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Sound Performance Lab Phonos

RIAA Phono Preamplifier

Article code: PROMO


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.
- 120 V rail phono preamplifier for record players
- RIAA equalization (after Douglas Self)
- Suitable for MM (Moving Magnet) and MC (Moving Coil) cartridges
- Max. preamplification: 50dB (MM); 71.5dB (MC)
- Capacitances for MM: Off, 150 pF, 220 pF and 330 pF
- Impedances for MC: 100, 220, 470; 2k2, 4k7 and 10 kohms
- Styroflex condensers used throughout the RIAA equalizer
- Switchable Gain: Normal, -10 dB, +4 dB
- Gold-plated RCA in- and outputs
- Audio ground connection for record player
- Switchable rumble filter (Subsonic)
- Standby/power on switch
- Linear power supply with toroidal transformer
- Front and Lid made from aluminum, housing made from sheet metal
- Made in Germany

The technical basis of all Professional Fidelity units is our proprietory 120 V Rail Technology, which we also call VOLTAiR technology. The name makes reference to the unequalled high voltage of 120 V (+/-60 V DC) and the huge dynamic range of over 140 dB that goes with it.

RIAA equalization
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). The construction of the RIAA equalizer follows a design made by Douglas Self. In this design larger single capacities are exchanged against smaller multiple capacities.

Moving Magnet
Moving magnet cartridges tend to produce lush, mellow sound. By moving a magnet within copper coils a small voltage is created. MM cartridges sport very high inductance and impedance. In the latter, cable capacitance can negatively affect the flatness of frequency response and linearity of phase response. Phonos offers a selection of four capacities to fine tune the flatness of the frequency response or to willingly increase high frequencies in playback. The capacities are 150pF, 220pF and 330pF. In the OFF position the capacitance is determined by the cable capacitance. 

Moving Coil
The MC design is again a tiny electromagnetic generator, but (unlike an MM design) with the magnet and coils reversed. The resulting signal is only a few hundred microvolts, and thus more easily swamped by noise, induced hum, etc. Thus it is more challenging to design a preamplifier with the extremely low noise inputs needed for moving-coil cartridge. Phonos provides a 20dB higher preampfification for the MC stage compared to the MM stage. MC cartridges offer very low inductance and impedance, which means that the effects of capacitance (in the cable that goes from the cartridge to the preamp) are negligible. The impedance of cartridge can be set in six values: 100, 220, 470, 2.2k, 4.7k, and 10kOhm. If in doubt which impedance matches the cartridge’s impedance you can empirically determine the value for the flattest frequency response.

Subsonic filter
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. 

Professional Fidelity • Pro-Fi-Serie
Phonos is part of our Pro-Fi series of products. Pro-Fi stands for Professional Fidelity and it expresses that these products have their roots in professional studio technology being optimized for high-fidelity music playback. Mastering studios give your records and CDs the final tough – with SPL 120 V technology. And because the Phonos is built with the same technology it belongs to best phono preamplifiers on the planet. With its extraordinary specifications and enormous headroom Phonos plays back audio in the most relaxed and uncompromized fashion.


Inputs and Outputs
- RCA, unbalanced, gold-plated
- Input impedance (MM): 47 kohms
- Input impedance (MC): switchable 
- Output impedance: < 5 ohms
- Crosstalk: -80dB (at 1 kHz)

- RIAA equalizer (after Douglas Self)

Moving Magnet (MM) preamplifier 
- Amplification: 46 dB (Norm.), 36 dB (-10 dB), 50 dB (+4 dB)
- Switchable capacitance: Off, 150 pF, 220 pF and 330 pF
- Noise (A-weighted): -85,3 dB

Moving Coil (MC) Verstärker
- Amplification : 67 dB (Norm.), 56 dB (-10 dB), 71.5 dB (+4 dB) 
- Schaltbare Impedances: 100, 220, 470, 2k2, 4k7, 10 k ohms
- Noise (A-weighted): -61,7 dB

Internal Operating Voltage
+/- 60 V

Power Supply
- Mains voltage (switchable): 230 V AC / 50 Hz or 115 V AC / 60 Hz
- Fuses: 230 V: T 500 mA; 115 V: T 1 A 
- Power consumption: max. 30 VA
- Stand-by power consumption: 0.7 W

Dimensions (incl. feet)
- 278 mm W x 57 mm H x 330 mm D
- 10.95 in W x 2.24 in H x 13 in D

- 3.2 kg; 7.05 lbs (unit only)
- 4.3 kg; 9.5 lbs (shipping)

1759.00 € 1595.00