Moonriver Audio Phono Stages

Model 505

Four inputs. Every adjustment. Zero compromise.

The 505 Hybrid is a world-class phono preamplifier born from over two years of dedicated R&D. It supports four separate inputs for multiple turntables, tonearms, and cartridges — each with independently stored settings that auto-recall on selection. Twelve gain settings span 34 dB to 72 dB (×4000 amplification), with front-panel controls for capacitance, impedance, EQ curve, and stereo/mono — all adjustable on the fly without powering down. A dual-mono power supply with 70,000 µF of capacitance across six separate rails ensures absolute silence and dynamic authority.

At a Glance

●4 phono inputs (RCA + XLR)

●72 dB maximum gain (MC)

●12 gain settings (6 MM, 6 MC)

●70,000 µF total capacitance

●6 separate power supplies

●Dual mono operation

●Passive RIAA / Decca / Columbia EQ

●Per-input memory via microcontroller

●XLR and RCA outputs

●Double-shielded chassis

●Hand-assembled in Sweden

Key Features

72 dB MC Gain

Ultra-low noise active gain stages deliver up to 72 dB of gain — enough for the most demanding low-output MC cartridges. Six discrete gain steps for both MM and MC ensure a perfect match for any cartridge.

Per-Input Memory

An onboard microcontroller remembers the gain, loading, capacitance, and EQ settings for each of the four inputs independently. Switch between turntables and the 505 instantly recalls every parameter.

Front-Panel Mastery

Four oversized aluminium knobs and five switches give direct, tactile control over every parameter — no menus, no displays, no need for the manual. Adjustments are live and immediate.

70,000 µF Dual-Mono PSU

Six separate power supply rails with a combined 70,000 µF of capacitance in a full dual-mono configuration. Linear discrete regulators with dedicated noise-rejection circuits deliver the black background a phono stage demands.

Technologies Inside

Through-Hole Construction

Built to last. Built to be serviced.

Every Moonriver product uses through-hole components in its analog circuits — hand-soldered onto PCBs designed for the shortest possible signal paths. This traditional construction method is more labour-intensive than surface-mount, but it produces more robust joints, is easier to inspect and service, and allows components to be replaced individually decades from now.

Surface-mount technology dominates modern electronics for cost and density reasons, but Moonriver deliberately chose a different path. Through-hole components have larger solder joints that resist fatigue and thermal cycling. The PCB layouts are optimised for minimal trace length rather than maximum component density, keeping the signal path as short as physically possible. Tool-free lid removal means any qualified technician can inspect and maintain the amplifier without special equipment.

Hybrid Topology

The right technology for each stage.

Moonriver combines integrated circuits, discrete solid-state, and — where appropriate — valve circuits in a single product. Rather than adhering to a single design ideology, each gain stage uses whichever topology sounds best and measures best for that specific application.

In the 505 phono stage, IC op-amps handle initial amplification where their vanishingly low noise floor matters most, while a discrete high-current output stage provides the body and dynamic slam that only discrete circuits deliver. In the 404 Reference, National Semiconductor LM3886-derived output devices are paired with a fully discrete preamp for the most natural, uncoloured presentation. This pragmatic, technology-agnostic approach is central to the Moonriver sound — warm and organic like valves, yet controlled and dynamic like the best solid-state.

Gallery

A closer look at the Model 505.

Experience the Model 505

Visit our showroom for a personal demonstration. Hear the difference for yourself.

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For complete specifications and technical details, visit the official Moonriver Audio website.