I just finished my testings of the
Line Input...
Manufacturer's specs:
SNR: >-102dB A-weighting
THD+N: <0.0025%@1k, <0.0030%@20Hz-20kHz
Frequency Response: 20Hz-20kHz ±0.2 -3dB@46kHz
Channel Crosstalk: >-97dB
Input Level: 2.0VRMS Maximum
As a reminder, the Mini-i Pro 3 with USB-in / XLR-outs measures as such:
RMAA summary
Test | Results | RMAA rating |
Frequency response (from 40 Hz to 15 kHz), dB | +0.02, -0.02 | Excellent |
Noise level, dB (A) | -123.2 | Excellent |
Dynamic range, dB (A) | 123.1 | Excellent |
THD, % | 0.00028 | Excellent |
THD + Noise, dB (A) | -107.0 | Excellent |
IMD + Noise, % | 0.00046 | Excellent |
Stereo crosstalk, dB | -123.2 | Excellent |
IMD at 10 kHz, % | 0.00038 | Excellent |
Now, when using Line-in / XLR-outs. By the way, what I plugged to RCA inputs is the
Topping D90SE (
4V mode, the half as that SE)
Frequency response (from 40 Hz to 15 kHz), dB | +0.33, -0.36 | Good |
Noise level, dB (A) | -124.2 | Excellent |
Dynamic range, dB (A) | 91.9 | Very good |
THD, % | 0.00317 | Very good |
THD + Noise, dB (A) | -84.0 | Good |
IMD + Noise, % | 0.010 | Very good |
Stereo crosstalk, dB | -122.8 | Excellent |
IMD at 10 kHz, % | 155.267 (???) | Very poor |
These are the results at fixed output (0dB). Quite a significant drop in performance and one
major concern being the IMD. I measured different levels (attenuation by volume control), which still showed quite unremarkable performance....
Test | Line In 0dB | Line In -3dB | Line In -6dB | Line In -9dB | Line In -12dB |
Frequency response (from 40 Hz to 15 kHz), dB | +0.33, -0.36 | +0.33, -0.37 | +0.15, -0.28 | +0.03, -0.11 | +0.03, -0.11 |
Noise level, dB (A) | -124.2 | -124.3 | -123.2 | -120.4 | -117.7 |
Dynamic range, dB (A) | 91.9 | 92.4 | 90.6 | 92.0 | 92.1 |
THD, % | 0.00317 | 0.00277 | 0.00309 | 0.00312 | 0.00332 |
IMD + Noise, % | 0.010 | 0.011 | 0.011 | 0.00914 | 0.00838 |
Stereo crosstalk, dB | -122.8 | -121.6 | -119.0 | -116.8 | -113.6 |
This tab does not tell you everything. Yet, graphs do :
Noise level
THD + Noise (at -3 dB FS)
Intermodulation distortion (swept tones)
Intermodulation distortion
...Overall, there are
plenty of issues. Worst ones happening from -6 to 0dB levels. IMD is simply unacceptable, with clipping that just breach the roof of audibility, even at -12dB level.
What's your thoughts,
@MatrixAudio ? Please don't tell me it comes from the DAC I paired with. I have a complete picture of both D90SE and Mini-i Pro 3 regular performance. The only reason I could consider is the 2.1Vrms output of the D90SE being a touch too high and brings some clipping as such. Yet if 2.1Vrms is "too much", it will be quite a concern for many, many gears with regular 1.8-2.3Vrms RCA outputs...
Until further explanations, I give it a
failing grade...