Partly curiousity. The M200 has the AKM chip and the Topping has the ESSs but I thought for the sake of 10 or 20 quid it was worth it for the lesson in what I prefer. No matter what I did with the A50 it always sounded distant and like it was producing a separate image from each side rather than a single image in front of me. That doesn't happen with the SP200 and the soundstage is actually apparent. The balanced input on the A50 also broke early-doors so perhaps I'd got a slightly defective one. It's no critisicm of Topping. I loved the D50s but with the way we can buy and sell hifi gear now it'd be silly not to spend the equivalent of a couple of beers on a reasonably researched hunt for a slightly better sound. And for the sake of a couple of beers the SMSL stack sounds suitably better than the Topping stack. I was also convinced by the THX label and some top drawer technical reviews from places like here. It sounds superb btw.