Accuphase DP-75V CD player Measurements

Sidebar 3: Measurements

Given J-10's raving about the sound of the Accuphase player, you should expect its measurements to reflect the current state of the art. They do.

But getting the basics out of the way: The DP-75V's maximum output level was 2.5V from both balanced and unbalanced outputs---almost 2dB above the CD standard's 2V. The player was noninverting from its single-ended RCAs, inverting from the XLRs due to these being wired with pin 3 hot. (The AES standard is for pin 2 to be hot.) The source impedance was low, at 46 ohms in the midband from either set of outputs, this rising inconsequentially to 70 ohms at 20Hz (balanced) and 54 ohms at 20kHz (unbalanced). The digital-domain volume control operated in accurate 1dB steps.

The DP-75V's frequency response (fig.1, upper traces) was identical from both sets of outputs, while the de-emphasis error (fig.1, lower traces) was negligible. There was a very slight mismatch in channel balance, however. Any crosstalk was buried in the noise floor below 1kHz, with a slight rise to a still negligible -116dB at 10kHz in the L-R direction.

Fig.1 Accuphase DP-75V, balanced frequency response with (top) and without (bottom) de-emphasis at -12dBFS (right channel dashed, 0.5dB/vertical div.).

Fig.2 shows a spectral analysis of the balanced output while the Accuphase decodes data representing a dithered 1kHz tone at -90dBFS, with both 16- and 24-bit data. The increase in word length drops the noise floor by up to 13dB, depending on frequency---one of the best resolutions we have seen on this test. No AC power-supply components are apparent. Repeating this measurement with "digital black" data and extending the bandwidth to 200kHz revealed an absence of any ultrasonic spuriae (fig.3).

Fig.2 Accuphase DP-75V, 1/3-octave spectrum of dithered 1kHz tone at -90dBFS, with noise and spuriae, 16-bit data (top) and 24-bit data (bottom) (right channel dashed).

Fig.3 Accuphase DP-75V, 1/3-octave spectrum of digital black, with noise and spuriae, 16-bit data (top) and 24-bit data (bottom) (right channel dashed).

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