As you see style is very much the same as other Gustard products. I like the high resolution display with larger volume indicator.

Back panel shows the usual connections:

Gustard X18 Measurements
Let’s start with our usual dashboard with balanced output with digital input adjusted by -2 dB to get nominal 4 volt output:

That is extremely good performance. The second harmonic dominates distortion profile but it is down -135 dB (25 dB below threshold of hearing). This easily qualifies X18 as state-of-the-art, placing it in top 3 DACs ever measured:

EDIT: post these measurements, the company advised that the X18 has a high performance post DAC attenuator and as such, performs better using its volume control than attenuating the input signal. So I tested that with volume set to -2:

As you see, the attenuation is slightly less than making the same change in the source. I usually allow 0.1 volt variation but this is a bit much as far as fairness to other DACs. Still, going with it, the X18 changes position to #2 best DAC ever tested:

Switching to unbalanced RCA output, we still get superb performance:

Allowing the output to get up to 5.4 volt, we get even better performance due to increased dynamic range:

Dynamic range is exceptional:

Intermodulation+noise performance is superb as expected:

Jitter test over USB is great:

But there is some inconsequential jitter components if you use Toslink or Coax:

Linearity is nailed:

As usual, you have an array of reconstruction filters to choose from:

Using default L-FAST, we get extremely clean wideband distortion+noise performance:

Edit: forgot the multitone test initially:

Conclusions
I live for happy days like this: another instrument grade, exceptionally well engineered audio product in the form of X18. It is clear a ton of effort has gone into providing full transparency to input signal. Yes, the cost is up there but if you want the best, you now have one more option.

It is my pleasure to recommend the Gustard X18 DAC.

https://www.audiosciencereview.com/forum/index.php?threads/gustard-x18-review-stereo-dac.28988/