This is a review and detailed measurements of the SMSL DO300 balanced stereo USB DAC with Bluetooth. It was sent to me by the company and costs US $549 although I see it on sale for $490.
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The DO300 naturally follows the design language of other recent SMSL products. I like the colorful display and largish displayed volume level. Back panel doesn't provide any surprises:
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A minor nit: I like to see color codec RCA jacks with red indicating right channel. Looking from above, it is hard to know which channel is which. I like to see trigger support to sequence powering on downstream products as well.
SMSL DO300 DAC Measurements
As usual, let's start with our usual dashboard and XLR Output with volume set to default 0 dB (it goes up to 2 dB):
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You would think I would get used to such high SINAD (sum of noise and distortion) in products from SMSL but I still get a pleasant surprise when I see numbers north of 123 dB! This naturally lands in our (rather silly) top 20 best DACs ever tested rankings:
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RCA output shows the typical reduction in SINAD but still fully transparent:
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Volume control is dead on accurate so -30 dB is indeed, that level in output. Using that, I measured the effect of volume control on output SINAD:
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The glitches are instrumentation issues. Response naturally scales with output voltage.
IMD test shows no sign of "hump" despite use of ESS DAC:
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Multitone performance is exceptional of course:
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As is noise performance:
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Linearity is perfect as we would expect:
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Jitter is perfect over USB and essentially the same over Toslink:
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We have our usual suite of filters including "off:"
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I would personally use Fast Linear and be done with it. Note that "off" causes a large rise in output level so be careful when comparing that to other settings:
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It also has that screwed up frequency response so best left unused.
The excellent filter response translates to superb THD+N versus frequency:
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Conclusions
What can I say other than the DO300 being extremely well executed as we expect from SMSL. Yes, company produces many such DACs. It is not my job to sort through them. It is yours!
I am happy to put SMSL DO300 DAC on my recommended list.
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