Bleed cap question

adam_swapp · Post by **adam_swapp** » Thu Mar 03, 2005 10:16 pm

FWIW, I've got a PP pot (from AllParts) in a 620 - which is just as thin as a 330/360. One thing to look out for - the shaft diameter for the PP pot is usually less than the 3/8" for the stock pot. You can either a) buy a bushing designed for that purpose, or b) use duct tape (which is what I did).

harvey49 · Post by **harvey49** » Fri Mar 04, 2005 6:43 pm

Guys you're killing me here! a) what is a push/pull pot used for b) what's the benefit for using one?

You've got to forgive my ignorance, but keen to know what all these mods do

Cheers

Ron

adam_swapp · Post by **adam_swapp** » Fri Mar 04, 2005 8:15 pm

A push/pull pot is actually two components in one package; a pot and a DPDT switch. There is no default electrical connection between the two components. The pot works like any other pot. The shaft also actuates the switch; press it in and it closes one set of contacts, pull it out and it closes the other. You can also get push/push pots. They work the same, except that you push the switch to close one set of contacts, then push it again to close the other set. These pots are typically used to save space or to avoid drilling new holes in a pickguard.

You can see a picture of one here.

harvey49 · Post by **harvey49** » Fri Mar 04, 2005 10:23 pm

Thanks for your patience Adam, you must think "I've got a thick one here", but as I said previously, not having any involvement with the wonders of electonics, my knowledge in limited in this area.

So now I know what a push/pull pot is, where typically would you use it if it could be installed in your guitar. An out of phase switch on a three pickup guitar maybe, to avoid using a toggle switch? Others?

adam_swapp · Post by **adam_swapp** » Fri Mar 04, 2005 10:32 pm

Yep, that's a good use. I usually use them to engage a coil tap on a humbucker. There are all kinds of other uses: selectively engage a tone cap, change the resistance on a volume pot, put pickups in series/parallel, etc. They're quite useful, actually, if you're not the type to leave well enough alone. It's too bad they're such a PITA to solder.

porge · Post by **porge** » Tue May 31, 2005 1:29 am

I've used a Push Push pot (nice things, but they're fragile) to control the middle-pickup on a 340.

rictified · Post by **rictified** » Tue May 31, 2005 2:05 am

"Since the cap works as a high-pass filter, and given the value of the cap, wouldn't it allow only the "highest of the highs" through?"

Incidently, the cap (or any cap) only acts as a high pass filter when it is in series in a circuit, if it is in parallel it acts in the opposite way, it is a treble cut (or bass pass) filter.