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.

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.

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 SPDIF DAC
The add-on dac module is based on the 9000 series ESS Sabre dac chip. The SPDIF supports PCM streams up to 192kHz/24bit due to the limitation of the SPDIF (coaxial) specifications. There are 3 separated power supplies with very low noise regulators, 2 for the ESS dac board and 1 for the analog circuit. The capacitor bank is massive and it uses 42000uF (in case of 404 Reference) from the power amplifier's power supply.

Specially care has been given to the voicing of the analog output stage to match the dynamic and natural character of Moonriver sound. The result is an impressive sounding digital-to-analog converter which respects the timing, the space and the color of the music and unfolds the dynamic contrast - the definition of every musical event.

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.

The add-on USB dac module is also based on the 9000 series ESS Sabre dac chip with native DSD support. The USB dac supports PCM up to 384kHz/24bi and DSD up to 128. The USB input section is separated with discrete, very low drift clocks, XMOS input based chip with custom firmware. There are 5 separated power supplies with very low noise regulators, 2 for the USB board, 2 for the ESS dac board and 1 for the analog circuit. Specially care has been given to the voicing of the analog output stage to match the dynamic and natural character of Moonriver sound. The capacitor bank is massive and it uses 42000uF (in case of 404 Reference) from the power amplifier's power supply.

A new USB DAC for the Moonriver 404 Standard and Reference will be announced shortly.

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