I'm not sure if your question was already answered Day, but traditionally yes, the IRS-Beta's sound best, and in fact were voiced with big ss amps driving the bass towers & ARC tube amps driving the mid/tweeter towers. The Ayre MX-R Twenty mono's are great amps with good power, and sound fairly neutral. Therefore adding some CJ tubes to the mix should be a nice combo. Though personally I would flip them around & try the Ayre mono's driving the bass towers, and CJ mono's on the mid/high towers.