Alps Potentiometer Question

[nomoneyx]

About ten years ago I started building a headphone amp but I was not able to finish it. Just recently I pulled all of the parts for the amp out of storage and found these four Alps potentiometers. I am not sure what model these are or if they could be used on a headphone amp. They all have "ALPS", "321", and "MADE IN JAPAN" on the back. They also have a sticker on the back that has the number "050t" and "100KX". Does anyone know if these would work for the volume control on a headphone amp?"

 

[tomb]

1. There doesn't appear to be anything similar in the current Alps catalog.
2. I suspect that the "100K" portion means that they are 100K pots. Also, it appears that they are multi-segmented and setup for two channels, which would imply that they could be used as volume pots.
3. The question is whether the response is logarithmic, which is what is needed for audio.

A simple DMM can be used to plot the resistance at various positions of the pot shaft. This will answer questions #2 and #3 for you. Here's a resource from Head-Fi user Tangent: https://tangentsoft.net/audio/misc/pot-curves.zip . If your measurements are similar in either value or curve/line shape, then you will know.

 

[nomoneyx]

At zero rotation they have 1 ohm resistance and at full rotation they have 98.2k ohm resistance. At half rotation it has about 13k ohm resistance, so it looks like they are logarithmic. Thanks.

 

[HiGHFLYiN9]

100K should be good. They look a little like these: https://www.ebay.com/itm/Alps-Model...h=item4d50df1c37:g:ZSIAAOSw-0xYWuAw:rk:8:pf:0

I bought a few a little while back and they work well for headphone amps. I shot you an email if you are willing to part with 1-2. I love trying obscure old parts in new builds, and I bet these are better than vintage Allen Bradley.

 

[nomoneyx]

I looked at the RK271 data sheet but they are 27mm wide and these are 40mm wide. This spec sheet is the closest thing I could find:

http://avpg2.homepage.t-online.de/PDF/RK40312.PDF

So, I think they are RK40321A0?