Nakamichi 730

The Nakamichi 730 is an odd one in the catalog. Period advertising from 1978 calls it a stereo receiver with an unconventional control scheme - no buttons, levers or knobs, just fingertip sensors that respond to a brief touch. Audio (December 1978, p.119) ran this copy, which promised "timeless elegance" and a receiver "light-years ahead in styling, operation and performance."

The technical record is thin. One Audio test report from December 1978 (p.70) survives in fragmentary form. It lists manufacturer's specifications for an FM tuner section with mono sensitivity of 12.0 dBf (2.2 µV), stereo separation of 45 dB at 1 kHz and 30 dB at 10 kHz, and SCA rejection of 70 dB. Signal-to-noise figures were stated at 83 dB (phono, "A" weighted), 94 dB for high level, and 115 dB for the main amplifier. Bass and treble control range was ±12 dB at 20 Hz and 20 kHz, and record output levels were 100-300 mV.

Some things are not documented: the 730's power output, its exact position in Nakamichi's late-1970s lineup, and whether it shared circuitry with the company's 610/620 separates or the 600 cassette console (which Nakamichi's own advertising grouped as the "Recording Director Series" in 1976). If you own a 730 or have a service manual, the archive would welcome documentation.

Known specifications (from the period test report):

- FM tuner mono sensitivity: 12.0 dBf (2.2 µV)

- Stereo separation: 45 dB at 1 kHz, 30 dB at 10 kHz

- SCA rejection: 70 dB

- S/N: 83 dB phono ("A" weighted), 94 dB high level, 115 dB main amp

- Tone controls: ±12 dB at 20 Hz and 20 kHz

- Rec out level: 100–300 mV