A phono pre-amplifier: RIAA de-emphasis, cartridge gain and a rumble filter for a turntable plugged into a line input.
Inlets
Audio
2
Outlets
Audio
2
Records are cut with the bass reduced and the treble boosted, and a cartridge puts out millivolts, so a record played straight into a line input sounds thin and very quiet. Phono undoes the curve and restores the level. The de-emphasis filter is fitted to the analog RIAA response at the running sample rate, top octave included. Cord it directly after a SoundIn and before a Deck, a Console or a Mixer. If the interface channel has a phono/line switch, set it to line, or the correction is applied twice. Signal flow is de-emphasis, then rumble filter, then gain.
Parameters
Curve
RIAA is the standard playback curve. RIAA + IEC adds a gentle 20 Hz roll-off that some phono stages include. Flat skips the equalisation and keeps only the gain, for transfers you will equalise later or for records that predate the standard.
Gain
Cartridge gain in dB. A moving-magnet cartridge, which is every standard DJ cartridge, wants about 40; a low-output moving-coil cartridge wants about 60. Too high clips.
Rumble
An 18 Hz high-pass that removes warp wobble and turntable rumble before they eat headroom. On by default; turn it off for measurement work.
Recipe
Turntable in
Cord SoundIn into Phono and Phono into a Deck or a Mixer. Curve RIAA, Rumble on, Gain 40 for a moving-magnet cartridge; raise Gain in steps of 5 until a loud passage reads just under full on the meters.
