My wife and I would love to build a listening room where we can use different headphones from a single source for a shared experience. The equipment we currently have are a PC as source, a Sennheiser HD600 and Hifiman 4XX, both terminated with blanaced cables, but would still need to pick up the amp(s) and DAC(s). I've looked into A/B switches but none seem to hit all the features we want, which included balanced output, as well as seperate volume control. We would like to build the system to be scalable for more headphones in the future. Was wondering if anyone on the forums has built something similar? Thanks for any advice you can give!