Yes, they are both connected to a Panamax surge protector. No, they are right next to each other about 6 inches apart. As far as cable bundled, video and audio are as best as possible separated from the power cords of any electronics. As far as the amp, I have a A23. I have tried to connected the AV receiver to a different part of the house using a power cord extention, but that did not eliminate the humming noise. Tried different RCA cables, and the humming noise is still there. I have been looking at Jensen transformers and Ebtech for possible solutions. Please advice.
Your electrical outlets- three prong, right? If you're using a grounding adapter on the Panamax and the green wire or the small metal tab isn't screwed to the center of the wall plate, your Panamax isn't going to work properly and the ground pin on the Parasound isn't connected to anything, which can cause this problem, as well as being a safety issue. Those adapters aren't designed to be used to lift a ground, but they can be used as a diagnostic tool- if the outlets are all grounded and in good condition, unplug the Pioneer and Parasound from the Panamax and unplug the Panamax from the outlet. Plug the AVR and power amp into the outlet and listen for hum. If it doesn't hum, the Panamax is causing this and you'll need to contact them about it.
How old is the A23? If it's more than about a year, it may have a third toggle switch on the rear, marked Ground Lift and Normal. If it has that, put it in the Lift position and listen for hum.
Have you tried different cables? Have you tried moving them apart? Are you using the power cord that came with the Parasound AND the pioneer?
If you have a battery powered boom box or other amplified speaker for an iPod/smart phone, connect the cable from the Pioneer to the amplified speaker, using any adapters necessary. If you hear hum, it's coming from the Pioneer. If you have a test light, disconnect the cable and any other connections, then touch the wire from the test light to either and the tip to the other. If you see the bulb illuminate at all, there's some resistance between them and this needs to be remedied.