Accuphase DP-70V (1990)

Front-loading CD player with discrete 20-bit D/A conversion and fully separated digital/analog circuitry, released in November 1990.

Overview

The Accuphase DP-70V is a high-end front-loading compact disc player from Accuphase Laboratory, Inc. It came out in November 1990 as the successor to the DP-70. It was positioned as a state-of-the-art player, with advanced digital-to-analog conversion and isolation between the digital and analog sections. It also works as a digital control center, with multiple digital inputs and outputs, and its design uses technology from the separate transport/processor combination DP-80L/DC-81L. It was made in two versions, likely differing in laser pickup - either the Sony KSS-190A or the KSS-281A with integrated RF amplifier.

Specifications

Product type	Front-loading Compact Disc Player
Disc format	CD
Number of channels	2
Rotation speed	500 ~ 200 rpm (CLV)
Performance speed	constant 1.2 ~ 1.4m/s
Reading system	Non-contact optical reading (using semiconductor laser)
Laser	GaAlAs (double hetero diode)
Transport mechanism	Sony KSS-190A with BU-1C/D laser head combo
Digital Outputs	coaxial (0.5Vp-p/75 Ω), optical (660 nm, -21 to -15dBm)
Digital Inputs	coaxial (0.5Vp-p/75 Ω), optical (received power -15dBm to -27dBm)
Quantization	16-bit linear
Sampling frequencies	32.0 kHz ± 0.1%, 44.1 kHz ± 0.1%, 48.0 kHz ± 0.1%
Frequency response	4.0 Hz to 20 kHz ± 0.3 dB
D/A converter	Discrete 20-bit, 8x oversampling
Digital filter	Independent 20-bit 8x oversampling per channel; attenuation -110 dB (24.1 kHz to 328.7 kHz)
Total harmonic distortion + noise	0.0016% (1kHz), 0.002% (20 Hz to 20 kHz)
Signal-to-Noise Ratio	119 dB
Dynamic range	98 dB
Channel separation	109 dB
Line output (unbalanced)	2.5V / 50 ohm (RCA)
Line output (balanced)	2.5V / 50 Ω (XLR)
Output level control	0 to -40 dB, 1 dB step (digital)
Semiconductors	IC: 74, Transistor: 32, Diode: 66
Power supply	100V/117V/220V/240V, 50Hz/60Hz
Power consumption	23 W
External dimensions (W x H x D)	475 x 135 x 389 mm
Weight	24.3 kg
Remote control	RC-7 (infrared, DC 3V, 2x R6 batteries), dimensions 64 x 176 x 18 mm, weight 180g (with batteries)

Design

The DP-70V uses a discrete, current-addition type 20-bit D/A converter for high linearity. Each channel gets its own 20-bit 8x oversampling digital filter. Digital and analog circuits are isolated with ultra-high speed opto-couplers (40Mbit/sec, 4 per channel). The digital and analog sections have separate power transformers, and the analog transformer has independent windings per channel. The audio low-pass filter is a 3rd order GIC Butterworth active filter. The transport sits on an aluminum die-cast frame that floats from the chassis, and the disk table floats too. A linear motor tracking system is run by an 8-bit microprocessor. The front panel shows only a few controls - Play, Track Search, Pause - and the rest are behind a flip-down panel. The chassis uses a sturdy frame with brass legs for resonance control, a gold-colored metal front, and wood side panels. The display uses blue LEDs. The servo board has no potentiometers, but three 2.2kΩ trimmers on the pickup may drift over time.

Context

The DP-70V sits chronologically between the Accuphase DP-70 (1987) and the DP-75V (1999). It was marketed as a state-of-the-art player in its era and is often compared favorably to contemporaries like the Sony CDP-X7ESD and Marantz CD-7. Accuphase Laboratory, Inc. was founded in 1972 by former Kenwood engineer Jiro Kasuga.

Market

The original retail price was ¥480,000 (approximately USD 10,000 at period exchange rates). As of 2017, mint-condition units were valued between €1500 and €2000. Common problems are aging or failure of the laser pickup and drift in the trimmer potentiometers on the pickup. Maintenance typically means cleaning the lens, greasing the guides, and possibly replacing the pickup trimmers. Original spare parts are getting scarce, and the service manual is not widely available.