I've been searching a while and haven't found any direct comparisons. The CA-9 seems to get the thumbs up sound-wise here, although it's reliability has been questioned. Not worried about weight, just bottom end response, transient handling and reliability. Also how the K2 fares without a fan on hot days. They all seem pretty similar in output. The CA-9 model here has Speakons which I would prefer. The rest of the rig is a STT-1 preamp and an El Whappo. Thanks for any opinions and experience!