Crack got noise when connect the braided wire to volume control

[ko853]

Hi! My new crack got noise when I connect the braided wire from input jacks to volume control. Noise appears at 50% volume and louder at higher volume. If I touch the braided wire by hand, the noise will be louder. But if I disconnect braided wire from volume control, the crack will be dead silent even max volume.
Note: the crack (got speed ball) is not grounded and not connected to DAC yet. Headphone is HD650.

If I connect braided wire to volume control and grounding the crack, it will be dead silent in any case.

what I want to ask is why braided wire from input jacks to volume control can generate noise or I got mistake while building the crack?

Thanks.

[Paul Birkeland]

You should do a search on "Shorting plugs" and read the Crack FAQ, specifically item number 5: http://bottlehead.com/smf/index.php?topic=4295.0

An open input will pick up some ambient noise, so in order to draw any useful conclusions, you will need to use shorting plugs on the RCA jacks.

-PB