Preamplifier Air Tight ATC-7

Air Tight ATC-7 — a valve control preamplifier based on physical interaction and a robust power supply

The ATC-7 is a reference valve preamplifier designed as the control centre of a hi-fi system, in which the valve circuit architecture is combined with an emphasis on direct, mechanical control. Instead of touch interfaces, it utilises physical controls, the texture, rotational resistance and response of which were integral to the design process. Development took place without any time pressure, with the aim of achieving a reproduction with a vivid, lifelike sound and dynamics close to that of live music.

The basis of the electrical design is a combination of an ultra-high-power regulated power supply and a (choke coil) — a solution not commonly used in preamplifiers, but which provides a calmer and more stable power supply to the signal stages in audio circuits. The chassis, made from a combination of steel and bakelite, combines mechanical rigidity with the distinct resonant properties of both materials, thereby helping to dampen the microphonic behaviour of the electron tubes.

The stable power supply and vibration suppression result in a deep soundstage, clear localisation of instruments and dynamics without compression during dynamic transitions. The redesigned control knobs with precise knurling allow for fine and repeatable level adjustment, facilitating precise volume tuning to suit the character of the recording and the room’s acoustics.

Key features

• Power supply: Regulated power supply with a choke for stable circuits
• Chassis: A combination of steel and Bakelite with damping properties
• Controls: Mechanical knobs with precise knurling
• Sound: A vivid soundstage and undistorted dynamics
• Concept: Reference-class valve preamplifier