How is the OTL sound like?

Ditto to what's been posted above. When I first heard my Atma-Sphere M-60's (I bought them used, without an audition) I literally had that same warm/fuzzy feeling I had when I was courting my wife.

Thomas, did you first hear the M-60's paired with the Köchel's? If so, I can imagine how intensely profound your experience was. It is profound even when listening to this combination on a daily basis.

I have owned the Atma-Sphere MA1 and M60. I have also had the MA2 in my system and OTL is the way to go IMHO. Now I haven't heard other OTL designs so this might just be an Atma-Sphere thing but these are the best amps I have heard or had in my system. The only drawback is they run hot. Now I don't know too many Class A amps that don't run hot. You do need to listen to OTL designs.

I've owned 2 OTL amps and I liked the sound of both of them very much. I still have one of them, and expect to keep it for a long time. It is very hard to go back to traditional output transformer amps after hearing a good OTL amp.

I agree with most of the above comments, especially the one about using speakers that have 8 ohm loads or more. The output impedance of OTL amps is usually higher than transformer coupled amps, and the higher speaker load gives them a better match.

Thanks everyone to educate me. I am thinking about one to match with my Merlin vsm-se.

Thanks again

Vxphan for the Merlins I recommend you listen to, if you can, both the Berning zh270 and the Joule. You can't go wrong with either although each give a different presentation. but offer that speed, clarity and presence that is the hallmark of this design. The Transcendent is also very good, less expensive but also less power. It may not be enough but for a small space. The Atma-spheres I haven't heard with the VSM.