When NAD had a good design team.
The 1300 is a Monitor Series preamp with FET-charged & eight low-noise transistors per channel MM/MC inputs with 3-step capacitance switch, very low-impedance outputs and buffered tape i/os.
The second "high" preamp output offers a +13dB level to output up to 15V at 600 Ohm (100 Ohm at lower levels) ; the front headphones terminal is parallel-wired to that preamp out.
The tone section are multiplemultiple and even includes two-octave semi-parametric bass & treble controls.
The null function replaces normal stereo output by a stereo difference signal (L minus R) - useful for checking phase balance, FM multipath sub-carrier problems, play lateral/vertical LP tests, check stereo separation or do away with center-recorded dialog while keeping Dolby-encoded surround sound...
Of course, to offer as much for as little as 498$ in 1987, the actual build-quality is far from luxurious or even beautiful and inside is no Bugatti - lots of hectic cabling made in Taiwan.
But the 1300 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.