Slight buzz through speakers

So let me understand your minimum setup.  You have your McIntosh preamp plugged into your Simaudio power amp and your speakers are connected, but nothing else, right?  Does the McIntosh or Simaudio amp have a three prong plug on the power cord?  If so, use a ground cheater adapter that converts three prong to two prong.  If the buzz goes away, then the problem is line leakage and bleed in.  There are two ways to fix this - first, the ground cheater is not a solution, as it leaves the chassis ungrounded, which could become an electrical hazard.  Jensen makes a galvanic isolator that will eliminate the problem, see this link:  

They make it in mono and another one in stereo and mono for subwoofers, too.  Another option is building your own by putting two RCA connectors in a plastic box, connecting a capacitor from center pin to center pin and another one from ground to ground. The caps need to be at least 2 uFd and polyproplyene.  If you use a metal box, then the input RCA jacks must be isolated from the chassis but it is okay to ground the output RCA.  

Hi @spatialking thanks for replying. So I have my McIntosh preamp plugged into my Furman Elite 20PFi power conditioner (along with everything else except the Sim amp). I have my Simaudio amp plugged directly into the same wall outlet as the Furman Elite. It is a dedicated 20 amp line. So on that dedicated 20 amp line the Furman is plugged into the bottom receptacle and the Sim amp is plugged into the top receptacle. Both the Sim amp and the Mac pre have 3 prong plugs-the Sim is a C19 20 amp power cord. 

Just this morning I tried unplugging the McIntosh from the Furman and then plugging it directly into a different wall outlet altogether. No change buzz still there.I also removed all of my Transparent Plus XLR IC's from the McIntosh to the Sim amp (McIntosh still plugged into the Furman at this point). I completely removed the XLR IC's. So the only thing connected to the Sim amp was the speaker cables. And no buzz. This confirmed the buzz wasn't coming from the Sim amp (and I never had this buzz before so I knew it wasn't the Sim amp).

Just this morning I also unplugged every component 1 at a time from the Furman. Buzz still there so the buzz isn't coming from any other component so it has to be the McIntosh preamp, right? 

I have never plugged to Mac into the amp directly, not even possible.

Thank you for the suggestion of the cheater (many others have suggested this-I will try that). I will check out the Jensen piece you reference. I also ordered the Hum-X which will arrive tomorrow and I'm really hoping plugging the Mac into the Hum-X and then connecting to either a different wall outlet or the Furman-I'll try both and see if either works.

Again the buzz/hum is very faint and can only be heard without anything playing and putting my ear within a couple inches of the tweeters, But it was never there before and changing volume does not change the buzz it remains low (thankfully) and certainly not at all audible from the listening position...

While I applaud all your efforts and certainly sympathize, the best/easiest thing to do at this point is to call Mac and see what they suggest.  I personally am not a fan of Mac products — just not my taste — but they’re a quality company and expect they have good customer support and care about having happy customers.  Best of luck!

Based on what you said, I believe the Mac is instrumental in the problem, but not exactly the source.  This sort of problem is cumulative and system dependent, so it is more of a system problem than a particular component.  

In general, plugging a component into a separate outlet will usually make things worse, not better.   This is especially true if the other outlet is on the other leg of your distribution box. 

You are on the right track, you do want to eliminate that buzz, as it will muddy the sound significantly.  I am not sure the Hum-X will do the job you need but it won't hurt to try.  Do note it is only rated for 6A, that may have an impact on your system. 

Post your results here, I will follow up.

@soix thank you. I have contacted Mac for other questions before I bought the MX122 and their tech support was always available. I’ll give that a shot certainly. Ya Mac from what I’ve seen/heard/read isn’t for everyone (just like every other component maker out there huh?)…thanks for the well wishes👍🏻!

@spatialking thank you so very much again for taking the time and interest to help…I will certainly post here what happens once I get the Hum-X. Someone in the preamp-amp forum where I also posted this, said he had the exact same problem and the Hum-X fixed it. I had already been familiar with it and pulled the trigger right then and there after reading that reply. If it doesn’t work I can return it no harm. At $81.00 why not-I’m ready to pay 10x that if there’s a solution! And thanks for the support-nice to know I’m on the right track😊

The hard part to swallow (even though many have said since it’s not audible at the listening position and it’s on the quieter side no problem to live with it as so many do) it wasn’t there with my previous Marantz AV8802A preamp (which I still have, not sold yet). I know the Mac is in another class than the Marantz which is why I wanted to get my hands on it. So hard to wrap my brain around living with it at this point…

You have a cable box. What company do use for cable service? I have found that conventional cable causes RFI hum that is impossible to eliminate. There are two ways to fix this problem:

1) Hire a service that uses light to conduct the signal, like Verizon FIOS. The FIOS signal is clean because it is carried by light up to your home. Light signals do not cause RFI. Once it reaches your home, the light signal is converted and runs through CAT 5 cable. This short run does not result in RFI. When I switched to Verizon FIOS many years ago, I was shocked when the faint hum was completely eliminated.

2) Another option: Get rid of cable service and use exclusively streaming for content. This will eliminate cable RFI as long as you don’t hook any of your equipment to conventional cable.

3) I have found that the expensive,’high end’ fancy looking power line and cable filters are totally useless. The best way to clean up your power line is to hire a master electrician to install dedicated lines for your audio/video system. You might be surprised to find it is not significantly more expensive than the useless high end filters that are marketed today. This is a permanent simple solution that won’t break down, become out-dated, does not require updates and does not take up rack space or floor space.

4) Hum can also be caused by poor, loose connections and/or old, frayed cables. But, in my experienced, I have found the the cable source was always the worse offender for hum, interference, RFI.

5) In conclusion, I bet most of the hum is from cable, not the power lines. Here is a simple test: disconnect cable from all of your equipment. If the hum disappears, you have identified the culprit.

6) One last thought: The hum may be due to a noisy transformer in the new McIntosh. If that is the case, that is the way they are made, unfortunately. If you feel the sound/performance is not significantly better that the Marantz, return it and get your money back.

6) GOOD LUCK! Let me know if this works!

Hello @straightwire and thanks so much for taking the time to send such a thorough and detailed reply😀!

I currently have Comcast/Xfinity. Unfortunately, Verizon FIOS is not available in my area and because of my location (lots of woods/tall trees) satellite dish is not available either. It's Comcast or none. I already tackled the cable box buzz as it was very loud and went louder as volume was turned up. Unplugged the coax and hum disappeared completely. I bought a coax hum eliminator and once installed no more buzz/humm whatsoever (this was when I had my previous Marantz AV8802A as my processor). Soon as I upgraded to the Mac and reconnected a very faint buzz could be heard. I started with cable again disconnecting and hum still there. One by one I disconnected and reconnected every component in the system. Buzz never went away. The volume of the buzz has stayed consistent never changing with volume or anything else...

Once I tried unplugging my XLR cables leaving only the Mac and my Sim amp (with speaker cables connected to my amp) connected buzzing went away. As I reconnected the XLR cables 1 at a time the buzz returned to that speaker/channel. At this point it seems (unlike the Marantz/Sim combo) like the Mac and Sim just "do not play well together". There's only 1 other thing I haven't tried and that's going RCA instead of XLR. But I have spent a very small fortune on my Transparent XLR's so that's not really an attractive option-though I will try to see if that takes away the buzz just for kicks as I have a few RCA's hanging around. So I'll try just to see if that changes anything.

The only other thing I can think of is that whilst I never had this issue with my Marantz, the Marantz is a 2 prong plug and the Mac is a 3 prong. Maybe somehow this makes a difference? Though I did try a cheater plug on the Mac and the buzz was still there...

I have had many folks reach out and tell me they have the same issue and that because it's so faint and can only be heard ear within 2 inches of the tweeters, do not worry about it at all. So, I'm starting to wrap my brain around it🙄, It cannot be heard at all away from the tweeter and from any listening position and is not intrusive at all (other than my OCD knowing it's there) so I can certainly live with it. Besides I have tried pretty much everything...except calling in a priest to get rid of this evil entity but I've seen the mess that makes afterward😂🤣

Thanks again for the thoughtful reply...I'm still open to any/all suggestions...

The RCA cables are worth a try, but I doubt that will make a difference.

The third prong in the plug is the ’ground’ which can pick up RFI. This can be defeated with a two prong plug converter.

Sometimes there is a hum in standby, but it clears up when content is played.

If the McIntosh has a noisy transformer, nothing will eliminate the hum. Try putting your ear to the unit while it is turned on, with no content playing in a very quiet room. Better yet, if you have access to a good stethescope, use the stethescope to listen for hum coming from the unit. If you hear a slight hum coming from the unit, it has a noisy transformer. If that’s the case, they are probably all made that way.

If you like the new McIntosh better than your old Marantz, try calling Marantz technical support for additional ideas. With or without hum, it should out-perform the old Marantz by a significant margin to justify the cost.

Thanks again @straightwire. I did try the 2 prong cheater plug and the hum was still there. There is no noise coming from the Mac unit itself, but through the speakers. I am pretty convinced that somehow introducing the Mac with it's 3 prong plug somehow opened the gateway and allowed this entity to get in.

You are definitely correct this unit is a definite upgrade from the Marantz, and I have called Mac's Tech Support. But they really couldn't diagnose, everything they suggested I had already tried... I guess this unit like others have said "just doesn't ply nicely with others". At this point I am learning to accept it. It is by no means intrusive, and you cannot hear it when music is playing (though with ear to tweet and low volume I can hear it but that's because I'm listening for it too). But when volume is at normal levels you cannot hear it at all. It is very faint so I guess in some ways I should feel lucky (others have said this as well) because this is so common and much worse in many cases...