The RIAA Phono Preamp
The Phonos is a phono stage for turntables with Moving Magnet (MM) or Moving Coil (MC) cartridge systems. The RIAA equalization curve is based on the legendary Douglas Self design. It is suitable for all vinyl records released since 1954. With up to 71.5 dB of gain for MC cartridges and 50 dB of gain for MM cartridges, the Phonos is among the most powerful phono preamplifiers.

MM & MC
There are two types of cartridge systems for turntables:

Moving Magnet (MM) and Moving Coil (MC).

Moving Magnet
Moving Magnet cartridges generate a small voltage through the movement of a magnet between copper coils. MM cartridges have very high inductance and impedance.

The Phonos offers a choice of three capacitances to correct the linearity of the frequency and phase response.

The capacitances are 150 pF, 220 pF, and 330 pF.
In the Off position, the capacitance is determined by the capacitance of the cable.

Moving Coil
The MC cartridge is also a small electromagnetic generator, but with the magnets fixed in place and the coils moving between them—the exact opposite of an MM cartridge.

However, the output voltage is very small, measuring only a few hundred microvolts, making it more sensitive to noise and induced hum. This makes the preamplifier design a challenge, as the very low output voltage must be amplified with extremely low noise. With up to 71.5 dB of preamplification, Phonos offers one of the most powerful phono preamplifiers for MC systems, providing extremely low-noise, linear, and phase-stable amplification thanks to 120V technology.

MC cartridges have very low inductance and impedance. This means that the effects of cable capacitance (from the turntable to the preamplifier) are negligible.

Impedance, however, is relevant and can be adjusted across six positions: 100, 220, 470, 2.2k, 4.7k, and 10 kOhms.

If there is any doubt as to which impedance matches the cartridge, you can simply cycle through the impedances until the linear frequency response is acoustically determined.

Perfect Level
The gain switch allows you to determine the amplification power, i.e., the output level of the Phonos.
Three values are available to choose from.
In the "Norm" position, the gain is +46 dB for MM systems and +67 dB for MC systems.

With the switch set to "-10," the gain is reduced by 10 dB (MM = +36 dB, MC = +57 dB). This is optimal when combined with standard HiFi equipment that operates at a reference level of -10 dBV.

If the switch is in the "+4" position, the gain is increased by +4 dB (MM = +50 dB, MC = +71 dB).
This makes the output level roughly as loud as that of modern DA converters at a reference level of 0 dBfs = 15 dBu.

Subsonic Filter
Rumble from the turntable's drive mechanism is also amplified during playback due to the high gain in the bass range provided by the RIAA equalization.

The Phonos offers the option to remove this rumble with a switchable subsonic filter.

Connections
Gold-plated RCA jacks are provided for connecting the turntable and for routing to a preamplifier such as the Director Mk2 or the Elector.

A ground terminal for the turntable is designed as a banana jack.
The ground wire can be either clamped or plugged in.

Sounds Good
For all devices in the Professional Fidelity series, we develop not only according to plans from the start, but also by ear. Many of the fundamental components are installed on the circuit boards using through-hole technology (THT). This allows us to ensure that we use the components that sound the best.

The RIAA equalization is a specification for the recording and playback of vinyl records proposed by the Recording Industry Association of America (RIAA). The RIAA equalization curves introduced a global de facto industry standard for vinyl records from 1954 onwards.

RIAA equalization uses pre-emphasis when cutting the record, during which low frequencies are reduced and high frequencies are boosted (the blue RIAA curve).

The bass is reduced by up to 20 dB to create more space and allow for longer playing times on the record.
The high-frequency range is boosted by up to 25 dB to increase the signal-to-noise ratio between the record's surface noise and hiss and the audio signal.

During playback, the Phonos performs the exact opposite. The de-emphasis filter (red RIAA curve) compensates for the pre-emphasis, resulting in a linear frequency response.

Douglas Self Design
The RIAA equalization of the Phonos was developed according to the recommendations of Douglas Self.
Concept: Many small capacitors instead of a few large capacitors.
Benefits: The capacitors charge and discharge faster, resulting in better resolution and faster transient response.

Audiophile Styroflex capacitors are used exclusively throughout the entire RIAA equalizer.

About: Douglas Self is a British electronics engineer with a keen passion for audio. He holds honorary degrees from the University of Cambridge and teaches psychoacoustics at the University of Sussex.

Analog input & output: RCA

Input impedance (MM)
47 kΩ

Input impedance (MC)
switchable

Output impedance
75 Ω

Frequency response (-3 dB)
4 Hz – 300 kHz

Crosstalk (1kHz)
-80 dBu

Moving Magnet (MM) amplifier

Gain (norm.)
46 dB

Gain (-10 dB)
36 dB

Gain (+4 dB)
50 dB

Capacitances (switchable)
Off, 150 pF, 220 pF and 330 pF

Noise (A-weighted, 46 dB gain)
-85.3 dBu

Dynamic range (46 dB gain)
131.3 dB

Moving Coil (MC) amplifier

Gain (norm.)
67 dB

Gain (-10 dB)
56

Gain (+4 dB)
71.5

Impedances (switchable)
100 Ω, 220 Ω, 470 Ω, 2.2 kΩ, 4.7 kΩ, 10 kΩ

Noise (A-weighted, 67 dB gain)
-61.7 dBu

Dynamic range (67 dB gain)
128.7 dB

Internal power supply; linear power supply with shielded toroidal transformer

Operating voltage for analog audio electronics
+/- 60 V

Operating voltage for relays and LED
+ 12 V

Power supply unit

Mains voltage (selectable, see fuse box)
230 V AC / 50 Hz; 115 V AC / 60 Hz

Fuse for 230 V
T 500 mA

Fuse for 115 V
T 1 A

Power consumption
max. 30 VA

Stand-by power consumption
< 0.3 W

Dimensions & weight

W x H x D (width x height incl. feet x depth)
278 x 57 x 300 mm
11 x 2.24 x 11.81 inches

Device weight
3.2 kg

Shipping weight (incl. packaging)
4.3 kg

Herstellerangaben:

SPL electronics GmbH
Sohlweg 80
41372 , Niederkrüchten
Germany
info@spl.audio