Tube Integrated Pairing For Harbeth Monitor 30.1

Looking for advice to help a friend who is building a system around a pair of Harbeth Monitor 30.1's. His room is medium/small (14 X 16 X 8)and his listening habits mostly chamber music, jazz and acoustic singer-songwriter with some occasional rock and big band. He wants an integrated tube amp under $3-4K. It will need to have enough power to drive the M30.1's which are 86db sensitive but a fairly easy amplifier load. I'm thinking Cayin or Jolida and would be interested in hearing from those that have used these brands with the Harbeth line. I'd also like to know which models within these brands provide the best value for money and ease of use (i.e. he doesn't want to have to bias the tubes periodically, wants excellent build quality and reliability, etc.). I'm open to other brands but the Jolida and Cayin seem most appropriate from the little research I've done. Your input is appreciated.