Linn Sondek CD12 CD Player Measurements 1
The Linn Sondek CD12 was pretty good at error correction, coping easily with the Pierre Verany Test CD up through track 31, which has a 1mm gap in the data spiral. It did start to stumble on track 32, which has a 1.25mm data gap. The output polarity was noninverting from both single-ended and balanced outputs, the latter wired with pin 2 hot. The maximum output level at 1kHz was 1.987V single-ended, 3.87V balanced, with source impedances of 235 ohms and 596 ohms, respectively.
The CD12's frequency response from both unbalanced and balanced outputs at 0dBFS is shown in fig.1. Not only do the plots overlay exactly, but so do those of the individual channel responses, revealing precise circuit implementation. There is a slight (-0.45dB at 20kHz) droop in the top octave, but I doubt this will be audible. Channel separation (not shown) was excellent.
Fig.1 Linn Sondek CD12, frequency response at 0dBFS, balanced and unbalanced outputs overlay (right channel dashed, 0.5dB/vertical div.).
Fig.2 shows a swept 1/3-octave spectral analysis of the Sondek's output while it decoded data representing a dithered 1kHz tone at -90dBFS. The traces are completely free from spuriae and the noise level is very low. For fig.3, I changed the data to "digital black" and extended the measurement bandwidth to 200kHz. Again, the audio-band noise can be seen to be very low. It is so low that I wondered if the CD12 turns off when it detects this signal. However, repeating the test with a -1LSB offset gave the same result.
Fig.2 Linn Sondek CD12, spectrum of dithered 1kHz tone at -90.31dBFS, with noise and spuriae, 16-bit data (right channel dashed).
Fig.3 Linn Sondek CD12, spectrum of digital silence with noise and spuriae, 16-bit data (1/3-octave analysis, right channel dashed).