I did not seek out the manual and remain unsure how this thing powers on. You hit the power button but nothing happens until you press one of the input buttons???
The unit appears to run cool but there are large holes on the bottom where the amplifier heatsink is and if you touch that heatsink, it gets quite hot.
In testing, without undue stress, the unit went into protection and would not reset until I cooled it off with a fan and left it off for a few minutes. Most amps survive my testing without going into protection mode since I only push them to max power for seconds.
Also, in the process of changing my setup for 4 to 8 ohm, the unit went into oscillation, producing 107 watts on its own with no signal. So there is some instability in the design. This happened when I changed my load impedance to 8 ohm so perhaps you won't see it if you don't mess with speaker output while the unit is on.
Personally, I think 67 watts is not enough for home listening.
I just found this review and I think that I can add some possible explanations for a few of the review findings. I own two examples of NAD C340 in different systems. This C320BEE appears to be very similar. I am pleased to see that it still tested so well.
There is only one common fault with these amplifiers.The loudspeaker protection board contains a relay which connects after quite a few seconds, avoiding any switch on thump. Unfortunately the loudspeaker protection board is in a place where it gets hot, and a capacitor on this board sometimes fails. This can result in the loudspeakers being connected very slowly, or not at all. This may account for the confusion about how to switch it on. The fix is to replace this capacitor, which is both simple and inexpensive. I have been lucky so far, as I have not had to do this with either of mine.
The amplifier has a feature where it senses the impedance of the connected loudspeakers (actually the DC resistance, I expect), and adjusts itself to provide the rated power into 4 or 8 ohms. I expect that it does this by selecting a different power transformer tap, though I haven't checked this. I am guessing that the designers did not consider the use case where the speakers were changed while it was switched on. This may account for the overheating problems and the oscillation, neither of which I have ever encountered in real world use.
In UK rooms, which tend to be smaller than USA rooms, and with 1990s loudspeakers (has it really been that long?), these amplifiers are plenty loud enough for me.
Nice review, Amir, Thank you.