I have checked for clipping at woofer terminals and can't get 40hz sine wave to clip on scope, but at 40hz at 18volts, red LEDs are lit solid. I of course turned things down immediately. Perhaps it's the servo system going into overload?? Still had nice smooth crest's?? I am now trying speaker level connection's but can't get signal to pass through to mains at all ?? Wondering if this could be a Class D integrated issue?? I'm going to have to get with NAD on this I'm afraid. Kind of at a loss right now? Have any of you had issues with speaker level inputs not passing to mains ?
OK. You see a nice clean 40Hz sine at the woofer terminals. That should mean the sub amp output is a clean, non-distorted signal. Hmmm, so what do the LEDs mean?
Do you know for a fact that the LEDs indicate clipping? I would assume they are there to indicate some sort of problem, but assuming only leads to trouble.
Did you check for DC offset at the sub amp input/NAD output?
What does the servo signal at the woofer look like?
More investigation with a scope and voltmeter might uncover the problem. However, pointed questions for NAD and Brian are more likely to sort this problem. Nobody using GR Research subs has yet to come forward with a similar problem. This is a head scratcher.
