Moonriver Audio
Inspired by the famous song, Moonriver Audio is a combination of the vintage and the contemporary in audio reproduction.
Classic, timeless, user oriented design. Organic texture acquired within an open space, dynamic behavior unrestrained while preserving natural color, provisions made for modular upgrades and direct access to all functions.
Moonriver loves vinyl records, analog tapes, compact discs and digital streams and features upgradable modules for all those formats. We employ every technology available today, without staying dogmatically exclusive to one design principle versus another, be it solid state, integrated circuit or vacuum tube.
We are fond of hybrid designs that fuse well known and fresh tech elements, but, most of all, that fit the application.
Made in Sweden
Our products are designed and made in Sweden. We hand-assemble each unit, a painstaking but precise procedure. Through a global inventory that is constantly updated, it is our sophisticated research, efficient development and extensive listening tests -the fun part- that lead us to select the right component for a no-compromise audiophile sound.
We also care for sustainability as well as for reliability. Moonriver products are covered by a 3-year warranty and are designed to last for decades without any need of maintenance.
The 404 integrated amplifier
Moonriver Model 404 is the outcome of a 3-year research, the aim being to achieve incredible performance regardless of price range. The 404 amplifier will extract hidden elements and render textures from within any audio format, with the source, speakers and room to set the limits. Its culture will suit all music, as the Model 404 is by design set to define the faintest nuances of which tone integrity is composed.
A hefty supply section ensures that ample healthy power is available at all times at all stages through separate rails. A fully discrete preamp section serves for acute dynamic awareness, while a high output stage that is custom-optimized for bandwidth and distortion warrants for neutral predisposition and transient fidelity. A laborious selection of components armors the design against tonal alteration, pretentious or not, thus preserving naturalness throughout the shortest feasible path.
Furthermore, an integrated phono stage, a USB DAC, two preamp outputs and a tape monitor loop expand functionality to form an ideally flexible integrated amplifier.
Modular Architecture
Moonriver 404 amplifier is modular by nature; it can accommodate an MM or MM/MC phono stage and a USB asynchronous DAC. Fitting these modules is simple and can take place at any time, on or after purchase. The USB DAC may also be upgraded with a newer version to meet future needs.
Balance Control
You may find this feature to be vanishingly scarce in audiophile products as a result of today’s “minimalist” design mentality and the various myths accompanying it. However, balance control addresses a common problem; speakers that are positioned in asymmetry, in a non-balanced room environment. It thus provides the simplest tweak towards achieving a proper sound stage.
Living rooms and house furniture are meant to serve everyday life and may not be provisioned with an ideal listening spot, evenly distanced from each speaker to form an equilateral triangle. It is also not uncommon for one speaker to have to be placed nearer room boundaries than the other, having various frequencies boosted in a more or less predictable pattern. More often than not, balance control would come in handy in that it drastically helps overcoming volume level unevenness and in some cases even reclaiming stereo effect and the resulting focused sound stage.
As expected, the way balance control is implemented on the Moonriver 404 amplifier, in parallel, will not degrade or affect the signal in any way determinable.
Discovering the layout
Model 404 incorporates no less than 5 separate power supplies, each featuring overload protection. The power amplifier specifically runs on a dual mono configuration, beginning from separate windings on the toroidal transformer.
Signal switches are implemented via relays, while volume attenuation is trusted on the legendary blue ALPS pot.
A soft start circuit based on a 30A relay ensures that even the on/off switch is thought out to work with virtually no burden or wear for decades.
Components are carefully selected for both suitability and reliability. We make no use of surface-mount in analog circuits, despite the fact that through-hole costs more and requires advanced space management & layout strategies.
Each element utilized has to be of proven stability and sustained higher performance -proficient implementation provided- before making it into our analog paths.
As for the sound, we are not to say whether Model 404 is virtually transparent or inherently forgiving. Voicing it to appreciate the playlist and respect the user at all times has been the sum of all of our effort; a sincere effort to achieve effortlessness.
The Importance of Tape Monitor Loop
Probably most of today’s manufacturers reject the idea of their product featuring a tape loop. At Moonriver Audio, we have concluded that the tape monitor loop is essential. Not only does it add the option of monitoring the difference between recorded and source material at a real time.
It also, and most importantly, makes possible to insert to the chain -at will- a digital or analog room correction processor, a buffer, a noise reduction system or any other line device available to improve the sound of connected sources.
Stereo/Mono Switch
The pristine era of analog recording being long gone, features like the stereo/mono switch have been gradually chased out into obsolescence. Who wants to go back to one when they have two channels? “Less is more” and “more is better”. Well…
As vinyl record revamping climaxes, whether a modern rage, a fashion thing or a real movement, countless monaural pressings emerge out there, often along with their digital… image. Too many of them, among others waiting to be rediscovered, have currently become collector’s items, 78 rpm direct-cut gems being no exception. This is not unreasonable, as what happened between say the 30s and the 80s in terms of both musical interpretation and recording technique is by many considered to be “most of the music” – this sentence doing perhaps no justice to stunning actual developments in creation and reproduction. Stereo/mono switch gives you the chance to enjoy recording art milestones with respect to how they were initially intended to please; in genuine mono, 2-channel, doing away with artificial phase discrepancies induced by mandatory stereo mode.
So, “less” may well be “more”, but better is to have a choice.
Optional Phono Stage
Model 404 comes with two options in the phono stage department; one is MM only and the other is MM/MC selectable. Both follow the exact quality principles that Model 404 is built on. Quality components and massive power supplies are also employed here, to efficiently accommodate very low noise, high performance op-amps.
The gain in the MM/MC phono can be adjusted, simply by changing the dip switches position. The MC input load can be set also, by replacing the original 100 Ohm input resistor with a higher or lower value. No soldering is required.
Optional USB DAC
What was desired for our USB DAC module was not to make an addition rather than an omission; instead we had to be confident of substantially raising the true value and functionality of Model 404.
A new USB DAC is under development for the Moonriver 404 Standard and Reference.
Specifications
Inputs: 5 (line 1 and 4 optionally occupied by phono stage and USB DAC respectively, 1 x tape loop)
Outputs: 2 x preamp out, 1 x rec out
Max output power: 50 W per channel into 8 Ω
Frequency response: 10 Hz to 50 kHz
Total harmonic distortion: 0.05%
Signal to noise ratio: 85 dB (line)
Idle Consumption: 22 Watts
Dimensions (mm): 430 (W) x 390 (D) x 135 (H)
Weight: 12 kg
The team behind it are not just exceptional engineers but are also very obviously music lovers themselves. I am lucky to have a lot of great hi-fi come and go through my system. Much of it I have admired, much of it I have enjoyed, but most of it is packed up and returned with gratitude but without regret. I shall be genuinely sorry to see the Model 404 depart. If I was in the market for a new amplifier this would be at the top of my list.
Read the full review here
"It sounds more powerful than 50 Watts. It was also very dynamic, from the smallest gradations of chamber music, to large-scale orchestral works. However, I think that the most important characteristic is the coherence of the sound. I don't want to use the word "smoothness," because that might give the impression of rounded-off highs. The highs are not rounded off. And that's certainly not what the designer intended, because the small script word "fågelsång" on the front panel means "birdsong." There is a very organic "togetherness" to the sound. Both in the time domain, and in the frequency domain. After one of the listening parties, one participant remarked that it was a true measure of how great an audio product the Moonriver 404 is, that nobody really had any comments to make about it. They just listened to it, and enjoyed the music.
To sum up: Highest Recommendation".
Read the whole review here:
Positive Feedback
Moonriver Audio 404: Green Award effortlessly earned 09/2020
Green Audio Review website awards the Moonriver 404 with a Green Award:
"The Moonriver 404 does that most important of jobs with flair: it makes our loudspeakers sound good. Any loudspeaker I threw at it was a great match. The see-through capabilities of this amplifier are simply amazing. The first time I plugged in the 404 it was revelatory. Clarity, insight, momentum, crisp smoothness. But when it had been in my system for a while and it was time to say goodbye it was harder than usual to let it go. Other amplifiers – even my beloved Croft separates – sounded, well, off. Better than Croft? That is high praise indeed".
Read more: Greenaudioreview
Classicismo Sueco | A Moonriver Audio 404 Review in HIFICLUBE magazine 05/2020
“The 404 is an amplifier with modern, vibrant and young sound, with a high "athletic" capacity. It is difficult to define the type of the sound: Voices sound clean, clear, without artificial 'chest', which can often be confused with body and texture. It sounds like a thin cambric which, by letting the light through, show us the threads that makes the texture of the fabric: the smallest details are heard as part of the music, and not just as sound 'fireworks'.
The sound is so delicate and rich in information, that even conventional speakers seem to exhibit the characteristics of transparency and harmonic richness typical of electrostatics. It is a unique product from a new brand which can help you to solve the old valve vs. transistor dichotomy, offering colorless transparency, speed and dynamics without "aggression".
Portuguese version:
English version
Moonriver Audio 404 Integrated Amplifier Review in Stereo+ magazine issue 02/2020
“Absolutely fantastic with full control in the base and with an almost overwhelming musicality. It plays music in an open and transparent way, allowing for full insight into a well-defined three-dimensional soundscape. The Moonriver amplifier is incredibly nimble and precise, and has a transient response that makes your favorite music a festive moment. Everything merges into a rich and vibrant soundscape with massive amounts of information and timbre nuances".
The 404 Reference integrated amplifier
Following the runaway success of The Moonriver Model 404 (Standard), we decided to move a step further by improving on the already excellent design platform of the Standard 404 model. The Moonriver Model 404 Reference achieves even better performance over the Standard Model, while retaining a sensible price point.
Just like the Standard Model 404, the 404 Reference amplifier will extract hidden elements, and render textures from within any audio format; but with the capability to drive any speaker on the market – despite its moderate power. Only the source, speakers and room will set the performance limit. Its culture will suit all music, as the Model 404 is by design, set to define the faintest nuances of which tonal integrity is composed.
The power supply section has been improved to the maximum. The 404 standard uses a total of 57000uf capacitance. The 404 Reference lifts the capacitance to a spectacular 107000uf of which 21000 of them are reserved for the preamp only. This enormous increment expands the driving behaviour; the dynamic character; digs out more detail; low level information; a deeper and more articulate soundtstage; space between instruments is vast, while the bass has greater authority and is more confident than ever before.
The texture of each individual instrument is exposed exponentially in comparison with the Standard version. A fully discrete preamp section serves to provide acute dynamic awareness, while a high output stage that is custom-optimised for bandwidth and distortion, gives neutral character and transient fidelity. A sophisticated selection of components fuses the design against tonal traits, therefore preserving naturalness throughout the shortest feasible signal path.
Furthermore, an integrated phono stage, USB DAC, (two) preamp outputs and a tape monitor loop expand functionality to form an ideally flexible integrated amplifier.
Design & Ergonomics
We had a very clear vision when conceiving the Model 404 Reference amplifier: Classic design with a modern touch; high-quality materials such as over-sized aluminum controls, solid walnut cheeks, sturdy chassis and an ergonomic user interface.
There are no ‘for show’ aesthetics here, no display with complicated serial menus and hidden functions, nor a single multi-function knob for ‘minimalistic’ purposes.
The heart of the Model 404 is pure and minimal, but the interface is user-oriented and easy to operate by anyone in seconds, with no need to resort to the user manual. Four knobs and three switches give direct access to any function.
Modular Architecture
Moonriver 404 Reference amplifier is modular like its brother; it can accommodate an MM or MM/MC phono stage and a USB asynchronous DAC. Fitting these modules is simple, and can take place at any time, on or after purchase. The USB DAC may also be upgraded with a newer version to meet future needs and technologies.
Balance Control
You may find this feature to be vanishingly scarce in audiophile products as a result of today’s ‘minimalist’ design mentality and the various myths accompanying it. However, balance control addresses a common problem: speakers that are positioned in asymmetry, in a non-balanced room environment. It therefore provides the simplest tweak towards achieving a proper soundstage.
Living rooms and house furniture are meant to serve everyday life and may not be positioned in an ideal listening spot, evenly distanced from each speaker to form an equilateral triangle. It is also not uncommon for one speaker to have to be placed nearer room boundaries than the other, having various frequencies boosted in a more or less predictable pattern. More often than not, balance control is incredibly useful as it drastically helps overcome volume level unevenness and in some cases, even reclaiming the stereo effect and the resulting focused sound stage.
It is to be expected, the way the balance control is implemented on the Moonriver 404 Reference amplifier – in parallel, will not degrade or affect the signal in any way that is determinable.
Discovering the layout
Model 404 Reference, like the standard model, incorporates no less than 5 separate power supplies, each featuring overload protection. The power amplifier specifically runs on a dual mono configuration, beginning from separate windings on the toroidal transformer.
WBT nextgenTM speaker terminals ensure the massive flow of current from the amplifier’s output stage, is able to drive even “difficult to drive” speakers.
Signal switches are implemented via relays, while volume attenuation is trusted on the legendary blue ALPS pot.
A soft start circuit based on a 30A relay ensures that even the on/off switch is thought out to work with virtually no burden or wear for decades.
The 404 Reference chassis reduces unwanted resonant vibrations even further with absorbent materials, and better integral mechanical support.
Components are carefully selected for both suitability and reliability. We make no use of surface-mount in analog circuits, despite the fact that through-hole production costs more, and requires advanced space management & layout strategies.
Each element utilised has to be of proven stability and sustained higher performance – proficient implementation provided, before making it into our analog paths.
As for the sound, we are not to say whether Model 404 Reference is virtually transparent or inherently forgiving. Voicing it to appreciate the playlist and respect the user at all times has been the sum of all of our effort; a sincere effort to achieve effortlessness.
Optional Phono Stage
Model 404 Reference comes with two options in the phono stage department; one is MM only and the other is MM/MC selectable. Both follow the exact quality principles that Model 404 Reference is built on. Quality components and massive power supplies are also employed here, to efficiently accommodate very low noise, high performance op-amps.
The gain in the MM/MC phono can be adjusted, simply by changing the dip switches position. The MC input load can be set also, by replacing the original 100 Ohm input resistor with a higher or lower value. No soldering is required.
Optional USB DAC
What was desired for our USB DAC module was not to make an addition rather than an omission; instead we had to be confident of substantially raising the true value and functionality of Model 404.
A new USB DAC is under development for the Moonriver 404 Standard and Reference.
Specifications
Inputs: 5 (line 1 and 4 optionally occupied by phono stage and USB DAC respectively, 1 x tape loop)
Outputs: 2 x preamp out, 1 x rec out
Max output power: 50 W / channel into 8 Ω
Frequency response: 10 Hz to 50 kHz
Total harmonic distortion: 0.05%
Signal to noise ratio: 85 dB (line)
Idle Consumption: 22 Watts
Dimensions (mm): 430 (W) x 390 (D) x 135 (H)
Weight: 13 kg
A Dreammaker From Moonriver | Moonriver Audio 404 Reference review in Stereophile by Jason Victor Serinus 02/2020
"A Roon search led me to Trio Tapestry (Qobuz 24/96 FLAC), which is led by saxophonist Joe Lovano with Crispell and percussionist Carmen Castaldi (Qobuz 24/96 FLAC). I couldn’t believe how realistic Castaldi’s gongs sounded on “One Time In.” On “Seeds of Change,” sonics and musicianship were mesmerizing. The varied heights of instruments in the deep and spacious soundstage were enthralling. Everything felt so right that there was nothing to do but bliss out.
I wrote at the beginning of this review that the Moonriver 404 Reference is the least expensive integrated amplfier I’ve had in my system; that makes it difficult for me to proclaim the Moonriver 404 Reference integrated amplfier a new benchmark for sonic excellence in an integrated costing $5000 or less. But I’m tempted to anyway, because it does justice to complex and demanding recordings and it sounds tonally spot on, well balanced, clear, and musical.
For some of you, the Moonriver 404 Reference integrated may be the longed-for component, just waitin’ round the bend, that transports you to audio nirvana. With dutiful attention to setup and component matching, the Moonriver Model 404 Reference integrated amplifer can deliver Class A sound at a Class B price, and joyful listening".
Download the Stereophile review Here
The 505 Hybrid phono stage
The Moonriver Audio 505 phono stage meets all the needs of any demanding audiophile who loves vinyl records, both now and in the future. Designed with audiophiles, record collectors and vinyl freaks in mind, it boasts 4 inputs for all your turntables, tone-arms and cartridges. It also supports every possible adjustment on the fly with dedicated knobs and switches to ideally match your MC or MM cartridge.
The unique, adjustment feature of the Moonriver 505 hybrid phono stage allows “on the fly” listening tests with various adjustments without the need to switch off, remove the cover, switch on again and wait to warm it up.
The hybrid design combines the use of ICs and discrete solid-state circuits to form an ideal, high performance and ultra low noise circuit. While the IC op amps offer very low noise levels, a discrete circuit offers lifelike drive and dynamics which is impossible to get from IC op-amps.
As for the sonic signature of all Moonriver Audio products, we strive to balance the fine line between musicality & resolution. The soul of the music is in the midrange, this is where most of the emotion, the passion, the joie de vivre is contained.
On a technical level, it’s within the frequency band of 200 – 4,000Hz. Without a solid foundation underneath the midrange, the music sounds thin & brittle and often un-involving. If the brain perceives that the sound is artificial, then it’s difficult to be swept away by the message contained within the music.
Similarly, accurate timbre reproduction is essential. A New York Steinway does have noticeable sonic differences from a Hamburg Steinway, while a Guarneri violin sounds distinct from a Stradivarius. To capture all those nuances, the loudspeakers & electronics need to act in unison, neither obscuring, nor exaggerating detail.
The sound and the level of performance of the Moonriver 505 phono stage is hard to describe and it must be heard to be believed.
Layout highlights
The layout of the PCB is designed with 3 principles in mind: Isolation in-between noise sources and sensitive audio signal as the transformer and gain stages, a minimalistic approach with less components as possible in the signal and the shortest signal path possible. Moonriver 505 is using double shielding, one for the transformer and one for the active gain circuits. This approach eliminates the need for an external transformer and the disadvantages of it.
Design & User Interface
We had a very clear vision when conceiving the Model 505 hybrid phono stage: Classic design with a modern touch; high quality materials such as oversized aluminium knobs, solid walnut cheeks, sturdy chassis and an ergonomic user interface.
There are no “for show” aesthetics here, no display with complicated serial menus and hidden functions, nor a single multi-function knob for “minimalistic” purposes.
The heart of the Model 505 is pure and minimal, but the interface is user-oriented and easy to operate by anyone in seconds, with no need to resort to the user manual.
Features
Giving direct access to all necessary adjustments, the 505 includes 4 knobs and 5 switches for all the adjustments: 4 inputs, 12 gain settings (6 for MM and 6 for MC), 5 MM capacitance settings, 5 MC load settings, including a custom option, 3 MM load settings and EQ choice for RIAA, Decca or Columbia 78 rpm records. The 505 phono stage will handle the signal from your precious MC cartridge with unmatched performance and it will make your everyday MM cartridge sound like never before.
Power supply
The Moonriver 505 hybrid phono stage contains 6 separated power supplies, including a massive 70000uf total capacitance and it is designed in dual mono operation. Each stage has its own power supply, including a linear discrete regulator circuit and a discrete noise rejection circuit.
Active gain stage
Using ultra low noise active gain stages, the Moonriver 505 delivers a maximum gain of 72dB (x4000 times) in the MC setting. The MM and MC settings use different input stages with different op amps specifically chosen for each case. All setting functions are performed with air sealed, extremely low impedance relays. Finally, a discrete, high current output circuit delivers lifelike dynamics on the output.
Microcontroller operation with save memory function
A microcontroller controls all functions and ensures an entirely silent operation. Every setting change is stored automatically for each of the 4 inputs. Every time you change the input, the last chosen settings are recalled automatically. For example, you can connect 4 MC cartridges or 4 MM cartridges or 2MC and 2 MM, or 3 MM and one MC, every combination is possible with different settings for every input.
De-emphasis EQ
The de-emphasis circuit is passive, the best possible approach for extreme flat frequency response without interference with the other stages. The EQ circuits involve 2 equalisation curves, a RIAA and a DECCA or COLUMBIA curve for 78rpm records. Both EQ circuits are formed using a minimalistic approach with very few, extremely low tolerance, audiophile quality components.