I also have the Emotiva A300. Originally ran it through a rebuilt Conrad Johnson Premier 2, all tube preamp. Still the sound was as yours, forward, bright, grainy and irritating. The CJ slowly expired and too much $ to fix. Got a previously owned Van Alstine SS/ Tube preamp from Van Alstine. Same sound problems. Replaced the Emotiva with a heavily modified Adcom 535 (done by Hoppe's Brain). Huge difference - sweet and rounded, full mids and lower mids. Just budget nice sound. Point is, no matter what you pair the Emotiva with, probably won't tame it. It is what it is.