NAD 216 issues

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Hi,

I experienced somewhat similar but still a different problem with my NAD216 THX. When I drive the amplifier with low input after a longer period of time, one of the channels either stops working or gives popping and clicking sound, like a peak detector. Problem dissapears when increasing the input signal to "more decent" levels.

Strangely enough, I had previously another NAD216 THX and it showed the same problem, beside ocassional white noise coming from one of the channels. Therefore I was thinking that something is wrong with my loudspeakers (4 Ohms, high sensitivity) for a long period of time, until I measured with oscilloscope and found out that the amp output experiences some disturbances.

I tend to think that something is wrong with the biasing current of the transistors leading to zero current distortion, kind of a gap without a signal, after an initial warm up. The "low" impedance of the loudspeakers probably is partly reason to the problem, because the amp needs to supply substantial current at low output voltage levets...

Does this make sense, or I should look for a problem some other place?

Regards,
P.
 
ratep2001, At low output levels the amp should have no problem driving 4 Ohm speakers. Check the speaker relay, RL201 and see if the contacts are dirty. If the relay plastic cover can be removed try cleaning the contacts with a cloth wet with alcohol. Some people recommend using fine sandpaper but that removes plating from the contacts and is really a last resort to be used only if chemical cleaning does not work.
 
Hi,

I have a Nad 319 and it's the same amp but in the 319 it's pre amp inbuilt too but it look like the same. My problem is that i have a laud background sound when i play music. like when you have laud on ex the amp and low on the computer you her a sound in the speakers and it sound look like that but lauder. I also hear this sound when i turn off the music and the amp is on. I also test with headphones and also there the nose sound.

Can it be the output relay who is broken? or what do you think?


//Andreas
 
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