AKG SE 300 B + CK 91 Blue Line Modular Cardioid Condenser Microphone 1990S — Made in Austria

AKG SE 300 B / CK 91 — Stereo Pair with Original Accessories A stereo pair of Austrian-made AKG SE 300 B amplifiers with CK 91 cardioid capsules, part of AKG’s modular Blue Line system. Both microphones are thoroughly tested, exceptionally well preserved and supplied with their original holders, foam windscreen protection, stereo bar and box. OPTICAL CONDITION Both microphones are in excellent cosmetic condition, with no apparent signs of wear or physical damage - apart from small previous-owner name markings near the CE lettering at the bottom of the bodies, beside the XLR connectors. These markings were subsequently crossed out. *Last picture Aside from this small cosmetic detail, the microphones are spotless. The SE 300 B bodies, CK 91 capsules and XLR connectors are clean and exceptionally well preserved. The original box is also in excellent condition. TECHNICAL CONDITION Both complete microphones have been thoroughly tested and are working perfectly. In our listening comparison, the two microphones sounded extremely similar, with almost no audible difference in timbre or behaviour. Both deliver the consistent performance expected from this model. THIS LISTING INCLUDES 2× AKG CK 91 cardioid capsules — Made in Austria 2× AKG SE 300 B amplifiers — Made in Austria 2× original AKG microphone holders Original AKG foam windscreen protection for this model Original AKG stereo bar Original box BUILD & DESIGN The AKG Blue Line is a modular condenser microphone system built around the SE 300 B amplifier and a selection of interchangeable capsules. The CK 91 is AKG’s classic cardioid capsule and arguably the most universally applicable configuration of the system. The Blue Line belongs to a particularly interesting period in AKG’s history. Developed in the 1990s and manufactured in Austria, it comes from an era in which AKG’s long-established microphone engineering was meeting increasingly mature industrial production and automation. The result was not merely precision, but exceptional repeatability. That quality is still tangible today. Separate CK 91 / SE 300 B examples produce remarkably similar timbre and behaviour—a particularly useful quality when working with a pair. These microphones feel less like temperamental pieces of vintage audio equipment and more like thoroughly developed professional tools: predictable, repeatable and reliable, backed by decades of Austrian microphone engineering. Although the SE 300 B is slim and cylindrical, each microphone has a surprisingly substantial visual and physical presence. More importantly, the modular connection never feels delicate. The capsule requires only a very short turn to disconnect—almost a simple click and release. Reattaching it produces an equally positive mechanical engagement, after which the locking mechanism secures the capsule. The electrical contact itself is small, but it is recessed and protected within the surrounding construction rather than exposed as a fragile protruding connection. This creates an almost tunnel-like structure around the contact and makes the complete assembly feel considerably more robust than its dimensions would suggest. There are no exposed, delicate-looking mechanical elements. Everything about the coupling feels deliberate, protected and engineered for repeated professional use. One of the most beautiful details of the CK 91 is its unusual grille construction. Viewed from the front, eight structural elements surround the capsule, but instead of simply converging symmetrically toward the centre, their geometry is subtly shifted and angled. Behind this sculptural outer structure sits a second, much finer metallic acoustic mesh. The combination of these two layers gives the CK 91 an unusually intricate appearance for what is otherwise a restrained professional microphone. It is a small piece of industrial design that becomes more interesting the closer one looks at it—almost a visual dance around the capsule. The SE 300 B itself is equally economical in design. Each amplifier provides a three-position selector: Flat response 75 Hz low-cut filter −10 dB pre-attenuation pad Because these functions share the same selector, the 75 Hz low-cut and −10 dB pad cannot be engaged simultaneously. This is perhaps the one slightly frustrating compromise in an otherwise exceptionally practical design. For use as a pair, the included original stereo bar and holders provide a convenient foundation for setting up both microphones together. SOUND & FREQUENCY RESPONSE The CK 91 initially presents itself as a balanced, detailed and natural-sounding cardioid, but extended listening reveals a definite character in the upper frequencies. There is a sheen to these microphones. We would not describe it simply as a narrow treble peak; perceptually, it behaves more like a broader upper-frequency coloration that gives the CK 91 a certain gloss, immediacy and forward movement. Three separate CK 91 / SE 300 B…