Kenwood DPX-510

The Kenwood DPX-510 is a double-DIN receiver pairing a cassette deck with a CD transport and an FM/AM tuner. It is the only cassette-equipped model in this archive to carry Kenwood's DSP and equaliser section. The manual carries publication number B64-1044-00.

The cassette deck runs at 4.76 cm/sec with wow and flutter of 0.08 percent WRMS, and completes a fast wind or rewind of a C-60 cassette in about 100 seconds. Dolby noise reduction is provided in both B and C forms, and the manual quotes three separate signal-to-noise figures accordingly: 60 dB with noise reduction off, 68 dB with Dolby B and 74 dB with Dolby C. Frequency response is 25 Hz -> 22 kHz within plus or minus 3.0 dB at the 70 microsecond equalisation, with stereo separation of 40 dB at 1 kHz.

The CD transport uses a GaAlAs double-hetero laser diode at 780 nm running 500 -> 200 rpm under constant linear velocity, feeding a 1-bit converter with eight times oversampling.

The DSP and equaliser section is specified separately for each conversion direction. Analogue to digital conversion uses what the manual names an Enhanced Dual Bit arrangement, a fourth-order delta-sigma converter at 20-bit with 64 times oversampling. Digital to analogue conversion is also fourth-order delta-sigma at 20-bit, but at 128 times oversampling. The equaliser offers nine bands centred at 60, 120, 250, 500 Hz and 1, 2, 4, 8 and 16 kHz. Its adjustment range is minus 8 dB to plus 8 dB, narrower than the plus or minus 12 dB of the later nine-band Kenwood units in this archive.

Output is rated at 25W x 4 into 4 ohms at 1 kHz, measured at 1 percent THD rather than the 10 percent figure Kenwood uses on later models, with a maximum of 40W x 4. The pre-out delivers 800 mV into 10 kohm. A card remote control is listed among the supplied parts.

DPX-510 SPECIFICATIONS
Media	Cassette with Dolby B and Dolby C noise reduction, and CD
FM tuner	76.0 -> 90.0 MHz in 100 kHz steps. Usable sensitivity 9.3 dBf (0.8 uV/75 ohm), S/N 50 dB sensitivity 15.2 dBf (1.6 uV/75 ohm), frequency response 30 Hz -> 15 kHz (plus or minus 3.0 dB), S/N 75 dB mono, selectivity 80 dB or more (plus or minus 400 kHz), stereo separation 40 dB (1 kHz)
AM tuner	522 -> 1629 kHz in 9 kHz steps, sensitivity 28 dBu, stereo separation 30 dB (400 Hz)
Cassette section	Tape speed 4.76 cm/sec, wow and flutter 0.08% (WRMS), fast wind and rewind about 100 seconds (C-60), frequency response 25 Hz -> 22 kHz (plus or minus 3.0 dB, 70 microsecond), stereo separation 40 dB (1 kHz), S/N (IHF-A) 60 dB with noise reduction off, 68 dB with Dolby B, 74 dB with Dolby C
CD section	GaAlAs double-hetero laser diode (780 nm), 8x oversampling digital filter, 1-bit D/A converter, 500 -> 200 rpm constant linear velocity, wow and flutter below measurable limits, frequency response 10 Hz -> 20 kHz (plus or minus 1 dB), THD 0.01% (1 kHz), S/N 93 dB (1 kHz), dynamic range 93 dB, channel separation 85 dB
Audio section	Maximum output 40W x 4, rated output 25W x 4 (4 ohm, 1 kHz, 1% THD), pre-out level 800 mV/10 kohm, pre-out impedance 600 ohm or less
DSP and equaliser	A/D converter Enhanced Dual Bit, fourth-order delta-sigma, 20-bit, 64 times oversampling. D/A converter fourth-order delta-sigma, 20-bit, 128 times oversampling. Equaliser centre frequencies 60, 120, 250, 500 Hz, 1, 2, 4, 8, 16 kHz, adjustment range minus 8 dB to plus 8 dB
Supplied parts	Power harness, truss screws M5 x 6 mm (six), bind screw M4 x 8 mm (one), card remote control
Electrical	14.4V (11 -> 16V), maximum current draw 10.0A
Form factor	Double-DIN, mounting dimensions 178 x 100 x 155 mm, mass 2.9 kg
Source	Kenwood owner's manual, publication B64-1044-00