This is a review and detailed measurements of the SMSL SU-1 stereo USB DAC. It was arranged to be sent to me by
shenzhenaudio from the company and costs US $79.99.
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Despite its simplicity, the SU-1 manages to look elegant with nice fonts and LED indicators for different inputs. Back panel has the basically what you want:
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My usual minor gripe applies here with right channel RCA not being red although in this case, it is easy to turn the unit around to plug in the cables. A USB-A to USB-C cable is provided. Note that you need to have a USB power supply even if you use non-USB input (it is the only source of power).
SMSL SU-1 Measurements
Let's start with our usual dashboard:
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Very nice performance with respect to noise and distortion, easily landing it in our "excellent" category of DACs:
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Zooming in:
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Full transparency is achieved not only for distortion but also noise:
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IMD distortion is basically non-existent with the performance limited by noise alone:
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Jitter shows some negligible spikes of no audible concern at all:
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Multitone shows extremely good performance:
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Linearity is almost perfect:
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Filter attenuation is very good:
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Resulting in good wideband noise+distortion measurement:
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Finally, frequency response is essentially flat in audible band:
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Conclusions
SMSL cuts the functionality to minimum many need to have high quality conversion of digital to analog from multiple inputs. Performance is superb for the cost as it provides full transparency to the source. It proves that performance requires great engineering skill, and not a ton of money. A lesson that I hope one day high-end audio companies and their customers appreciate.
I am happy to recommend the SMSL SU-1. There is no more excuse for having bad DAC performance!
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