Yeah it seems like a lot for a headphone amp, but considering it's an all-tube headphone amp with a frequency response that goes down to 25Hz, I feel like it's not terrible. The price would also cover the power supply, as this unfortunately has too high of a current draw for a Cioks (1200mA at 12V).
It's technically designed to be able to run in stereo, not just bridged mono like a lot of headphone amps, but for the purpose of NAMM demos I have these wired for a mono input. So if anyone wanted a stereo input (not sure how useful that is on bass) it would be a simple mod.