lloyd, I'd be interested to see what you think of the HD compared to the Havana. I've got an HD but keep on hand my vintage r2r dacs because I like the contrast of sounds; some days I will tell myself I prefer one over the other but flip flop the next day. I still haven't had a chance to hear an MHDT dac.
I'll make sure to post some impressions tomorrow when the package is due to arrive. I'm very familiar with the Havana's sound as I've had it for about a year and a half now. I think it's a fine DAC especially if you have a few tubes on hand. I probably would not have liked it if I didn't buy mine used with multiple tubes already available. I'm curious to see how much the concero will differ as well. So I will post soon~