Original 1.0 specs with the 12AT7 driver tube and built to use 300B output tubes. Replaced filament rectifier diodes with higher spec parts, new RCA jacks, fresh Sapele wood bases produced by the woodworker who makes Bottlehead's bases, fitted with a pair of Sovtek 300B output tubes that both test close to new, as well as a pair of RCA 12AT7 driver tubes. Sound awesome.