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A Switch For Two Different Tone Caps Sharing One Tone Pot


Pal

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I have a Lonestar Strat I'm modifying with a new pickguard that will have only one tone and one volume. I would like an on/on switch with two different caps on it. One cap, .022 for single coils and the other cap, .047 for the humbucker. This way I can switch between caps but use one tone knob (a 250K or 500k?). I was wondering if there was another option where I can put both caps on opposite ends of a 500K pot so if i roll the pot one way it's one cap; roll it the other way and it's the other cap, and in the middle it's pretty much neutral. is that a simpler yet still effective option?? Or maybe even one push/pull tone knob that switches between caps??

What would be my best option?

This is a great forum. I just started work on several old guitars of mine and I am learning so much. It's endless work and fun!

Thanks,

Pal

Edited by Pal
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Hi Mender,

Thanks so very much for the reply.

Since I'm using a 250K tone pot for the humbucker (as well as the single-coils), would it be useful to

use a .068 cap as opposed to a .047 cap to make up for the loss of treble from not using

a 500K tone for a humbucker? The other cap on the switch would be a .022 for the single-coils.

Thanks,

Pal

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The only thing you can do is try several different values and settle on one that you like. You probably won't hear any difference between a 250k and a 500k tone pot as one end of the pot is not connected, so you have no ground potential like you have on a volume pot. The volume pot is far more important one in that resect.

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with a screwdriver and a little patience yes you can make the tone pot do double duty. but as far as those cap values. go you realized that you are utilizing a larger cap for the humbucker which has more midrange and lo mids than single coils right? single coils tend to produce much more low and high end than humbuckers that is something we lose when using the humbuckers we love so much. F= 1/(2PIRC) if you plug in the values for your VOLUME pot as R. and your Capacitor as C you will find your freq or F. also here is a calculator online to show you. http://www.muzique.com/schem/filter.htm i didn't see your volume pot value list so i will do the common values. at 500k and a .022uf cap your freq roll off point is at 14.5hz which is more than 3 octaves below the fundamental freq of the low e string which is 82.4hz. for a 250k pot its 29hz which is a little over two octaves below the estring and for a .047 you roughly just half the freq i listed above.

now the reason for this long explanation is that if you were to set a slider on a graphic eq all flat and pull all freq except 14.5hz to down -18db or better and then panned the output of that between your regular guitar signal and the eq then you would have a good comparison on what the tone control is doing to your signal. it really matters very little on the size of the tone pot other than the spaces between 0-100 a one meg pot will give you a wider throw than a 10k ie the spaces between are a bit easier to hit. but it is not a movable filter ie when you turn the pot down just a little it isn't changing from 0 or 10 just the volume of the filter as the filter is made between the parallel combo of the cap and the volume pot as its the constant resistance to ground. now you can change the layout of your guitar and make it a variable eq which is quite easy with a wire switch and is very usable. but i digress. if you want to do both pots and have middle neutral then you will need a 500k or 1M preferable linear pot. disasemble the pot and at the 50% POINT either put some fingernail polish or simply cut the trace on the horseshoe of carbon on the pot wafer. now when at 5 or the middle it will not conduct the guitar signal to the caps to ground. put a cap on either side of it and there you go the circuit you need after all the bs rambling lol.. btw here is how i did it on my jem wiring you probably want to just ignore most of the schematic and look soley at the tone control. also i added trim pots to the pot inbetween the caps and ground as to vary how much of the cap will go to ground. just like a normal tone pot but with the capability of finding the sweet spot easier. edwiring.jpg to clear up any confusion on my crazy a$$ wiring diagram the aqua colored wire is from the pickup switch. the brass colored wire is ground the pot on the right is the volume pot showed upside down as you would see it in the guitar cavity or the pickguard. the two caps are for my freq responses alone that is why there are no values. as far as the resistors go i didn't have a stock photo of a trim pot so i used a simple resistor however you can use a fixed resistor if you like and yes the middle lug is grounded out see with the magic pot installed here i put a small pie shaped wedge in the carbon at approximately 40-60% rotation so it doesn't have to be dead in the middle to dropped out of the chain but once it is there it acts like a no load tone pot only in the middle lol. check out the wonderful tutorial on making a no load tone pot on this forum here. http://www.projectguitar.com/tut/pots.htm also look into the secret life of pots by rg keen at geofex http://www.geofex.com/article_folders/potsecrets/potscret.htm hope this helps. also if you need anything feel free to post i might even have a pic of my tone control somewhere

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this is a very interesting response. I'm reading it over and over and starting to get it (I think).

Are u saying I can have two caps on the same 1m pot on opposite ends and past the mid-point in either direction is how I adjust the tone for each cap (in their own respective directions)? And this is done by opening the pot and fixing the mid point so it becomes neutral? Would this mean both pickups would just be their "pure" sound unaffected buy the caps in the middle position?

Thanks,

Pal

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Shirt answer yes.

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Yes if you look at the secret life of pots you will see 50% is actually 50%

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sorry was on mobile phone couldn't type battery was low. but yes if you look at the secret life of pots you will see the rotation vs actual resistance. a linear pot will give you the best option. you can still use an audio taper pot and mark it in the middle but if you are relying on the pot's resistance you will need 1 M definitely but it will vary with audio taper so I would recommend utilizing a small trimpot to help set the range. However a 1 M lin would be the best option it is what I used.

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cool man glad to help.. say unless you roll your tone off all the way try looking into something like a 4n7 capacitor or a .0047uf. you will be surprised at the flexibility especially on the neck and middle pickups. for the bridge even though most people will point out that the freq range is completely off a .1uf has a bit of magic to it as the tone control. about half way down on a hot pickup it sounds like a bell like neck pickup.. a great trick if your not using a guitar with a neck humbucker. anyway that is one of the tricks we do here in the shop.

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A .1uf seems like it would take off too much treble. Did you mean .01uf?

I read that a .01uf is a good all purpose tone cap but the tone won't be as dark as a .022uf.

I was thinking I might try this because I prefer simplicity. I will eventually be putting in some pretty hot

Bareknuckles Alnico pickups in the guitar. This is a lonestar strat (hss) that I'm modifying. I'm trying to really hot-rod it up

While still sounding nice.

By the way, the reason why I'm using only one tone on the strat as opposed to two is because the volume knob is too close

To the strings so I'm moving the volume down one hole so there will be just one tone.

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got you. but no i was quite serious when i typed .1uf. you have to remember my explanation before. so since this is way below audible range it will attenuate differently than your average cap. sure at max its way to dark but still interesting. and theres a video on youtube where i fiddle with it a but it doesn't seem to dark btw its a weird camera angle from my phone i am not quite that fat. lol fat but not that fat.

[media=]

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thanks tim37 i appreciate it. you know its actually funny i have been working on book. it deals with all the freq shaping and stuff we can do at the guitar level before hitting the guitar cord. setup myths actual physics behind the guitar stuff like freq/distance. shredder mods potting pickups in non traditional ways. just a lot of fun stuff that i have learned over the years that i have not seen in regular guitar books. i learned all my basic stuff from reading melvn hiscock build your own guitar. and from just doing it. anyway i am in love with the title "Non Newtonian Guitar Wiring"

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Ansil,

I've decided to go with a cap switch for my guitar.

That is, 2 caps on a push/pull.

Here is my diagram. Is it correct??

http://img221.imageshack.us/img221/3212/capswitch.jpg

Some else suggested this (see link below) but it seems wrong to me.

Then again I'm new to this stuff (but learning soooo much!!)

http://img207.imageshack.us/img207/8257/caps2f.jpg

Your .1uf cap mod sounds amazing by the way!!!! I am going to try this on my les paul soon.

I'll make a cap swtich for it as well and have a "bright cap" and a really "dark" cap. It is a fantastic sound!!!!

Thanks,

Pal

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First diagram is wrong. But can be fixed by moving ground wire from pot to middle right on switch so the caps have a ground potential. Second one is correct althoughquite in unorthodox I like it. See when the switch is closed that cap is null do to the direct contact if the terminals. Good, luck I wish you the best on y your endeavors. ;p

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For a les paul I have a much better wiring diagram already posted on the forums.its the one gibson tried to get there hands on

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  • 4 weeks later...

I completed the project. It works great! My soldering job is a bit clumsey but it was my first time doing this sort of thing.

I ordered the components again so I can build another pickguard just like it except the soldering job will be much nicer.

I will add some Bareknuckles pickups as well and swap out what's inside now with an improved version.

here is a photo of the switch and the new pickguard without that annoying (to me) 3rd knob under the bridge which is typical on strats.

http://imageshack.us/photo/my-images/62/switchw.jpg/

http://imageshack.us/photo/my-images/138/guardd.jpg/

My next project is to refinish two old guitars of mine and put in all new electronics and pickups.

Also, rewiring a les paul with "jimmy page" wiring and new pickups from bareknuckles as well.

Thanks so to everyone in this forum for their help. I am addicted to fixing and rebuilding my guitars now.

It's an obsession! I'm sure I'll have more questions soon and more photos and hopefully I can answer some questions as well.

-Pal

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Sorry for only having skimread the previous posts. I hope I can bring something different to this.

If you like the combination of x value pot and x value cap for one set of pickup combinations plus the sound of y value pot/cap then it is quite possible to buy a couple of linear x/y value dual gang pots and swap out the rear wafer so you now have a dual value dual gang pot. The switching can then alternate between these two independent methods of dumping treble to ground. As for switching, it should also be possible (if the part is available and a straight swap) to have a five-way selector which also switches in/out the tone dump you decide to use dependent on position.

My own recent experience in this is that I have retrofitted a formerly passive vintage bass with dual mode making it switchable between active/passive. Given that both modes run different apparent impedances to the outside world, they need totally separate volume/tone pot and tone cap combinations (500k and 20k). Since dual value pots are not readily available outside of factory MOQ I modifed easy-to-acquire Alpha pots to achieve what was needed.

I was also thinking....would Fender's (expensive) pot/knob with the switch in the centre of the knob work with this also? I hate trying to gain leverage under a pull pot with Fender style knobs, especially when I end up pulling the knob off (fnar).

I know this is a little late into the game, however anybody else interested in this mod might find more perspectives and methods useful also.

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good idea on the fender switch i like that idea but could never find them when the first came out. but as far as getting underneath them thats why they make push push pots super cheap and high duty cycle. i use them exclusively on some of my special circuits. great idea on the dual gang idea i do that on my strats for different impedances and filter options for my super wiring. meq makes some killer pots triple ganged and push pull switch but they are like 25usd each but you can mix and match the impedance of it. i got a 1Meg 250k 500k for my old ibanez wiring. i never used the push pull on that one. Pal i am glad it worked for ya and yeah it looks quite nice

oh and i understand about the volume pot being in the way thats why my axe has them reversed when it was drilled out. i am converting all my guitars this way well one at a time its a bit of a pain in the arse.

strippeddown.jpg

a little off the path but here is something to try with the other side of the switch.

Ledsb4Gluing.jpg

they are all the same color but they change brightness depending on where you are at in the pickup selector. also the one by the bridge is drilled offset so you can tell where you are. in hindsight different colors would help but i had red and green and hell red leds are so 1980

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That's the same reason I never bought any of the Fender switches for builds. The price is far too high on some of these and many simple-but-difficult-to-find items. MEC (same as MEQ?) sell toggles in gold and black for over ten times their actual worth. Crazy.

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