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

INTRODUCTION The AKG Blue Line is a modular condenser microphone system built around the SE 300 B amplifier and a selection of interchangeable capsules. This example combines the SE 300 B with the CK 91, AKG’s classic cardioid capsule and arguably the most universally applicable configuration of the system. One compact amplifier body can be combined with different capsules depending on the application. what makes the Blue Line is a system engineered around modularity. short rotational movement releases or attaches the capsule with a positive mechanical action, additional locking mechanism secures it in position. The result feels unusually precise and stable. 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. This is perhaps one of the most convincing qualities of the Blue Line: it feels less like a temperamental piece of vintage audio equipment and more like a thoroughly developed professional tool — predictable, repeatable and reliable, backed by decades of Austrian microphone engineering. AKG conceived the CK 91 as a versatile general-purpose cardioid rather than a microphone dedicated to one particular instrument or recording distance. a recognizable sonic personality =particularly in the upper frequencies — perception of character that changes and diminishes considerably with placement. OPTICAL CONDITION The microphone is in good to very good used condition, showing normal signs of previous professional use. The SE 300 B body, CK 91 capsule and XLR connector are clean and well preserved. The capsule grille is intact and the mechanical connection between capsule and amplifier operates exactly as intended. TECHNICAL CONDITION The SE 300 B amplifier and CK 91 capsule appear original and unmodified as far as we can determine. The complete microphone has been thoroughly tested and is working correctly. Output is stable, noise performance is normal, and the capsule connects securely to the amplifier. All three positions have been individually tested and function correctly. THIS LISTING INCLUDES 1× AKG CK 91 cardioid capsule — Made in Austria 1× AKG SE 300 B amplifier — Made in Austria 1× AKG SA 40 microphone holder 1× microphone bag 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. BUILD & DESIGN The Blue Line system is a particularly satisfying example of compact AKG engineering. Although the SE 300 B is slim and cylindrical, the 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. The SE 300 B itself is equally economical in design. One selector handles the microphone’s two additional operating functions: a 75 Hz low-cut for reducing low-frequency energy and a −10 dB pad for higher sound-pressure levels. The SE 300 B provides a three-position selector: Flat response 75 Hz low-cut filter −10 dB pre-attenuation pad Because all functions share the same selector, the 75 Hz low-cut and −10 dB pad cannot be engaged simultaneously. This is simply part of the original SE 300 B design — perhaps a slightly limiting choice, but hardly a serious drawback in an otherwise exceptionally practical system. The inability to combine these two functions is perhaps the one slightly frustrating compromise for a more clean and…