In terms of subjective preferences, there are a lot of good reviews for all the TotalDACs on Audiostream. The tube output one had a glowing review too. That's fine and it got some of my interest, but from experience I know to take reviews with a grain of salt. Following Vincent's reply I understand if I were to summarize: - the maximum amplitude is limited to 14 bit and there is a relation to 0.01% distortion as a limiting factor - ENOB not clear/unconfirmed at the moment - I don't dispute the measurements, but it's still unclear to me how the above allows for such a high DR It seems quite clear also from this article the relationship between ENOB and DR: http://www.newelectronics.co.uk/electronics-technology/stretching-the-dynamic-range-of-a-d-converters/46404/ ENOB = (dynamic range – 1.76)/6.02 As it stands either the DAC has just over 26 bits (ENOB) or the DR should be much lower. Very interestingly someone pointed me to this link: http://www.totaldac.com/boitier_stereo.htm Even for what was the entry level the exciting DR figures come in again: 134dBFs which should correlate 22 ENOB. If we compare this to MSBs Analog DAC's 133dB, the Yggdrasil's 122dB (measured by atomicbob) or the Theta V A's 110dB, the TotalDAC A1 at a fraction of the cost to the MSB could look like a winner in these areas. Now as it happens I have actually heard the TotalDAC A1, at home and at length, and my comments are posted elsewhere. Not only that it didn't come anywhere within sight of the performance of the MSB Analog or Yggdrasil, but 3 of us independently on various rigs compared it with the Theta V A. The TotalDAC A1 came awfully short in resolution, DR, clarity or precision to the very old Theta V A. The Theta V A has a DR of around 108-110dB, which gives 17-18 effective bits. Did I think the A1 sounded nice - yes. It was organic, engaging, had good tonality etc. But at the same time it could not perform or resolve even remotely well compared to the Theta. The final proof, if any was needed, was that the TotalDAC A1 owner has purchased a Theta V A. I am not saying the TotalDAC D1 and monos will not be much better. I am sure they are. But in this only example of hearing a TotalDAC, the DR spec, which is (about) the only performance related spec published, unfortunately did not translate to anything remotely comparable when hearing the DAC. I look forward hearing the TotalDAC D1 (hopefully before the EOY) to know first hand if it can actually match the MSB Analog's resolution, clarity, background blackness, and go beyond. That would be impressive and I would be glad there is more worthy competition out there, from much closer to me.