Hello! I purchased an Aretha a few months ago from Holgar at Tube Nirvana and I am VERY pleased with it. I believe the Aretha's line stage is based on a Roy Mottram circuit design for his SP9 - the octal version. My only beef was that the tubes supplied were a bit noisy for my setup - a ST-70 clone driving a pair of extremely sensitive Klipsch Lascalas. A quad of NOS Sylvania 6SL7's fixed that. Also, the line fuse blew for no apparent reason after only a few hours but no troubles since. Each of these units are hand made and the quality of workmanship is outstanding! At this price point I've seen nothing that compares.