So, I’m currently running a Sony HAP-S1 as my base station with a pair of HD6xx’s. It’s a good multipurpose box since it’s a combo DAC/amp/hard drive. However, I know it can be run out to a bigger amp since it’s not designed to power much more than bookshelf speakers (it maxes out quickly on my Cabasse reference set). In short, as I understand it, it would work as a preamp+DAC if I ran an RCA out. Anyone have a take on whether it’s worth me adding a tube amp and, if so, which one is worth it? I’m interested in something that can still work with my headphones as well as my speakers.