The RIAA Phono-Amp Engine II - Burkhard Vogel

Burkhard Vogel set out to rectify some shortcomings of his Phono Engine I which was presented in “The Sound of Silence”, specifically the switching between the various input-output options. The aim was to facilitate quick comparisons between different cartridges, turntables and preamp configurations. Engine II allows the user to compare two different MC cartridges mounted on one or two turntables of the same type with two equal tonearms; to compare one or two different turntables/tonearms with the same type of MC cartridge; to compare the sound of triode driven vs. solid-state driven RIAA correction stages; to enhance the number of inputs by additional external amplifier stages for broader comparison needs, including MM cartridges and gain stages, with un-balanced and balanced outputs. Furthermore, Engine II allows testing various technologies of balanced input and output gain stages like transformers, op-amps, JFET or BJT, or valve based. Of course these solutions attain the highest possible technical performance levels. Finally, a possible realization based on two mono enclosures is presented.