Low buzzing through speaks

Hi @dilatante , thank you very much for sharing. And yes what I am getting seems exactly like yours and is through all 5 speakers. @dpop ​​​​@russ69 also believe it is the higher output gain of the Mac/Sim combo. 
 

And yes it can only be heard by putting my ear within about 2 inches of the tweets and is certainly not audible when anything is playing even at low volume. And it certainly cannot be heard from any normal listening position. So it is not intrusive and I know it’s common and many people live with it, but my OCD knowing it’s there when it wasn’t before won’t allow me to let it be until I’ve exhausted all feasible options, you know😬? I have a ground lift XLR adapter arroving tomorrow I’m going to try and then a 10db XLR attenuator arriving Friday. I’m really hoping/thinking one of these just may do the trick🤞🏻🤞🏻🤞🏻! If not, as I’ve mentioned I’ve got St John’s The Evangelist church on standby to send in the exorcist😂! I know that’ll get rid of this evil entity I’m just not up for the mess I’ve seen these things create😂! In all seriousness I know it’s something I can live with and if all else fails I’ll be fine…I literally connected the Mac (bought it used but new to my system) and my brand new 5 Revel’s at the exact same time expecting nirvana and as I was pulling the grills off I heard it😳😳! It was like that scene near the end from Jeepers Creepers when the Creeper literally punches a whole right through the cop-that’s how I felt😳😂

Thank you again for sharing and taking the time to reply👍🏻😊!

I have always found Transparent cables to be more “my taste” if you will. I have used several others but there just seems to be something extra once I bring in the Transparents.

...and I can respect that @kingbr. In my discussion of cable construction, I’m just wondering what amount of emphasis Transparent incorporates into their balanced interconnect shielding. Looking at their website, I see no display of it, or they don't boast about it. In your particular situation, it would be interesting to see how different XLR cables affect this noise that you’re hearing (possibly then related to shielding performance). I also can understand what @dilatante is mentioning about output gain from the Mac. It might be greater than your Marantz, which may be the reason behind you now hearing the noise with the Mac, compared to the Marantz.

Might a 20db attenuator be needed?

Keep in mind that these fixed attenuators will act like fixed volume controls. I don’t know how loud you play your system, but for every -dB of attenuation (5, 10, 20, etc.) that is used, you’ll lose that in volume when playing your system, so starting off with a -20 dB attenuator (or pad) might be a little high. Starting off with -10 dB attenuators, like @russ69 suggested, would probably be the better choice. Also, in your situation, and because of this noise, I would place them at the Sim inputs, and not the Mac outputs.

I also notice that there’s a Volume Limit adjustment in the Mac (choices are 60, 70 or 80). I might suggest switching between those (as they might be built in pads), and see if that changes anything. There’s also a Mute Level adjustment (-40 dB, -20 dB). I’d also try adjusting that to see if that makes any difference in this noise you’re hearing. It looks like the Marantz has these same setting adjustments.

Looking at the manual, this is the stated output level of the Mac (but at what volume level?):

Rated Output Voltage
2.5V Unbalanced Outputs (Main Zone)
5.0V Balanced Outputs (Main Zone)

Here’s the stated output for the Marantz:

Rated output: Unbalanced RCA pre-output : 1.2 V Balanced XLR pre-output: 2.4 V

I would hope that both would be 0.0V with no audio playing, or the volume turned all the way down.

What I like about power amps with volume/gain controls is that you can balance a system; not allowing a wide open amp when it’s not needed. I’m almost positive you would not be hearing this noise if the Sim had some sort of volume/gain control incorporated into it.

Don’t forget, we’re still interested in hearing if hooking up the RCA cables changes anything.

@kingbr 

So the only reason I didn’t hear the buzz with the 1 cable plugged in was because it was the rear and I didn’t listen to that one speaker. As I plugged the 2nd rear in that’s when I caught on that as soon as the XLR cable is plugged back in the buzz comes back in that particular speaker/channel…

I did catch that in a previous mention, but thanks for mentioning it again, so everyone reading this can absorb it, if they missed it.

There’s also a Mute Level adjustment (-40 dB, -20 dB). I’d also try adjusting that to see if that makes any difference in this noise you’re hearing.

To clarify, I'd also try turning ON the mute (trying either of the settings), to see if this has any effect on the buzz/hiss you're hearing.

for every -dB of attenuation (5, 10, 20, etc.) that is used, you’ll lose that in volume when playing your system

In almost all cases you'll have plenty of gain to fully drive the amp.

I would hope that both would be 0.0V with no audio playing, or the volume turned all the way down.

That is very seldom the case. Volume potentiometers knock down the preamps full power output. Once the gain drops below the audible range there is no need for further attenuation. That is why the idle hiss can be audible, there is still gain being passed through the preamp.