Moonriver Audio makes three products. That is the whole catalog: the 404 integrated amplifier, the 404 Reference above it, and the 505 hybrid phono stage. For a company in Malmö whose products are designed and made in Sweden and hand-assembled one at a time, this looks less like a limitation than a decision.
What the restraint buys is visible once the lid comes off — and the lid is meant to come off. The analog circuits are built with through-hole components rather than surface-mount, the preamplifier stage is fully discrete, and the power amplifier runs dual-mono from separate windings on the transformer. Both the top and bottom panels are removable, which is a serviceability choice almost nobody makes any more.
The power supplies are the other tell. The 404 Reference runs five separate supplies with individual overload protection and 107,000µF of total capacitance, 21,000µF of which is reserved for the preamplifier alone. The 505 phono stage uses six supplies and dual-mono construction, and offers four inputs, gain from 34 to 72dB, selectable loading, and RIAA, Decca, and Columbia equalisation curves — which is a specification you would expect on something several times its size.
The amplifiers are modular as well. Two of the line inputs accept optional plug-in boards: moving magnet phono, switchable moving magnet and moving coil, or a digital board with S/PDIF or USB. The company covers its products for three years and expects them to run for decades without maintenance.
An amplifier this unfussy suits an honest pair of loudspeakers — hear it with MoFi or Rega speakers, or a turntable from Music Hall up front. Arrange a listen.
