question about adding resistor to JB/500K pot setup

A

appar111

New member
Does anyone know what value resistor I would add to a JB and a 500K pot to make the pot see 250K?

I have the JB in a 2-humbucker guitar with a FRED in the neck, single volume knob, no tone knob. The JB's just a little too bright and I don't want to swap the pot to 250K because the FRED sounds perfect with the 500K.

Also, where does the resistor go in relation to the pickup and the volume pot?

thanks
J.
 
Re: question about adding resistor to JB/500K pot setup

470k resistor wired parallel from the pickup's hot lead to ground. Duncan's hot wire is black right? You solder a 470k resitor to where the black wire goes to your volume pot or blade switch then solder the other end to ground.
 
Re: question about adding resistor to JB/500K pot setup

cool, I think I have some 470K resistors at home-- thanks so much for the info!

I'm using a 3-way gibson style toggle switch-- will this essentially make the middle position (i.e. with neck + bridge pickups) 250K, or will it only make that bridge position see 250K?

thanks again,
J.
 
Re: question about adding resistor to JB/500K pot setup

ACH91332 said:
470k resistor wired parallel from the pickup's hot lead to ground. Duncan's hot wire is black right? You solder a 470k resitor to where the black wire goes to your volume pot or blade switch then solder the other end to ground.
Click to expand...


hmm
I may be mistaken but in order to make a 500K pot a 250K pot you need the resistor in parallel with the pot
either
volumepot.jpg


or ( and I really think its this one )
volumepot2.jpg


but maybe I read the thread wrong and thats not what you want or tha is what has already been said
if so excuse me
 
Re: question about adding resistor to JB/500K pot setup

I think these would be if I wanted to make the volume pot see both pickups as 250K, not just the neck pickup, since you show it going from ground to either the input or output of the jack, not one of the pickups specifically...

thanks for posting it though! That's handier than swapping a 500K pot out for a 250K should I ever decide to do that. For this situation, just 1 of the 2 pickups, I'll try what ACH mentioned.
 
Re: question about adding resistor to JB/500K pot setup

Oh, right you only have one volume.. I've never had to do it this way but maybe wire it so that you have the 470k resistor going to ground and then another wire going to the volume pot as the lead. I havent had to do that before but I dont see why it wouldnt work.

As for you ehdwuld I'm not an expert. I only have experience with residential wiring and dont have any real qualifications but if you were to put the 250k resistor in series then it would make your 500k a 250k pot value but I'm not sure how your tone would sound doing that.. When you put the 470k resistor in parallel so that it goes from the hot lead to ground with the hot lead also going to the 500k pot it will make it sound like a 250k pot since having two roughly 500k loads in parallel will make it 250k. When you put two 500k resistors in parallel the value is halved.

EDIT: The formula for this would be R1 X R2 divided by the sum of R1 + R2. In this case we will just round the 470k pot to 500k. So 500 X 500 divided by 1,000 which then equals 250 or 250kilohms.

Sorry if you know all of this but the diagrams you posted used a 250k resistor in parallel. Also the way I stated is the same as your first diagram which would be the way I would do it. The only time I did it I did it with a 3-way blade switch where I just soldered the 470k resistor in switch slot where my bridge single coil lead went into the switch and then soldered the other end to ground. Doing it on the pot should be the same thing If Im not mistaken.
 
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Re: question about adding resistor to JB/500K pot setup

ACH91332 said:
Oh, right you only have one volume.. I've never had to do it this way but maybe wire it so that you have the 470k resistor going to ground and then another wire going to the volume pot as the lead. I havent had to do that before but I dont see why it wouldnt work.

Sorry if you know all of this but the diagrams you posted used a 250k resistor in parallel. Also the way I stated is the same as your first diagram which would be the way I would do it. The only time I did it I did it with a 3-way blade switch where I just soldered the 470k resistor in switch slot where my bridge single coil lead went into the switch and then soldered the other end to ground. Doing it on the pot should be the same thing If Im not mistaken.
Click to expand...

There's a separate wire going to the volume off of the 3-way switch, so I'll run the resistor from ground to the lug on the 3-way switch for the bridge pickup. I think that the middle position will end up making both positions 250K since on a gibson style 3-way toggle, the way it works the bridge and neck lugs connect in the middle. I could be completely wrong on that (not the first time, that's for sure!)
 
Re: question about adding resistor to JB/500K pot setup

sorry to bring up an old thread but im thinking of doing this to my hss strat and im still a little bit confused. would i need two 500k resistors? one for each of the single coils? do i solder one to each of the lugs on the switch where the single coils are connected and then to ground?
 
Re: question about adding resistor to JB/500K pot setup

Jake
Yeh, if you've got HSS you'll need two resistors (470k)...one for each single coil. One end of the resistor to the lug on the switch, the other to ground. This will make each of the singles "see" a 250k pot and the hummer will "see" a 500k pot.
 
Re: question about adding resistor to JB/500K pot setup

It's going to be a bit weird though, because it's not just a half, you've got a variable resistance moving in parallel to a constant? It's half the TOTAL, not half the pot. So you'd be moving between 125K and 250K IMO. Hardly ideal.
 
Re: question about adding resistor to JB/500K pot setup

Xplora said:
It's going to be a bit weird though, because it's not just a half, you've got a variable resistance moving in parallel to a constant? It's half the TOTAL, not half the pot. So you'd be moving between 125K and 250K IMO. Hardly ideal.
Click to expand...

At full volume the pickup actually 'see' a 250K R, it's the pot taper that could result strange decreasing the vol, it won't be a Log (or Lin) pot anymore.
 
Re: question about adding resistor to JB/500K pot setup

i just soldered the 250k resistor into a standard guitar cable to improve the tone of all my guitars, my new Kramer does not have a tone pot so its really bright, the cable mellows the sound out perfectly. now i get the sweet spot i was missing. i could not play a guitar so bright in tone, so i just made a cable i can use on any of my guitars
 
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