The RCM Audio The Big Phono is a reference two-chassis phono preamplifier designed to provide exceptionally low noise, wide dynamic range and precise RIAA equalisation for high-performance analogue systems. Its separate power-supply chassis employs independent supplies for the left and right channels with multi-stage stabilisation and extensive filtering, physically isolating the sensitive amplification and equalisation circuitry from the transformers and power-supply electronics.

The audio signal is amplified across four stages with passive RIAA correction, while two independently configurable RCA inputs allow two cartridges or analogue front ends to remain connected simultaneously. Gain and cartridge loading can be adjusted from the front panel or remote control, with seven sensitivity settings and eight impedance settings providing extensive cartridge matching. Both chassis are machined from massive 65mm-thick aluminium blocks, creating exceptionally rigid, heavily shielded enclosures for the sensitive phono circuitry.

Key Features

Reference two-chassis phono preamplifier

Separate phono and power-supply chassis

Independent left- and right-channel power supplies

Multi-stage power-supply stabilisation and filtering

Separate power feeds for left channel, right channel and control logic

Four-stage signal amplification

Passive RIAA equalisation

RIAA accuracy: ±0.1dB from 20Hz–20kHz

2 × RCA phono inputs

Independent configuration for each input

Adjustable input sensitivity from 0.3–5mV

7 sensitivity/gain settings

Gain range: 52–76dB

Adjustable input impedance from 30Ω–47kΩ

8 impedance settings

Input capacitance: 150pF

Front-panel display showing selected input and settings

Settings adjustable from front panel or remote control

Balanced XLR and single-ended RCA outputs

Output impedance: 70Ω

Nominal output level: 2Vrms

Maximum output level: 9Vrms

THD: <0.01%

Signal-to-noise ratio: 87dB

Each chassis machined from two 65mm-thick aluminium blocks

Enclosure wall thickness approaching 30mm in some areas

Hand assembled and individually tested

Preamplifier dimensions: 430 × 410 × 145mm

Power-supply dimensions: 430 × 410 × 145mm

Preamplifier weight: 20kg

Power-supply weight: 30kg

Maximum power consumption: 25W

The RCM Audio TheRIAA Mk II is a reference MM/MC phono preamplifier designed around a fully dual-mono architecture with an external power supply. The separate PSU houses the rectification and first stage of voltage stabilisation, while additional filtration is located within the main chassis close to the sensitive amplification and equalisation circuitry. Extensive internal shielding further isolates the left and right channels and helps maintain an exceptionally low noise floor.

Passive RIAA equalisation employs low-noise resistors and polypropylene capacitors individually measured and selected for precise channel matching, while adjustable gain from 52–76dB and eight impedance settings from 20Ω to 47kΩ provide extensive cartridge compatibility. The input circuitry can also operate in balanced or unbalanced mode, taking advantage of the inherently balanced signal generated by a phono cartridge to improve noise rejection and dynamic range when appropriately configured.

Key Features

Reference MM/MC phono preamplifier

Fully dual-mono architecture

Separate external power supply

Three-stage power-supply stabilisation and filtration

Symmetrical power-supply design

Extensive separation between power supply and sensitive audio circuitry

10mm shielding between left- and right-channel audio boards

Additional 5mm shielding within the power supply

Passive RIAA equalisation

Low-noise resistors and polypropylene capacitors in RIAA network

Individually measured and selected RIAA components

RIAA linearity: ±0.1dB from 20Hz–20kHz

Selectable balanced or unbalanced input operation

RCA phono input

Cartridge matching via high-quality Omron DIP switches

Input sensitivity adjustable from 0.2–5mV

9 sensitivity settings: 0.2 / 0.3 / 0.4 / 0.6 / 0.9 / 1.4 / 2.0 / 2.5 / 5mV

Gain range: 52–76dB for 2Vrms output

Input impedance adjustable from 20Ω–47kΩ

8 impedance settings: 20 / 30 / 50 / 100 / 200 / 400 / 1,000 / 47k Ω

Input capacitance: 100pF

Signal-to-noise ratio: 85dB

THD: 0.01%

Output impedance: 70Ω

Balanced XLR and single-ended RCA outputs

Nominal output level: 2Vrms

Maximum output level: 9Vrms

High-quality components from Elna, Sanyo, Nichicon, Wima, TDK Epcos, Vishay, Omron, Burr-Brown and Analog Devices

Main chassis dimensions: 440 × 265 × 120mm

Power supply dimensions: 205 × 270 × 105mm

Main chassis weight: 9kg

Power supply weight: 4.5kg

Maximum power consumption: 17W

The RCM Audio Sensor 2 Mk II is a high-performance MM/MC phono preamplifier designed to provide extensive cartridge matching, low noise and high output capability from a compact two-chassis design. Its separate power supply houses the transformer, rectification and first stage of voltage stabilisation, with a second stabilisation stage located within the main preamplifier chassis to isolate the sensitive audio circuitry from power-supply interference.

RIAA equalisation is performed by a two-stage passive network using low-noise resistors and polypropylene capacitors, with individual components measured and selected to achieve accurate channel matching. Seven sensitivity settings provide gain from 52–76dB, while eight impedance settings from 20Ω to 47kΩ allow precise matching with a wide range of moving-coil and moving-magnet cartridges. Selectable balanced or unbalanced input operation and both XLR and RCA outputs provide additional system flexibility.

Key Features

High-performance MM/MC phono preamplifier

Separate external power supply

Symmetrical power-supply architecture

Transformer, rectification and first stabilisation stage housed in separate PSU

Second power-supply stabilisation stage located within preamplifier chassis

Two-stage passive RIAA equalisation

Low-noise resistors and polypropylene capacitors in RIAA network

Individually measured and selected RIAA components

RIAA accuracy: ±0.3dB from 20Hz–20kHz

Selectable balanced or unbalanced input operation

RCA phono input

Balanced XLR output

Single-ended RCA output

Input sensitivity adjustable from 0.3–5mV

7 sensitivity settings: 0.3 / 0.4 / 0.6 / 0.9 / 1.4 / 2.5 / 5mV

Gain range: 52–76dB for 2Vrms output at 1kHz

Input impedance adjustable from 20Ω–47kΩ

8 impedance settings: 20 / 30 / 50 / 100 / 200 / 400 / 1,000 / 47k Ω

Input capacitance: 150pF

Nominal output level: 2Vrms

Maximum output level: 8Vrms

Output impedance: 70Ω

THD: 0.01% at 1kHz

Signal-to-noise ratio: 85dB at lowest gain setting

Non-magnetic chassis construction

Optional Furutech gold or rhodium RCA, XLR and IEC connections

Preamplifier dimensions: 245 × 227 × 110mm

Power supply dimensions: 122 × 230 × 70mm

Preamplifier weight: 3.5kg

Power supply weight: 1.7kg

Maximum power consumption: 17W