Bests & Worsts Reviews from Amazon

Test: iPhone SE & standard apple earbuds. DAC/AMP combination is a bit warmer and the bass seems punchier than the DAC/AMP in the phone itself. A very pleasant listening experience. The range does NOT great however 15 - 20 ft is pretty much the max even without walls between the phone and the receiver. Also the volume control only increases/decrease UP TO the setting on your phone . . . if phone vol is set at min than the unit will only go up so far, for louder output you have the increase the volume setting on your phone. Finally the time between volume up/down or forward/back in the playlist is fairly short . . . Despite the drawbacks: recommended. UPDATE 7.11.18 Still like this thingy BUT . . . . it's fine for low complexity music (as in most modern mainstream stuff). However, at least some high complexity classical music induces artifacts at times. The Mozart piano concertos accompanied with a full symphonic orchestra are fine for the solo parts but when the full orchestra comes in (especially the crescendos) the top end goes ... wonky ... and this is NOT the file (256 kBps AAC encoded in iTunes from CD), it's fine direct out of the iPhone, the uBTR DAC just can't handle it, the high end breaks up BADLY. The same thing happens in the Mozart flute concertos (same file encoding) though there are less 'incidents' possibly because the music isn't as 'dense' (It's a chamber orchestra accompaniment not a full symphonic orchestra). It's not the high notes per se that are the problem though as the flute solo pieces (particularly the cadenzas) reach into the 3rd octave of the flute and are rendered satisfactorily without the obvious artifacts, leading me once again to the conclusion that it's the complexity of the signal throws the DAC for a loop. I also threw Mahlers 5th at it and surprisingly that did alright without any real noticeable 'incidents', the caveat is that most of it is tonally complex but not necessarily 'dense'. For the majority of the work instrumental parts are 'separated' and not so much concurrent. Same with Dvorak's 'The new world' symphony. So it seems that a distinct set of parameters have to be satisfied for the 'breakup' to occur, possibly a certain 'denseness' coupled with a high frequency signal somehow and no clear primary instrument. Subtracted 1 point as for this price some 'defects' aren't a deal breaker, but it's not perfect. UPDATE 7.23.18 The artifacts mentioned above are rare but seem to occur mainly when there is a very high frequency signal (such as piccolo or 3rd octave flute) over a fairly complex background - but not always - it seems a fairly specific set of conditions have to be met before it happens and something that will probably only very rarely occur in popular music - I haven't encountered it in any of my tracks - but does make this item unsuitable for listening to some classical works . . . UPDATE 8.2.18 Baroque Music for Trumpet by W Marsalis also has the above mentioned artifacts (although they are minimal) even though the background is rather 'sparse'. But so far I've not been able to detect these in any popular music.