Atoll Electronique PR400 Evolution

Atoll Evolution Integrated Pre-Amplifier - Made in France

Overview

The PR400 EVO is the latest generation of our high-end preamplifier. The IN400 EVO inspires its design.

Its power supplies and electronics have been reworked to significantly improve audio performance. We’ve added the ability to rename the inputs and select the standby mode: Low Power or Preheat. It operates in dual mono (one low-noise linear transformer per channel) and pure balanced. The selection relays are also separate for the two channels. The coupling capacitors (high-end MKP) are shielded in independent enclosures to avoid radiation issues. Volume is controlled by two independent and perfectly synchronised ALPS motorised potentiometers. We use a proprietary servo system based on non-intrusive real-time audio measurement.

Features

10 mm brushed, micro-blasted, and anodised aluminium front panel, with high-precision engraving.
Machined aluminum heatsinks and knobs.
2 mm steel chassis.
Four toroidal transformers: 2 x 10 VA (audio) + 10 VA & 1.6 VA (logic).
High-quality shielded MKP coupling capacitors.
Full dual-mono structure:
– Two toroidal transformers: One per channel.
– Four independent audio stages, perfectly symmetrical structure.
– Two motorised ALPS potentiometers: One per channel.
Bipolar transistor input stages.
Bipolar transistor current sources and LEDs.
Perfectly symmetrical audio stages with very low feedback.
Precise balance adjustment, with the ability to store it.
Input renaming is available.
Sleep mode selection: Low power or preheating.
Adjustable button backlighting.
High-contrast OLED display: On or off (after 5 seconds of inactivity).
ATOLL global remote control is included as standard.
The PR400 Evolution can receive the following optional boards:
– DAC boards: DA100 and DA200.

Connectivity

Inputs

5 Line Inputs: AUX or PHONO (optional), CD, TUNER, DVD, TAPE.
2 Stereo XLR Inputs.
1 BY-PASS Input.

Outputs

1 TAPE Output.
2 XLR Outputs.
2 Stereo Line Outputs.
1 12V Trigger Output.

Miscellaneous

1 Ø 6.35 mm headphone jack.
Optional addition of the DA100 and DA200 digital boards.

The discrete audio stages feature a purely symmetrical structure, with a circuit based on a dual-input differential pair and an original Class A biased circuit with very low feedback. This structure includes perfectly stabilised current generators based on transistors and LEDs, minimising overall and intermodulation distortion. When listening, this enhances the spatial and physical perception of the instruments. The display is a low-power OLED model chosen for its excellent contrast and low electromagnetic radiation. Furthermore, its power supply and control devices are entirely independent of the audio power supplies.

Specifications