I'm using Wilson Watt Puppy 7s. I just moved from all Krell electronics (KP28c, KCT & FPB-200c) to Spectral DMA150 series II amp and DMC-30R pre-amp. Previously I owned the Martin Logan Prodigies. When I changed to the Wilsons I was very happy with the increased resolution, detail and better bass but I found that something was missing, there was an odd coloration in the mid-range especially on female vocals that left me missing my Logans. I also heard the same coloration at my local Krell dealer when I took my KCT in and tried it with Krell FPB250cx amps. To my ears the Krell gear just didn't work with the Wilsons. I was advised that a change to Spectral might help. Initially I purchased the DMC-30R preamp here on Audiogon but was astonished to hear lots of hissing/noise in my system where previously there was none. I was bitterly dissapointed, there seemed to be no benefit that I could measure with the new preamp, plus it was making a noise. I had been warned the Spectral electronics need to be used together so I soldiered on and bought the DMA150 series II. The change was utterly remarkable. The noticeable hissing was completely gone and the system sounded just fantastic. I heard stuff on my CDs that I have never, every previously heard even though I have played some of them literally hundreds of times! Plus, the odd coloration that I had noticed with the Krell had completely dissapeared. I have been into the hobby for 30 years and have owned and heard many many components in that time but I must say that the Spectral with the Wilsons is the absolute best sound I have every heard, anywhere. I'm a complete convert, now I'm looking for a Spectral CD player combo. For me, once I'd heard the Spectrals, there is no going back! You owe it to yourself to check the Spectral electronics out, you may become a convert too.