Agreed - a woo amp would be a great choice. I love my maxed WA6 which has some some additional upgrades (pseudo dual power supply and Sophia Princess rectifier). With all the mods and tube upgrade it goes for about $1200 USD, and sounds fantastic with the RS-1, any other Grados, and even HD600/HD800. Side by side with a $2,200 Zana Deux it holds it's own and to me sounded just as good.