non-Signature. Both brands are fantastic. But, I think if you can eliminate transformers and still drive your speakers, it is hard to beat OYLs for transparency, clarity, speed, and presence. Given that, the CAT is very, very good in those areas, with incredible bass and drive and can obviously perform well with a wider array of speaker choice (almost all). We are talking cream of crop with both brands IMHO. I'm also fortunate in that 60 watts (M-60s) is way more than enough power to drive my Merlins.