Jmjm 2019 electronics upgrade

For help with setups and other technical issues.
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metsam
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Jmjm 2019 electronics upgrade

Post by metsam » Mon Aug 10, 2020 12:24 am

Hey there,

Thinking to replace my jmjm's electrics :w00t:

Anybody has a list of what is inside so I can order the lot and then remove the pickguard, once?

Thinking of getting same value pots etc, and replacing the switches, especially the 3 way switch off the lead circuit.

Also open to alternative suggestions, thank you in advance for your time!

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timtam
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Re: Jmjm 2019 electronics upgrade

Post by timtam » Mon Aug 10, 2020 1:42 am

Are you having issues with the switch or other components ? By all means replace any that are causing problems. But otherwise there's not much to be gained by a like-for-like swap. Resistance is resistance. Capacitance is capacitance. Alternative log pot tapers are available (only the lead tone pot is log/10% in a JM) but generally you want to know what taper you're after if you're picky about those. You could replace the uninsulated conductors with all shielded wiring. But it's difficult to predict any likely change in the noise floor given the existing pickguard shielding and cavity shielding paint. This is the 3way toggle used by Fender ...
https://darrenriley.com/store/fender-ja ... 053694000/

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"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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jvin248
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Re: Jmjm 2019 electronics upgrade

Post by jvin248 » Mon Aug 10, 2020 4:39 am

.

Do you love the tone of the guitar as it is?
Are you swapping pickups (for style or tone)?
Are you editing the circuit so you have more/less functionality than currently?
Are the parts worn out and just need replacement?

Pots 'n Caps can push your guitar's tone around as much as swapping pickups, for 1/10th the cost, so keep that in mind. If you love the guitar's current tones then getting random parts may move you somewhere you don't want to go. Therefore, take the pickguard off and measure all the pots and caps plus measure the pickups. "Blueprint" what you have so when you get new stuff you know if you are nudging it into something different or not. Include pickup height measurements if you are swapping pickguards.

Example: volume pots have a 20% tolerance range. If it says "500k" then it may actually measure 450k to 550k -- and those end points make a guitar sound dark to bright. Just like you may inherently know what "250k" vs "1Meg" can change a guitar's output tones.

.

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metsam
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Re: Jmjm 2019 electronics upgrade

Post by metsam » Mon Aug 10, 2020 10:20 pm

timtam wrote:
Mon Aug 10, 2020 1:42 am
Are you having issues with the switch or other components ? By all means replace any that are causing problems. But otherwise there's not much to be gained by a like-for-like swap. Resistance is resistance. Capacitance is capacitance. Alternative log pot tapers are available (only the lead tone pot is log/10% in a JM) but generally you want to know what taper you're after if you're picky about those. You could replace the uninsulated conductors with all shielded wiring. But it's difficult to predict any likely change in the noise floor given the existing pickguard shielding and cavity shielding paint. This is the 3way toggle used by Fender ...
https://darrenriley.com/store/fender-ja ... 053694000/

Image
What I really want to do is to shield the pickguard and replace the 3 way switch. It feels sloppy, at least in comparison to my VM's 3 way switch. Every time I use it, it makes a big clicky sound and the whole shield vibrates, like if I would hit the pickguard with something! :/

Thanks for your answer! :)

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metsam
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Re: Jmjm 2019 electronics upgrade

Post by metsam » Mon Aug 10, 2020 10:21 pm

jvin248 wrote:
Mon Aug 10, 2020 4:39 am
.

Do you love the tone of the guitar as it is?
Are you swapping pickups (for style or tone)?
Are you editing the circuit so you have more/less functionality than currently?
Are the parts worn out and just need replacement?

Pots 'n Caps can push your guitar's tone around as much as swapping pickups, for 1/10th the cost, so keep that in mind. If you love the guitar's current tones then getting random parts may move you somewhere you don't want to go. Therefore, take the pickguard off and measure all the pots and caps plus measure the pickups. "Blueprint" what you have so when you get new stuff you know if you are nudging it into something different or not. Include pickup height measurements if you are swapping pickguards.

Example: volume pots have a 20% tolerance range. If it says "500k" then it may actually measure 450k to 550k -- and those end points make a guitar sound dark to bright. Just like you may inherently know what "250k" vs "1Meg" can change a guitar's output tones.

.
Thanks you for the tip!

Useful to know! :)

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Re: Jmjm 2019 electronics upgrade

Post by Debaser » Sat Aug 15, 2020 7:28 am

metsam wrote:
Mon Aug 10, 2020 10:20 pm
What I really want to do is to shield the pickguard and replace the 3 way switch. It feels sloppy, at least in comparison to my VM's 3 way switch. Every time I use it, it makes a big clicky sound and the whole shield vibrates, like if I would hit the pickguard with something! :/

Thanks for your answer! :)
I also don't think you have much to gain by replacing every component, value for equal value. I get it though, I've been there and done the same for my VMJM, for AV-level Switchcraft and CTS components, only because I wanted to and I was doing a pickup swap anyways.

First thing, the pickguard is the shield, no additional shielding needed. If you want to up the game, then copper foil on the cavities is the only true upgrade.

Second is the switch. The VM has a short toggle, and I don't care for it. I'd get a Switchcraft L-shaped switch and be done with it, IMHO. Is the big click sound coming through the amplified signal? Or is it just mechanical noise? Probably both, but it's part the nature of the beast: the ano guard will amplify the acoustic sound. Better grounding might help (is there enough anodized finish removed around the switch?) the amplified click but nothing you can do about the acoustic click other than switch to a plastic guard. You could make a 'fiber washer' out of thin cardstock too, one that follows the shape of the current switch, and that could damper some of the mechanical click.

Hope that helps!
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Embenny
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Re: Jmjm 2019 electronics upgrade

Post by Embenny » Sat Aug 15, 2020 9:40 am

Debaser wrote:
Sat Aug 15, 2020 7:28 am
First thing, the pickguard is the shield, no additional shielding needed. If you want to up the game, then copper foil on the cavities is the only true upgrade.
...
Better grounding might help (is there enough anodized finish removed around the switch?)
Listen to this advice. There is no point whatsoever to "shielding" a giant, thick aluminum pickguard with a thin layer of copper or aluminum...it's literally the best shield ever put on an electric guitar. It covers every single component and is thicker than any pickguard shield ever added to a guitar, but the key is to make sure it's grounded (by having exposed, unanodized aluminum on the underside of the holes where components are mounted).

Before worrying about changing anything, just pull out a multimeter and check if the pickguard is continuous with the guitar's ground. If it is, no action is necessary.

Foil shielding the cavity, as was suggested, may or may not make a difference depending on the quality of the factory shielding job. Again, pull out the multimeter - if the cavities register as continuous with ground at the output jack, you likely don't stand to gain much.

I've experienced "clicky" 3-way toggles on cheap guitars. A Switchcraft right-angle is the way to go if you want to stop that - i have two Jazzmasters with gold guards and Switchcraft toggles, and they don't make any noises beyond what I'd expect.

I also vote along with the others that it's not worth replacing any other components unless there's a specific reason you want to, like if you want to change the taper on the pots, or their values, or they're scratchy and aren't responding to contact cleaner. I don't care if components are "cheap", only if they work well. I have 500k unbranded mini pots in one guitar that read ~480k and ~530k and have a nice smooth taper - they'll stay put unless they die. But I also had a different guitar with unbranded full size pots, and the volume taper was the classic "on-off", with 80% of the sweep changing precious little and then the last 20% suddenly being virtually zero. That's the kind of pot I'll replace regardless of what is stamped on the casing.
The artist formerly known as mbene085.

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timtam
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Re: Jmjm 2019 electronics upgrade

Post by timtam » Sat Aug 15, 2020 8:51 pm

Puisheen did an interesting vid on the subtle sonic effect of a vintage anodized aluminium guard vs plastic (shielded) recently ...
https://www.youtube.com/watch?v=uT2sKbdZh50
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Re: Jmjm 2019 electronics upgrade

Post by Lost In Autumn » Sun Aug 16, 2020 5:15 am

I replaced the pots on mine with CTS 1 meg, added an orange drop cap and a treble bleed circuit, & replaced the switch and jack with Switchcraft units, but I left the rhythm circuit stock. I also replaced the pickups with LakeSurfers from Bootstrap Pickups in Ohio, which was a dramatic improvement, and shielded the cavity, as well. Then I got bored and turned it into a 12 string, but that;'s another story...
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