Atoll Electronique Internal phono module P100 MM / MC

Designed to transform the auxiliary input of an Atoll amplifier or preamplifier into a high-performance phono input, the P100 module represents a sophisticated technical solution for vinyl enthusiasts. This expansion board, entirely manufactured in France, combines a symmetrical architecture with discrete components to deliver precise RIAA preamplification, compatible with both moving magnet (MM) and moving coil (MC) cartridges.

Symmetrical Architecture and Discrete Components: Atoll’s Technical Signature

The P100 module stands out for its rigorous electronic design, true to the philosophy of the Normandy-based brand. Its fully symmetrical structure ensures optimal channel separation, drastically reducing crosstalk and preserving the stereo image. This architecture, combined with the complete absence of integrated circuits and operational amplifiers, reflects a purist approach to amplification.

The exclusive use of discrete components—individually selected transistors, resistors, and capacitors—allows for precise control of each stage of the circuit. This approach, more complex and costly than an integrated solution, offers total freedom in optimizing performance. The transistors are biased in class A, ensuring exemplary linearity and harmonic distortion kept to just 0.05%.

RIAA equalization, a crucial element of any phono preamplifier, is carried out with meticulous precision. This equalization curve, standardized since 1954, compensates for the modifications made during vinyl record cutting: attenuation of low frequencies and amplification of highs. The P100 applies the inverse correction with three transition points (50 Hz, 500 Hz, and 2120 Hz), faithfully restoring the original tonal balance of the recording.

Installation and Configuration: Thoughtful Integration

Installing the P100 module requires opening the host device—a simple operation, though some care is needed. Four screws at the corners of the chassis provide access to the internal circuits. The board plugs directly into the dedicated connectors, automatically transforming the AUX input into a PHONO input.

Configuration is done via two four-position DIP switch blocks, one for each channel. This manual approach, rather than front-accessible switches, reflects a desire to preserve signal purity by minimizing cable lengths. The available settings include:

• MM/MC Selection: positions 3 and 4 determine the cartridge type and associated gain
• Input Impedance: 47 kΩ or 100 kΩ depending on the position of switch 1
• Input Capacitance: 100 pF or no additional capacitance via switch 2

For a standard MM cartridge, switches 3 and 4 remain in the OFF position, providing 40 dB of gain. High-output MC cartridges require switch 3 ON (46 dB gain), while low-output MC cartridges require both switches 3 and 4 ON (52 dB gain). This flexibility allows the module to adapt to virtually any cartridge on the market.

A ground point, supplied with the module, is attached directly to the chassis near the connector. This connection, essential for avoiding unwanted hum, completes the installation by ensuring proper grounding of the turntable–preamplifier system.

Broad Compatibility and System Scalability

The P100 integrates with almost the entire Atoll range, from the IN50 integrated amplifiers up to the high-end IN400, including all the brand’s preamplifiers. Only the entry-level IN30 model cannot accommodate this module. This cross-compatibility reflects Atoll’s coherent design philosophy, where scalability remains a priority.

This modular approach offers several advantages. Users can purchase an amplifier without a phono input, saving on features not immediately needed, then add the module later as required. This flexibility is especially relevant as many audiophiles rediscover vinyl after years of exclusively digital sources.

The P100’s MM/MC compatibility also anticipates future system upgrades. A beginner starting with an affordable MM cartridge can, without changing the preamp, upgrade to a high-performance MC cartridge. The impedance and capacitance settings allow for performance optimization with different cartridges, ensuring precise adaptation to the specific characteristics of each transducer.

Technical Specifications

Compatibility

• Supported cartridge types: moving magnet (MM), moving coil (MC)
• Universal compatibility with all MM and MC cartridges on the market
• MC levels: high output, low output

Input Parameters

• Input impedance: 47 kΩ, 100 kΩ (configurable)
• Input capacitance: 100 pF or disabled (configurable)

Audio Performance

• MM gain: 40 dB (configurable)
• MC gain:
  • High output: 46 dB (configurable)
  • Low output: 52 dB (configurable)
• Total harmonic distortion rate: 0.05%

Technical Design

• Symmetrical discrete-component circuit for detailed and natural musical reproduction
• Class A operation for optimal biasing and low noise
• Fine adjustment of impedance, capacitance, and gain for precise matching with your turntable

Installation

• Plug-in format for Advance integrated amplifiers and preamplifiers
• Compatible with all Advance models except the IN30
• Easy installation with no modifications required