I realize that. However, the current headphone stages of new integrated amplifiers and receivers are quite horrible. The sound gets too watered down and sounds nothing near the output that one can garner from using speaker taps. I do have my wire-wound resistors that I have to install on the positive leads, which I'll take care of this weekend. This will perform a benefit by protecting my receiver / amp as well as the headphones.
Edit: Since I use a Squeezebox for my player device, I do desire some control over the music tone. Having the access to the bass, treble and variable loudness control that the Yamaha offers, puts me into quite a good sound category, and I'm probably still a few bucks less than some of that other Schiit costs.
I wouldn't dream of using the headphone stage of an AVR! I've used it a few times with my HD650's. It wasn't horrible, but it wasn't good. The Denon headphone stages are nicer than the Onkyo ones though.
Are you using an AVR or an integrated amp? I can't speak for integrated amps, but AVRs generally have modest-at-best DACs, and if you're using an outboard DAC into the pre/power amp, they generally have even worse analog in stages (Marantz and HK excluded actually).
Obviously, you already had the amp around, so you're way ahead of the curve price-wise of buying a dedicated head-amp, but my headphone Schiit cost quite a bit less than my AVR! Actually I think I got my Denon 2310ci as $700 closeout when the 2311ci was released, a great price for a good AVR, not the best, but pretty darned good. Lyr + Bifrost is a bit pricier, but if you're not getting into really good dedicated DACs, the Squeezebox DAC is pretty good on its own....no reason not to just get an amp with it. It's a heck of a lot more convenient, ant a lot safer. No tone controls though. And variable loudness...I do use that feature on my Denon for certain content since I have my speakers set up as monitors, but that usually is gain control in the digital domain, which means bitrate conversion in most cases. For critical listening, I turn it off.
Something tells me, though, that if it wasn't homebrewed, you just won't enjoy it as much But for me, my 6w amp has caused enough trouble for my headphones (note that may be tube related). I'll be darned if I'm going to hotwire the things to a 105w amp! That might almost be enough power to feed the HE-6 though....