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
Bloggers and YouTubers have tried this product—so we've summarized their strongest opinions below. Links to full reviews follow.
Product Strengths
- Strong physical presence and handsome aesthetics, featuring lacquered copper heatsinks, venturi tunnels, and Breguet-style dials.
- MxV upgrades bring significant improvements in core music reproduction areas such as sound stage, detail, and dynamics.
- The Momentum M400MxV sounds 'louder' and more powerful even when set to the same levels as its predecessors.
- The Momentum MxV amplifiers have the ability to bring out the best in loudspeakers
Product Considerations
- The D'Agostino Momentum MxV monoblock is a heavy piece of equipment, weighing 43kg apiece without optional stands.
- The Momentum M400MxV may run warm
- DIP switches for input loading are inside the unit, which requires removing the top cover when switching between cartridges
Comparisons (according to reviewers)
- The Momentum MxV amplifiers bring much of what inspired the larger Relentless Epic 800 and Relentless Epic 1600 to a smaller form factor and price point
- The early Momentum Stereo delivered around half the power of the monoblocks, compared to the Momentum Stereo.
Takeaway: The D'Agostino Momentum MxV amplifiers bring high-end performance in a visually striking package, capable of significantly enhancing the listening experience through improved detail and dynamics. The upgrade path for existing owners also makes it a worthwhile long-term investment.
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Momentum MxV
reviews

Manufacturer details
- Frequency Response: 0.1 Hz to 100 kHz +0/-3 dB, 20 Hz to 20 kHz, ±0.1 dB
- Signal-to-Noise Ratio: 75 dB, unweighted
- Total Harmonic Distortion: 0.05% @ 1 kHz
- Input Impedance: 1 MΩ
- Output Impedance: 0.7Ω
- Power: 250 watts @ 8Ω, 500 watts @ 4Ω, 1,000 watts @ 2Ω
- Inputs: 3 pr stereo balanced XLR, 1 pr stereo single-ended RCA
- Outputs: 1 pr stereo balanced XLR, 1 1/4" headphone jack, 1 pr binding post
- Dimensions: 18.25 x 9.5 x 17.8 in (46.4 x 24.1 x 45.2 cm)
- Weight: 112 lb (50.8 kg)
Benefiting from extensive development previously applied to the Momentum Series separate components, the Momentum MxV integrated Amplifier executes on the potential that an integrated solution offers.
The Momentum MxV integrated Amplifier is a modular design that is configurable to a listener's preferences. The core line stage preamplifier section can be augmented to include a digital streaming and/or a phonostage module.
When fully equipped, the Momentum MxV Integrated Amplifier topology is a seamless circuit working as one from input to output. Each internal section is still highly specialized but knowing the exact complement of power supply, control, and audio circuitry being used together, affords engineering a vison of the system that is typically not possible.
Brand highlights
Taking a step back to look at reviewers' thoughts of the brand's entire lineup—not just this product—what stands out most is the following:
- The lacquered copper heatsinks with venturi tunnels and Breguet-style dials are distinctive visual elements that have been a consistent feature of D'Agostino's amplifiers from the beginning.
- Dan D'Agostino designs his solid-state creations to be as accessible and 'ear-friendly' as the best valve amps, achieving a sound that is organic, natural, pleasant, and even friendly.
- D'Agostino amplifiers are meticulously hand-built, with painstaking attention to detail and precision in component placement.
Select products
Progression Series
- Positioning: The entry-level line in the D'Agostino amplifier lineup.
- Description: Known for powerful output and musical finesse, making them suitable for larger rooms and those seeking high power without the flagship price.
Momentum Series
- Positioning: Sits in the middle of the D'Agostino lineup.
- Description: Delivers substantial power and refinement in a compact chassis. They incorporate advanced circuit topologies and a unique input stage, setting them apart from the Progression series, which focuses more on raw power.
Relentless Series
- Positioning: The flagship line of D'Agostino amplifiers, representing the pinnacle of performance and luxury.
- Description: Designed without limits, offering practically unlimited power and the ability to drive any loudspeaker to its fullest potential. They feature groundbreaking circuit topologies and new power transistors, differentiating them from the Momentum series, which focuses on compact design and refinement.
Our take on the brand
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Used
Dan D'Agostino
What if you spend more?
The company's inaugural creation, the Momentum Mono Amplifier, served as the foundation for its product line. The Momentum M400 MxV Mono Amplifier, the latest iteration, enhances the iconic design to new heights. Incorporating techniques and topologies from the Relentless Mono Amplifier, the Momentum M400 MxV models represent the pinnacle of Momentum circuitry evolution. The new model name, MxV, signifies Mass times Velocity—the fundamental equation for Momentum, a recognition that resonates particularly with individuals having a physics background. Explore the cutting-edge Momentum M400 MxV for an unparalleled audio experience.
Our summary
Product Strengths
- Exquisite aesthetics with a sleek design and a power meter that glows green
- Delivers a smooth and satisfying sound
- The sound is described as 'louder' and more powerful
- Said to be able to drive any speaker to its maximum output
- Upgrades are retrofittable to earlier Momentum models
- Balanced input only
Product Considerations
- Runs warm
- The scale on the power meter is essentially uncalibrated
- Requires a return to the factory for MxV upgrades on earlier Momentum Models
Comparisons (according to reviewers)
- The Momentum M400 MxV incorporates technology from the Relentless line and gets very close to the Relentless sound regarding space and depth
- The Momentum M400 MxV is smaller and lighter than the Karan Acoustics POWERa mono
- The Momentum M400 MxV is smaller and lighter than the D'Agostino Progression M550 Mono amplifier
Takeaway: The Momentum M400 MxV monoblock is a beautifully designed and powerful amplifier that delivers a smooth and satisfying listening experience. It incorporates technology from the flagship Relentless model, making it a top-tier choice for audiophiles.
Video review
Our take on the brand
Since its introduction in 2022, Apex has been hailed as the finest power amplifier ever created. Critics and connoisseurs have universally praised its combination of shattering power and sublime delicacy; its ability to drive any loudspeaker balanced with unimpeachable tonal neutrality. It has always been Gryphon’s mission to achieve the highest possible audio performance in terms of sheer musicality, transparency and realism. With Apex Mono and Apex Stereo, Gryphon Audio Designs has elevated pure Class A power amplification a titanic leap above what was previously considered possible. Gryphon Apex takes us several significant steps closer in the quest for the most natural and convincing musical illusion.
Product Strengths
- Delivers lots of current due to a new 2000VA toroidal transformer
- The Apex Stereo's ease of presentation was immediately obvious—it fully engaged the reviewer
- The amp exuded supreme self-confidence
- The amp simultaneously speeds things up and slows things down
- Superior speaker grip, improving organization, timing, and musical flow
Product Considerations
- Initial start-up can be alarming due to flashing error lights
- The size and weight (445 lbs) can make installation challenging
- It's gigantic and heavy, requiring special equipment and tools to handle its production
Comparisons (according to reviewers)
- Vs Boulder 2060: The Apex revealed more tonally saturated sounds
- Vs Boulder 2060: Apex cast a larger soundstage, and within those huge spaces, images were generally larger and more three-dimensional
- Vs Boulder 2060: Apex exposed more detail in the music
Takeaway: The Gryphon Apex Stereo is a powerful amplifier that brings music to life with a balanced and full sound at any volume. Its ability to reveal the resonant nature of instruments transforms listening sessions into immersive experiences.
Video review
Our take on the brand
Product Strengths
- Fully balanced design, handcrafted in the USA
- Employs a sextet of KT170 valves, ECC83, and 6H30, with hand-selected and matched valves
- Features Audio Research's 'Auto-Bias' circuitry and an internal hour meter for monitoring valve usage
- Aesthetically elegant design with unique 'Ghost Meters' which are LED-illuminated and can be dimmed or switched off
- Capable of delivering high power at low frequencies, controlling and driving speakers like a big solid-state amplifier
Product Considerations
- High price point
- Requires a 20A IEC cable (supplied)
- The bass control and sheer bass output of the Gryphon Audio Antileon EVO (solid state) could not quite be matched by the Reference 330M
- The unit use a variable speed fan, although it was essentially silent during testing, this may still present a point of concern for some users
Comparisons (according to reviewers)
- Vs Gryphon Audio Antileon EVO: The Gryphon Audio Antileon EVO (solid state) has slightly better bass control and output
Takeaway: The Audio Research Reference 330M is an intelligently engineered and beautifully styled amplifier that embodies the meaning of 'Reference' in sound quality. Its powerful valve design delivers excellent performance and is sure to be a conversation piece in any high-end audio setup.
Video review
Our take on the brand
Possessing formidable power, unrivalled technology and a herculean appearance this amplifier delivers electrifying signals to your loudspeakers, transforming your music into a thrilling experience.
craftsmanshipLow frequencies are faithfully reproduced without a whiff of constraint. Spellbinding vocals have astonishing reality and territory around them.
Monopolizing your leisure time, the addictive clarity and power of each musical note, riveting you into a state of blissful abandonment.
Highly skilled craftspeople take enormous pride in hand building each amplifier, scrupulously checking and testing every parameter, so your enjoyment is forever untroubled.
Power on tapUnprecedented power is yours to unleash, delivering an astonishing musical performance. Concealed within the crafted exterior lurks a gargantuan 2300VA mains transformer delivering mountainous levels of current to feed your musical hunger.
Accomplishing the largest crescendos turns into child's play with 272,000uF of electrical brawn just itching to be discharged.
Reassuringly cool, even under your most sustained inclination to blast away the cobwebs, it is gratifying so much power is on tap.
Product Strengths
- Build quality is among the best, with all pieces fashioned from solid aluminum
- The system delivers an effortless and truly reference-level sound
- Produces deep and powerful bass that energizes the room with ease
- Offers stunning analogue playback with incredible soundstaging, holographic image, depth, and width
- Delivers music with startling clarity across all genres
Product Considerations
- The Reference Preamplifier lacks a remote, focusing on a purist design
- The Reference Three speakers are very heavy—weighing 100kg net
Comparisons (according to reviewers)
- The Avid Hifi Reference system performed similarly well with Fanfare for the Common Man, producing impressive bass and dynamics, compared to the YG Acoustics system with Boulder
Takeaway: The AVID HiFi Reference system is a top-tier system delivering exceptional sound quality and effortless power. It is designed to provide an extremely enjoyable and immersive music experience, making it a worthwhile investment for serious audiophiles.
Video review
Our take on the brand
What competes at this price?
Our Summary
Product Strengths
- Visually stylish, luxurious, well-built, and enjoyable to look at
- Offers extensive functionality including preamp gain adjustment, channel balance, mute, and display brightness settings
- Combines qualities of both tube and transistor designs, having transparency and magical realism with easy power
- Produces a clean, succinct, holographic, and exciting sound, with great dynamic capabilities
- Exceptionally well-balanced frequency response, fitting between the warmth and energetic explicitness of other amps
Product Considerations
- Massive and heavy, making it not easy to move around
- Single ended inputs only with no balanced inputs
- The vast disparity between the damping factors—synergy can vary with speakers
Comparisons (according to reviewers)
- Aavik I-880 was leaner, more illuminated, outlined and energized, spatially grander, less intimate and occupied via shorter key sound sources, compared to Trilogy 915R preamp and twin 995R mono amps
- The I-880 was internally juicy, admirably outlined, enjoyably angry, instantaneous, and powerful in the lower end range, where the twin 995Rs were boomier, fuzzier, slower and sensibly shallower on the very bottom
Takeaway: The Aavik I-880 is a high-performing, visually stunning integrated amplifier that brings music to life with both elegance and power. This amplifier is designed to be a centerpiece, both sonically and aesthetically, in any high-end audio system.
Video review
Our take on the brand
Our Summary
Product Strengths
- Employs Pathos InPoL Technology/Dual InPoL Circuit, aiming for Pure Class A amplification and a warm, natural sound
- Delivers substantial power: 100 watts per channel into 8 ohms, and 170 watts per channel into 4 ohms
- Uses high-quality components and a power supply based on 1,800 VA toroidal transformers per channel
- Features a tube preamp (using Tun-Sol ECC803 and 6H30 Sovtek tubes) and MOSFETs in the power amplifier
Product Considerations
- The amplifier is large (540 x 800 x 300 mm) and very heavy (100 kg), possibly making it difficult to integrate into standard hifi setups
Takeaway: The InPoL is engineered to deliver a natural sound and substantial power, using high-quality components and a sophisticated design. This could be a compelling option for individuals seeking a high-end amplifier.
Video review
Our take on the brand
Our Summary
Product Strengths
- Refined and powerful sound that can compete with the best
- Big and authoritative sound, dynamics, and deep bass
- Natural and lifelike midrange, and a treble that's so extended that it allows you to find the magic in hi-rez digital
- Enormous soundstage in all directions
- Able to play loud without strain, distortion, or compression
- Offers a refined and powerful sound that can compete with the best
- Big and authoritative sound, dynamics, and deep bass
- Able to play loud without strain, distortion, or compression
Product Considerations
- The power receptacle is 20 amps, and a suitable power cord was not included
- Large and heavy amplifier weighing 55 kilos without packing material, so placement needs consideration
Comparisons (according to reviewers)
- Vs Burmester 909 and 088, the True Life Audio TSI-300 did not make singers ten feet tall, like some big systems do, but there was a stronger sense of the sound going far beyond the room boundaries, while the Burmester gear had an unexpected talent for keeping the images and the soundstage confined to a realistic, lifelike size
Takeaway: The True Life Audio TSI-300 seems to do everything it needs to do without compromise, delivering drama and raw emotion. It will appeal to those who love a big and authoritative sound, dynamics, and deep deep bass without sacrificing musicality.
Video review
Our take on the brand
Our Summary
Product Strengths
- The Brama's graceful sound, looks, fit, finish, and feel make it a standout as a complete package, delivering the sonic goods.
- The Brama offers a finely resolved ease to the sound that does not trade resolution for warmth, but rather offers grace and delicacy.
- It is a completely clean, clear silent runner, with absolutely no discernible self-generated interference.
- The Brama's greatest appeal lies in presenting music as a door already open, without obstruction caused by perceived sonic shortcomings.
- It is a master at fluidity, richness without ever sounding overripe, and dynamic impact that feels right as opposed to overcooked.
Product Considerations
- The control knobs get warm to the touch, but that is just aluminum doing its heat dissipation thing.
Comparisons (according to reviewers)
- Using the Brama's pre-out as pre, the Riviera monoblocks turned the rich cornucopia of sounds into a more believably dense and dimensional garden as compared to the Brama as integrated amp.
Takeaway: The Vinnie Rossi Brama Integrated Amplifier offers graceful sound and attractive design, making it a compelling choice. Its effortless purity and full-range reach invite the listener into the music.
Video review
Our take on the brand
Our Summary
Product Strengths
- Incredibly resolving, with plenty of detail
- Perfectly controlled, 'wide' sound in terms of dynamics and panorama
- A quieter background brings forward a level of detail
- A clearly structured form, with symmetrical divisions and repetitions
- Inspired by the Relentless Epic amplifier series
Product Considerations
- Speaker jacks accept only spades and bare wires, and connecting spades from the top bends the cable significantly
- Components on the rear panel are placed close to each other and not particularly convenient to use
Takeaway: The Momentum S250 MxV amplifier delivers an immersive and detailed listening experience, making it great for those who enjoy actively listening to music. It brings out the best in loudspeakers, offering tremendous dynamics and a wide soundstage.
Video review
Our take on the brand
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