i'm contemplating myself on which amp to get. Jack Wu recommended me the WA2 instead of the WA6SE. WA2: - gorgeous - scale to higher end, high impedance headphones - can be used as a pre-amp, and add another amp after that WA6SE: - just tiny bit cheaper than WA2 - has better soundstage(or so i heard from reviews) - has better compatibility with other headphones any other suggestion or perhaps preference? my budget is $1000, and my current headphones are HD600 and ATH-AD700. amps, iBasso PB-2 and iBasso DB-2 DAC. thanks for the help! tube recommendations are very welcomed!!