When NAD had a good design team.
The 3300 is a Monitor Series integrated amp made of most of the 1300 preamp and half of the 2600 power amp :
MM & MC inputs with 3-step capacitance switch, low-impedance outputs, buffered tape i/os, "lab" input (to be fed from the preamp out and bypass all filters and controls), 30A and 400W of peak current/output available maintained in listenable regions with NAD's staple Soft-Clipping circuit.
That much output goes with the Power Envelope circuit : two voltage rails for high and low power ranges. When listening loud, switching back and forth between rails therefore happens...
I believe the 3300 was first available without the PE circuit. (?)
Of course, to offer as much for as little as 598$ in 1987, the actual build-quality is far from luxurious or even beautiful and inside is no Bugatti : one bigga EI trafo, one long sharkfin heatsink, two main caps, two smaller ones, lots of hectic cabling made in Taiwan.
But the 3300 works and was planned to do that for a long time.
And it is pretty, because, then, NAD, like Proton, really had a very good design team.
The owner's manual is still available for download at NAD's NAD's.