Question about stereo headphone pots (w/ 6 tabs)

I considered tacking this on the other pot question but decided not to.
I'm trying to figure out which pot to order for a replacement for a stereo headphone pot that is bad in my mixer.

The pot has absolutely no indication as to any kind of value on it. But I'm figuring maybe one of the panasonic pots in my digikey catalog that say under applications: "audio mixer" might work. What the hell.

Anyway, the pot that is bad has two sets of three tabs stacked on top of each other, and the replacement that looks like it will work has six in a row.

I'm wondering if there's any kind of standard tab configuration for six tab pots w/ six in a row. I can tell which two tabs are the ground on my bad pot, but I'm unsure how to wire it up if I get the six in a row version.

Anyway, any help would be appreciated.

JW

How bad is the old pot? If it is crackly, then there is a good chance that you can measure its resistance. Tracks rarely fail end-to-end, it's more likely that the wiper is dirty/intermittent/damaged.

Get a DMM, set it to a high Ohms range (2000k or 200k to start). Connect your probes across the two outer tabs (the central one is the wiper) and observe the reading. Adjust the range switch on the DMM to get a sensible reading. Check both gangs to see if they tally. This is the value of the pot.

The best way to find the pin out is to consult the manufacturers datasheet. Most suppliers have pdf link to this, and it'll show the pinout, ratings, tolerance, size etc.

If you can't find this, then get the DMM out again! A bit of investigation will soon sort out one gang from the other, and then start-of-track, end-of-track and wiper for each gang. Let me know if you need extra details for this!

Mark

Pinouts of inline 6 or 7 pin pots are often bizarre. Moreover, be careful to look at the power ratings---they are often quite low, and as well you may be using a particular pot at a small fraction of its rotation, and depending on the source and the headphone impedance getting a lot of localized dissipation.

Hmmm,

Do you mean bizarre like this:

A3-B1-B2-A1-A2-B3

That's one of the diagrams in the digikey catalog. I can figure it out I think if the grounds are the 1's. Not sure which pins to put the two wires from the two gangs though.

I'll get out the multimeter and see if I can measure the pot.
It's really pretty bad. Cutting out a lot.

Okay,

I'm getting 4.8 ohms on both gangs. Does that sound right?

So, I havn't looked yet in the catalogs, but as long as I get a pot w/ the same ohm rating, I'll be okay? assuming I get it wired right?

JW

That's a very specialized low-R pot, almost certainly wirewound. I doubt you will get anything close in the 6-in-line varieties, which are usually carbon film and very limited dissipation.