Thanks for the insight! I'm aware the consensus is OTL tube for HD 650. I've listened extensively out of an old Fisher integrated tube amp and I like the tonality a lot, but i found that i lose much by way of control and detail as compared against my dedicated SS amp (Meier Corda Jazz ff). The Fisher wows you at first, but after extended listening, I prefer the Jazz. However I still find I miss a bit of the fullness/body that the tube amp (and the headphone outs on vintage SS receivers) provides, which I suspect also has to do with their higher output impedance, as you suggest. I guess I'm looking for the best of both worlds, which led me to Violectric/Lake People, as I see these amps described as full bodied and holographic, but with precision and detail. Even the comparatively narrow but well layered/separated soundstage appeals to me, as I'm not generally a fan of exaggerated soundstage. Perhaps a dedicated tube amp would improve upon the performance of the Fisher, but the only comparison I was able to find has the Fisher coming out on top against the Bottlehead Crack, which is the most common recommendation for HD650. So I thought I'd stick with SS. From your observations it sounds like I might not hear a world of difference going from RS08 to V281 - good to know. I might have a chance to listen to a Woo amp locally before deciding, but I'm still leaning towards Lake People.