I have both these units and have measured on the digital in-pre out and get quite different results. The older unit has only AC line noise, where as the NR1710 has both line noise and "digital" noise (100 Hz jitter). The 100 Hz jitter applies to the 1510 unit as well. Also older units did not have this "jitter noise". There are of course some differences between the units, but many things are remarkably similar including the 5V switching PSU for the video/digital part. One difference of the 1710/1510 units is the addition of a RIAA stage and a "signal ground" screw attached to the chassis. My suspicion is that the grounding of these units differ and that the addition of RIAA stage with chassis/signal ground has led to parasitic current and noise into the digital ground. I also note that the 50 Hz signal noise decreases in the NR1710 unit vs the NR1506, while the 100 Hz jitter is introduced. The 100 Hz jitter is only found during digital input/digital processing. Analogue/pure setting only gives AC noise.
I have both service manuals and are studying them, but I would like if someone could have a look as well (i can send them). I am well aware that these are complicated units, but I suspect that the problem is more ground-related and I am suspicion of the RIAA stage/chassis/signal ground causing troubles, which may or may not be fixed quite easily.
Below are measurements from pre out of the 1506 and 1710. Never mind the distortion components - they are from the sound card.
NR1506:
NR1710:
I have both service manuals and are studying them, but I would like if someone could have a look as well (i can send them). I am well aware that these are complicated units, but I suspect that the problem is more ground-related and I am suspicion of the RIAA stage/chassis/signal ground causing troubles, which may or may not be fixed quite easily.
Below are measurements from pre out of the 1506 and 1710. Never mind the distortion components - they are from the sound card.
NR1506:
NR1710: