[ralflar]

I received the amp new last week. At medium volumes this amp is very resolving and transparent. I like how it sounds. It is doing many things right. But at idle or low volumes a background hiss is quite obvious. It is independent of the volume of the pre-amp (MCP-18). It is also there when I disconnect all inputs. This plugs into a Belkin PF60. I tried directly into the wall as well. That background hiss is always there. Easy to hear from 8’ away.

So alright, the amp’s 89 dB S/N ratio is not impressive, but surely it cannot be this audible? Is this normal or is my unit defective?

[scouter]

Must be defective, or you have some kid of ground loop problem.  I have a MCA-18 in a second system, and it is super quiet. Get a cheater plug and see if it makes a difference.

[ziv]

I confirm that the noise floor of the MCA-18 is high, much too high to my taste. I tested 2 copies (with the same results) before exchanging it to a Marantz power amp, which does not have any audible noise.

[ralflar]

scouter:

It was indeed defective. Not long after I posted here, the amp failed to power up. I got RMA from Optoma and had them repair it. The amp returned today, and has been playing for the last hour. The noise is gone.