AMS Neve 31105 ()
A hand-built, console-grade mic preamp and EQ that still makes engineers gasp when they hear vocals come to life
Overview
Plug a ribbon mic into a 31105 and hit record. These modules still show up on session sheets at Abbey Road and Electric Lady. The 31105 isn't flashy. It doesn't self-oscillate or turn into a synth voice. What it does is carve space in a mix with surgical grace while adding that Neve warmth, and that remains unmatched. It brought the tonal authority of the 80 Series consoles into standalone format, so engineers could pick that sound without buying a full frame.
The 31105 was originally designed for Neve's large-format consoles of the late 1970s, and it found a second life as a rack-mounted unit. Unlike the more common 1073 or 1081, it flew under the radar for years. It wasn't lesser, just rarer. It was built while Neve was refining its topology and component sourcing, and it combines the early discrete Class A design with a more refined EQ section. It's a complete tonal tool rather than a preamp with EQ slapped on, and each stage interacts with the next in a way that feels organic, almost musical, in how it responds to the source.
Its reputation grew in the shadows of its siblings. Engineers working on dense rock and orchestral sessions prized it for cutting through a mix without sounding aggressive. A vocal chain with a 31105 doesn't need much else. The preamp's 72dB of gain is clean and sturdy, the transformer-coupled output gives subtle saturation when driven, and the EQ has four bands with switchable frequencies and plenty of precision without sounding sterile.
Specifications
| Manufacturer | AMS Neve |
| Production Years | 1977–1985 |
| Original Price | $1,850 per module (1980) |
| Gain Range | 10–72 dB |
| Equivalent Input Noise (EIN) | –128 dBu (20Hz–20kHz, 60dB gain, 150Ω source) |
| Frequency Response | 10Hz–60kHz (±0.5dB) |
| Total Harmonic Distortion (THD) | <0.02% at +20dBu output |
| Input Impedance | 1200Ω balanced |
| Output Impedance | 150Ω balanced |
| CMRR | >70dB at 1kHz |
| Maximum Output | +28dBu into 600Ω |
| EQ Bands | 4-band (LF, LMF, HMF, HF) |
| EQ Frequency Selection | Switchable: LF (35/70/110 Hz), LMF (140/280/560 Hz), HMF (880/1.76/3.52 kHz), HF (5/8/16 kHz) |
| EQ Gain/Attenuation | ±16dB per band |
| Phase Switch | Yes, per channel |
| High-Pass Filter | 18dB/octave at 50Hz |
| Power Requirements | ±24V DC (via external power supply or console backplane) |
| Weight | 3.2 kg (7.05 lbs) per module |
| Dimensions (H×W×D) | 132 mm × 112 mm × 245 mm (5.2" × 4.4" × 9.6") |
| Connectors | XLR input, XLR output, rear-panel power |
Key Features
Discrete Class A Preamp with Custom Transformers
The core of the 31105 is a fully discrete, Class A microphone preamplifier, built on the same topology as Neve's console channels. It uses Mullard BC108/173 or equivalent transistors in a direct-coupled design, which keeps phase shift minimal and headroom high. The custom-wound input and output transformers are the same type used in the 80 Series consoles. They add a subtle harmonic richness that grows more pronounced as you push levels. Op-amp-based designs can sound clinical when driven. The 31105 saturates smoothly, so you can add weight to thin sources or let it sit transparently in the background.
Four-Band Sweepable EQ with Musical Curves
The 1073 has a three-band EQ. The 31105 adds a fourth band, which gives more control in the upper mids, a range critical for vocal clarity and instrument definition. Each band uses inductor-based circuitry, which gives the EQ its smooth, musical response. Frequency selection is switchable rather than continuously variable, but the choices are well thought out. The low-mid band, for example, lets you target boxiness at 280Hz or add warmth at 140Hz. The high-frequency band's 16kHz option adds air without harshness, and many engineers use it on acoustic guitars and overheads. The EQ sits after the preamp stage, so it processes a hot, transformer-saturated signal. Boosts feel more integrated and less peaky than on inline EQs.
Console-Grade Build and Signal Path Integrity
Every 31105 was hand-assembled on point-to-point wired circuit boards using military-spec components. The faceplate is thick steel, finished in the classic RAF blue-grey, with machined aluminum knobs that feel substantial and precise. Internally, the signal path is kept as short and direct as possible, with minimal shielding and grounding compromises. The unit also has on-board power regulation, so performance stays consistent with fluctuating supply voltages. Many outboard units of the era used basic voltage rails. Downtime in a 1970s recording studio meant lost revenue, and the 31105 was built to stay running.
Historical Context
The 31105 emerged when Neve was at the peak of its engineering prowess in analog console design. By the late 1970s the company had already built its reputation with the 1073 and 1081 modules, but demand was growing for more flexible, higher-bandwidth EQ options in large-format consoles. The 31105 was developed for the 80 Series consoles, particularly the 8048 and 8078, where its four-band EQ gave mix engineers more control over dense arrangements. Rock bands were layering tracks and orchestral sessions needed careful tonal balancing. The 31105 offered precision without sacrificing musicality.
It arrived alongside competitors like the API 550B and the SSL 4000's EQ. API leaned into aggressive midrange punch and SSL favored surgical parametric control. The 31105 struck a balance, with transformer-driven warmth and enough flexibility to handle complex mixes. SSL's later "black knob" EQ could sound clinical when overused, while the 31105 always kept a sense of analog cohesion.
Rupert Neve himself considered the 31105 one of the most refined iterations of his console EQ designs. In later interviews he said the inductor selection and transformer matching were "as close to ideal as we ever got." It never reached the pop-culture status of the 1073. It became a quiet favorite among engineers who valued subtlety over hype, and you'd find it tucked into the vocal or bass channels of a top-tier studio.
Collectibility & Value
Today the 31105 is a sought-after rarity, with pairs routinely selling between $6,500 and $9,000 in good working condition. The 1073 has been endlessly cloned and reissued. The 31105 has never been officially reissued, so original units are the only way to get the real thing. That scarcity drives the market, and it means buyers need to be cautious. Many 31105s were pulled from decommissioned consoles and later rack-mounted by third parties, most notably by Neve engineer Steve Butterworth in the late 1970s, using original Neve components. These "Butterworth mods" are highly regarded and often command a premium, especially if certified by known Neve experts like Geoff Tanner, who later founded Aurora Audio.
Common failure points include aging electrolytic capacitors in the power regulation stage and dried-out potentiometers, particularly on the EQ knobs. The inductors are generally sturdy, but physical damage from improper handling can cause microphonics or hum. A full recap and pot cleaning can run $400-$600 per module, so factor that into any purchase. Units still in console frames are rarer and often in better condition, since they were less likely to be mishandled during removal.
When buying, insist on a full audio test. Listen for channel imbalance, noise floor discrepancies, and EQ band smoothness. A healthy 31105 should be dead quiet at idle, with no crackling or popping when you adjust controls. Serial numbers from the late 1970s (1977-1979) are particularly desirable, as they represent the earliest production runs with original UK-sourced components. Avoid units with replaced transformers or non-original faceplates. They may function, but they lose much of the sonic character of the original.
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