Audio Note M9 RIAA Phono Stage

The M9RIAA is the penultimate phono stage in the Audio Note range. Housed in two full size chassis, as you’d expect at this level the design and component quality are about as extreme as possible.

The EQ circuit uses what Audio Note dub as their “Virtual Component” design, where a specially wound Nickel-Iron cored silver wired transformer is placed at the centre of the RIAA circuit and whose inductance forms part of the correction curve - basically an LCR (Inductor, Capacitor, Resistor) EQ circuit but using a transformer rather than an inductor. Audio Note claim that the benefits of the transformer in this application is that there is no stray capacitance if you just were to use an inductor in its place, and that it allows a much higher impedance design, making the driver stages job much easier (600 Ohms is fairly normal for an LCR circuit, the M9 runs at 50k Ohms!).

This is combined with Silver foil capacitors, a Philips SQ E80F input valve and an E80CC is used for the following stage, all hard wired onto the phenolic treated wood boards, as seen on all top Audio Note products. The result is an flat RIAA response (within +/- 0.1dB) from a seemingly very simple, but very clever circuit. Naturally the output is through 55% Nickel-Iron cored silver wired output transformers, facilitating both single ended and balanced connections.

The sophisticated valve rectified and regulated power supplies fill a second chassis and are connected via umbilical cables to the box containing the actual stage itself.

Technical Specifications:

Input Impedance: 47K Ohms - Phono
Output Impedance: <10 Ohms
Unit Weight: 30 kg (between two units)
Unit Dimensions: 140mm (h) x 440mm (w) x 410mm (d) - PRE & 140mm (h) x 440mm (w) x 410mm (d) - PSU
Mains Input: AC 100-120V/220-240V 50/60Hz
Max. Power Consumption: 81 Watts