Warm Audio and Sound Techniques have collaborated on the Sound Techniques JUDE-MP and JUDE-MP2 microphone preamps, two new designs built around the original Sound Techniques A-Range console preamp circuit associated with Trident Studios. Released together, the JUDE-MP provides one channel in a compact desktop format, while the JUDE-MP2 provides two independent channels in a 1U rackmount chassis.
The history behind these preamps goes back to the 1960s and 1970s, when Geoff Frost designed Sound Techniques consoles used in studios including Trident, De Lane Lea, Sunset Sound, and Elektra Sound Recorders. Those desks were part of recording sessions involving artists such as The Beatles, David Bowie, Elton John, Queen, Fleetwood Mac, Jeff Beck, Led Zeppelin, The Who, and The Rolling Stones.
Rather than developing a modern preamp loosely based on that period, Warm Audio worked directly with Sound Techniques to reproduce the original circuit topology. The JUDE series retains the dual-discrete 3035 Class-A amplifier design, transformer-balanced signal path, and Geoff Frost's impedance-matching approach.
The Original A-Range Preamp Circuit
Both JUDE models are based on the preamp circuit used in the original Sound Techniques A-Range consoles at Trident Studios. The design uses dual-discrete 3035 Class-A amplification and transformer coupling to produce the depth, punch, saturation, and harmonic character associated with the original consoles.
Sound Techniques specified the component choices and construction approach for the new preamps. The circuit uses Wima and Nichicon audio-grade capacitors, carbon resistors, hand-wired PCB construction, and custom CineMag transformers.
Custom-wound CineMag input transformers handle the selectable input impedance, while the output stage uses a custom-wound high-purity nickel CineMag transformer. These elements are part of the actual signal path rather than cosmetic references to vintage studio equipment.
For engineers looking for a preamp that can contribute audible character during tracking, the JUDE series offers a different approach from a highly neutral front end. Microphone choice, input impedance, gain structure, and transformer behaviour all become part of shaping the recorded sound.
Nine Z-Match Positions
One of the most distinctive features of the JUDE design is the 9-position Z-Match control derived from Geoff Frost's original impedance-matching circuit.
Changing the Z-Match position alters the electrical interaction between the microphone and the preamp. Depending on the microphone, this can affect gain, frequency response, transient behaviour, saturation, and overall tonal balance.
That makes the control especially useful with a varied microphone collection. Ribbon microphones, condensers, and dynamics can respond differently as the input conditions change. Instead of treating the nine positions as fixed EQ curves, it is more useful to think of them as nine different ways for the microphone and preamp to interact.
This gives engineers another way to shape a recording before reaching for EQ. A familiar microphone can behave quite differently depending on the impedance setting, which can be useful when trying to find the right amount of weight, clarity, density, or transient response at the source.
JUDE-MP Single-Channel Microphone Preamp
The Warm Audio Sound Techniques JUDE-MP packages the Sound Techniques circuit into a compact single-channel desktop preamp. It is suited to vocals, individual instruments, overdubs, voice recording, and mobile sessions where one high-quality channel is enough.
The JUDE-MP provides between 65 and 76 dB of preamp gain with a 40-ohm source impedance. Its microphone input impedance options are 60 ohms, 200 ohms, and 1.5 kilohms, controlled through the Z-Match system.
The signal path uses a custom-wound three-impedance CineMag input transformer and a custom-wound high-purity nickel CineMag output transformer. The preamp also includes 48V phantom power, polarity reverse, line-level switching, XLR microphone input, 1/4-inch TS or TRS input, and both XLR and 1/4-inch TRS line-level outputs.
Frequency response is specified from 10 Hz to 25 kHz within plus or minus 2 dB. EIN is rated at -128 dBu A-weighted, self-noise at -99 dBu A-weighted, and THD at 0.008 percent. A VU meter provides level indication, and the chassis combines an aluminum faceplate with steel construction.
For a vocal chain, guitar amplifier, bass, piano, percussion source, or individual drum microphone, the JUDE-MP provides the complete Sound Techniques preamp concept without requiring a rackmount stereo unit.
JUDE-MP2 Dual-Channel Microphone Preamp
The Warm Audio Sound Techniques JUDE-MP2 takes the same basic concept and expands it to two independent channels in a 1U rackmount format.
That makes the MP2 the more natural choice for stereo microphone techniques and paired sources. Drum overheads, stereo acoustic guitar, piano, room microphones, orchestral recording, and other two-microphone setups can be recorded through matching Sound Techniques circuits.
Each channel provides its own preamp path, CineMag transformer-balanced circuitry, variable input impedance, gain and output controls, instrument input, 48V phantom power, and polarity switching.
For stereo work, having two matching channels in one chassis is useful because both microphones pass through the same circuit architecture while each side can still be adjusted independently. That flexibility matters when microphone sensitivity, placement, or source level differs between the two channels.
A Preamp Designed to Shape the Recording
The JUDE series is intended to be part of the sound rather than simply provide clean gain.
The original Sound Techniques consoles became associated with recordings that had density, punch, harmonic colour, and a distinctly analog presentation. The new JUDE preamps retain the circuit elements responsible for that behaviour rather than reducing the design to a visual reference to vintage studio equipment.
The combination of discrete Class-A amplification, transformer-balanced input and output stages, and variable impedance creates several opportunities to influence the source before it reaches the converter.
Electric guitars can be recorded with additional density and transformer character. Piano can gain weight while retaining transient definition. Drum overheads can benefit from added body and impact. Vocals can be pushed toward a fuller or more saturated presentation depending on the microphone, impedance setting, and gain structure.
Choosing Between the JUDE-MP and JUDE-MP2
The main difference between the JUDE-MP and JUDE-MP2 is workflow.
The JUDE-MP makes sense for engineers who usually record one source at a time and want the Sound Techniques circuit in a compact desktop format. It is well suited to vocal chains, overdub setups, instrument stations, and rooms where rack space is limited.
The JUDE-MP2 is better suited to engineers who regularly need two matching channels. Its 1U format is a natural fit for permanent studio installations, particularly for drum overheads, piano, stereo acoustic instruments, room microphones, and other paired recording techniques.
Both models are built around the same Sound Techniques design philosophy. Choosing between them is primarily a matter of deciding whether one channel or two channels better fits the studio.
Sound Techniques History in a Modern Recording Setup
There are many modern preamps influenced by British console designs from the 1960s and 1970s. The JUDE series takes a more specific approach by involving Sound Techniques directly and reproducing the original A-Range preamp architecture with the amplifier stages, transformer coupling, and impedance behaviour central to the design.
For engineers familiar with Trident Studios and the Sound Techniques consoles used across major recording facilities, the appeal is straightforward. The JUDE-MP and JUDE-MP2 provide access to that specific preamp architecture in formats that fit modern recording setups.
The JUDE-MP offers a focused single-channel desktop front end. The JUDE-MP2 brings the same concept to a two-channel rackmount format for stereo and multi-microphone work.