Replacing concentric pots with push pull

[53buick]

I've got a Danelectro 56-u2 reissue that I'm modifying. I've upgraded the bridge to an intonatable one and installed some grover machine heads. So now I'm down to the electronics. Currently the setup is: 3 way toggle switch, 2 concentric pots and 2 lipstick pickups. Each pot controls volume and control for each pick up. All I want to do is replace with push/pull pots. I want the (neck) pot to control volume in the "down" position and tone in the "up" position for the (neck) pickup. And the same for the bridge pot/pickup respectively. This seems like a logical way to wire for this setup, but I can't find any schematics or info on anything remotely like this. I'm new to guitar modding and I've read the stewmac information, but am at a loss. Can anybody help me out or guide me in the right direction? Thanks!

[ashcatlt]

Welcome.

This can be done. I tend to question the logic you mentioned.

You're aware that, without some pretty fancy active circuitry, the settings aren't going to "stick" when you flip the switch, no? Like, you've got in the down position, turn down your volume, then pull up the switch to adjust tone. The volume control will then be forced to jump to some default value.* The pot itself will have to be taken out of the volume control part of the circuit all together so that it can function as the tone pot.

I can't imagine that being particularly useful except in specific circumstances.


*One would presume the default value would correspond to "10", or "all on", but we could probably find a way to choose any value you might desire.

[53buick]

nah, i wasn't aware - i'm not too familiar with circuitry. so you're saying that once i set the volume or tone on one of the pots, that once i flip the toggle switch for the other pot, the previous pot will default? it just seemed logical to me in that one knob could control both volume and tone for one pickup. however, i think i realize now that a concentric pot is basically a volume pot stacked on a tone pot and a push pull is more of switch, correct?

to be honest, the only reason i wanted to try to put in push pull pots, was because I don't like the look of the stock danelectro stacked knobs and couldn't find any other types of stacked knobs (besides chrome, gold or black for fender strats)

any suggestions?

[sumgai]

53buick,

Hi, and welcome to the NutzHouse! ;D

Pots are inherently simple mechanical devices. More or less, it's one wiper, one resistance element, and one duty (volume, tone, blend, whatever). If you'll look at any diagram, be it a simple connection drawing or a complicated schematic, you'll note that no resistance element (pot) ever does more than one thing, for that particular circuit. To put it another way, at no time is a resistance element ever switched between duties. It may be switched into or out of a circuit (examples would be blast or kill switches), but it doesn't get tasked with more than one job.

The reason is easy to see, given what ash just said - if you physically switch the pot to perform some other duty, what happens to the circuit that just had its guts ripped out? If you say "well, that's what the push-pull switch is for, to replace the pot", I'll simply ask you "with what value of resistance, please?" Surely you don't mean that the guitar should suddenly jump to a pre-determined resistance value, do you? That would negate the whole reason for a control in the first place!

Sorry, but the short answer is, nope, can't be done. However, in the digital world, this would be child's play. ;D Not to mention, uber-cool. Sadly, such designs seem to be a Romper Room No-No for most Nutz. (Whether they're registered here or not.)

HTH




sumgai

[53buick]

ah-ha! i think i get the gist now. my digital mind was definitely in the forefront. sorry to take up space on the forum with this!

[ashcatlt]

Don't worry about. This is why we're here.

There are those old car radios which have knobs that do exactly what you're talking about. I'm pretty sure those are something like concentric pots only somehow pushing or pulling the knob changes which of the wipers gets turned. I think, though, it would be hard to find these in values and sizes that would work inside a guitar.

I think you could accomplish what you're looking for with some form of an active analog circuit. Sumgai says that digital would make it easy. Well, I'll leave that to him. Seems to me, though, that only the control circuitry would need to be digital. Your guitar signal itself could remain safe and happy in analogland.