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Two stage tube phono preamp with RIAA equalization
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After building a number of diy jFet based phono preamps, on request from a friend, I built this two stage tube phono RIAA preamp. The circuit design is from the TubeCAD Journal and is one of the simpler designs on the site. The circuit construction is contained on veroboard (perfboard) and housed in extruded aluminum enclosures from Hammond. The external PS run from a 24VAC wall wart. A step-up tranni converts this to 260V and a two stage C-R filtering ensures clean power. The heater voltage is DC. Tubes are Golden Dragon 12AX7s. Russian PIO caps are used in the inter-stage coupling/output and Sprague orange drops for the RIAA stage. With my Grado Reference MM wood body cartridge this preamp sounds divine.
Mark - retro-thermionic
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