Happy with the amplifer. Well built. Simple to use. Delivery was on time.

Had very high hopes for this all in one dac/amp. While the DAC part of the unit was alright for CS logic chipset, my Schiit Audio (Hel+) delivered much better dynamics through the ESS chipset. The CS logic chip just did not have much presence in it. It was possibly made worse by the fact that the headphone amp could barely drive my Hifiman Ananda Stealths. This is a very low impedance headphone. I had to crank the amp all the way up to maximum gain level (vol 99) to get approx 60% of what my Schiit Audio amp produced at a medium gain level. I tried to look for a HIGH gain function through the SMSL and could not find additional gain levels. So I unfortunately have to return. I will test the amp on passive speakers and provide an update if I can get to it. But I've already started a product return through Amazon. Very very disappointed. Will give the A0300 a try and see if the older model has a better output for headphones.Update: I did a bit more digging and it looks like the CS Logic chipset only produced approximately 30mV - not nearly enough to drive most medium demanding headphones. These are only good to drive most DD IEMs but that defeats the purpose of this all in one.I also hooked this up to my RP-600m ii and while, it reaches good volume levels - the dac seems to be missing soundstage and imaging. Again, if you're looking for a VERY flat sound profile and the ability to sit at your desk with IEMs, this may be a decent choice given the features and input/output options.Lastly - a HUGE issue with this unit is that both my MacBook and Windows PC loses the USB connection constantly. This may be the number 1 red flag with this unit for me. I am constantly having to restart or switch off the SMSL unit to try and reconnect with my PC. This may cause early failure on this unit. I am not certain if I have a dud, but my Schiit Audio stays connected and I can always switch between sound option outputs. SMSL isn't found until I switch off and switch off half a dozen times before the unit is found in the sound settings.Final Update: Spending sometime over a couple weeks before return period was over. I drove a pair of RP-600MII with SMSL as an AMP only, running the Schiit Audio's preamp/dac. I have to say they delivered with enough power. I will update to include an additional Star. If this was primary used for driving passive speakers and the occasional IEM for convenience, this will be a good unit. However, the previous reviews still stands. In the sense that the quirks about the USB dac which provides the highest sampling rate is near useless, if the DAC cannot pair. The SMSL unit must be powered OFF/ON for it to find a connection. This is a huge flaw that should be addressed. Using RCA is not ideal because there is a hiss, meaning it's noisy above 60 volume. Both on passive speakers and headphones. I was hoping to keep this as an All in One unit, but since I cannot fully get rid of my Schiit DAC, I will give 3 stars.