Speakers hum and buzz when rr and dbx installed??

Hi guys and gals, this is my first post here but I have been
an avid reader here for quite some time and have learned alot. Thanks! I have a question concerning my stereo system.
I have a new Jolida JD-801 powering a wonderful old pair of
JBL L300s but when I decided to move my reel to reel tape deck and dbx noise reduction unit into this system from my
ht receiver, I am getting an unexceptable amount of hum and
buzz coming out of the speakers. I have the system plugged into a cheap surge protector (soon to be replaced)and the amp is plugged into the wall outlet thru a gfci. The recepticle is a dedicated ps audio power port on a 20amp breaker. If I unplug the dbx from the tape output on the amp, the noise goes away. I know my system needs attention in the area of power conditioning and I am trying to learn all I can to make an educated purchase in this area. I feel I may have a ground loop going on here but I don't know for sure. Any ideas on this subject and/or recommendations would be greatly appreciated! Thanks!
If the DBX has a three prong power cable, try using a two prong adapter. If this does not work try another pair of patch cables and be certain that they are plugged in all of the way.
Rwwear, thanks for responding! I have the same cables that I
was using on my home theater plugged into the tube amp. I know they are plugged in all the way. The power cable is just a 2 prong cable and I have reinserted the power cables
in different directions on both the reel to reel and dbx unit. I suppose it's possible that when I removed the patch cables something could have broken in them but they worked fine on the other receiver. I will test them asap and let you know the outcome. Thanks again!
Well, I tested the cables and they are fine. I disconnected the dbx all together and just had the reel to reel plugged into the amp and it still makes the noise. It also gets louder when I turn up the volume so I am wondering now if it is the output on the amp? The tape deck does not make any noise unless it is connected to the tape out on the amp.
The tape input works fine. Any thoughts?
Try the DBX unit in another system. It could be at fault.