We get similar questions a lot. The DAC DAC has only one input, coax SPDIF. The product was designed to be as simple as possible to eliminate noise sources and unnecessary complexity. We do recommend running Cherry amps directly from a DAC DAC when possible because they are designed to work together.
Many systems are driven by computer audio these days. The computer may be in the form of a “streamer” or “end point” or just a regular laptop/notebook/desktop computer (typically connected via Cherry USB). In this case, there is almost always a digital volume control and only one audio source, so the system is PC > Cherry USB > DAC DAC > Cherry Amp.
So, how to add a sub? How to add multiple sources? We are developing the Cherry DPA (digital preamp) for driving one or two DACs. I’ll add a link later.
The alternative is like you said, using a preamp. I’ll add more to this thread later.
There are ways to add a digital selector, too.
Don’t mean to leave you hanging, but I’ll add more to this thread soon.