Blower switch on push/pull tone pot question

eru

Hi,

I've just added the "blower switch" mod to an LP Junior-style guitar with one P90 pickup, a volume knob and a tone knob. I've wired the mod onto a push-pull tone pot so that when it's in the up position the controls function as normal; in the down position the volume and tone pots are bypassed.

The mod seems to work as planned, but an issue I've found is that there's a "blip" noise when using the push/pull knob. After experimenting a bit, I've found that if I push/pull the knob very slowly (oo-er) there's actually a point between the two different positions where the sound cuts out completely. This wasn't obvious when switching at normal speed.

As I've never used a push/pull pot before (or a mod like this), I'm wondering if the cause of this is: a dodgy pot, incorrect wiring, some other issue, or if this might even be normal for this mod?

Thanks for any advice.

CasperCaster

I'd guess it depends on the spec of the switch on your push-pull pot. My guess is that it is a 'break before make' switch, hence the brief silence between positions. I don't tend to use push-pull or push-push switches much, so I'm not certain if this is usual for this type of pot or if some brands of pot have a 'make before break' switch action. Someone else on the forum my be able to advise. 

ICBM

It's normal. It's a break-before-make switch, as CasperCaster said.

I don't know of any push-pull switch - or normal mini-toggle, if you had thought of changing it for one of those - which is make-before-break. 

eru

Thanks for the replies. I had no idea about "make-before-break" vs "break-before-make" switches, just learnt something new. If the latter are the standard type for switches used on guitars then I think I'll just leave things as they are. I had considered using a mini-toggle switch but didn't fancy drilling a hole in the body so opted for the push-pull instead.

ICBM

Break-before-make is by far the most common type of switch for more or less any application.

This is also why I don't like 'superswitches' for Strats or even the 4-way Tele switches - they're also break-before-make so you get a louder than normal switch pop, or if you're unlucky and the switch sticks just at the critical point, silence.

It's the original Strat and Tele switches that are unusual in being make-before-break. Whether that was a factor in their choice originally or whether Leo Fender just picked what was easily available and fitted in the guitars, I don't know.

Funkfingers

Leo Fender simply stocked up on cheap military surplus items - pots, switches, valves, transformers et cetera. Most of these had been thoroughly combat tested in field radios.

axisus

I have to say that I always try and get push-push pots, they are so much easier to use on the fly. I wired mine the opposite to you, I figured that the guitar should look 'normal' most of the time then different when you use the feature.

Anyway, back to your problem  - I've never had that issue myself, maybe a dodgy pot? or a dodgy brand?

Funkfingers

CasperCasper and ICBM are correct. The issue is the break/make order. I had the same problem on my PRS SE One with the push-pull “woman tone” preset switch I added. Eventually, I solved this by adding a proper tone control.