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Atoll Electronique IN400 Evolution
The IN400 EVO is an integrated amp-preamp with high musical capacity. The concept is based on technical and aesthetic choices dedicated to optimal musicality. Mechanically, the chassis is made of 2 mm steel, and the front face is 10 mm aluminium, brushed, micro-blasted, and anodized, with high-precision engraving. The side heatsinks are machined from solid aluminium blocks to absorb mechanical vibrations and ensure perfect heat dissipation.
- Front face in 10 mm brushed, micro-blasted and anodised aluminium, with high-precision engraving.
- Heatsink and buttons in billet aluminium.
- 2 mm steel frame.
- One toroïdal transformer: 1050 VA for audio section
- One transformer: 1.6 VA for control logic.
- Integral double mono structure:
– Separate windings for the tracks.
– 1 attenuator per channel (with switched resistors). - Bipolar transistor input stages.
- Current sources with bipolar transistors and LEDs to ensure perfect voltage stability.
- Darlington transistor driver stages.
- Audio stages with perfectly symmetrical structure and very low counter-reaction.
- Power stages with MOS FET transistors (8 per channel) are rigorously matched.
- Precise adjustment of the balance and the possibility of memorising it.
- Possibility of choosing the standby mode: Low consumption or preheating.
- Configurable button backlighting.
- High contrast OLED display: ON or OFF mode (after 5 seconds of inaction).
- ATOLL global remote control delivered as standard.
- The IN400 Evolution can receive the following optional boards:
– DAC boards: DA100 and DA200.
– PHONO boards: P50 and P100 (can be combined with DAC boards).
CONNECTIVITY
Inputs
2 XLR inputs.
5 Line inputs: AUX or PHONO (optional), CD, TUNER, DVD, TAPE.
1 BY-PASS input.
Outputs1 Ø 6.35 mm headphone jack output.
1 12V Trigger output.
Various
Possibility of adding DA100 or DA200 digital boards (optional).
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Professional Reviews 94/100
Deliciously Crispy
Sound Quality
96/100
Build Quality
95/100
Features Connectivity
93/100
Value for Money
91/100
Powerful and highly resolved, the Atoll IN400 Evolution delivers a big, stable soundstage with taut bass, natural treble and an emotionally vivid midrange. The Ear Editor praises its effortless dynamics and transparency, while the amp’s extensive analog connectivity and solid French-built chassis make it a serious, polished choice for demanding listeners.
What Reviewers Are Saying
Pros
Delivers superb transparency, supreme detail retrieval, and a natural tonal balance that keeps bass, midrange, and treble in proper proportion.
Produces an enormous, stable soundstage with spot-on imaging and no hole-in-the-middle effect.
Handles demanding dynamics and high playback levels with ease, sounding composed even when pushed hard.
Offers unusually generous connectivity for an integrated amp, including eight analog inputs plus optional phono and digital boards.
&
Cons
Its near-20kg weight and substantial size demand a sturdy rack and careful placement.
The Bluetooth input is convenient, but the review suggests it does not match the quality of a good external streamer.
SOUND QUALITY PERFORMANCE 96/100
Reviewers praise the IN400 Evo for superb transparency and very high resolution, with one describing its overall balance as having "beautiful transparency" and "supreme" detail retrieval. The tonal balance is repeatedly described as natural and well proportioned, with the treble “not overly exaggerated or muted” and the midrange carrying emotion and lushness without strain. It also earns strong marks for dynamics and scale, with comments about effortless power, speed, and an enormous soundstage without a hole in the middle.
Transparency Resolution
97/100
The amp is described as having "beautiful transparency" and "supreme" resolution of detail, with "without audible blemish" standing out as especially strong praise. Reviewers present it as highly revealing while remaining clean and unforced.
Tonal Balance Musicality
95/100
The tonal balance is repeatedly framed as correct and natural, with the treble neither exaggerated nor muted and the midrange clearly vocal and emotionally involving. Reviewers also note a full, passionate, melancholic lushness that feels secure and musical.
Dynamics
96/100
Comments on speed, intricacy, and power delivery are consistently enthusiastic, with the amplifier said to cope with demanding music “so well” and to shrug off dynamics “as though it’s no effort at all.” It stays composed at higher volumes and is credited with substantial power that makes the system sound just as good, if not better, when pushed.
Soundstage Imaging
96/100
Imaging is described as spot-on and the soundstage as enormous, with no “hole in the middle” effect. That points to a large, stable, and well-organized presentation rather than just width for its own sake.
Assessments of Build Quality, Usability, and Overall Propositions.
Build Quality
95/100
Reviewers are clearly impressed by the construction, citing the 2mm steel chassis, thick aluminum fascia, solid-machined heatsinks, and the amplifier’s substantial 19.5kg mass. They also praise the tactile controls and say the unit is beautifully constructed and very well designed.
Features Connectivity
93/100
This is a very well-connected analog-focused integrated amp, with eight line inputs on XLR and RCA, plus a tape loop, phono stage option, and optional digital board. With USB, optical, coaxial, and Bluetooth available on the fitted digital card, it offers a lot more flexibility than a bare-bones integrated.
Value for Money
91/100
The review language is strongly favorable on value, placing it in the highest echelons for its price bracket and saying it cannot be recommended highly enough. The only real tradeoff mentioned is that convenience is sacrificed versus Atoll’s all-in-ones, but reviewers imply the sonics and connectivity make the asking price worthwhile.
Reviews
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Authorized dealers for Atoll Electronique IN400 Evolution
- A Tube High Fidelity — in-store — Almere, Flevoland, Netherlands (website)
- Absolute Audio - Canada — in-store — Calgary, Alberta, Canada (website)
- Akustik Strauss — in-store — Garmisch-Partenkirchen, Bayern, Germany (website)
- Alpha High End — online and in-store — Brasschaat, Vlaams Gewest, Belgium (website)
- AM Audio Design — in-store — Beauvais, Hauts-de-France, France (website)
- Ambiance Concert — in-store — Angers, Pays de la Loire, France (website)
- Ars Antiqua Audio — in-store — Boadilla del Monte, Comunidad de Madrid, Spain (website)
- Art Sonique — France (website)
- Audio Alternative — online and in-store — Fort Collins, Colorado, United States (website)
- Audio Ark — in-store — Edmonton, Alberta, United States (website)
and 85 more verified dealers