Originally Posted by pickering.tim
so what would i do before the amp to accomplish this? not that i am attemtping anything after the amp, but I am curious if you have suggestions given your comment.
the only thing after my amplifier would be two stranded OFC 12 AWG speaker cables, both 15 feet in length, bought off amazon for $14.95. I have not done any exhaustive testing vs the audioquest cables I was given (rocket 33 and type 4) because they aren't long enough to run from my components to my left speaker. So far I have gotten the best sound with these speaker cables vs even audioquest in previous setups where things were a bit closer together.
my issue is the RCA interconnects I have running from my marantz receiver sr7009 (under the television) to the component stand (off to the right of my front right speaker. I have balanced cables connecting my other sources to the jc-2 and once I finish setting this all up successfully I will most likely use digital cables to connect any source that doesnt convert digital to analog better than my benchmark dac2 DX into the benchmark dac and then from there to the jc-2. I may swap out my dac2 dx for a hgc model in order to have analog ins but I doubt having the dac between my jc2 and power amplifier is going to be any cleaner than my existing chain.
Because my marantz sr7009 needs a lot of cables coming from the back to run the 5.2 setup I have I was considering bagging the whole bypass mode idea and just simply swapping out speaker cables and/or sending my marantz preouts to the power amp directly for movies/surround sound or anything that I would prefer hearing with subwoofers and then swap back in either speaker cable or inputs to the amp from my jc-2when i want analog sound. IMHO it really is not significantly more convenient to use a remote to switch back and forth (with the risk of more noise/distortion/variables to deal with) then to walk over and swap a cable out. The biggest drawback would be that in theory I should be cutting power to everything when making that switch so that could be annoying.
Either way i dont have any way of getting something that rejects noise any better than rca cables because the sr7009 doesnt have any balanced connections.
One thing I may try is adding in my subwoofers via rca cable stereo sub style just to see what it sounds like. probably between the jc-2 and a21 but i think (correct me if anyone knows better) that the loop outs on the a21 could do this a bit easier but obviously i would be doubling the bass of my mains with he subs instead of offloading it.
I think the sr7009 does a fine job in surround movies and for the most part surround sound music, so i dont think i would really miss the a21 or jc-2 in these type of setups a great deal. two channel sounds amazing with these components with the sr7009 out of the loop and unless i can figure out a clean way to connect things togehter without noise I may just leave it that way. less power drain and components being turned on all the time during playback.
In looking at the back of the Marantz, I see that it has a Signal Ground next to the IR port. Connect a wire from this to the ground on the JC-2. This will bond the chassis to the JC-2 and could remove the noise.
You can use the balanced and unbalanced preamp outputs at the same time, so that would be where the subs get their signal.
If you could list each piece of equipment in the system including all of the video pieces, whether you have cable, satellite, U-Verse, antenna, the signal path for everything and what's plugged in & where, it would help.
This seems like a PITA, but there's often a simple cause for most noise problems.
If you have cable, unplug the coax from the cable box while the system is on- it won't hurt anything. If the noise stops, put an isolator on the cable feed- cable installers frequently install the cabling without the required ground being connected according to the National Electric Code. There's a whole section on low voltage requirements and AV & communications is Low Voltage.
I see that the TV is over the AVR- does this noise occur when the TV is off? If not, you'll need to move the AVR or re-route the cabling, to prevent the noise from the TV entering the signal path.
ANY time analog signal cabling is bundled with other types of cables, the chance of noise increases and it can even come in from HDMI. If the analog cables are bundled with or running parallel to power cords or if the electrical wiring in the wall is parallel to these cables, move the cables away from these. If they're bundled, it should be easy- if you need to find out if the noise is from being close to the electrical wiring, it's just a matter of increasing the distance from your cables to the wall. Easy for me to say, right? Distance is your friend when it comes to noise that's radiated into a component or cable.
I REALLY, REALLY like optical connections- it's not wire, so it can't possibly cause a ground loop. If you can change from digital coax to optical for anything, try this.
As far as signal path and cable routing, I like to use the AVR for all of the video and audio switching and then, send one cable to the TV for the video. The TV's input is set to the highest resolution it can handle, the output from the AVR is set to match and if it can up-convert the video, I do that. I don't like to have redundant cabling unless it's needed to provide analog audio for Zone 2, which may not be necessary for yours if it's new enough and it strips the analog audio after it's converted internally or if you're not using Zone 2. One HDMI (or component video/stereo L&R) for each source going to the AVR, AVR's HDMI to the TV, AVR's optical out to the DAC with any other sources connected to the DAC, as well and one optical from the DAC to the Preamp.
Make a list of your cable assignments and, while it's not a lot of fun, start over by unplugging everything, leaving the speakers connected (if you want to do this with closed headphones, go ahead). Connect the AVR to the preamp and the preamp to the power amp. Power it up and listen for noise- if no noise, connect the TV to the AVR. Noise? If yes, and the AVR is still under the TV, move the AVR and listen for any changes. If no, connect the next source to the AVR and repeat the procedure.
I don't remember the last time a noise problem had anything to do with the speaker wiring when the system used the normal 4/8 Ohm output (wasn't 70V equipment) and I started going this in 1978. I have even seen speaker wires bundled with power cords and that didn't even matter. There's no guarantee that bundling cables with power cords will be a noise problem, or not.
Re: the RCA cables from the Marantz to the JC-2, if you find that the noise occurs only when this cable is connected (and you can verify this by unplugging one channel, then listening for changes), this is where the IsoMax would be connected. While a Radio Shack isolator could eliminate the problem, it isn't going to be neutral-sounding.