Concentric Pots - PCB mountable?

FunkMetalBass · #1 10-22-2010, 10:23 AM

I feel like trying my hand at a PCB for this next project, because it should be simple for learning. The project involves some 500k/500k concentric pots that are PCB mountable.

Anybody have any idea where to find some? I can't find a source of Bourns pots without a huge minimum order, and I don't want to spend $40 on MEC pots. I know Alpha makes a bunch of pots that would work fine (like these; note the straight terminals), but I can't track down alpha concentric pots with this option.

PhiDeck · #2 10-22-2010, 10:53 AM

Did you check all the Bourns distributors listed on this page?:
http://www.bourns.com/proaudio/pamm.aspx

FunkMetalBass · #3 10-22-2010, 10:56 AM

The only concentrics that Bourns has (from what I can tell) are the PTH and PTJ series. I need neither the rotary switch, nor the push-pull. I also would like the shafts to be smaller than what they offer (they are incredibly long and there's no way I found find knobs for them).

EDIT: But yes, Mouser, Allied Electronics, and DigiKey were the first places I checked.

**line6man** · #4 10-22-2010, 11:00 AM

Why on earth do you actually want a (preamp?) with PCB mounted pots!?
(Unless each pot has it's own small PCB, rather than one large board with pots mounted to it.)

I would run a short length of wire from each pot to the PCB, that way the pots will be easy to swap out and re-arrange physically if you put your (preamp?) in a different bass.

FunkMetalBass · #5 10-22-2010, 11:04 AM

It's actually entirely passive. Two vol, tone, 3-toggle switches.

I just want to make a PCB for something that I'll actually use, and I thought experimenting around with one in a bass would be a good learning experience and would keep things tidy inside the cavity.

**line6man** · #6 10-22-2010, 11:09 AM

Quote:

Originally Posted by FunkMetalBass

It's actually entirely passive. Two vol, tone, 3-toggle switches.

I just want to make a PCB for something that I'll actually use, and I thought experimenting around with one in a bass would be a good learning experience and would keep things tidy inside the cavity.

Sounds fair enough, but I still dislike the concept of PCB mounted pots and switches, unless each component gets it's own PCB, like some of EMG's systems.

Are you having some boards manufactured, or are you going to etch them yourself? I suppose it would be cheap and easy to reconfigure things in the future if you are doing them yourself.

FunkMetalBass · #7 10-22-2010, 11:16 AM

Quote:

Originally Posted by line6man

Sounds fair enough, but I still dislike the concept of PCB mounted pots and switches, unless each component gets it's own PCB, like some of EMG's systems.

Are you having some boards manufactured, or are you going to etch them yourself? I suppose it would be cheap and easy to reconfigure things in the future if you are doing them yourself.

I'll be doing it myself - unless enough people want to pay for my products and services (beyond unlikely).

PCB design is a bit of an art form, and I like the puzzles they present as you start getting into multiple layers.

**line6man** · #8 10-22-2010, 11:24 AM

Quote:

Originally Posted by FunkMetalBass

I'll be doing it myself - unless enough people want to pay for my products and services (beyond unlikely).

PCB design is a bit of an art form, and I like the puzzles they present as you start getting into multiple layers.

PCB designs are time consuming.
The hard part is trying to get every trace where it needs to go without overlapping other traces.
Care to guess how many hours this took? (I actually didn't keep track.

)

FunkMetalBass · #9 10-22-2010, 12:10 PM

That's impressive. I have no idea what you are making, but sweet.

Still, I have the issue of 500k concentric pots that can be mounted on a PCB. Help?

FunkMetalBass · #10 10-22-2010, 02:55 PM

So, here's the closest I've found:
http://www.alphapotentiometers.net/h...mm_pot_53.html

I'm really not a fan of the fact that the outer shaft has a max of 120-degrees rotation, especially since I'll be using it for dual volumes.

SnakeKappele · #11 10-22-2010, 05:11 PM

I would use the pots with solder lugs.

Straighted the lugs and snip the loops off. I think they will be long enough to go through the board. If you're making the PC board, the lug/pin spacing won't be a problem.

FunkMetalBass · #12 10-24-2010, 09:29 PM

The loops on most lugs begin right after the initial bend. I might try squeezing them with pliers to make them a bit slimmer. Otherwise, I'll just have to drill a bigger hole.