Hissing Markbass compressor

[kbuschmann]

I have a Markbass compressor that makes an intermittent and seemingly random hissing/shshing noise. Fiddling with connections doesn't seem to either induce or suppress the noise. When the compressor is bypassed, the noise disappears. It is not dependent on gain or any other settings on the box. Any suggestions, short of sending back to the vendor?

[octaverazor]

Might be a bum tube.

[Matthew_84]

or as Yoda would say:

A bum tube, it might be.