REFURBISHED UNITRA MDU 24 1960S STEREO SYSTEM - XLR

fascinating Eastern European interpretation of late-1960s and 1970s stereo microphone design. The MB Unitra Tonsil MDU-24 is unmistakably related to the famous Grundig GDSM 331 concept — from the rotating stereo arrangement and detachable capsules to the presentation box and integrated tripod system. Whether it was directly inspired by the German design or developed in parallel, the resemblance is impossible to ignore. The Polish-built version has its own personality: slightly rougher mechanically, visually quirky in places, but sonically astonishing. This particular set delivers a surprisingly full-range and highly sensitive stereo image with deep, dramatic low-end extension and crisp, controlled highs. The result is an unusually cinematic stereo character that feels larger and heavier than expected from microphones of this format.

OPTICAL CONDITION

Good condition overall with visible but signs of use. The housings show light scratches, handling marks, and some fading to portions of the printed text. Considerable cleaning work has already been carried out

TECHNICAL CONDITION

Fully functional and sounding exceptional. Both capsules are working perfectly with very strong output and impressive sensitivity and output. The microphones have been rewired to modern XLR connectors using a simple signal/shield configuration. Internally, the design is noticeably simpler than the German counterpart, using only signal and shield conductors.

THIS ITEM INCLUDES

• Original stereo tripod system
• Original presentation/storage box
• Dual detachable microphone Both capsules carry the matching serial number 015707.

BUILD & DESIGN

The MDU-24 follows the same rotating stereo concept made famous by the Grundig stereo systems of the era. Both microphone capsules mount onto a central stereo bar and can be rotated independently into various stereo configurations. Like the German version, the capsules are detachable and fully usable as individual mono microphones.

The mechanical construction is slightly less refined than the German equivalent. One small design flaw appears when rotating the lower microphone capsule past extreme angles, where it can lightly contact the tripod housing due to tight spacing between the mount and microphone body. In practice this creates no meaningful limitation, as all realistic stereo angles remain fully usable, but it does reveal the more utilitarian Polish engineering tolerances.

The tripod assembly combines metal and plastic elements, with a solid-feeling upper structure and lighter lower construction. Despite the simpler build, the overall system remains practical, stable, and visually very characteristic of Eastern Bloc industrial design.

Capsule

Dynamic stereo microphone capsules with detachable modular construction. The tonal presentation strongly suggests a design philosophy very close to the Grundig counterpart, with excellent sensitivity and unusually extended frequency behaviour for compact vintage dynamic capsules.

Circuit

Passive dynamic moving-coil design with extremely simple internal wiring topology. The microphones use a basic signal-plus-shield cable arrangement, now professionally adapted to modern XLR connectivity.

TECHNICAL SPECIFICATIONS

Type: Stereo dynamic microphone system
Polar Pattern: Cardioid-style directional behaviour
Frequency Response: Estimated 50 Hz – 15,000 Hz
Sensitivity / Impedance: Very high output for a vintage dynamic design
Output: Balanced XLR conversion

FREQUENCY RESPONSE

Estimated Frequency Response:
50 Hz – 15,000 Hz

• Strong emphasis on deep low frequencies
• Reduced muddy low-mid buildup
• Smooth upper-mid presence
• Crisp but controlled high-frequency extension
• Wide and dramatic stereo imaging behaviour

SOUNG SIGNATURE

The MDU-24 delivers a remarkably dramatic stereo sound signature. Compared to the German stereo equivalent, the Polish version feels even more weighted toward deep low frequencies, producing an almost sub-like low-end emphasis without excessive muddy low-mid buildup. The bass extension feels unusually large and spacious for compact vintage dynamic capsules.

At the same time, the high frequencies remain surprisingly present and refined. The treble is crisp and articulate without becoming sharp or overpowering, creating a very balanced but emotionally exaggerated stereo presentation.

The overall effect is cinematic, wide, and highly engaging — excellent for room ambience, experimental stereo recording, vintage drum overhead applications, acoustic instruments, or atmospheric live recording situations where character matters more than absolute neutrality.

Love this item? Explore more! Check out our store for more amazing Microphones. You might discover a new favourite mic!