This was the thing that @Bill-P brought over from Vietnam where the manufacturer wanted honest input. The Leptoni has SE inputs and SE and balanced outputs. There are preout RCAs and XLRs on the back. The tubes are EL84 and ECL82. The ECL82 is an oddball in that is a triode / pentode combo. I don't know much about the ECL82, nor do I know much about the amp's topology or how the ECL82 is used. @Bill-P indicated that this amp is SET. I didn't have anything to compare it to other than the Af. I'm posting these early impressions at @Bill-P's urging. Impressions are that this amp is very good. It's a good sounding amp. I only have a few nitpicks, and really, they are nitpicks. As configured with the tubes, the tonality is a bit hollow (there is warmth and good highs, but lower midrange body seems attenuated). In addition, I feel the lowest octave in the bass just isn't quite there. The Af by contrast is more even throughout the entire band with fuller mids and a extended bottom octave. The space and layering isn't quite as deep and separated. On occasion, the Leptoni has a hole-in-the middle presentation without a strong center image. Again, also nitpicking here - all headphones sound like this to me to some extent. Overall microdynamics and microdetail is excellent, equivalent to the Af, with the exception of spatial detail. Bass seems just a tick less tight and also with less slam compared to the Af. Af edge macrodynamics was the first that that I had noticed - the most immediate difference to me. I will listen to this amp a few more days to make more sure of what I am hearing. The differences are not huge. This is definitely good amp and it took my some time and repeated listenings to discerne the differences. Bill-p can attest to this. Normally, if something is junk, it only takes me 2 seconds. Now @Bill-P and @brencho will offer their 2 cents.