Laboratory test report
Newport Test Labs measured the audio-band frequency response of the Parasound JC 3 Jnr as 20Hz to 20kHz ±0.2dB, which is exactly as specified by Parasound, and is shown in the accompanying Graph 1.
You can see from the graph that the response has a very slight boost at low frequencies (peaking at around +0.2dB at 40Hz) then slowly rolling off to to 1kHz, after which there’s an even smaller boost in the response that ‘peaks’ at 8kHz, before rolling off to 20kHz. The response is certainly wideband, being 3dB down at 8Hz and at reference level out to 100kHz.
Channel separation was outstanding, with Newport Test Labs measuring a best result of 101dB at 1kHz, but it was still at or better than 93dB at 16Hz and 20kHz, as you can see from the tabulated figures. Channel balance was superb, at 0.009dB.
Total harmonic distortion was measured as 0.01%, and you can see the distortion spectrum in Graph 2. The second harmonic distortion component is at –100dB (0.001%), the third at –109dB (0.0003%), the fourth at –115dB (0.00017%), the fifth at –120dB (0.0001%) and the sixth at –128dB (0.00003%). Obviously this is a very clean, almost distortion-free amplifier.
Signal-to-noise ratio was measured at 73dB A-weighted, referenced to an output of 500mV out (with a 5mV input required to deliver this output). This was measured using the unbalanced outputs, so the balanced outputs will return even better figures. This figure is slightly lower than Parasound’s specification of 85dB A-weighted, so I can only assume Parasound used a higher input voltage (and thus ended up with a higher output voltage) which will always result in a higher S/N ratio.
Gain was measured for all three gain settings, using the unbalanced output and, as you can see from the tabulated figures, was exactly 60dB at 60dB as claimed by Parasound, and very close at the other settings, with Newport Test Labs measuring gain for the 40dB setting as 40.91dB, and for the 50dB setting as 50.45dB.
Input sensitivity for a 1 volt output was 9.0mV at the 40dB gain setting, 3.0mV at the 50dB setting and 1.0mV at the 60dB gain setting. The input overload margin was an exceptionally good 24dB.
Power consumption was a miserly 9.63-watts, so leaving the Parasound JC 3 Jnr on all the time is not going to impact on your power bills, but if you go green (and I think you should) and switch to stand-by when you’re not using it, it will consume just 0.66-watts, which is next to nothing, but still a tad over the 0.5-watt consumption target the Australian government will soon mandate.
Overall, the Parasound JC 3 Jnr returned outstanding performance on Newport Test Labs’ test bench. Steve Holding
Channel separation was outstanding, with Newport Test Labs measuring a best result of 101dB at 1kHz