- Posted by Hank Murrow (A) on October 19, 2009 at 18:45:05
This project drew on the innovation and dedication of the whole Bottlehead team. At VSAC in Vancouver, I displayed my mockups of a 300B amp and 6C45Pi linestage(w. MQ iron) while running my Glow One SET into Omega speakers in the Craftsman’s Room. I had been collecting Mike’s tasty parts for eight years to build a Soul Sister line stage and Blues Master amps; but busy with my job as a potter, I never could seem to get the iron hot and something built. At VSAC, Doc introduced me to Paul Birkeland, fresh from teaching the amp-building class, who agreed to turn my eight-year collection of parts into a Final Music System(Ha!). We decided to work on the preamp first, using a pair of I.A.G./Sowter transformer volume controls, and 6C45Pi tubes driving MagneQuest B7 Cobalt outputs, all fed by a very trick shunt-regulated power supply using EL84s(kudos to PJ!) for a sort of Soul Sister/Kugelis on steroids. Once the circuit was designed, a 17.5" x 10" x 2" h. box was drawn up by Paul, reviewed by me, and sent to Front Panel Express for machining. My friend Mark Nelson machined the knobs for the source and 28-step volume controls, which will be driven together by a belt internally, the belt will slip to adjust balance thus obviating the need for a pot(saw this first on Wardsweb's Foreplay, thanks). The knob on the right controls six inputs, and there are 2 pairs of RCA outputs and a pair of Neutrik outputs on the back panel, while a Neutrik headphone output resides on the front panel. The pic of the unit shows how all this looks with the Auricaps sitting just behind the signal tubes.
