Dynaco ST-70 Amplifier Excellent Condition!

This is an Amplitube ST-70 / Dynaco Stereo 70 reissue kit that I purchased long ago directly from Amplitube (Mariposa, California). I personally assembled this kit in 2005. Both the materials and build quality of the kit are excellent. It was built strictly to the original point-to-point wiring design, with the only change at the time being an upgrade of the power transformer to the PA-060S — a significant improvement over the stock unit. The amp has never had any issues and plays beautifully. Bias for the KT66 tubes was set at 1.64 V for both channels. While originally designed for EL34 tubes, the circuit can also accommodate KT66 or KT88 for enhanced performance. The amp includes bias adjustment pots, and tubes must be biased according to the specifications in the manual. Original full build instructions and schematic are included. After running the amp for about 5 years, I carefully stored it in its box in my garage until last year, when I brought it out again and performed a series of thoughtful upgrades: Upgrades & Maintenance: Russian PIO (Paper-in-Oil) audio coupling capacitors CE Manufacturing Mallory 525V can electrolytic (80/40/30/20 µF) Tube adapter allowing the use of 6GH8A or 6U8A in place of the original 7199 Fresh electrolytic capacitors throughout "Yellow sheet" diode mod added to protect the tube rectifier Small series resistors added to screen grids for additional tube protection All plastic tube sockets replaced with high-quality ceramic sockets Power transformer fitted with rubber O-rings to reduce vibration Additional small parts added to further reduce noise The result is an amplifier that is dead quiet — even with my ear against the speakers, I cannot hear any hum or noise in my system. Included tubes / extras: . 11 × 6GH8A . 3 × 5AR4 . 4 × Genalex Gold Lion KT66 . 2 x 7199 I have now decided it’s time to part with some of my collection, so this amplifier is available for a new home.