Snared one of these second-hand largely on impulse. Best (and one of the lesser expensive) impulse I've had on Head-Fi!
The above "review" was a late-night effort when all I was really trying to do was add the KICAS to my equipment list, but Head-Fi automatically pops up a box inviting you to write a review of each item you add to a list, so I tossed off a couple of casual lines and went to bed. Now I realize that the way Huddler (the software platform that powers Head-Fi) works, this is going to be at the top of "recent reviews" for awhile and be displayed on a good many dynamically-generated pages, so I'll try to expand a bit on the previous effort by the light of day since this will draw a few eyeballs until subsequent reviews push it out of the headlines.
First a disclaimer: I really shouldn't be reviewing equipment at all, because it is entirely about relative comparisons, and I simply don't have enough experience with contemporary high-end headphone and digital audio gear to make those kinds of comparisons. I used to sell analog-only high-end equipment in the 1970s and 80s, so I have some sense of what good sounds like, but have very limited exposure to the components featured on Head-Fi, so anything I say should be taken with that caveatt.
That said, I was very impressed with the KICAS amplifier, given that my Sennheiser HD650s had only been powered by lesser equipment like a Maverick Audio D1 and A1 and and Indeed 6N11 single tube/mosfet hybrid amp before getting the KICAS. Given that $20 of my $180 purchase price went to great, quick shipping from the Head-Fi-er I purchased it from, a lot of my enthusiasm probably stems from the value side of the acquisition. Most discrete headphone amps that seemed to be good quality matches for the 650s were out of my immediate budget, so getting something so affordable that sounded so much better than what I had heard before was exciting.
The KICAS is now a three-year-old design and out-of-production while the Canadian folks who make up Purity Audio are on sabbatical before they resume business with a new line of amps. My unit has jumpers inside so you can switch between the "Caliente" mode (gentle lower-bass EQ boost applied) or the "normal" mode, and it was shipped in the "normal" mode, which I may leave it in for awhile, since I discovered it is not trivial to open the well-designed case to change the jumpers.
There have been plenty of reviews and impressions written about the KICAS on Head-Fi, which I researched for the first time the night I saw the for sale listing and then went ahead and made the purchase. "Reviewer Pontificus" (love that title) Skylab raved about it (principally from a value perspective); others have been less enthusiastic. But I am happy with it. My previous experience in high-end audio in the analog-only days gave me a personal prediliction toward solid-state as opposed to tube amplification, and the KICAS has the qualities I associate with a good solid-state design: clarity, detail, good extension at both ends of the frequency spectrum, and a very low noise floor, which contributes to a greater sense of dynamic range to my old ears. The volume potentiometer is quite useful through its entire range, and is smooth and quiet. Like Skylab, I am not crazy about external "wall-wart" style power supplies, but the KICAS designers have implemented it so well in terms of sound quality it is hard to hold this against the amplifier.
Bottom line: If you are on a budget and looking for a good amplifier for a relatively low price, the KICAS continues to hold its value and is now quite affordable as a lot of owners are moving up to more recent products. Amps tend to be a more "mature" technology than DACs and transports, so getting a product that is well-proven even though it is no longer being made is a nice way to save yourself some coin if circumstances dictate.
