Lol I remember this, took me a while to figure out how to use it properly for my needs!
I wasn't using it properly at the beginning, or I don't think I was anyway. I originally had it in the FX loop of the amp to kill the noisy pre-amp noise, but I decide to have the lead channel modded so its silent. I noticed the problem was actually my Tubescreamer pedal making excess noise when kicked on so put that in the loop of the ISP. Now its more controllable without sacrificing gain on the amp and pedal. Works well, the ISP G-string version is very smart indeed!