Kenwood DPX-910MD

The Kenwood DPX-910MD is a double-DIN receiver with MiniDisc and CD transports and an FM/AM tuner. It shares its DSP, equaliser and amplifier specification with the cassette-equipped DPX-510, making the two a matched pair in the same generation. The manual carries publication number B64-1042-10.

Both transports use a GaAlAs double-hetero laser diode at 780 nm with an eight times oversampling digital filter and a 1-bit digital-to-analogue converter. The MiniDisc mechanism runs at 800 -> 400 rpm under constant linear velocity, the CD mechanism at 500 -> 200 rpm. Wow and flutter on both is quoted as below measurable limits. The manual names the MiniDisc coding scheme explicitly as Adaptive Transform Acoustic Coding, or ATRAC, which the later Kenwood MD entries leave unstated.

The DSP and equaliser section is specified separately for each conversion direction. Analogue to digital conversion uses an Enhanced Dual Bit arrangement, a fourth-order delta-sigma converter at 20-bit with 64 times oversampling. Digital to analogue conversion is fourth-order delta-sigma at 20-bit with 128 times oversampling. The equaliser offers nine bands centred at 60, 120, 250, 500 Hz and 1, 2, 4, 8 and 16 kHz, adjustable from minus 8 dB to plus 8 dB.

Output is rated at 25W x 4 into 4 ohms at 1 kHz and 1 percent THD, with a maximum of 40W x 4. Kenwood quotes the rated figure at 1 percent distortion here, where the later DPX models in this archive are quoted at 10 percent, so the numbers are not directly comparable across generations. The pre-out delivers 800 mV into 10 kohm with an output impedance of 600 ohm or less. A card remote control is listed among the supplied parts.

DPX-910MD SPECIFICATIONS
Media	MiniDisc 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)
MD section	GaAlAs double-hetero laser diode (780 nm), ATRAC coding, 8x oversampling digital filter, 1-bit D/A converter, 800 -> 400 rpm constant linear velocity, wow and flutter below measurable limits
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, 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 10A
Form factor	Double-DIN, mounting dimensions 178 x 100 x 155 mm, mass 2.9 kg
Source	Kenwood owner's manual, publication B64-1042-10