Phonos is a preamplifier for record players using either moving magnet (MM) or moving coil (MC) cartridges. The equalization curve is according to RIAA and suitable for all vinyl records since 1954. The RIAA filter is designed after Douglas Self.

With up to 71.5 dB gain for MC cartridges and 50 dB gain for MM cartridges Phonos belongs to the most powerful phono preamplifiers. RIAA equalization is a specification for the recording and playback of phonograph records, established by the Recording Industry Association of America (RIAA). The RIAA equalization curve was intended to operate as a de facto global industry standard for records since 1954. The purposes of the RIAA equalization, which is a form of pre-emphasis on recording and de-emphasis on playback, are to permit greater recording times by decreasing the mean width of each groove, to improve sound quality, and to reduce the groove damage that would otherwise arise during playback. A recording is made with the low frequencies reduced and the high frequencies boosted, and on playback the opposite occurs. The net result is a flat frequency response, but with attenuation of high frequency noise such as hiss and clicks that arise from the recording medium. The RIAA equalization curves for recording (blue) and playback (red) of vinyl records. The recording curves perform the inverse function, reducing low frequencies and boosting high frequencies. RIAA equalization has transition points in three places: 75 µs, 318 µs and 3180 µs, which correspond to 2122 Hz, 500 Hz and 50 Hz (rounded values).  Rumble from the playback turntable's drive mechanism is amplified by the low frequency boost that occurs on playback. The Phonos offers a switchable Subsonic filter to eliminate the rumble. The preamplification is switchable and offers three values for MM and MC. The Normal gain is +46 dB (MM) and +67 (MC). In the -10dB position the Phonos produces enough output level for standard consumer electronics products operating on -10dBV. In the +4dB position the output is equally loud as modern DA converters at 0dBfs = +15dBu.