I also wanted to share my experience with Mike. My mono amps started having issues and rather than sending them to the manufacturer I decided to give Mike a try in San Diego (I live in LA). I dropped them off on a Sunday and by Tuesday he called with his analysis. He even found two errors in the overall design of the amps and fixed those as well as a burned capacitor. He checked all solder points with a magnifying glass, tightened tube sockets, re-biased the amps, tested all tubes, and provides warranty on his work. He shipped the amps back to me and they are now singing better than ever before. VERY HIGHLY recommended.