j mascis » Thu Oct 08, 2020 2:43 pm

timtam wrote:
Thu Oct 08, 2020 3:22 am
The volume pot tab and the end of the cap are usually grounded together, as shown here. But it's one of those little connections that is almost hidden - you'll miss it if you don't know that it must be there somewhere. The black wire is a ground wire that grounds the roller plate/pot bodies, and then there's a little grey wire from there to the bottom tab of the volume control, where the cap also attaches.
Just reading back on the thread to see if I missed something. So I don't have a small grey wire as mentioned in this post ^.
I have the volume pot far right lug with a capacitor in it, and also a small black wire in it that goes to ground on the bracket. Where would the small grey wire connect?

This is so frustrating because I know I'm 99% there, and this is probably something stupid and simple. : :(

I'm attaching some images via imgur. https://imgur.com/a/ZC2NOGn
I grounded to the bracket, though it's not a great connection IMO, and I'd like to redo that somewhere else. In the second photo, that black wire on the right is also on the bracket, and it goes to the main circuit volume pot for ground. Does anything there look wrong? I know it's all white wires (all I had were black and white) and therefore confusing, but I checked the wiring about 10 times, and those are correct, so it has to be something with the cap, ground, etc, I think. Where in this photo should the grey wire you mention be connected?

Thanks, guys!

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Re: Wired my First Jazzmaster Today

Post by timtam » Thu Oct 08, 2020 7:57 pm

j mascis wrote:
Thu Oct 08, 2020 2:43 pm
timtam wrote:
Thu Oct 08, 2020 3:22 am
The volume pot tab and the end of the cap are usually grounded together, as shown here. But it's one of those little connections that is almost hidden - you'll miss it if you don't know that it must be there somewhere. The black wire is a ground wire that grounds the roller plate/pot bodies, and then there's a little grey wire from there to the bottom tab of the volume control, where the cap also attaches.
Just reading back on the thread to see if I missed something. So I don't have a small grey wire as mentioned in this post ^.
I have the volume pot far right lug with a capacitor in it, and also a small black wire in it that goes to ground on the bracket. Where would the small grey wire connect?

This is so frustrating because I know I'm 99% there, and this is probably something stupid and simple. : :(

I'm attaching some images via imgur. https://imgur.com/a/ZC2NOGn
I grounded to the bracket, though it's not a great connection IMO, and I'd like to redo that somewhere else. In the second photo, that black wire on the right is also on the bracket, and it goes to the main circuit volume pot for ground. Does anything there look wrong? I know it's all white wires (all I had were black and white) and therefore confusing, but I checked the wiring about 10 times, and those are correct, so it has to be something with the cap, ground, etc, I think. Where in this photo should the grey wire you mention be connected?

Thanks, guys!
From your pics, it looks like the short black wire from the bracket to the mini vol pot tab is performing the role of the short grey connection in the diagram - grounding the bottom lug of the volume pot and the tone cap (as long as the bracket itself is grounded).

The only other thing that could be playing into your issues is the fact that the rhythm circuit and lead circuits are not wired the same in the stock circuit. So even though you now have all 1meg pots in both, they're still wired differently. Fender never explains why they did it this way. The difference between the two is clearest on a JM schematic - volume pot comes off the tone pot wiper in the rhythm circuit but not in the lead circuit ...
Image

There are a few JM wiring diagrams floating around that have the rhythm circuit wired differently. Like this somewhat rare one from SD (most SD JM diagrams show the common Fender wiring). I have seen the difference described as "rhythm circuit tone pot wiring swapped to prevent VOL roll off with tone roll off". Sounds exactly like your description "if I turn the tone down, the volume goes down". ;)
Image

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Re: Wired my First Jazzmaster Today

Post by j mascis » Thu Oct 08, 2020 8:41 pm

timtam wrote:
Thu Oct 08, 2020 7:57 pm
From your pics, it looks like the short black wire from the bracket to the mini vol pot tab is performing the role of the short grey connection in the diagram - grounding the bottom lug of the volume pot and the tone cap (as long as the bracket itself is grounded).
Oh okay, cool. The bracket is grounded.
Here is a full image of how I wired it: https://imgur.com/a/RfMjmGe
You can enlarge it to see details here: https://i.imgur.com/RmrEz47.jpg.

The lead circuit has 500k pots and WRHBs with .022 cap. I wanted the Rhythm circuit to be different and thought this would be cool to have a brighter circuit and then use the tone knob to shape it.
The only other thing that could be playing into your issues is the fact that the rhythm circuit and lead circuits are not wired the same in the stock circuit. So even though you now have all 1meg pots in both, they're still wired differently. Fender never explains why they did it this way.
Wow. That's crazy. So you're essentially saying you have to keep it as a 50k pot for it to roll of tone?
Do you think there could be anything to what the guy on TDPRI said in the thread someone linked above:

Did the tech also transplant the tone cap?
...if they did, the old cap value may not be 'enough' to be shaping the tone with the new 1M pot...
50k pot and (for example) 22nF cap (marked 223) rolls frequencies off down to roughly 144Hz (if my spreadsheet doo-hickey is correct).
The same 22nF cap with a 1M tone pot rolls off down to 7Hz - big difference.
To give a similar tonal range, you'd need a new 0.68nF cap (marked 682).


If you read the full thread, his tech did his wiring, and he came home with the exact same issue:
https://www.tdpri.com/threads/jazzmaste ... me.664136/

This is fascinating thanks for the help and discussion on it. This is literally the first time I wired a guitar, so this is all enlightening.

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Re: Wired my First Jazzmaster Today

Post by timtam » Fri Oct 09, 2020 5:49 am

Anytime you adjust values of stock components you raise the possibility of unintended effects. A JM is a hard guitar to have as your first wiring job, let alone with adjusted pot values. ;)

Assuming you had the same components in both the rhythm and lead circuits, and they were wired the same, the sonic effects should of course be the same. So your modified rhythm circuit tone pot should get you the sound/function like a 1meg/0.02uF lead circuit would, if Fender wired them identically. But the way they have it wired is indeed probably specific to the stock 50k tone pot.

The TDPRI discussion you linked failed to realize the lead vs rhythm circuit (ie wiring) differences. This other TDPRI guy's testing suggests that there is both the volume effect and a sonic difference between the two ways of wiring the rhythm circuit if you keep the original 50k tone pot (the 'different' one he describes as 'modern' is the SD circuit above, although he mistakenly says the AVRI62 uses it ... I am not sure that Fender has ever used it, but I haven't checked every circuit).
https://www.tdpri.com/threads/jazzmaste ... on.516890/

So your volume loss issue should probably be fixed by changing the rhythm circuit to the SD wiring (similar to the lead circuit wiring). Changing the rhythm cap value shouldn't be necessary. At best, you should be left with just some treble loss when winding down the volume, same as most volume controls without a treble bleed.

Looking at your new pic, the only obvious thing I notice is that the 'hot' leg of the uninsulated lead circuit cap looks very close to the grounded body of the tone pot - so you're risking a short there, that would stop that tone circuit working. Always best to insulate long cap legs, or cut them very short.

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Re: Wired my First Jazzmaster Today

Post by j mascis » Fri Oct 09, 2020 6:43 am

timtam wrote:
Fri Oct 09, 2020 5:49 am
So your volume loss issue should probably be fixed by changing the rhythm circuit to the SD wiring (similar to the lead circuit wiring). Changing the rhythm cap value shouldn't be necessary. At best, you should be left with just some treble loss when winding down the volume, same as most volume controls without a treble bleed.

Looking at your new pic, the only obvious thing I notice is that the 'hot' leg of the uninsulated lead circuit cap looks very close to the grounded body of the tone pot - so you're risking a short there, that would stop that tone circuit working. Always best to insulate long cap legs, or cut them very short.
Thanks. I'm going to try this today.

That leg was actually laying on the pot - glad you saw that. Somehow it wasn't shorting. I don't have any insulation unless I can use electrical tape - would that work? Thanks for all the help. Yeah this sucked as a first wiring, but I've been building this guitar since 2018 and wanted to hear it, and my tech wanted $120 to wire it. So all that was motivation! I'm bummed I got 95% of what I wanted then failed. Hopefully that SD wiring fixes the last issue.

The good thing is any other wiring should be very easy now.

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Re: Wired my First Jazzmaster Today

Post by j mascis » Fri Oct 09, 2020 8:41 am

TimTam, that SD diagram works!

The tone now changes the tone while keeping the volume. Awesome.
The only issue is the sweep is really crappy. It goes from very bright to mud fairly fast...you have to barely move the roller wheel it in the middle range of the wheel to get different tones. Do you think the .068 cap would fix this? Or is just the nature of linear pots?

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Re: Wired my First Jazzmaster Today

Post by HarlowTheFish » Fri Oct 09, 2020 10:16 am

j mascis wrote:
Fri Oct 09, 2020 8:41 am
TimTam, that SD diagram works!

The tone now changes the tone while keeping the volume. Awesome.
The only issue is the sweep is really crappy. It goes from very bright to mud fairly fast...you have to barely move the roller wheel it in the middle range of the wheel to get different tones. Do you think the .068 cap would fix this? Or is just the nature of linear pots?
Changing the cap can give you more usable range, because while you're cutting the same amount of treble, the frequencies you're cutting are different. Linear pots will give you a less drastic cut, if anything, from the top of the range to 50%, but more from 50% to 0. I'd try a smaller cap (I think smaller caps give less treble cut? somebody please fact-check me here) to see if it gives you more favorable results.

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Re: Wired my First Jazzmaster Today

Post by Bradley-Jazz » Fri Oct 09, 2020 10:33 am

The sweep is a function of the pot taper, but if the tone off is too dark, a lower cap value will help with that, so, yes try that. The previous discussion on cap values was based on the idea of this being wired like the stock rhythm circuit with different pots (and maybe that TDPRI link wasn’t helpful - sorry! ;D ). What you have now is like the standard lead circuit, so lead circuit cap values (0.02 or even less) can work well. This may also make the pot sweep more usable as the overall treble-reducing effect of the pot will be reduced so the effect may sound to be be more spread out, if that makes sense.

From memory, I have a 0.015 cap with the 1Meg pots in the lead circuit on my JM.
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Re: Wired my First Jazzmaster Today

Post by j mascis » Fri Oct 09, 2020 11:12 am

Thanks. Just to get more accurate feedback on cap values...

1. The guitar has WRHBs in it.

2. In the main circuit I have 500k pots with a .022 cap.

3. In the rhythm circuit, I have two 1meg pots with a .047 cap. (it sounds almost identical to the main circuit neck pickup, but I can now roll off tone and get a more mellow sound, which is how I have it set up).

I'm open to any ideas. It sounds great, everything functions as it should, and dead quite. But not a huge difference between the circuits on neck pickup.

However, that static issue is back, and it seems to be coming from the pickups (I tapped them with a screwdriver and hear a static "click" or "pop" through my amp - is it possible they picked up a charge while working on the harness? I had the entire harness on my carpet while working on it. I'm wondering if that's what happened, kind of like how we pickup charges walking on carpet. If so, is there any way to dissipate the charge from them? If it hit chords hard I hear it more than if gently picking notes. It's strange. I'm reading online to use dryer sheets, but I don't have any. Is there any other option?

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