I have been listening to the MHA100 with its own DAC this afternoon.
First let me say that I don't think comparing the MHA100 internal DAC sound to the Bricasti M1 + MHA100 amplifier is not a fair comparison. Remember that the Bricasti is a high end DAC that cost double the price of the MHA100.
The comparison was done using the same source for both DACs. The source was a Mac Mini with 16Gb RAM, 120Gb SSD drive for the software and 1TB HDD for the music files. It also uses an external linear power supply from Mojo Audio and the player was JRiver for Mac. The cables are WireWorld Platinum USB and also in the line are the iUSB and iPurifier.
When using the Bricasti it is connected to the MHA100 using a pair of Wireworld Eclipse 6 XLR cable to the analog balanced input of the MHA100.
Now to the sound. Yes, there is a difference in the sound between the 2 DACs. The sound when using the internal DAC is warmer or darker in comparison. This darker presentation takes some of the detail and dynamics from the sound. Because of this the soundstage presentation is not as clear or transparent. There is also less "air" or separation between the instruments and voices making it less three dimensional and the soundstage is narrower.
Now, that is doing a direct A/B comparison between the 2 DACs which as I said I do not consider fair. If I did not have the Bricasti would I be happy with the sound of the MHA100 DAC? Probably I would. The real question is how the DAC of the MHA100 compares to a $1,500-$2,000 DAC. I think that would be a more fair comparison.