Reverse Suhr wiring diagram.

[mwbjr13]

Let me start by saying that I'm completly clueless when it comes to anthing wiring or electronics related. I know how to solder and I can do basic wiring jobs but I need help. I saw on here Jumble Jumble's '80 superstrat and that turned me on to the "Suhr wiring diagram". I'm in the process of designing a tele with Dimarzio Area T in the neck and a Chopper in the bridge. I really want the neck to have a 500k volume pot and a 250k for the bridge. When I saw what Jumble Jumble and Suhr have done, that got me thinking. And thus, my question is there a way to get a 250k pot to, i guess act, like a 500k or visa versa?
Thanks in advance  :rock-on:

 

[line6man]

People make way too much of pot values.
Just get a 500k pot and roll it down a touch when you want to drop the impedance. Otherwise, switch in a fixed resistor when you want it.

 

[mwbjr13]

Cool. Thanks

 

[Dan025]

can't make a 250k act like 500k but you can make a 500k act like 250k. basically you run a 470k resistor (i dont think they make 500k, 470k is close enough) in parallel to the pickup that you want a 250k load on. but really try it without the resistor first and only add the resistor if it is a bit of an icepick in the ear.

 

[line6man]

can't make a 250k act like 500k but you can make a 500k act like 250k. basically you run a 470k resistor (i dont think they make 500k, 470k is close enough) in parallel to the pickup that you want a 250k load on. but really try it without the resistor first and only add the resistor if it is a bit of an icepick in the ear.

Technically, you can increase the pot value, but your must accept the compromise of limiting the range of control at one end.

 

[Dan025]

and thus it doesn't act the same.  :icon_biggrin: but i hear ya...

yeah, you could argue that an extra resistor from pin 1 to pin 3 changes the taper and the way it acts vs an actual 250k pot, but the taper is only off if the input impedance of the amp is somewhat low since the extra resistor doesn't affect the resistance ratio of pins 1 and 3 to the wiper. (maybe that's poorly worded but i'm tired)

 

[Jumble Jumble]

Happy to help you with this. Let me know what I can do.

It's not much effort to switch in the resistor and I'm happy with the sound. However I have NOT tried it without the resistor. So I don't make any claims about the effect it had.

The taper is slightly affected by the resistor as the one in parallel doesn't change in value. However it's not much of a difference, I graphed it here:

http://www.jumbleguitar.com/2012/04/06/electronics-part-3-volume-control-resistance/

I used a 510k resistor as they're just as easily available and are a little closer to 500k.

 

[Dan025]

damn it, i guess i didn't consider all the possible paths and how it could have an effect on the voltage divider. it's too late to try to think about it in depth but i'd say it's still an acceptable curve. i was kinda doubting myself as i wrote that last post. oh well thanks for the education and lesson in humility.  :doh:

 

[mwbjr13]

Thanks to all of y'all for you help. I'm still not sure what a lot of it means but atleast I have some place to start.

 

[Jumble Jumble]

The most difficult thing is, what do you want to happen with the switch in the middle position? 500K or 250K? Will the humbucker be split or not in that position?

Also you'll need a three-position super switch, I know a guy in Germany who makes one but I'm not sure how easily available the are elsewhere.

 

[Dan025]

Thanks to all of y'all for you help. I'm still not sure what a lot of it means but atleast I have some place to start.

just math you dont need to be concerned with unless you are really interested. if it affects taper it should be considered minor. i'm still not sure it does, it's a problem i thought i solved a few years ago and i'm second guessing myself. if jumble wants to discuss it it's probably best to do over pm. i'm going between what he is showing and another model and i keep coming back to what i said first and for some reason i'm not trusting my judgement. this is the problem with being analytical, stupid things like resistor networks can give me insomnia. i have two models going on in my head and can't find fault with either of them but they each suggest a different result.  :help: i shouldn't do this when im already tired but i can't help it...  and now the sun is coming up :doh: 

 

[Dan025]

The most difficult thing is, what do you want to happen with the switch in the middle position? 500K or 250K? Will the humbucker be split or not in that position?

Also you'll need a three-position super switch, I know a guy in Germany who makes one but I'm not sure how easily available the are elsewhere.

i'd have the 250k in the middle unless you want it to be bright for some reason. the biggest difference between a single and a humbucker in the circuit is the inductance. the pickup and the capacitance of the cable and tone circuit create a resonant peak where the voltage is high and the current is low. the load of the pot changes how much the peak influences the peak in the actual signal. lower inductance raises the frequency of the peak making it more irritating and though i'm rusty on the math i think it also makes the peak stronger, but the lower dc resistence might also have a bit to do with how peaky it gets. lower pot values are normally used for lower impedance and inductance puckups because the effects on the peak tend to mellow them out a bit  so you don't get that ice pick in the ear sound. when to pickups are in parallel it gives lower impedance and inductance than either pickup alone so the lower value is likely desired there.

you could literally solder the 470/510k resistor onto the pickup that you want a 250k load itself and not worry about the circuit looking weird or being hard to analyze.

 

[mwbjr13]

I want the 250k in the middle. I'm not using a humbucker in the neck. I'm using two noisless tele pickups but I want the neck to be bright but I don't want all the twang from the bridge. And since I'm not puting a tone knob out the guitar I figured this might be a good way to go.

 

[Dan025]

yeah, just solder the 510k resistor to the pickup that yo want 250k on. strait from ground to the hot lead of that pickup. no need for anything else in that case.

since you aren't using a tone you cant use my next original idea (and i have done this) which is to use 500k on the tone and volume and to tie in the 3rd lug of the tone to the pickup or switch position you desire 250k on. in this case you use the tone pot as your load as well but selectively. not only does this give you the desired load but it also makes the tone cap invisible to the circuit when it is at "10" and you are in 50k mode. now that does affect taper of the tone knob. on a strat you can use the tone knob that is not active if you don't want that to happen.

 

[mwbjr13]

That's awesome! Thanks again for all the help.
:rock-on: