Atoll Electronique AV500 black (with trigger)

The AV500 from Atoll Electronique is a 5-channel amplifier designed for home theater setups. It delivers 85 watts per channel at 8 ohms and is built on a MOS-FET transistor architecture, with a power supply featuring two toroidal transformers. The device uses discrete components and symmetrical circuits, in line with the manufacturer’s usual design choices.

Sleek Design and Robust Construction

The AV500 sports a deliberately understated look, a hallmark of the Normandy-based brand. Its 4-millimeter-thick brushed aluminum front panel, finely machined and slightly curved, features only the Atoll logo and a power LED. This visual simplicity conceals particularly meticulous construction.

The 1.5-millimeter steel chassis ensures excellent mechanical rigidity while contributing to vibration isolation. The sides and top are dotted with small ventilation holes arranged in concentric patterns, ensuring effective natural cooling despite the absence of a fan. This passive design eliminates any mechanical noise, preserving the silence essential for critical listening.

All the connectors are logically and ergonomically grouped on the rear panel. Five large screw-type speaker terminals, compatible with banana plugs, are aligned with their respective RCA inputs. This layout greatly simplifies wiring and helps prevent connection errors. The IEC power socket allows the power cable to be replaced with an audiophile-grade model, while the power switch remains accessible. A 12V trigger connector (included on this model) enables automatic power-on synchronized with a compatible home theater preprocessor.

Electronic Architecture and Technical Performance

At the heart of the AV500 lies an ambitious technical design for this price range. The power supply, a crucial element of any quality amplifier, is built around two 340 VA toroidal transformers, for a total installed power of 680 VA. This partially dual-mono configuration improves channel separation and power supply stability under heavy current demands.

The filtering, with a total capacity of 73,000 microfarads, provides a substantial energy reserve. This generous capacity keeps the supply voltage stable even during the most demanding musical passages, preserving dynamics and transient impact. The capacitors are carefully selected for both their acoustic performance and electrical characteristics.

The output stages use MOS-FET transistors, a technology favored by audiophiles for several reasons. These components behave electrically much like vacuum tubes, with soft, gradual harmonic distortion rather than abrupt clipping. Their transfer curve is naturally more linear than that of standard bipolar transistors, contributing to a smooth yet robust sound. MOS-FETs also offer extended frequency response and excellent thermal stability.

Measured performance confirms the quality of this architecture. The bandwidth extends from 5 Hz to 200 kHz, well beyond the audible spectrum, ensuring exemplary phase response in the useful range. The 100 dB signal-to-noise ratio guarantees remarkably quiet operation, preserving micro-details and the atmosphere of recordings. Total harmonic distortion of just 0.005% at 1 kHz attests to the circuit’s linearity. The ultra-fast 1.3-microsecond rise time reflects the speed of the circuits, essential for faithfully reproducing instrument attacks.

Bi-Amping: Unlocking Full Potential

The AV500 features a particularly interesting function: the possibility of bi-amping thanks to the five RCA outputs available on each channel. This setup allows you to use multiple amplifier channels to separately power the bass and mid/high sections of compatible speakers equipped with dual terminals.

Passive bi-amping, achievable with the AV500, brings tangible acoustic benefits. By dedicating separate amplification channels to different sections of the speaker, intermodulation distortion between low and high frequencies is eliminated. Each amplifier works over a narrower frequency range, improving its control over the drivers. The effective damping factor increases, resulting in tighter, more articulate bass.

To implement this setup, the AV500 can be used in vertical bi-amping (one channel for bass, another for mids/highs of the same speaker) on two main speakers, with the fifth channel available for the center channel. The gain, matched with other amplifiers in Atoll’s AM and AV series, makes it easy to combine multiple power amps in complex configurations.

Integration and Practical Use

The AV500 naturally finds its place as a complement to an integrated home theater amplifier equipped with pre-out outputs. By assigning amplification of the main channels (front left/right, center, and surround) to the AV500, the integrated amp is freed up to handle only the rear surround and Atmos channels. This delegation significantly improves the overall sound quality of the system.

The extra current reserve provided by the AV500 also benefits the processor section of the main amplifier, which then has more resources for digital processing. Speakers that are difficult to drive regain dynamics and bass control, literally transforming the playback of the most demanding soundtracks.

The high 47 kohm input impedance ensures universal compatibility with all preamplifiers on the market. The adjustable sensitivity from 1.58 to 1.77 V allows the gain to be matched to different sources and setups. Standby power consumption remains reasonable at 14 watts, reflecting an efficient design despite the available power.

The AV500 can also be used in a high-fidelity stereo setup by using only two or four of its channels (in bi-amping). This versatility makes it a future-proof investment, able to adapt to changes in your audio-video system over time.

Technical Specifications

Output Power

• 8 Ω impedance: 5 × 85 W RMS or 2 × 100 W RMS
• 4 Ω impedance: 5 × 100 W RMS or 2 × 140 W RMS

Audio Performance

• Frequency response: 5 Hz to 200 kHz
• Signal-to-noise ratio: 100 dB
• Total harmonic distortion: 0.005% at 1 kHz
• Rise time: 1.3 µs
• Input impedance: 47 kΩ
• Input sensitivity: 1.58 V to 1.77 V

Power Supply and Filtering

• Transformers: 2 toroidal transformers, each 340 VA
• Total filtering capacity: 73,000 µF
• Output stages: Symmetrical MOS-FETs with discrete components

Connectivity

• Audio inputs:
  • 5 stereo RCA jacks
  • 1 12V trigger input
• Audio outputs:
  • 5 RCA jacks for bi-amplification or linking
  • 5 high-capacity screw speaker terminals, banana plug compatible
• Gain matched with Advance Paris AM and AV series amplifiers

Construction and Finish

• Front panel: 4 mm thick brushed aluminum
• Chassis: 1.5 mm steel for optimal vibration isolation
• Architecture: Separate dual-transformer power supply for stability and dynamics
• Design: Symmetrical discrete stages for natural sound reproduction

Dimensions and Weight

• Dimensions (W × D × H): 440 × 291 × 95 mm
• Weight: 12 kg