Hi all...

Today I connected my Nad T753 to my Nait 5i's AV channel and had the "unity gain" enabled. I will be using this setup to watch DVDs.

I was surprised by a pretty loud hiss from the two front speakers (the ones powered by the Nait). No his is present at the center or rear speakers which are driven directly by the NAD. Hiss is present regardless of the source feeding the NAD. I switched to a different power outlet in the wall (for the NAD) and things didn't change. The hiss only goes away when I "mute" the NAD or bring the volume down to -infinity. The hiss doesn't increase with volume increase either. I got my dBl meter about 2 feet from the speakers and the hiss is registering 55dB. Kinda loud ain't it?

Anybody has had similar issues? Oh by the way, connection between the two is via Chord Cobra 3 RCA cables. Didn't have the same problem last month when I was trying out the Nac112 with 90.3 But then the connection was made to the DIN AV input (with cobra 3 custom interconnect). Dealer will visit this evening but your input is (as always) very helpful. Thank u all

For sure, the NAD is the problem. Because when you're muting it, the problem stops.

The Nait 5i consist of an amp with a pretty basic preamp section, so it probably don't have the noise rejection circuits that a preamp like the NAC 112 have.

The presence or not of the noise rejection circuit is not a problem IMO, the real problem is that you have a noisy source.

Bye.

Check this out guys;

Dealer came. We played around with the connections. First of all my Naca5 cable with "F" speaker ends sounds amazing. Much better than the chord cables I had. As for the hiss, Thomas (from mate Hi-Fi) was pretty surprised. Moreover, I was surprised when we found out that the hiss was only present on the AV channel. We connected the NAD's pre-out to the tape-in and tuner-in on the Nit and they didn't exhibit the same hiss. Actually, they were extremely quiet. We don't know where to take it from here, but for sure things are gonna get interesting

Can you disable untiy gain on the AV in?

Keith

Keith;

Yeah, but I haven't tried that. Assuming that disabling unity gain resolves the hiss issue then what does that signify?

Instability.

sounds like you may need to slug the lead between source and Nait 5

huh?! Slug????

Nait5i has been picked up by the dealer. email sent to Naim. Most likely, a 122x/150x is arriving in a couple of weeks (will be significantly poorer )

I have the same problem with my av-integration (Nait 5i via unity gain). Although, the source for the hiss is cd5x in connection with my dvd-player. I have taped the earth connection of the cd5x plug (elctricity). That hiss was gone, but no I had the hiss on the cd-input. I still do not know what to do.

quote:

Originally posted by dukeofhazard:
I have taped the earth connection of the cd5x plug (electricity).

NOT the solution.

This seems to indicate a problem which can be fixed by systematic attention to the earthing within the various (ALL) items connected directly or indirectly to you system.

Please discuss with your retailer to find a solution which DOES NOT involve removing the safety earth of any equipment.

Must_Be_Earthed.jpg (13 Kb, 9 downloads)

[QUOTE]Originally posted by Flame:
huh?! Slug????

QUOTE]

this was explained to you here:-

http://forums.naim-audio.com/eve/forums/a/tpc/f/78019385/m/6202908117

I had the same problem when I got a DVD5 instead of an Arcam player, connected to my AV2/200/175. The 'slugged' lead solved it after a lot of other trial and error.

Neil.