500k pots to master volume.

[Brian5531]

Hi I’m attempting to spilt three humbuckers, each with their own on/off switch and pot(250k or 500k?) and I want to gather all to one master volume. Does the master volume pot have to be equal or greater to the some of the six pots? My inspiration for this are the Teico, Vox phantom, and Eastwood Airline guitars with all their wild knobs and switches. 
Brian

[Bizman62]

Hi @Brian5531 and welcome to the addiction!

You don't get a comprehensive answer from me, there's others who know their ohms stellarly better.

This much I know: Any pot will basically work. The question is how much it affects the tone. With humbuckers 500k pots are mostly used as the pickups by nature sound quite dark compared to single coils. The higher ohmage pots allow the brighter tones come through (lots of information if you Google it).

Thus I'd choose the 500k pots for individual pickups. Logically the master pot should be at least the same to prevent muddiness. But should it rather be of higher ohmage? That's a question for someone else to answer.

[nakedzen]

Second. It all depends on if you want/need more highs to come through.

But you might want to check into partial split resistors for your wiring, could come in handy.

https://www.fralinpickups.com/2018/10/17/using-resistors-in-guitars-101/

[henrim]

Can't wrap my head around how this would need to be done. I would have to draw it. Anyway what you need to take in account is that resistance adds up in series connection while in parallel connection sum is less than the amount an individual resistor has.

E.g.
If you have two 250K pots connected in series you effectively end up having a 500K pot.
Two 250K pots connected parallel sums up to 125 Kohm resistance.

I can see the benefit from a master volume. Although personally I would not like to have all those pots on my guitar  And don't get me wrong I LOVE pots, but I need to save them to my synth module builds    

[nakedzen]

As long as the parallel pots are wired in series to the master volume the resistance would total always over 500K? I'm not too familiar with circuits or how they work.

Personally, I'd do the pickup selectors as on/off switches.

[mistermikev]

altho you'll have 3 pots in feeding one pot in series... when they are at 0 they have (in theory) 0 resistance.  In reality there is generally a little bit of resistance still there on the line... and it will make a minor difference in the highs... but not the end of the world.  pretty much std op proceedure on any gretsch altho it's two vol feeding a master volume.  I have not looked at their layouts... but that'd be a good place to look and see how it's done.  you could opt for a couple of 350K pots for the initial and a 500k for the master but I suspect you won't hear a whole lot of difference.  the one thing you may want to consider is how you wire them.  if you use the pickup as the middle lug on the pots... you sweep the pickup to ground... and get better "independent" control of the volume for ea pu.  if you sweep the live to ground... when any one pickup is fully off they are all off... but you'll get more highs.  every choice has an upside and downside.  

 

the wiring below... essentially just remove the 3-way and hardwire those wires together and you are 66.6% there!

and here is an epiphone wireup using the alternate "preserve highs but one volume will turn down all volumes" approach

[mistermikev]

i guess the above might beg the question: what happens if you wire middle/neck as "independent" ie sweep the pickup to ground, and the bridge as "more highs" ie sweep the live to ground... well... I have oft wondered that myself.  in theory the bridge pickup will act as a pseudo master volume in addition to being a volume/blend itself... and the middle/bridge volumes will have a more "blend-able" control (downside being that the bridge would always have to be on to get signal on the other two... but nothing  push/pull wouldn't fix).  

(hope something there helps)