MCA-18, high noise floor?

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ralflar

MCA-18, high noise floor?
« on: 12 Apr 2015, 10:34 pm »
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

  • Jr. Member
  • Posts: 3
Re: MCA-18, high noise floor?
« Reply #1 on: 26 Apr 2015, 11:37 am »
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

  • Jr. Member
  • Posts: 11
Re: MCA-18, high noise floor?
« Reply #2 on: 30 Apr 2015, 08:04 pm »
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

Re: MCA-18, high noise floor?
« Reply #3 on: 9 Jul 2015, 01:57 am »
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.