Distorsion with Nait XS, Duet and Paradisea DAC at 100% volume

Posted by: busaganashi on 22 December 2009

I've got a Nait XS, MHDT Paradisea DAC and Squeezebox Duet. Monkey'ing around until I can get my hands on the Naim DAC.

The output impedance on the Paradisea is 800 ohms. I've tried both the CD and HD input on the Nait. I get distortion unless I turn the volume down on the Duet from 100 to approximately 94-92. I'd prefer not to use the volume control on the Duet since I think it degrades the signal...?

If I use the Duet's DAC and connect directly to the Nait I get no distortion at 100 volume. I tried connecting my MAC laptop via USB to the Paradisea and swapping out the power cable and using RCA/RCA instead of my blue heaven RCA to Din cable and got the same distortion. I also swapped out the speakers with another pair. I'm using NACA5.

I'm thinking the DAC is too hot?

Posted on: 23 December 2009 by Richard Dane

What is the output of the DAC? Naim preamps should be able to take 7V signal before overload.

Posted on: 23 December 2009 by james n

IIRC this is a NOS DAC - could the ultrasonice crap coming out be giving the Nait issues ?

Can you try it on another amp ?

James

Posted on: 23 December 2009 by busaganashi

Richard, the output is 2v, 800 ohms. The distortion sounds like you've turned up the music too loud or the tweeter is bad. It is most obvious on male voices.

Posted on: 23 December 2009 by kent

I have a MHDT Paradisea Plus and a Naim Nait 5i-2. Using a PC/media Monkey instead of SB.

I do not hear any distortion at all level.

Posted on: 23 December 2009 by busaganashi

Well if I plug the RCA outs on the SB Duet directly to the Nait XS there is no distortion. If I insert the Paradisea in the system I get the distortion. It's subtle but it's there. Even my wife can hear it. :-)

Posted on: 24 December 2009 by js

Sounds like something in the paradise is clipping either outright or because a v rail is low. Swap the tube. It's not an output tube and I don't know this circuit but if it's a dig volume control it could effect the buffer tube after the DAC that's also probably used for v-c conversion. If you picked it up used, somebody may have had a not so great idea about using old stock or odd tube type. This may be entirely wrong but it's easy to check by just plugging in something else.