I've had my 4425's for about a month now, powering them with my old Marantz 2238B. A friend of mine has a number of Crown amps he told me he would part with, if I was interested. He has some DC300 II amps, and some PS400 amps. I'm thinking I may go with either one PS400, or two strapped for mono. My question is, would one PS400 be adequate, or would I benefit from using two strapped for mono? Thank you.