The owner was curious how the analog input on the MRX 520 performs since I
measured that for the NAD M17 V2 processor. Which sadly did not perform well.
Anthem MRX 520 Analog Input Audio Measurements
Here is our dashboard view in unity gain (input = output):
View attachment 33570
That is 10 dB better noise and distortion performance than the NAD M17 V2! It is not that the SINAD of 84 dB is great but that the NAD's performance is so poor.
Crosstalk was neck and neck with NAD:
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IMD distortion and noise was better as we would expect:
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I have shown it both with 0 dB volume and -4 dB I used for my other tests. Both are substantially better than NAD M17 V2 but again, way, way worse than desktop products.
Signal to noise ratio for unity gain is thus:
View attachment 33573
So we can only clear 15 bits of dynamic range.
THD+N versus frequency was quite high but also had an oddity at the highest frequencies:
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So I ran a sequence of 1, 10 and 20 kHz to see what is going on:
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At 20 kHz, we a sudden rise in a tone above 75 kHz. I have not done the math but I suspect that may be an aliasing component due to weak filter at the sampling rate they use. So not an audible concern.
Speaking of sampling rate, here is the frequency response:
View attachment 33576
This is falling short of the NAD because there, I could set the sampling rate to 192 kHz. But it is not a practical concern since there is plenty of bandwidth there to give you ruler flat audible response.
In summary, nothing seems badly broken but you definitely can NOT use this input with external DAC to get better performance. You will be taking a step back actually relative to the internal DAC.