Replace Volume pot with Super Switch?

[chrisemills]

I'm going to outline my plan for some wiring mods, and any corrections or confirmations would be greatly appreciated. Thanks.

Ok so I want to have a blend control for my HH Ibanez RG321MH, as well as a tone pot with a push pull coil tap switch, but since I dont want to drill and fill, all I have left is an unused 5-way pickup selector switch and no volume control.

So here is my idea: wire a 5-way super switch to emulate 25% increments on a 500kohm log volume pot. Here is the sketch:


with these values obtained from testing with a multimeter and rounding:

Values – Hot Side
1 – None – Perhaps a 10ohm to add load
2 – 180k
3 – 400k
4 – 490k
5 – 500k
Values – Grounding Side
1 – 500k
2 – 330k
3 – 100k
4 – 10k
5 – None – Perhaps a 10ohm to add load

So anticipating this works out, my main schematic should look something like:



Both Pots = 500k Ω
Tone capacitor = 0.022 µf (on current tone control)
Neck Pickup = Dimarzio Air Classic (new)
Bridge Pickup = Dimarzio PAF 36th (new)

Thanks for any info.

[ashcatlt]

Welcome aboard! Interestingly, my first post on this forum was also about this type of "stepped attenuator". I don't have a link right now...

The way you've drawn it looks like it'll work, but it's far more complicated than necessary. You can accomplish the same thing with one pole of the 5way (two I guess if you want the "no load" position) and a bunch less resistors. Take it as a hint, see if you can work it out. If you don't get it before tomorrow night, and nobody beats me to it, I know I can dig up something.

[chrisemills]

Thanks for the welcome! I found your post but it seemed to go on more about the resistor values rather than the actual configuration. There was one link to a schematic (i assume) but it was broken.

I see how it could be simpler. Use one pole as the wiper and have two resistors coming off each setting, one to hot and one to ground. I dont see how I could reduce the amount of resistors though. Although more complicated on the schematic than necessary, I feel like this will be easier to wire and neater in the cavity.

[chrisemills]

Thought it out through during the day and you're completely right. Redrafted my diagram.



Look about right?

I still need the super switch for the 5 positions so at least it wasn't a waste of money.

[ashcatlt]

Wow, I said I'd be back "tomorrow night" three days ago! Sorry about that.

You figured it out anyway. That won't give you the "No Load" option that you wanted. Luckily you've got plenty of poles to work with! Look at Sw4a+b, and Sw5a+b from this scheme that's in my Rickebacker:

They are Neck V and Bridge V, respectively, and both do "No Load".

Edit - Those are wired "backwards" for some reason that I'm sure made sense at the time. You could (probably should) swap the two commons to get normal V control action with shorting of the jack when off.

[chrisemills]

Oh thanks for that. Mine will work fine if I dont care about no load, right?

[ashcatlt]

Yep! Fine job going from my intentionally vague description to a perfectly functional diagram.

[chrisemills]

Thanks.

[chrisemills]

Good news! Got the parts today and after 5 hours of soldering, everything worked on first try! Works just like I planned. I'll be honest, its not pro or anything, but it gets the job done! Volume works, blend works perfectly, and push/pull tone is great.

I've attached the schematic which is accurate except for the tone lugs are reversed (cap should be connected to side lug and vice versa).

Haven't got strings back on yet but can't wait to hear the Air Classic and PAF 36th I've replaced the stock ibanez ones with.