How much noise is acceptable when no music is playing?

[W9TR]

McIntosh specs the MC 8207 noise at -112 dB below 200 watts.

If you reference that to, say 1 watt, the snr is 23 dB worse, or -89dB below 1 watt. The 23 dB is just the ratio of 200 watts to 1 watt.

That's the math and most manufacturers reference noise to full output power because you get a better number.

1 watt is still pretty loud, (not sure you would put your ear next the speaker) so if you have moderately efficient speakers, like 90 dB 1 watt/1 meter, you probably won't hear the amplifier noise 1 meter away or at your normal listening position. The room ambient noise will be higher than the noise coming from the amp. But you will hear the amplifier noise if you put your ear next to the tweeter.

This is just a guess, but I'm pretty confident the 8207 is performing to spec and there aren't any issues with noise coming in on the power line.

Tom

[leftside]

Is there a wifi router in close vicinity?

[Mouse]

Originally Posted by CGabriel

You said that you can hear a hiss from 3 away from the speakers with the preamp turned off. Correct? And you said that you can hear a hiss at 30 feet away with the volume control set to 60 and that you normally will only listen at a maximum position of 60. Correct?

Of course, the devil is always in the details and in this case it is in the context. But in general I would say that audible hiss from 3 feet away, using a solid-state amplifier is not exactly normal and hiss from 30 feet away at any volume setting is definitely not normal.

My first suggestion would be to consult with your dealer about this and have him evaluate the situation.

There are many contextual things that would need to be considered to find the solution. Here are just a few: What speaker are you using and what is it's efficiency rating? Are you using RCA or XLR type interconnects? What brand of interconnects are you using and are they well shielded? How old is the amplifier? Has this hiss always been present since the first installation? If you completely disconnect the interconnects from the amplifier - does the amount of hiss change? Is there any low frequency hum associated with the noise or is it 'just' a high frequency random noise hiss that you hear?

Now that the electrician is done things changed A LOT. The noise is considerably lower. Now at 70 it's audible at around 3 feet, just like when the preamp was turned off. No longer can I hear it at the listening position. If I crank it up full blast it's still audible at 30 feet, but less loud than before.

Before the electrician connected a new ground and ran a dedicated 20 amp line:
Yes, 3 feet away and the hiss is still barely audible. Past 3 feet and I can't hear it. This is with the preamp turned off. As long as the preamp was off it didn't really matter whether or not the XLR was plugged in.

I often listen around 70, and when it was paused or nothing feeding it was audible at 30 feet.

Sonus Faber Olympica 3. 90 dB SPL (2.83 V/1m). NOMINAL

XLR Audioquest Mackenzie x 5. They aren't supposed to be terrible, but one is defective and not sending the full signal so until I buy my new set I'm 3.1 instead of a 5.1 system.

My pre and pro amp is about 1-2 years old.

I think it was audible from the beginning, but I thought it to be acceptable noise until I heard other systems dead quiet. I never was critically analytical to the noise when judging other systems until I heard expensive cables and was amazed at how black the noise floor can get. Only recently have I been OCD'ing over power and cables.

When the preamp is off and the amp left on the noise only comes from the tweeter. When the preamp is turned back on I get noise from both the tweeter and the midrange speaker.

[Mouse]

Originally Posted by leftside

Is there a wifi router in close vicinity?

Nearest wifi router is about 40-50 foot. The MX122 connects to wifi, as does many devices next to it. I have a wired ethernet switch in the cabinet though.

[Mouse]

Originally Posted by W9TR

This is just a guess, but I'm pretty confident the 8207 is performing to spec and there aren't any issues with noise coming in on the power line.

Tom

The electrician dropped the noise considerably. It's not audible from the listening position anymore at a reasonable distance. At 100% volume ~91 it's still audible at 30 feet though, but less noisy than before.

[MtnHam]

Any noise audible from the listening position is unacceptable!

[Mikado463]

Originally Posted by MtnHam

Any noise audible from the listening position is unacceptable!

agreed .............

[Msegal]

I would definitely take Mr. Gabriel’s advice and have your dealer troubleshoot the problem.

I am glad it improved but the system still seems “off”.

If you do not have an available dealer than I would start with unplugging every thing and plug the amp in alone to the outlet. There should be no hum. If there is ANY noise this needs to be addressed first. Check the speaker to amp connection. Better to use spades or bananas rather then bare wires.
If there is a hum try floating the ground as I suggested. If this works you will need to reground the receptacle.

Next I would go with a high quality power cord between the amplifier and the new 20 amp circuit.
Once this is cleaned up did back in the preamp. Keep it very close to the amp, plug it into the same 20 amp circuit and connect it with a good high quality interconnect (balanced if possible).
Even at full volume I would expect this to be dead quiet except at full volume where a very faint rush MAY be audible.

Try various power cables, interconnects and power conditioners if this is not satisfactory.

Sometimes it can be other appliances in your home or heavy machinery at a neighbors home polluting your power. Other times I have seen problems with nearby high voltage lines, transformers, radio or TV transmitters etc.

Let us know how it goes.

Good luck.

[ylee]

Originally Posted by Msegal

Once this is cleaned up did back in the preamp. Keep it very close to the amp, plug it into the same 20 amp circuit and connect it with a good high quality interconnect (balanced if possible).

+1. Definitely make sure your preamp and amp are drawing current from the same circuit.

[robd2]

This detail caught my eye

Originally Posted by Mouse

I often listen around 70