Tubes in phono amplification and RIAA de-emphasis The final goal in phono stage design stands in two pillars. First is to invert the RIAA curve in order to get a flat response out of the recording and the second is to amplify the vanishingly low signal generated by the cartridge to an adequate level for the preamplifier to receive. In 1954 the Recording Industry Association of America established a universal recording  format (RIAA equalization), which compressed the low frequencies during the record cutting and allowed for longer duration of LP’s with lower distortion. This compression must be inverted during playback in order to get a flat response and it is obvious that the closer the de-emphasis is to the original compression scheme the more “high fidelity” the play back itself will be. The second point that a phono stage must achieve is to amplify the magnetic cartridge’s electrical signal so that it can be properly handled by any given amplifier. When it comes to moving magnet carts, the output signal is usually somewhere between 2 and 5 mV, which it may not look as much but it is enormous when compared to the low output moving coil (LOMC) designs who … Continue reading Review: NVO SPA one Phono Preamplifier