Note that this is a discontinued product. You may want to visit the brand's page here to browse their newer products.
What reviewers think
Magazine reviewers and YouTubers have tried this product—so we've summarized their strongest opinions below.
How useful are hifi reviews? We consider them useful for three things: (1) Surfacing new products you should demo in person at a dealer. (2) Learning which products reviewers unanimously praise as the best they've ever heard (this means they probably are legitimately great). (3) Identifying a product's unique attributes that satisfy your idiosyncratic needs and tastes. Beyond that, we discount what reviewers say because they heap praise on everything—rarely being negative for fear of souring relationships with manufacturers. Further, they seldom have more than a couple products on-hand at once, relying on their imperfect memories to compare to past products.
Video Review
Compared to their other products
We think it's helpful to understand how this product fits into the brand's full lineup (below). To learn more about these products, visit the brand's page.
MA-1
- Positioning: The entry-level amplifier designed for compact and simple setups.
- Description: Uses a straightforward circuit and build with essential connectivity that makes it ideal for small rooms and modest sonic goals. Compared to the MP-3 or MA-3, keeps costs low while delivering the basic functions needed for everyday audio without additional features.
MP-3
- Positioning: A mid-range solution that balances simplicity with added digital and connectivity features.
- Description: Offers a cleaner digital processing design and improved signal clarity compared to the MA-1, making it a step up for users seeking more control. In contrast with the higher-tier MA-3, M-60, and GEM, provides moderate performance improvements and connectivity enhancements.
MA-3
- Positioning: A higher-performance amplifier aimed at audiophiles requiring refined audio detail.
- Description: Integrates advanced circuitry and improved power supply management to deliver a richer sound compared to both the MA-1 and MP-3. When compared with the more powerful M-60 and flagship GEM, offers a balanced mix of technical upgrades and connectivity options.
M-60
- Positioning: A robust integrated amplifier built for larger environments and more versatile functionality.
- Description: Uses a more sophisticated design with higher power output and expanded connectivity that distinctly outperforms the MA-3 in handling larger room acoustics. Relative to the lower-priced models, provides additional technical features and a broader suite of functionalities.
GEM
- Positioning: The flagship model delivering the most advanced audio performance in the lineup.
- Description: Incorporates groundbreaking technologies and premium components that ensure unmatched clarity and dynamic range compared to the M-60 and all other models. In contrast to every other product in the series, its refined build, extensive functionality, and top-tier performance are aimed at users with high budget tolerance and demanding sonic goals.
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MA-3
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Manufacturer's notes
The MA-3 is the culmination of a massive project we began in 1998 at the behest of one of our customers. It was 7 years in design, with 15 different chassis and 12 different circuit concept explorations. The goal: to build the largest OTL amplifier the world has ever seen, while at the same time retaining the qualities our amps have made famous. The end result is arguably the the best amplifier in the world!
The MA-3 is the culmination of a massive project we began in 1998 at the behest of one of our customers. It was 7 years in design, with 15 different chassis and 12 different circuit concept explorations. The goal: to build the largest OTL amplifier the world has ever seen, while at the same time retaining the qualities our amps have made famous. The end result is arguably the the best amplifier in the world!
There is clearly a need for such an amplifier that can make serious power while being completely transparent and musical; fortunately our OTL technology is well-suited to the task. Since we are not limited by issues that plague conventional amplifier designs, the MA-3 retains a wide bandwidth and low distortion simultaneouly. No transformer-coupled amplifier can produce 200, yet alone 400 watts and get it right at every audio frequency; yet the MA-3 makes 500 watts easily, without electronic artifacts. It's high-power amplifier that is fast and truly musical!
The MA-3 has all of the features as our other models, plus a few not seen in any other amplifier ever produced. It is class A, all-triode, and fully differential, with our patented direct-coupled output circuit and patented automatic bias control. There is only a single gain stage in the amp, so the signal path is very direct - something unknown in amps of this class. And with all it's customised components, includin...
There is clearly a need for such an amplifier that can make serious power while being completely transparent and musical; fortunately our OTL technology is well-suited to the task. Since we are not limited by issues that plague conventional amplifier designs, the MA-3 retains a wide bandwidth and low distortion simultaneouly. No transformer-coupled amplifier can produce 200, yet alone 400 watts and get it right at every audio frequency; yet the MA-3 makes 500 watts easily, without electronic artifacts. It's high-power amplifier that is fast and truly musical!
The MA-3 has all of the features as our other models, plus a few not seen in any other amplifier ever produced. It is class A, all-triode, and fully differential, with our patented direct-coupled output circuit and patented automatic bias control. There is only a single gain stage in the amp, so the signal path is very direct - something unknown in amps of this class. And with all it's customised components, includin...
Manufacturer Specs
- Output Power: 500 watts per channel, 2-16Ω load before clipping
- Input Impedance: 100 KΩ single-ended, 200 KΩ balanced selectable to 600 ohms
- Input Sensitivity: 2.5 V
- Tube Complement: 42 x 6AS7G output tube (per channel), 12 x 6SN7 driver tube (per channel)
- Power Storage Capacity: 1/4 Farad per channel
- Power Bandwidth: 1Hz-100KHz within ½ dB
- Frequency Response: 1Hz-200KHz within 0.5 dB (1 watt, open loop)
- Output Section Risetime: 600 V/µs
- THD: 0.5% at full power
- IM Distortion: 0.004% at full power
- Power Supply Weight: 152 lbs (68.9 kg) per chassis
- Power Supply Dimensions: 34" deep x 21" wide x 12.5" tall (86 x 53 x 32 cm) per chassis
- Amplifier Weight: 80 lbs (36.3 kg) per chassis
- Amplifier Dimensions: 31.5" deep x 21" wide x 15" tall (80 x 53 x 38 cm) per chassis
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Average Price
$100,001+
Used Products
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Brand Popularity
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Products
9
Founded
1976
Our take on the brand
Atma-Sphere pioneered the Output TransformerLess (OTL) amplifier design and created the first balanced-line preamplifier, the MP-1, both of which eliminate common audio components that can reduce sound quality. Their products are handcrafted and made-to-order with hand-selected components, and while traditionally known for tube electronics, they recently introduced their first solid-state Class-D GaN Mono Amplifiers.
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What if you spend a bit more?
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What else competes at this price?
Relentless 800
195500
/
Released
2023
Dan D'Agostino
After setting the measure for amplifier excellence, the new Relentless 800 Mono Amplifier extends the Relentless sound quality to a smaller platform. Every major section of the Relentless circuitry - power supply, input, driver, and output stages - have all been enhanced and these all feature in the new Relentless 800. The Relentless 800 incorporates the same circuit platform as its bigger brother with a lower power output. Mind you, the Relentless 800 is virtually unlimited when it comes to power delivery and is only outdone by the Relentless 1600 itself. Nuanced and musical at low volume levels, the Relentless 800 delivers the striking dynamic contrasts – that brings music to life.
Dan D'Agostino is an ultra-premium hifi brand distinguished by its unique copper heat sinks with holes and distinctive circular green-lit VU meters that give their amplifiers a steampunk aesthetic. Their amplifiers feature proprietary "Super Rail" technology that maintains high voltage for front-end transistors, while their three-chassis Relentless Preamplifier uses 30-pin interlocking connectors to eliminate wiring anomalies.
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Our Summary
Product Strengths
- Exceptional sound quality right away that continues to improve
- Capable of uncompressed dynamics at both loud and soft volumes, micro and macro, and doesn't harden or distort when playing loud
- Can handle big scale, orchestral, beautiful music to really raw, crazy metal music, all played convincingly at loud and soft levels
- New details are revealed without being hyper-analytical, sterile, or harsh
- Built like military materiel
Product Considerations
- Each monoblock weighs 145kg, so owners will welcome assistance when receiving it
- Inputs are on balanced XLR only, while the solid copper speaker terminals are designed for spade lugs, not 4mm bananas
- The Breguet watch dial-inspired meter's 'time-keeping' is less accurate
Takeaway: The D'Agostino Relentless 800 reproduces a wide range of music genres with detail and dynamics, offering an immersive and enjoyable listening experience. It brings out the best in music.
Video review
Our take on the brand
Dan D'Agostino is an ultra-premium hifi brand distinguished by its unique copper heat sinks with holes and distinctive circular green-lit VU meters that give their amplifiers a steampunk aesthetic. Their amplifiers feature proprietary "Super Rail" technology that maintains high voltage for front-end transistors, while their three-chassis Relentless Preamplifier uses 30-pin interlocking connectors to eliminate wiring anomalies.
Visit
Relentless 800
Page
Product Page
KMA i800
139995
/
Released
2023
Krell
The Krell KMA i800 represents the pinnacle of monoblock amplifier design, delivering extraordinary power and precision for the most demanding audio enthusiasts. As a flagship model in Krell's lineup, the KMA i800 is engineered to drive even the most challenging speaker loads with effortless authority, revealing every detail of your music with stunning clarity and depth. Whether you're listening to a delicate piano solo or a full orchestral crescendo, the KMA i800 delivers a sonic experience that is both powerful and profoundly immersive.
Krell is a hifi brand whose amplifiers use iBias technology to operate in Class A up to full power without excessive heat, while maintaining the ability to double power output as speaker impedance halves. Their amplifiers feature XD technology for better control over speaker drivers, and modern models like the K-300i include Bluetooth, HDMI, and streaming features for contemporary audio setups.
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Our Summary
Product Strengths
- Delivers 800W of class-A power regardless of the speaker load
- Features XD technology that lowers output impedance, resulting in more control over the speaker drivers and improved soundstage depth
- Employs Sym-Max technology to significantly reduce second-order harmonic distortion, bringing out more detail and improving the sense of timing and pacing
- Has a power supply consisting of 5400VA of transformers and 188,000µF of filter capacitance for substantial power delivery
- Offers protection against excess direct current, short circuits, and voltage sags—brown outs
Product Considerations
- It may be too much power for some users
- High idle heat dissipation at 890 btu/hr per channel
Takeaway: The Krell KMA-i800 is a powerful amplifier with technologies that aim to provide a clean and controlled sound. Its high power output helps to improve sound quality even at average listening levels.
Video review
Our take on the brand
Krell is a hifi brand whose amplifiers use iBias technology to operate in Class A up to full power without excessive heat, while maintaining the ability to double power output as speaker impedance halves. Their amplifiers feature XD technology for better control over speaker drivers, and modern models like the K-300i include Bluetooth, HDMI, and streaming features for contemporary audio setups.
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KMA i800
Page
Product Page
Telos 4800
260000
/
Released
2024
Goldmund
Telos 4800 is a revolutionary addition to Goldmund's illustrious collection encapsulates the technical brilliance of the Telos 8800 within a more compact form, setting a new pinnacle in high-fidelity audio for discerning audiophiles who seek supreme sound quality and precision. Meticulously crafted with Goldmund's legendary attention to detail and harnessing the latest advancements in audio technology, the Telos 4800 redefines audio performance standards.
Goldmund is a Swiss hifi brand known for its "mechanical grounding" technology, which reduces vibrations through heavy, precisely engineered components, and its proprietary Telos amplifier technology that significantly reduces intermodulation distortion. The brand appeals to audiophiles who prioritize pure sound reproduction, focusing on musical realism through minimalist design and high bandwidth circuitss.
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Our Summary
Product Strengths
- Designed to drive even very low-impedance loudspeakers without compromising distortion levels
- Delivers unmatched sound clarity and power with a maximum power output of 1050 watts RMS at 8 ohms and a total harmonic distortion (THD) of only 0.005% across 20 Hz to 20 kHz
- Features a damping factor of 600 at 1 kHz and output floor noise of less than 3 μV, delivering an impeccably clean and detailed sound free from unwanted background noise
- Ensures maximum thermal security and short-circuit protection with fully analog circuitry from input to output and an automatic shutdown feature
- Equipped with analog and digital inputs, including RCA and XLR connectors
Product Considerations
- A preamp is required to supply input switching and any processing needed before sending signals to the Telos 4800 to power the speakers
- As a mono power amp, two units are required for a stereo setup, increasing the overall cost significantly
Takeaway: The Telos 4800 is designed to meet the needs of any audio system and delivers unmatched sound clarity and power. With impeccable specs, it offers a high-end performance for audiophiles.
Video review
Our take on the brand
Goldmund is a Swiss hifi brand known for its "mechanical grounding" technology, which reduces vibrations through heavy, precisely engineered components, and its proprietary Telos amplifier technology that significantly reduces intermodulation distortion. The brand appeals to audiophiles who prioritize pure sound reproduction, focusing on musical realism through minimalist design and high bandwidth circuitss.
Visit
Telos 4800
Page
Product Page
Eric Encore
174965
/
Released
2021
Engstrom
Named after a great Swedish choir conductor, ERIC is our no-compromise statement power amplifier. Fully balanced and transformer-coupled, it was created to drive even the toughest loads. ERIC uses separate power supplies for input and output stages and DC filaments.
Engström is a Swedish hifi brand that handcrafts amplifiers with a minimalist Nordic design, featuring fully balanced, transformer-coupled circuits and no negative feedback to preserve natural sound dynamics. Their amplifiers, which use KR Audio's T-100 power tubes, are known for creating an expansive, three-dimensional soundstage with what audiophiles call a "Scandinavian Sound"—characterized by open, detailed, and natural sonic qualities.
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Our Summary
Product Strengths
- Crisp, tight rhythms are allied to a sonorous, close-focused view of vocals
- Capable of bags of detail and definition, while bathed in a lovely warmth
- Massive bass weight is available, with fabulous rosiny bite to the low strings, silky violins, and the feeling of space and air around the performers
- Big, substantial sound makes the most of remasters, bringing out all the character of vocals
- Focus and warmth contributes to a solid, three-dimensional soundstage, and remains clean and tight when cranked
Product Considerations
- The precious bottles should never be left unattended or used without the purpose-designed glass hood installed
- The amps' thermal characteristics may be a problem in a globally-warmed English summer
- Each amp draws 430W from the wall
Comparisons (according to reviewers)
- Vs Dan D'Agostino Relentless Monoblocks—the ERIC Encores are more expensive per watt
Takeaway: The Engström ERIC Encore Mono Power Amplifiers offer a captivating and enthralling presentation that challenges old clichés about valve amps. One should hear them if given the chance, for they sound glorious.
Video review
Our take on the brand
Engström is a Swedish hifi brand that handcrafts amplifiers with a minimalist Nordic design, featuring fully balanced, transformer-coupled circuits and no negative feedback to preserve natural sound dynamics. Their amplifiers, which use KR Audio's T-100 power tubes, are known for creating an expansive, three-dimensional soundstage with what audiophiles call a "Scandinavian Sound"—characterized by open, detailed, and natural sonic qualities.
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Eric Encore
Page
Product Page
Jubilee Mono Ultimate
135000
/
Released
2023
Octave
The Jubilee Mono Ultimate - the next generation. It has the most sophisticated and uncompromising amplifier design in our amplifier hierarchy and sets a new benchmark for state-of-the-art power amplifiers. It features a number of detailed improvements including the use of eight KT 170 tubes with 440 W per channel. The basic idea of the Ultimate series is the extreme expansion of the power bandwidth and the bass range with our highly specialized (newly developed) and oversized high performance output transformer.
Octave is a hifi brand specializing in tube amplifiers that use enhanced pentode configurations to ensure stability with difficult speaker loads down to 2 ohms, while their Super Black Box technology increases power supply capacitance for better dynamics
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Video review
Our take on the brand
Octave is a hifi brand specializing in tube amplifiers that use enhanced pentode configurations to ensure stability with difficult speaker loads down to 2 ohms, while their Super Black Box technology increases power supply capacitance for better dynamics
Visit
Jubilee Mono Ultimate
Page
Product Page
Note that this is a discontinued product. You may want to visit the brand's page here to browse their newer products.
What reviewers think
Magazine reviewers and YouTubers have tried this product—so we've summarized their strongest opinions below.
How useful are hifi reviews? We consider them useful for three things: (1) Surfacing new products you should demo in person at a dealer. (2) Learning which products reviewers unanimously praise as the best they've ever heard (this means they probably are legitimately great). (3) Identifying a product's unique attributes that satisfy your idiosyncratic needs and tastes. Beyond that, we discount what reviewers say because they heap praise on everything—rarely being negative for fear of souring relationships with manufacturers. Further, they seldom have more than a couple products on-hand at once, relying on their imperfect memories to compare to past products.
Video Review
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