I have built two of the foreplays, actually. One is a complete change of circuit: a (tube) constant current source topology, nothing new but I wanted to try something different. Sounds great. The second one is a much prettier (painted per doc's instructiosn) stock version. Only mods are dc on the filaments, gold rcas and the stepped attenuators. Very, very pleased with both. I like building these things. I have some fantasy of selling them off and building more. Joe