Help me choose treble cut cap in jag switch plate

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Help me choose treble cut cap in jag switch plate

Post by CROSS_guitars » Wed Feb 05, 2020 4:49 am

What value capacitor do I use for the treble cut strangle Jaguar switch plate?

The specs are:
Neck pickup = single coil
Bridge pickup = humbucker
Pots, vol and treb = 500k

No rythym circuit

I currently have the .033 cap that is used in regular Jaguars. But it does nothing!!

what cap would work for this?

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Re: Help me choose treble cut cap in jag switch plate

Post by 601210 » Wed Feb 05, 2020 5:39 am

Double that for the same cutoff frequency, by my extremely rusty calculations, but I'd wait for someone else to corroborate.

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Re: Help me choose treble cut cap in jag switch plate

Post by timtam » Wed Feb 05, 2020 6:31 am

The strangle cap is 0.003 uF. And the strangle circuit is little strange if you look at it closely ... the cap is always in circuit. The switch turns a parallel bridging route on or off. It's also possible that the 56k resistor is part of the deal.

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Re: Help me choose treble cut cap in jag switch plate

Post by 601210 » Wed Feb 05, 2020 6:36 am

timtam wrote:
Wed Feb 05, 2020 6:31 am
The strangle cap is 0.003 uF.
This is probably the actual issue, I skimmed past it. Just halving the pots would shift the cutoff but not enough that you wouldn't hear it at all.

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Re: Help me choose treble cut cap in jag switch plate

Post by CROSS_guitars » Wed Feb 05, 2020 4:42 pm

601210 wrote:
Wed Feb 05, 2020 6:36 am
timtam wrote:
Wed Feb 05, 2020 6:31 am
The strangle cap is 0.003 uF.
This is probably the actual issue, I skimmed past it. Just halving the pots would shift the cutoff but not enough that you wouldn't hear it at all.
I have already changed the pots from 250k to 500k to accommodate the humbucker.

So, should I go with a 0.006 UF / .066 whatever cap?

And what's the deal with the resistor? does there need to be one on the volume pot for this to work?

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Re: Help me choose treble cut cap in jag switch plate

Post by timtam » Wed Feb 05, 2020 5:16 pm

So to be sure, your cap is actually 0.003 uF, not 0.03 uF like you said originally ?

The strangle circuit (high pass/low cut) is odd like I said, and the proximity of the 56k resistor in the schematic (although actually wired equivalently at the tone pot) has raised the possibility that it is indeed part of the strangle circuit, since there doesn't seem to be a convincing alternative explanation for its presence ... also it doesn't exist in jags without the strangle (eg Am Pro). Stock vintage-style jag schematic ...
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Re: Help me choose treble cut cap in jag switch plate

Post by CROSS_guitars » Wed Feb 05, 2020 7:07 pm

Cool. Thanks.

I believe it's .003. whatever the standard cap is on a Jag.

I need someone to dumb it down for me though?
what will work?

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Re: Help me choose treble cut cap in jag switch plate

Post by timtam » Wed Feb 05, 2020 9:19 pm

0.003 uF should work if wired to the switch in the same way as vintage. I don't think we have a definitive answer on the effect of adding/omitting the 56k resistor .... so if it's not working with just the cap wired in, try adding the 56k resistor. If it's still not working that would suggest something is not quite right.

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Re: Help me choose treble cut cap in jag switch plate

Post by mbene085 » Wed Feb 05, 2020 9:28 pm

I definitely used a .003 cap in a jag with no resistor and it worked fine.

From my recollection, the smaller the cap value, the higher the cutoff frequency (and more noticeable the effect).

You could try a .0022uf cap. That's what Leo put in the G&L PTB circuit. .0022uf should essentially sound like a PTB circuit with the bass rolled all the way off. You can even go nuts and put a .001uf cap in there if you want to get really aggressive with how much signal you're cutting.

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Re: Help me choose treble cut cap in jag switch plate

Post by CROSS_guitars » Wed Feb 05, 2020 10:13 pm

Oh cool.
I'll try both of those.

So the Jury is out on the 56k resistor.

I have a treble bleed wired to the volume. Maybe that's affecting it too?

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Re: Help me choose treble cut cap in jag switch plate

Post by 601210 » Fri Feb 07, 2020 1:35 am

Unless I'm an idiot, the 56k is shorted out of the circuit when the tone pot is wide open.

When the tone pot is closed, it's in parallel with the full value of the tone pot, which lowers it's equivalent value to roughly 53k.

That makes the cutoff frequency of the LPF formed by the tone knob (i.e. the treble rolloff) go from 16Hz without the 56k to about 300Hz with it. Probably a way to keep a very high tone pot value so it's practically out of the circuit when wide open, but all the way closed it'll be a milder rolloff. Remember that the way a simple RC HPF or LPF works is by rolling off -6db per octave starting more or less at the cutoff frequency. I reckon they didn't bother with this on the Am Pro because the pot is 250k and the capacitor is .022, which gives you a frequency response people are already used to anyways.

The cutoff frequency of an HPF or LPF is 1/(2πRC). Halving either R or C cuts off less treble in an LPF, and more bass in an HPF. So to keep the actual cutoff the same, you'd do the opposite of whatever you did to R to the value of C.

Regarding timtam's comment about the cap being always in the circuit -- I mean, I guess. It's just shorted out instead of physically disconnected. Same effect, easier to wire.

What's the deal with the treble bleed you've got going on? I have to admit I haven't given treble bleed circuits a close look yet, but I can't imagine you couldn't simplify it to something where it shouldn't make too much of a difference. This is all based on the assumption that the tone circuit can be treated as a pure HPF between the strangle capacitor and the volume pot with the tone pot all the way open, and a pure LPF between the tone pot and the tone cap with the strangle off and the tone knob all the way closed, and then some wibbly wobbly stuff occurs in between.

If someone comes along with better circuit analysis than mine (I did pass that class, but barely) I'd be happy to defer, but it's a bit better than speculating.

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Re: Help me choose treble cut cap in jag switch plate

Post by CROSS_guitars » Fri Feb 07, 2020 5:53 am

The treble bleed I used is a 150k Resistor with 0.001 uf Capacitor

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Re: Help me choose treble cut cap in jag switch plate

Post by ChrisDesign » Sat Feb 08, 2020 10:05 pm

Volume: 500k
Tone: 250k
Cap: 0.1uF

This is the spec for the Fender Player Jazzmaster, which has no rhythm circuit and two Humbuckers.

It works amazing and sounds like magic. With volume at 10 you get the full tone you expect. The tone nob is very responsive so easy to dial in the sound you need. With the tone nob at 0, you are in mute city.

I know the values sound strange, but they really work! I have tried replacing the tone pot with 500k. The magic disappeared. Tone was unresponsive. Some of the life was gone. I put a 250 back in and I was happy again.

Also, consider a treble bleed on the volume pot. These cost almost nothing but make the volume work much better. Fender put these on all of their high end guitars. The is a clone of Fender’s treble bleed I’ve installed on all my guitars.

https://rover.ebay.com/rover/0/0/0?mpre ... 970502737
"I own a '66 Jaguar. That's the guitar I polish, and baby - I refuse to let anyone touch it when I jump into the crowd." - Kurt Cobain

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Re: Help me choose treble cut cap in jag switch plate

Post by CROSS_guitars » Sun Feb 09, 2020 5:20 pm

ChrisDesign wrote:
Sat Feb 08, 2020 10:05 pm
Volume: 500k
Tone: 250k
Cap: 0.1uF

This is the spec for the Fender Player Jazzmaster, which has no rhythm circuit and two Humbuckers.

It works amazing and sounds like magic. With volume at 10 you get the full tone you expect. The tone nob is very responsive so easy to dial in the sound you need. With the tone nob at 0, you are in mute city.

I know the values sound strange, but they really work! I have tried replacing the tone pot with 500k. The magic disappeared. Tone was unresponsive. Some of the life was gone. I put a 250 back in and I was happy again.

Also, consider a treble bleed on the volume pot. These cost almost nothing but make the volume work much better. Fender put these on all of their high end guitars. The is a clone of Fender’s treble bleed I’ve installed on all my guitars.

https://rover.ebay.com/rover/0/0/0?mpre ... 970502737
Thanks. what capacitor is on the strangle, tone cut switch?

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Re: Help me choose treble cut cap in jag switch plate

Post by ChrisDesign » Mon Feb 10, 2020 5:33 pm

A circuit is all the components. Changing one piece can impact every other component’s response.

Looking at the USA original 60’s design, you need a .003uF on mid cut switch, a .01uF on the tone pot, and - crucially -
a 56k resistor between the tone pot’s central post and the post with the wire tuning to the mid cut switch.

That 56k resistor works with the mid cut’s .003 uF capacitor. If you haven’t got that resistor, add it in. If the cut is insufficient, a larger value capacitor.

You will have to experiment. I would stand by a 500k volume, 250k tone, and .1uF tone cap, but add in the 56k resistor to the tone pot, then play from there. Keep notes to remember which combinations you’ve tried and loved the most.

I would still add a treble bleed to the volume pot.
"I own a '66 Jaguar. That's the guitar I polish, and baby - I refuse to let anyone touch it when I jump into the crowd." - Kurt Cobain

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