I sense there is a developing consensus in terms of Headphone of choice, going on in this community as applied to this Opera. That the Beyers (in my case and many others 990s), are quite the synergistic match to what the Opera does so very well. Whereas they were a tie as to my preferance asside my k701s in my previous component chains. The Beyers simply seem to SING as I've never heard them before. Quite magical in fact
I'm wondering if any members with a larger inventory of cans or perhaps a, "just must be heard" suggestion, might chime in and share as to what works as well as these Beyers with the Opera....
Oh, BTW Doug, the MHDT Labs DAC is practically a mirror image sonically to the Operas on board DAC; Although, it has a tad more bass promenance, as well as being a bit more forward leaning in its treble presentation than the Operas. The Operas DAC section, coined by one reviewer as being, more midrange centric leaning, is the impression I also get, vs the Constatine+ specifically... Only by selector A/B switching was i able to find myself slightly prefering the Operas slightly more neutral and balanced presentation. As with DAC sections within a competitive price class, I believe this is what it would come down to, a slight personal preferance only when A/B'd ...
Also, I feel one major benefit where the intergral DAC in the Opera has an advantage, is that the good doctor voiced it to work in tandem as one synergistic match as it could be, in light of its design for PC applications..
I'll venture further, IMO the good doctor also has taken into consideration the ills of the recording industry as applied to our high resolution headphone listening, by design, in this , his flagship one box solution.
I do find it on the more comfortable side vs aggressive presentation, of the DAC choices within its price range. I even found the Constatines NOS DAC to have more "edge" or "bite" or "aggression" which at least to my ear was not as pleasent with my choice of far ranging recordings of questionable quality. The utility and useability or listenability of this rig, with poorer recordings would tag it as being a forgiving yet high resolution and dynamic S.S. rig! IMO