NAD 6040 (circa 1980)

Not much is documented about the NAD 6040. It was a stereo cassette deck, reviewed in the December 1980 issue of Audio (December 1980, p.41). The spec sheet in that review tells us most of what is known. These are NAD's published figures for a deck that took standard, CrO₂ and metal tapes, with the metal formulation extending the high-frequency response.

The known specifications from that profile:

Type: Stereo cassette deck
Frequency response: 30 Hz – 15 kHz (standard tape), to 16 kHz (CrO₂), to 18 kHz (metal)
Harmonic distortion: 1.0% at 333 Hz, 0 dB
Signal/noise ratio: 56 dBA
Separation: 40 dB
Erasure: 70 dB
Input sensitivity: mic 0.25 mV, line 60 mV
Output level: line 550 mV into 50 ohms
Speed accuracy: ±1.0%
Fast-forward/rewind time: 100 seconds for a C-60 cassette
Dimensions: 16.5 in (420 mm) W × 4.5 in (115 mm) H × 9 in (230 mm) D

That one contemporary source is about all there is. No marketing materials, no service literature and no other period reviews have been located. The 6040 appears to have been a fairly straightforward NAD cassette deck from the early 1980s, likely aimed at the same value-conscious buyer the brand courted with its amplifiers and tuners of the era.