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Crusader

ES-137 wiring

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I have an ES-137 which sounds quite "dark" and I want to brighten the tone up. I heard they use 300K pots but I took the harness out last night only to find they are all actually 500K So I'm wondering why it sounds like its got 300K pots

Looking at the harness I notice the Cap goes from the middle lug on the Tone control, then earthed to itself (like on a Les Paul Axcess) But it also has a wire going from the lug on the Vol pot that you wire the pickup to, to the opposite lug on the Tone pot

Could this wiring setup achieve a similar result to using 300K pots?

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Do you mean that the tone pot has lug 1 wired from pickup, lug 2 wired to cap and lug 3 wired to ground (plus other side of cap also wired to ground)? That sounds very much like an error, or at least a very specific modification to the tone circuit to introduce a particular effect from the tone pot.

If it's wired like I think it is, with the tone pot all the way up you'd get the same effect as having the guitar fitted with 250K pots.

What happens when you remove the link between the tone pot and the pickup?

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Not quite, lug 3 on Tone pot is just cut off and goes nowhere

What happens when I remove the link.... Good question but it would take a lot of work to try the experiment

Here's some pictures to help. The pickup is actually unsoldered but you should get the idea

The wire on the bottom left of picture goes across and curls around and ends up on the Tone pot lug on top rhs of picture

IMG_4561.thumb.JPG.601de052e73546957215add4ceafb10c.JPG

 

And here's the lug that's cut off. And I'd say the pot is earthed through the Cap. As mentioned the LP Axcess Cap was also wired this way

IMG_4562.thumb.JPG.62c86ebbfbc26965c1b8b0767af7d021.JPG

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57 minutes ago, Crusader said:

The wire on the bottom left of picture goes across and curls around and ends up on the Tone pot lug on top rhs of picture

Looks like a pretty standard tone pot setup to me. Signal from pickup -> outside lug of tone pot. Middle lug of tone pot -> cap -> ground.

If it sounds particularly dark, maybe check that the cap is the correct value for the intended circuit. Also check that the pot values are what they claim to be.

Or it's just the way those pickups sound.

 

1 hour ago, Crusader said:

What happens when I remove the link.... Good question but it would take a lot of work to try the experiment

Isn't it just a case of desoldering the wire on the right hand lug of the tone pot in your first pic?

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Putting pickups back in and stringing up again is still a fair bit to do, and in any case I think if I was to desolder that wire the Tone wouldn't work would it?

By the way what was that wiring you said would make it like using 250K pots?

Just for the record this is the LP Axcess. If I remember correctly the green wire is hot from output and the black is hot to switch. I think it essentially does the same thing as the wire in question on the ES

IMG_0305 Axcess.JPG

Edited by Crusader

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I suppose the question I really should have asked is, does the ES-137 have Modern wiring or 50's wiring?

After studying the differences I think its Modern

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12 hours ago, Crusader said:

Putting pickups back in and stringing up again is still a fair bit to do, and in any case I think if I was to desolder that wire the Tone wouldn't work would it?

My point was that your OP seemed to suggest that maybe the tone circuit was contributing to the dark sound, hence my suggestion of temporarily disconnecting the tone circuit to see if it cleared things up. As a quick check you could also just hold the removed pickups above the strings of another guitar to save you reinstalling them into the original instrument.

 

13 hours ago, Crusader said:

By the way what was that wiring you said would make it like using 250K pots?

Volume pot wired normally. Tone pot wired with input signal from pickup/volume -> left lug. Middle lug -> cap -> ground. Right lug -> ground. The tone pot then sits in parallel with the volume pot 24/7, but the capacitor is swept up and down along the variable resistor element. I have no idea how it would sound, probably darker than your standard tone circuit with a more extreme degree of variance.

 

9 hours ago, Crusader said:

I suppose the question I really should have asked is, does the ES-137 have Modern wiring or 50's wiring?

After studying the differences I think its Modern

There is no difference between 'Vintage' and 'Modern' Gibson wiring with both volume and tone pots full up. In that situation they are electrically identical. The differences only start showing up when the pots are wound down away from maximum. Is that the behaviour you're seeing?

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17 hours ago, curtisa said:

There is no difference between 'Vintage' and 'Modern' Gibson wiring...

LOL yes of course with everything on full there is no difference. With all this deep thinking I forget things like that!

In regards to the wiring that makes a 500K pot act like a 250K, I was thinking along those lines. Apparently ES-137's used to have 300K Vol Pots then at some stage they changed to all 500K. I wondered if they wired it somehow to get the same effect as having 300K pots

I think the easiest test is to connect the pickups straight through

Thanks for your comments and replies, it all helps

Cheers

Edited by Crusader

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I got some more done today. I altered the tone circuit to 50's wiring and I'm sure it sounds brighter. I will check it again tomorrow and see if I still think the same thing

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I did some testing yesterday and no I don't think I've fried the caps and altering the harness to 50's wiring was unnecessary. I've done so much testing, comparing and experimenting over the past 30 years I'm sick of it and didn't want to do all this LOL

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The brightest you can possibly make the guitar is to connect the output of the pickup direct to the amp. No volume, no tone, no nuffin. Adding 'stuff' to the pickup is generally a subtractive process on the signal.

If you can be arsed, try it as an experiment. If it still sounds too dark, then the only option you have left (short of cranking the treble on your amp) is to install brighter pickups. If you've already got the wiring removed I'd be giving this a go as a last resort.

I'm not familiar with the ES137. Is it considered by the wider community to be a warm jazz box or an edgy rocker?

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