I have both of my amps plugged into APC-H15 power conditioner/voltage regulator/surge protectors. I had a lightning strike take out my old Sony center channel and went to the APCs after that. I only use 5 channels of my 7125 and a DLP TV so the 1500 watts are enough. My 7500 is in a system without a display and only 4 channels are being used. The APCs provide me with the "common ground" which is vital to eliminating that hum. I also have my subs plugged into the APCs for lightning protection. I am not a big proponent of crediting power conditioning for better sound but I did get almost 10000 hours out of my first DLP projector bulb.

Hey guys, I have installed mostly all my equipment back. I run (2) Monster HTS 3500 MKii, 7700 amp, Marantz AV7005, Oppo 103, Optimum cable box, Xbox 360, PS3, Wii, Sony ES CD player and a DVD/VCR burner. Epson 5020 PJ, Stewart electric screen and 2 sunfire JR subs with all Klipch speakers, KLF 20 line. With everything on, system is quiet.

I flip on the Marantz 7005 and the worst hum comes out of all speakers. It is not a steady hum. It changes pitches, softer, louder etc. I didn't have time to do anything else yet. Ugh.

Start disconnecting peripheral equipment one piece at a time, then turn the system on at low volume in between disconnects, and see if you can find out what piece is causing the problem. Make sure you disconnect all of the cables/wires for each piece of equipment including power/signal/grounds and any other input to the system from that piece. Many times the cable box coax is the problem and no-one disconnects it until last. Alternately, disconnect everything from the AV7005 and leave it connected to the amp. Turn it on to make sure its not the AV7005 and then install one piece at a time, turning the system on to check if that piece works. You have a lot of equipment connected and you probably have something connected to the wrong place

I will try when I get home tonight but I have double checked all wiries and fired up each piece of equipment one at a time to make sure it works, good picture and sound from each. I am running balanced connects from my 7700 to my 7005.

Thanks for the help.

I'd say that's worth the price alone



If you tried each piece in turn, when did you notice the hum? Are you routing all your components through the 7005 or just a select few?

If you follow XenonMan's advice, the part about the cable box first hopefully does the trick! If not then I'd opt for his "alternate" method. Chances are you'll strip the whole system before you get to the problem anyways. Quicker to start from scatch.

I got those APC H-15 for $99.00 each back when Amazon had a sale. I bought the first one and as soon as I took it out of the box and realized the quality construction I ordered the second. Their combined cost is less than the replacement bulb.

$318 each now...

The next week they were triple what I paid. A friend told me about the deal and it went my way. The funny thing was they were in a silver finish vice black. The black ones never went on sale as far as I know.

Got home too late to do anything, but...I did turn everthing on except the Marantz 7005. With the amp on and everthing still wired up, no noise at all. Turn on the Marantz and all 5 speakers, (not subs) start humming, pitch changes a bit if you listen.

Also with everything on, including the Marantz, all wired, I pull the power plug out of the back of the Oppo and the noise gets louder.

Also I must be crazy but in my opinion playing a blu ray with my older Pioneer BDP51 seemed sharper then the new Oppo? Can't be...

More testing tonight. Thanks.

Without the Marantz powered there is no path for the hum/noise to get to the amp. Let us know what you find when everything is disconnected with the Marantz on and connected to the amp. I would then start connecting my most valuable equipment in order to figure out that the problem was not major $$$. Have you been able to do the setup with the Marantz yet? I would think the OPPO will be a better player based on the reviews I have seen and the performance of my BDP-83. I would also be careful disconnecting the power using the cord as it is not nearly as clean a disconnect as using the switch. Remember the old medical axiom "first, do no harm". If you want to ship the BDP-103 to me I will do some extensive testing on it and let you know what I find.