Jazzmaster tone knob hum

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DrPete
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Jazzmaster tone knob hum

Post by DrPete » Thu Sep 27, 2018 6:02 am

I'm quite proud to say that I upgraded the wiring of my CIJ Jazzmaster myself! New AVRI grade pots and wiring. Very happy.

One issue though - when the tone is at 10 there is no hum. But if I back if off from ten, a hum appears.

What might be the reason for this?

Cheers!

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timtam
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Re: Jazzmaster tone knob hum

Post by timtam » Thu Sep 27, 2018 6:32 am

Which wiring diagram did you use ?
"I just knew I wanted to make a sound that was the complete opposite of a Les Paul, and that’s pretty much a Jaguar." Rowland S. Howard.

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DrPete
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Re: Jazzmaster tone knob hum

Post by DrPete » Thu Sep 27, 2018 9:24 am

timtam wrote:
Thu Sep 27, 2018 6:32 am
Which wiring diagram did you use ?
I didn't use any. I bought a loaded pickguard with the wiring attached. I just copied the pickup soldering from the japanese wiring... is there a diagram you'd recommend?

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timtam
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Re: Jazzmaster tone knob hum

Post by timtam » Thu Sep 27, 2018 5:41 pm

Here's a vintage style JM wiring diagram ...
https://www.fmicassets.com/Damroot/Orig ... A_SISD.pdf

So you get normal sound, and the pots work the way they should, except for the extra hum when you wind down the tone pot ?

If you remade the final pickup wire solder point locations (rather than splicing existing wires mid-length) I'd check those first to ensure they are in the right place. Assuming the loaded pickguard is correctly wired, I'd then be looking for shorts around the tone pot, between tabs, or the capacitor, for example. If the guitar is shielded, check for shorts to the shielding (is the hum still there when the pickguard is off the guitar ?).
"I just knew I wanted to make a sound that was the complete opposite of a Les Paul, and that’s pretty much a Jaguar." Rowland S. Howard.

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DrPete
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Re: Jazzmaster tone knob hum

Post by DrPete » Sat Sep 29, 2018 4:24 am

Thank you that is great!

I've just ordered some Vintage 65 PUs, so I'll have a look at it again once they come.

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DrPete
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Re: Jazzmaster tone knob hum

Post by DrPete » Fri Oct 26, 2018 3:38 am

An update in case anyone is searching for the same issue in the future.

I bought a set of Vintage 65s PUPs and wired them up but I had an issue straight away. Clean, the JM sounded fantastic. Distorted there was ALMIGHTY hum and weird echo-y noises.

So I opened it again and after a few re-wiring tests, I found that my original idea to ground the bridge pickup to the bridge tone and the rhythm pickup to rhythm tone just didn't seem to be working. So, I ground both pickups to the bridge volume knob and hey-presto it sounds FANTASTIC. There is now no issue with any combination of sounds.

Of course it's perfectly possible that my original soldering sucked, but after grounding both to the bridge volume pot, it works a treat. Great sounds too.

EDIT: I used this wiring diagram https://www.fmicassets.com/Damroot/Orig ... 0-2016.pdf

I had used others, but I was still having issues. The grounding in the diagram above worked for me.

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