Crack build with Alps pot issues

[bala]

Hi Guys,

            I just finished my second crack build. This time I went with a 100k Alps blue pot. I followed the same wiring pattern as with the default pot, face the following issues;

- output in the right channel even when the pot is at zero
- no output in the left channel at lower volume levels (upto 12'0 clock), though volume rises in the right channel
- the output then levels out to both channels once the pot starts going past 12'0 clock and is balanced at max volume position

Attached some pictures for your valuable input, thanks.

 

[Paul Birkeland]

Did you build this kit stock first?  Did you pass your voltage checks?

 

[bala]

No, I went with the Alps pot directly. I have passed all the voltage checks as well! Would it now make sense for me to remove the Alps pot and go with the kit supplied one?

 

[Paul Birkeland]

Re-reading your post, can I infer that the amplifier would function perfectly with the volume pot half way up?

 

[bala]

At half way mark the left channel just starts coming to life and everything is perfect at max volume . I have just removed the Alps pot and gone back to the pot that came with the kit and it works as it should. Is there a different wiring pattern that I need to follow with the Alps pot?

 

[Paul Birkeland]

There was no issue with the way you had that pot installed.  Some thoughts that come to mind:

1.  It's easy to end up with a fake Alps pot.  There are lots of Chinese knockoffs being sold in the usual suspect places.  Occasionally a fake will sound better than the real thing!
2.  Some Alps pots are configured for other purposes (balance being one of them).  Your pot isn't stickered to indicate this.
3.  Somehow the pot is/was damaged.  Those little PC pins aren't really intended to be solder lugs, and it's entirely possible that it just didn't hold up to installation. 

In any case, I'm glad the factory parts are functioning properly.
-PB

 

[TomS68]

I have two identical pots that you show in the photo and both read fine. (They are marked just like yours.)

Input to ground you should read a constant 100k ohms. Input to wiper (center lug) you should track from 100k to zero ohms going from minimum to maximum turn on the pots. You need to measure both sections since these are dual ganged pots. Wiper to ground will track exactly opposite on an ohmmeter.

I suspect answer three is correct and the pot is damaged since my pots are stickered the same. I am using single ganged Alps pots so the dual ganged may or may not be used in my Crack builds so it is possible I could send you one gratis if yours is indeed damaged.