Audio Note (UK) M5 preamplifier is designed for sonic performance rather than technical specifications and meets all Audio Note (UK) Level 3 standards: –

Pure Class A operation

Zero negative feedback

Single-ended circuit topology

Vacuum tube rectification

Material and Component Quality

It is well known that the accurate reproduction of music—going beyond mere sound—requires preserving the purity of the input signal. Consequently, it follows that to achieve this goal and retain the musicality of the original performance, the complexity of the circuitry itself must be kept to a minimum. To this end, M5 preamplifier employs a single-ended, zero-feedback circuit topology. This design offers superior linearity, relies on pure Class A tube operation, and eliminates the need for a phase splitter, a component that would otherwise introduce unwanted crossover distortion.

Unlike much of the audio industry, our circuit designs aim to minimize non-harmonic and time-domain anomalies rather than simply achieving vanishingly low harmonic or intermodulation distortion figures. These non-harmonic amplitude and time-domain distortions have a highly audible, detrimental effect on the signal waveform; addressing them is far more important than engaging in the increasingly irrelevant numbers game of chasing “perfect” measured response.

Therefore, M5 is designed for maximum linearity and minimal transient distortion, avoiding the need for detrimental “corrective” measures such as inherently error-prone feedback loops.

Instead of using separate volume and balance controls, M5 Line features dedicated Audio Note (UK) stepped attenuators for each channel. This not only delivers the substantial improvement in sound quality expected from the now-legendary Audio Note (UK) stepped attenuators but also provides a level of channel balance precision unattainable with conventional volume and balance potentiometers.

M5 preamplifier features ECC82 and 5687 line-stage tubes and utilizes a 6X5 tube-rectified power supply based on the Galahad PSU found in M10. This power supply also incorporates an ECL82 for voltage regulation and a 5651 for voltage stabilization. Audio Note (UK) copper wiring, tantalum resistors, SILMIC filter capacitors, and Audio Note (UK) copper-foil signal capacitors are used throughout the circuit, alongside custom Audio Note (UK) output transformers—designed and manufactured in-house—featuring HiB C-cores and copper windings. M5 Line also incorporates a properly designed and implemented balanced output circuit.

At the heart of M5 RIAA is a highly refined moving-magnet (MM) phono stage utilizing three 5670 tubes. This is followed by a 5687 line stage; both sections are powered by a dedicated 6X5 tube-rectified power supply—the Galahad PSU, based on M10 design. These power supplies also incorporate an ECL82 for voltage regulation and a 5651 as a voltage stabilizer. Audio Note (UK) copper wiring and tantalum resistors, Audio Note (UK) copper-foil signal capacitors, and custom electrolytic capacitors are used throughout the circuit, alongside custom Audio Note (UK) output transformers—designed and manufactured in-house—featuring HiB double C-cores and copper windings. M5 RIAA also features a properly designed and implemented balanced output circuit.

Technical specifications

Input Impedance: 100k Ohms – Line Level

47k Ohm – Phono Stage

Input sensitivity: 126 mV for 1 V output

Output impedance< 10 ohms

Unit weight: 16 kg

Unit dimensions: 140mm (H) x 440mm (W) x 410mm (D)

Power Input: AC 100-120V / 220-240V, 50/60Hz

Note: Due to Audio Note (UK)’s ongoing research and development program, specifications are subject to change without notice.