got the item very fast, it worked without any problem.
the anti-feedback is good, but the best thing, it can be switched off! The same for the bypass button, that is good.
Note: after 6 months of usage: works well, though i had a hiss problem... i found that changing the power cable solved the problem.
As of now it is working, but some of the frequencies add a hiss when the knob is way off the center (top or bottom)...