Why scratchy sounds Denafrips DAC to Drop AAA 789

I assume you don't listen to your headphones and speakers at the same time so why not just plug the headphone amp in when you need it? Seems like  a small price to pay and not all components like being hooked up via more than one output.

Denafrips DAC’s only support one output at a time

+1 @marco1 nailed it. This is totally normal and somewhat common 

Same here, Denafrips can only support one output......that's not unusual, similarly with most other DACs

The Aires should only allow one input at a time.  If it’s allowing more than one, then something is wrong.  Send an email to Alvin.  He might not be prompt in his reply, but he will reply.