SMSL SU-6 Review (Desktop DAC) Audio science review

SMSL SU-6 Review (Desktop DAC) Audio science review

This is a review and detailed measurements of the SMSL SU-6 stereo Bluetooth and USB DAC.

I really like the slick look of SU-6 with its white LED:

SMSL SU-6 Review Bluetooth USB Stereo DAC Bluetooth.jpg

Yes, you can adjust the brightness level (I think there are four). The single touch button powers the unit and lets you cycle through inputs and settings. A remote control is provided to make that task easier. Back panel shows one of my favorite features: in-built power supply so no big dongle for that:

SMSL SU-6 Review back panel Bluetooth USB Stereo DAC Bluetooth.jpg

I think this is the smallest DAC with a built-in power supply.

SMSL SU-6 Measurements
As usual we start with our dashboard:

SMSL SU-6 Measurements USB Stereo DAC Bluetooth.png

I expected superb performance and we have it, especially in one channel. Averaging the two still leaves a very respectable score as far as SINAD is concerned (sum of distortion and noise):

best stereo dac reviewed.png

Zooming in:

best stereo dac reviewed reviewed.png

Dynamic range (how noisy the DAC is) is right up there as well:

SMSL SU-6 Measurements DNR USB Stereo DAC Bluetooth.png

Multitone shows superbly low distortion levels:

SMSL SU-6 Measurements USB Multitone Stereo DAC Bluetooth.png

Linearity is as good as it gets:

SMSL SU-6 Measurements USB Linearity Stereo DAC Bluetooth.png

Intermodulation distortion and noise is very low as well:

SMSL SU-6 Measurements USB IMD Distortion Stereo DAC Bluetooth.png

USB Jitter and noise shows some negligible (and utterly inaudible) unwanted tones:

SMSL SU-6 Measurements USB Jitter Stereo DAC Bluetooth.png

Switching to Coax input I initially saw a lot of jitter. But then remembered the options for Digital PLL (DPPL) so played with the 8 different ones in there to find the optimal one:

SMSL SU-6 Measurements Jitter Coax Stereo DAC Bluetooth.png

Typical trade off here is slow lock time vs performance. By slow lock time I mean if you switch sample rates, there may be longer delay before the DAC starts to play. Hence the adjustability.

Lots of filters are provided for you to play with:

SMSL SU-6 Measurements Filter USB Stereo DAC Bluetooth.png

Filter selection naturally impacts measured performance in our wideband distortion+noise test:

SMSL SU-6 Measurements USB THD+N vs Frequency Stereo DAC Bluetooth.png

Yes, we all get bored with one more desktop DAC with great performance. Here though, there is innovation in packaging and styling which works very well. The SU-6 definitely made me smile when I first powered it on in this regard.

I am happy to recommend the SMSL SU-6.

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