Follow up questions regarding my NAD C375BEE


I recently placed a posting regarding the protection circuit activating on my NAD C375BEE running Totem Model One Signature speakers. A poster on another forum indicated that the NAD is not robust enough to operate at the impedance load presented by the Totems and that I have damaged the amplifier. Prior to my purchase I did some internet research and found many folks running Totem speakers (including the Mani 2!) using NAD amplification without this issue. Any information or guidance regarding this dilemma would be greatly appreciated. If any readers noticed my first posting I failed to include my REL Strata II subwoofer in my roster of equipment. The REL developed a hum when I introduced the NAD into my system. Coincidence or related to my problem?
Thank you, Joseph
joseph54

Showing 3 responses by almarg

A number of good comments and suggestions have been provided above. I'll add one further thought while awaiting feedback on what has been suggested:

Are you certain that the two speakers are connected with the same phase, i.e., that + and - are not interchanged in the connections to ONE speaker?

If the two speakers are not connected in phase with each other, some of the results would be vague and diffuse imaging, and weak bass. I'm thinking that in some circumstances a result might also be the channel imbalance you have perceived, and also a perceived reduction in volume (which would be further compounded in one channel by the balance control offset). If so, to achieve reasonable volume and bass perhaps you are turning the volume control up high enough to overload the amp, with the clipping distortion that would normally result from doing that perhaps being prevented by the amp's soft clipping feature and/or by the amp's unusually large dynamic headroom.

Also, as Pgawan2b suggested, verify that the bridged mode switch on the rear panel is set to off/stereo. If the speakers are connected as a normal stereo pair but that switch is set to bridged mode, it would cause similar effects to those I described above for an out of phase speaker connection.

Regards,
-- Al
One more thought: Make sure that the black wire from the REL is connected to one of the negative (probably black) speaker terminals on the amp, and not to one of the positive (probably red) speaker terminals. If the black wire is interchanged with either the red or the yellow wire from the REL, and is connected to a positive speaker terminal on the amp, I believe that could account for all of the symptoms you have described here and in the other thread that was referenced above, and (consistent with what you have reported) could result in the amp shutting down even if the sub is turned off.

Regards,
-- Al
ZD, thanks for the good elaboration on the point I raised.

Joseph54, regarding my other point, even if you have verified that the black wire from the REL is connected to a negative output terminal on the amp, I would not rule out the possibility that the cable itself is miswired. In other words the black wire could conceivably be connected to a pin on the Neutrik connector which should be connected to either the yellow or the red wire, and vice versa.

Again, the possibility that the sub's ground (which should be the black wire in the cable) is connected to a positive output terminal of the amp seems very consistent with the symptoms you have reported in all of your threads, here and elsewhere.

Regards,
-- Al