Mercury m72s/1 mk IV

The Mercury M72s/1 Mk IV is a single-channel, all-valve microphone preamplifier designed with variable gain, selectable input pads, phantom power, phase reverse, and a proprietary FET Direct Input, delivering the legendary tonal character of the original V72s modules with modern enhancements.

Legacy and Design

The M72s/1 Mk IV draws its design inspiration from the iconic Telefunken/Siemens V72s amplifier modules, which were originally integrated into the REDD.37 recording consoles at Abbey Road Studios and used extensively on early Beatles sessions. These modules became revered for their tonal warmth and musicality, but due to limited original production and ageing components, functioning units are increasingly rare and expensive. Unlike the later, more common V72 modules that required modification for modern use, the Mercury M72s/1 Mk IV faithfully recreates the V72s circuit architecture, preserving the sonic signature while offering enhanced reliability and usability.

Technical Features and Circuitry

The gain structure of the M72s/1 Mk IV ranges from 28dB to 58dB, adjustable in precise 3dB increments using a high-grade rotary switch, allowing fine control for a wide range of microphone types and sound sources. Two input pad settings, -16dB and -28dB, further extend headroom and control; the -28dB setting, when paired with the lowest gain level, permits signal pass-through for tonal shaping on line-level sources like drum machines, synthesisers, or full mixes. The unit integrates +48V phantom power and a phase (polarity) reverse function, both essential for modern studio flexibility.

Direct Input and Signal Path

Each channel includes Mercury’s proprietary FDI (FET Direct Input) circuit, which is based on a class-A tube topology utilising a J-FET design. Unlike many DI implementations, this circuit passes the instrument signal through the entire preamp stage—including Mercury’s bespoke input transformers—allowing the amplifier’s tonal character to fully influence the signal. This design delivers exceptional nuance and depth for instruments such as bass guitar, electric guitar, and keyboards, making the M72s a powerful tool for both microphone and direct applications.

Sonic Character and Build Quality

The Mercury M72s/1 Mk IV reproduces the full-bodied, low-end richness and midrange punch characteristic of the V72s, while offering a more open top-end response. The unit introduces gentle harmonic saturation and musical breakup under gain, contributing to its reputation as a go-to for vocal clarity, acoustic realism, and low-end power. Unlike digital emulations or hybrid designs, Mercury constructs the M72s with only top-tier components—original-spec valves and custom transformers—ensuring authenticity, tone, and longevity. The unit is engineered to remain fully serviceable and robust for decades of professional studio use.

Warranty and Build Assurance

Mercury Recording Equipment provides a 2-year warranty on the M72s/1 Mk IV, along with a 3-year warranty on all tubes, reinforcing its commitment to durability and long-term performance.