Low buzzing through speaks

@kingbr 

Are you sure what you are hearing is an actual faint buzz, not a hiss coming from the speaker's tweeter? And you only heard it within half a foot away from the speaker, correct? And this only occurs with your Mac but not with the Marantz you had previously? It's possible that the Mac preamp's output gain is higher than that of the Marantz but it still shouldn't be buzzing IMO. 

But if the faint buzz is audible only when you put your ear right up to the speaker I wouldn't sweat it if I were you and as long as it doesn't distract from your listening to music or movies. And you said it isn't audible at all from half a foot away from the loudspeaker. Are the buzz on all speakers or just the front main LR speakers? 

I have exact same experience as you do with my current Cary Audio SA 200.2 ES stereo power amp (solid state). it's a faint buzz and is only noticeable when I put my ear right up to the speaker. This didn't happen when I had the Classe Sigma Amp2 power amp, it was dead silent. But when I swapped the amp to Cary with everything else unchanged I could hear a faint buzz when I put my ear right up to the speaker, and it's only audible within less than a foot away from the speaker. Apparently this faint buzz is pretty common with this Cary SA 200.2 ES amplifier design. I had discussions with other Cary SA 200.2 ES users on different forums and some could notice a faint buzz but some don't. 

I wouldn't sweat it if I were you as long as the faint buzz doesn't grow louder over time and as long as it doesn't distract from your listening to music or watching movies. You aren't alone in this.

@kingbr

You’re very welcome. I know how you feel about that. Once you heard it you cannot unhear it eventhough it’s only audible from inches away from the speaker’s tweeter 😁😁. What’s your speakers’ sensitivity? It’s even more audible through highly sensitive speakers (highly efficient speakers).

You don’t want want to use a ground lift XLR adapter or a 10db XLR attenuator, you don’t want to insert anything in the signal path as it would potentially degrade the signal purity thus will degrade and compromise the overall sound quality. Just leave it alone as is. Because you will be compromising the overall sonic fidelity (sound quality) while trying to fix or resolve something (faint buzz that’s only audible from couple inches away from your speaker’s tweeter) that isn’t even an issue to begin with.

Not all systems are dead quiet if you literally put your ear right up to the speaker due to various different AC induced environments in our homes. But it looks like you have the Shunyata AC power product and power cables in your setup. Shunyata makes great AC power products and power cables. I also use Shunyata AC power products and power cables in my setup at home but that faint buzz is still there when I use my Cary SA 200.2 ES power amp in the system, but then when I switch the amp back to the Classe amp the faint buzz goes away and is dead quiet. So, I know it’s the Cary SA 200,2 ES power amp (solid state) that’s causing that’s causing that faint buzz when I put my ear right up to the speaker (really close to the speaker). So, I just live with it since the Cary sounds better and more musical than my Classe Sigma Amp2 power amp. But I still have the Classe amp and decided to keep it as a back up amp (reserve). I mostly use the Cary amp since I like the way it sounds as it reminds me a bit of its tube amp counterpart since Cary Audio is well known for their tube gears. I have their SLP-05 vacuum tube linestage preamp in my setup and they make great combo. I only have stereo setup for listening to music only. I don’t do surround sound movies.

Trust me kingbr, just leave it as is and just relax and enjoy your music and movies.

Agree with @dpop as it will be tradeoffs because you will be compromising the signal purity thus overall sonic fidelity (sound quality) everytime you insert something in the signal path. 

@kingbr 

I wouldn't get any XLR attenuator or any sort in the signal chain because you will be compromising the overall sound quality of your system slightly. Just leave it the way it is since the faint buzz is only noticeable from like couple inches away from the speakers anyway and has no impact on overall sound. Don't sweat it. 

But I would just keep using the XLR balanced interconnects throughout especially if your gears are fully balanced design or true differential design internally. I don’t know if your Mac and Sim are true differential design or fully balanced design internally, but if they were, you will be better off using XLR cables throughout as it would sound better than using RCA single ended cables. it’s quieter (lower noise floor) when using XLR cables if your gears are fully balanced design or true differential design internally.

FYI, not all gears that provide XLR connectivity are fully balanced design or true differential design internally. Some are single ended design internally although they provide XLR connectivity (outputs & inputs). Marantz multi-channel power amps and their preamp surround processors are single ended design internally but they provide XLR balanced connectivity (inputs & outputs). So if your gears aren’t fully balanced design or true differential design design internally you can use RCA single ended interconnects and would sound the same whether you’re using RCA or XLR, or you would probably be better off using RCA in this case, unless if you're running long interconnects then use XLR cables. 

@kingbr 

You are most welcome. 

Usually most if not all Mac amps such as their monoblock amps and most of their stereo power amps are fully balanced design or true differential design but not sure about their entry level AV preamp surround processors such as your MX122, whish was based on the Marantz AV8802. Mac's flagship AV preamp surround processors such as as the MX 160/161/170 are most likely fully balanced design or true differential design. I have no clue regarding your Simaudio Titan multi-channel amp. 

Just enjoy your music and movies and forget about that faint buzz that's only noticeable from couple inches away from your speaker.