Scratching sound when adjusting volume

[Kitchener]

I speedballed my Crack a week ago.
I installed a new pot (TKD 2CP-601) a week before that.

After installing the Speedball there has been a slight scratching noise when adjusting the volume on the Crack.
It's barely noticeable on my HD6XX Senns (but much more prominent on my 80 Ohm Beyer DT770s)

Some observations:
The scratching is not constant; only slight stabs of scratching when I twist the pot,
the quicker I twist the louder the scratch,
it goes away after a while.

Is this expected behaviour or indicative of some malady?



Just to go off topic right off the bat:
After speedballing, my 80 Ohm Beyers really stopped playing nice with the Crack.
I notice the bass seemingly dropping off sometimes, like the headphones can't keep up.
This does not happen with the 300 Ohm Senns.

[Paul Birkeland]

80 ohm headphones are on the low side for the Crack.

We cannot really help much with an aftermarket volume pot that's noisy. 

[Kitchener]

Yeah totally, I know the Beyers aren’t a good fit at 80 ohms.

Okay, I just figured maybe someone here might have experienced something similar since some of you have been around for a while.

[Paul Birkeland]

I've run into some scratchy pots, but usually on equipment that's very old (with crud in the pot).

[Kitchener]

Some have suggests the pot might be defective.
So I’ll either switch it out with the stock pot or see if the vendor is willing to help out with a replacement.