DBaldock9
Headphoneus Supremus
Yes they are all 100+ ohm players, you can mod them adding resistors, I want to do it to the z1 and Walnut v2 but have not gotten around to it yet, the problem is the volume pot has a tendency to get too loud too quick, this is why I suggested that z3, it's also 100ohm but it has a lot better volume control for sensitive iems like the zsr, I can't use zsr on z1 or Walnut v2 as players, distortion and volume is too much, they work like amps better but still you have to turn volume up past 35-40 percent and at that point they get a bit of hiss. It's better in the z3, less hiss and lower volume
I'm not sure whether I tried using my V2 as a USB DAC, before I disassembled it (and it's not reassembled, yet).
But, the Z2 & Z3 will both work as a USB DAC on Windows 10 PCs, using the driver that's provided in the OS - so you don't have to install a driver (which is handy, when you don't have Admin rights to install drivers on a work PC).
One issue I have with the Z3, is that every time I get the settings the way I want them - if I use it as a USB DAC, when I unplug it (whether I turn it off first, or not), the settings all revert back to default - which means an Asian language on the display. So, I've memorized which Menu item I have to select, and which sub-Menu item will change the language back to English.
On any of these DAP/DAC/Amps - you should be able to reduce the gain of the op-amp circuit, by soldering 10KΩ - 15KΩ 1/4W resistors across pins 1 & 2, and pins 6 & 7 of the op-amp socket.
I know this mod works on the Walnut F1 amp (on the op-amp, not the differential line drivers for the Balanced output).