Reading all the previous posts, it looks like there is real interest in DPA, ADC, and continued growth over at Digital Amplifier Company! Glad to hear it because over all the years in this hobby and all the gear that passed though my hands, its Tommy's designs which have finally delivered the goods! DACDAC's, STM's, and Maraschino's have all exceeded my expectations. And due to that, I'm sure that once the feature set and product function are worked out, the forthcoming DPA will set a new standard for transparency and performance in our systems.
My .02 is this. As I get older, and things like retirement savings and children's educations continue to sap funds from my disposable income, it becomes increasing evident that simplifying the audio chain leads to saving money, and less chance of adding deleterious connections. An example of this would be the now additional SPDIF cables required to connect the DPA. I have found audible benefit in using a Nordost Blue Heaven to drive my DACDAC's SPDIF. If the DPA is a completely stand alone device then it adds considerably to the price for me to add another expensive SPDIF cable. And once I've heard that it works, I cant un-hear it... Same goes for those who tinker with outboard power supply upgrades. Everything but the amps in one box sure makes alot of sense to me.
So, my suggestion is a modular approach. Thinking really off the wall ideas here. Tommy has thus far been quite an innovator in not spending wastefully on casework, and keeping a family look to the product line. Keeping functionality in separate boxes may also have a sonic benefit, but then the cabling issues arise. My stake would land at an option to have the DPA, DACDAC, and good power supply in one fullsize chassis. Obviously the boards themselves would remain the same, but the option to have everything in one case would really be a mature and cost effective move. Maybe current DACDAC users could enjoy an exchange or trade up program. we'd all want to do that for the forthcoming DACDAC-2 anyway.
Otherwise, remote & physical volume knob (encoder)..... SPDIFon RCA & BNC & Toslink would be mandatory I think.
And Tommy... I think you are on to something with the 2nd SPDIF output. It would be great to drive a subwoofer without fear and complication of the rca's on many subs grounding out the main amplifier inputs (as we've discussed).. Would it be possible to slightly bias one SPDIF output a little higher than the other? I'm thinking here of a user with 2 DAC's and 4 Maraschinos, but the speakers/subs being driven are different sensitivities... Being able to boost or cut one output over the other could really lend better integration of subs for advanced users!