Probably normal noise from your amp. Try it with nothing plugged in. If it still hisses, it is the amp. Play with the controls to see if it goes away in any setting. It is probably not noticeable at gig level use. The manufacturer may publish a specification for it, and it nay be within spec, yet may also be noticeable while not playing an instrument through it.
My low cost Ampeg BA-110, and my 1967 Kasino/Kuston solid state amps hiss like crazy. My Ampeg PF-500 has noise in the direct out if I run it in post EQ node.
My Ampeg tube amps are silent. They are higher quality, and higher cost than the rest. You get what you pay for.
Last edited by P Town : 12-05-2013 at 05:58 PM.