Sounds like an interesting product.
I would prefer the SPDIF input to be an optional extra. I would prefer to only pay for the inputs needed. I like the idea of one input only as it eliminates ugly switches on the casework (and also simplifies the circuit, which cant be a bad thing).
I can only do 2 versions, not three. The versions are 2 different input modules. The S/PDIF input must be on-board, so no module. These are the constraints for making an affordable DAC that I can sell through dealers. One circuit board, one chassis, one set of panels.
All of the options on the Overdrive DAC prevent it from being something I can sell through dealers. It would have to be $50K and that is a non-starter.
If I eliminated the modules, I would have to make custom front panels with no input select pushbutton hole and custom back-panels with no module hole. It would be less expensive, but recouping my costs for the different panels would be difficult. I cannot just buy 10 of each. They would be too expensive, like $100 each. Then I need to rework the baseboard so that the S/PDIF is always selected. Manual rework adds a lot of cost. Cannot have it on this product.
Instead of IEC, would it be possible to have an option where you can order it configured to run off a Dynamo (12V DC)?
It will have one configuration and that is AC input. It needs multiple power supply voltages, so a single external DC supply would not work. The Overdrive uses 3 external DC supplies.