Accuphase DP-75V CD player Measurements part 3

The Accuphase's analog output stage could drive low impedances with ease. Fig.7 shows the spectrum of its balanced output while it reproduced a full-scale 50Hz tone into 600 ohms. No harmonics can be seen! Similarly, a full-scale mix of 19 and 20kHz sinewaves into 600 ohms gave the spectrum shown in fig.8. The only intermodulation products that can be seen lie at or lower than -100dB, which is superb performance into this demanding load.

Fig.7 Accuphase DP-75V, spectrum of 50Hz sinewave, DC-1kHz, at 0dBFS into 600 ohms (linear frequency scale).

Fig.8 Accuphase DP-75V, HF intermodulation spectrum, DC-22kHz, 19+20kHz at 0dBFS into 600 ohms (linear frequency scale).

Despite the claims made for the DP-75V's transport section, I found its error correction only fair: the Pierre Verany Test CD's track 31, which has 1mm gaps in its data spiral, resulted in dropouts. And the player's jitter rejection was surprisingly average, the Miller Analyzer measuring 760 picoseconds peak-peak. The spectrum of that jitter, calculated by averaging 64 32k-point FFTs, is shown in fig.9. Almost all the jitter is data-related: The ±229Hz sidebands are indicated with red "3" markers, though some low-frequency sidebands at ±12Hz (purple "2") and ±120Hz (blue "1") can also be seen, the latter power-supply-related. But note the astonishingly low noise floor in this graph, with noise components only just poking their heads above the -130dBFS level. Absolute frequency was a slight 43ppm high, according to the Miller Analyzer.---John Atkinson

Fig.9 Accuphase DP-75V, high-resolution jitter spectrum of analog output signal (11.025kHz at -6dBFS with LSB toggled at 229Hz). Center frequency of trace, 11.025kHz; frequency range, ±3.5kHz.

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