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Atma-Sphere Atma-Sphere Class D
Class D monoblocks, 2 x 100 Watts
Our Class D project has been in the works since 2017. Our goal was to expand on the positive attributes of our existing amplifiers, which have been getting great reviews and awards in the high end press for the last 30 years. So we felt we were in a good position to know if the goal was achieved. The result is a solid state amp that has all the smoothness in the mids and highs that you expect from an excellent tube amp but with considerably lower distortion, output impedance and obviously higher efficiency. Like our other amps, this one has a very nice first watt!
The Class D is a monoblock design based on GaNFET output devices and accepts both single-ended and balanced inputs. The circuit is entirely our own design and manufacture- it does not use anyone else's modules. The power supply employs a toroidal power transformer and has over-current protection to keep the amplifier and speaker safe.
FEATURES
- Single-ended and True Balanced input
- GaNFET output transistors
- rugged chassis
- Monoblock
- No adjustments needed
- Exclusive Atma-Sphere class D module
- Precision components used throughout
- Low-noise even on horn speakers
- Over-current protected
- Stable with all input and load conditions
- Classic Wrinkletex™ finish
- Three-year general coverage warranty
WATT RECOMMENDS
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Professional Reviews 90/100
Deliciously Crispy
Sound Quality
93/100
Build Quality
86/100
Value for Money
84/100
With a lovely midrange, quick bass, and a velvety treble, the Atma-Sphere Class D sounds more polished and involving than many solid-state rivals. AUDIOKEY REVIEWS heard rich, full-spectrum musicality, precise image placement, and a presentation that stays transparent without turning analytical.
What Reviewers Are Saying
Pros
Rich, polished full-spectrum sound with a standout midrange and natural musical flow.
Bass is quick and tuneful, giving the amplifier strong rhythmic control.
Treble is smooth, extended, and free of glare, helping the amp stay engaging over long sessions.
Excellent imaging and instrument placement keep complex mixes organized and easy to follow.
&
Cons
It is less about sheer sparkle and the widest possible soundstage than about smoothness and tonal ease.
SOUND QUALITY PERFORMANCE 93/100
Reviewers describe a richly polished, full-spectrum presentation with a lovely midrange, quick and tuneful bass, and treble that is tamed and velvety without losing extension. They also praise how the amplifiers remain transparent and involving without sounding bleached or analytical, though one note suggests they are less about sizzle and sparkle than sheer ease and color.
Transparency Resolution
92/100
The amplifier is described as fast and transparent without becoming bleached or analytical, which points to strong clarity with a natural rather than clinical edge. Reviewers also mention good clarity and fullness, suggesting detail retrieval is a real strength even if it is not presented as hyper-forensic.
Tonal Balance Musicality
95/100
This is the most repeatedly praised aspect in the review, with language such as lovely midrange, lush and relaxed beauty, euphonious voicing, and rich, polished, full-spectrum sound. The treble is said to be tamed, velvety and extended, and the overall result is described as more fun and highly involving.
Dynamics
91/100
The bass is called solidly quick and tuneful, and the review repeatedly stresses ease, drive, and musical momentum rather than compression or strain. There is no complaint about running out of steam, but the focus is more on fluidity and agility than brute-force punch.
Soundstage Imaging
93/100
Spatial placement is praised, with each instrument sitting comfortably in its spectral and panning pocket. The only caveat is that the stage was not as widely expansive as the comparison amplifier, so the presentation sounds organized and stable rather than exceptionally broad.
Assessments of Build Quality, Usability, and Overall Propositions.
Build Quality
86/100
The reviews themselves say little about long-term build quality or internal construction, beyond the fact that the design is positioned as a low-idle-draw amplifier and the specs list balanced or single-ended input capability. On the available evidence, there is not much to say about workmanship, but nothing in the review suggests any concern.
Value for Money
84/100
At a $6,120 asking price, the review does not directly argue that this is a bargain or an outlier in value terms. The language is strongly favorable about performance, but there is no explicit comparison to cheaper alternatives on value grounds, so the price discussion remains mostly unaddressed.
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Authorized dealers for Atma-Sphere Atma-Sphere Class D
- Afton Mountain Audio — in-store — Afton, Virginia, United States (website)
- Audio Perfection — online and in-store — Minneapolis, Minnesota, United States (website)
- Audio Revolutions — in-store — Khwaeng Thung Phaya Thai, Krung Thep Maha Nakhon (website)
- Phantom Audio — in-store — Jakarta, Jakarta, Indonesia (website)
- Salon One Audio — in-store — Ormond Beach, Florida, United States (website)
- Signature Sound — in-store — Liverpool, New York, United States (website)
- Sounds Of Silence — in-store — Nashua, New Hampshire, United States (website)
- Triode Picture + Sound — in-store — New York, New York, United States (website)
- USA Tube Audio — in-store — Phoenix, Arizona, United States (website)
- Wilbrand Acoustics — in-store — Nordhorn, Niedersachsen, Germany (website)