Atma-Sphere Atma-Sphere Class D
Atma-Sphere Class D brings velvety treble, a lush midrange and quick, tuneful bass to a compact 100Wpc platform that doubles into 4 ohms. Audiokey Reviews found its presentation richly euphonious yet clear, placing instruments neatly within the mix while avoiding an analytical edge. It is an involving, low-idle-power alternative to tube-like musicality without tube upkeep.
WATT RECOMMENDS
Save your favorites. Compare them anytime.
Create a free HiFi Hub account to save products to your Wishlist and compare your favorites side by side.
Nicely Roasted
Sound Quality
90/100
Build Quality
85/100
Value for Money
85/100
Pros
Rich, relaxed and highly involving tonal balance, with a lovely midrange and polished full-spectrum presentation.
Quick, tuneful bass and velvety, extended highs deliver clarity without harshness or analytical glare.
Maintains clear instrumental separation and stable placement within complex mixes.
Cons
Soundstage width was less expansive with the Boenicke W5 speakers.
Treble favors fullness and smoothness over overt sizzle, sparkle and maximum texture.
WATT RECOMMENDS
Save your favorites. Compare them anytime.
Create a free HiFi Hub account to save products to your Wishlist and compare your favorites side by side.
What Reviewers Are Saying
SOUND QUALITY PERFORMANCE 90/100
The review portrays a polished, highly involving amplifier with unusual midrange beauty, strong clarity, and a full-spectrum presentation. Its principal trade-off is a less expansive soundstage and less overt treble sparkle than some alternatives.
Transparency Resolution
91/100
The reviewer calls the amplifier fast and transparent without becoming bleached or analytical, and praises its clarity and fullness. Instruments remained distinct within the mix, while the treble was described as extended and velvety rather than grainy or aggressive.
Tonal Balance Musicality
94/100
This is the standout area in the review: the midrange is called lovely, vocals are tamed without being dulled, and the overall character is described as lush, relaxed, euphonious, and beguiling. The presentation favors richness and listener involvement over explicit sizzle and sparkle.
Dynamics
89/100
The low end is described as solid, quick, and tuneful, and the amplifier is said to be tuned for speed. The review offers less direct commentary on large-scale slam, extreme headroom, or control of especially demanding loudspeaker loads.
Soundstage Imaging
84/100
Image placement appears orderly and stable, with each instrument comfortably occupying its spectral and panning pocket. However, the reviewer explicitly found the soundstage less widely expansive, limiting its spatial performance against more open-sounding competition.
Assessments of Build Quality, Usability, and Overall Propositions.
Build Quality
85/100
The supplied specifications point to a compact, low-idle-power Class D design with balanced and single-ended compatibility, low output impedance, and power that doubles from 8 to 4 ohms. The review says little about chassis execution, internal construction, connections, or long-term durability.
Value for Money
85/100
At $6,120, this is a premium-priced stereo power amplifier, and the review compares its voicing with the Parasound JC 5 while finding the Atma-Sphere more euphonious and more fun. It does not directly assess whether the asking price represents strong value against its peers.
Reviews & Sources
Professional reviews and sources for this product's Watt'n Potatoes analysis.
Online Reviews & Mentions
YouTube Reviews
No reviews found yet
Forum Mentions
No forum mentions found yet
Specifications
- Output power
- 100 watts per channel into 8 Ω 200 watts per channel into 4 Ω
- Input Impedance
- 100 KΩ balanced/single-ended
- Output Impedance
- ~0.010 Ω
- Input
- 2.15 Vrms for full output
- Gain
- 22dB
- Power Bandwidth
- 1Hz-20KHz
- Frequency response
- 1Hz-20KHz
- Distortion
- Total Harmonic Distortion less than 0.1% at full power. IM distortion less than .04% at full power.
- Feedback
- 35 dB
- Power consumption
- 5 watts at idle (per channel)
- Dimensions & Weight
- 13" deep x 11" wide x 3" high (33 x 28 x 8 cm) per chassis 14 lbs (6.35 kg), per chassis
- Warranty
- Three year general coverage
Manufacturer's Description — Atma-Sphere
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
Verified Dealers
Online Dealers
All Dealers
Zoom out the map to see more dealers
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)
- Sun Mountain AV — in-store — Colorado Springs, Colorado, United States (website)
- Triode Picture + Sound — in-store — New York, New York, United States (website)
- USA Tube Audio — online and in-store — Phoenix, Arizona, United States (website)
and 1 more verified dealer