OTLs are the exception to the rule RE valve amps as in theory they ought to be more economical to produce (wrt the comments on cost of output transformers for valve amps V's SS). However, the few I've listened to have really floated my boat but that's a personal thing and very system dependant. Wasn't it Croft who perfected the OTL circuit? Still see some of Glenn's early OTLs knocking about on the used market.

