FWIW, I think anyone expecting the best out of their Stax system would be better served by moving up the Stax line than adding the ED-1 to the mix. I can say this with confidence, as I have owned the ED-1 and used it with my Lambda Pro and SRM-1, Mark 2. I moved up the Stax line to the 009s (with SRM-T1S) and the difference is not subtle. Also, I agree with frogman's comment that adding more electronics (not to mention extra cost) to the signal path is a bad idea.