Loud hiss

Posted by: Tiina on 18 April 2016

I've got for stereo system nac 202 and nap 150x. And as HT preamp audiolab ap8200 with the same nap 150x with unity gain and napv175 as HT amp. When unity gain is on and cd5i Is plugged in very loud hiss comes from the speakers. When cd5i Is not connected, everything works fine. What Could be wrong?

 

Posted on: 18 April 2016 by rjstaines

Hi Tina, take a minute to tell us what's connected to what?  I ask because you can't have unity gain on a NAP150x (it's all unity gain)... do you mean the NAC202?

and where's the NAPV175 connected? ...I assume the output from the audiolab?

What you're describing sounds like an earth loop problem. The CD5i provides earthing in a Naim system.  If your Audiolab is also connected to your TV, then here's the most likely source of your problem... the TV is messing with the earthing of the system.   This is what I found a while ago.  My answer was to insert one of those earth loop isolating thingys between the TV audio and the  A/V processor.

My best advice would be talk to your (friendly?) Naim dealer... or watch out on this forum for more advice... the good news is your problem IS solvable for not much money 

Posted on: 18 April 2016 by Tiina

Thanks for your answer. Napv175 Is connected to Audiolab, and  yeah, unity gain Is on nac202. Earth loop was my guess too, but I didn'n realise that tv also Could be part of the broblem.  I just took antenni cable of and no hiss. So there's the problem. So thank you very much!