Unusual noise on Demeter Compulator

[such]

I bought the Compulator from a user here, it arrived this morning. Unfortunately, there is so much noise that it makes it unusable. I've used this model before, and while it wasn't entirely noise-free, the noise was negligible and only happening at really high compression settings.
Here's what happening:
When I power the comp with a generic Boss-type psu through the adapter (supplied together with the pedal by the seller), there is a very loud, constant-pitched noise, almost as loud as the sounds I make with my bass. My suspicion is, as Compulator seems to work on a reversed polarity, that may be the problem. I don't really understand those electronic issues though. Is it possible that powering the pedal with a wrong polarity psu causes such a noise? Would a polarity-reversing-adapter solve it? The psu is probably not the greatest quality, but works with Boss and Digitech pedals.

Now with the battery, there is no such noise, but there is a completely different one. Not constant, sometimes completely silent, sometimes a slight sough/sizzle, sometimes irregular cracks, clicks and pops, some of them really loud. The battery is new and good quality.

Now, at both situations the general compression action seems to be unaffected, it does the job as I remember it should, there is just that noise accompanying it. The levels of the noises are also unaffected by tweaking the knobs on the pedal.

I won't be able to do any shopping or see a tech anytime soon due to work schedules, I also don't want to assume that the pedal itself is faulty. The seller is on holidays now and unable to receive messages.

Any thoughts?

[such]

Uhh... sorted. It was just a bad connection in the DC jack. I managed to see a tech unexpectedly quickly and it turned out to be a one minute resoldering job. Works brilliantly now! Which is a relief as Ed (the basschatter who I bought the pedal from) is on holidays and hard to reach.