Interesting - I find using the Iematch that Ultra (1.5 ohm) sounds thin and High (2.5 ohm) sounds uncolored. This is using GO2A SE and the balanced tinsel cable out of balanced output on the GO2A as 'reference' and then adding the Iematch in to see the difference. My original intent was just squashing the hiss. The conventional wisdom is that the lower the OI, the bassier it gets, so there must be other factors at play here, in the Iematch itself. I don't get a thinning out on the Chord Mojo which is even lower OI than GO2A, either. Not sure this is the same as the brightness @Hands experienced, but I'd be curious to see what you get listening for it, @jexby.