Dolby A-Type 361 Noise Reduction

Released in the late 1960s, the Dolby A-Type 361 was a professional noise reduction processor used widely in studios and broadcast. It divided the signal into multiple frequency bands and applied dynamic expansion to reduce tape hiss during playback.

Plugin Emulations

• Dolby A-Type – Plugin 1
• Dolby A-Type – Plugin 2
• Dolby A-Type – Plugin 3

How It Works

• Four-band companding system (compression on record, expansion on playback)
• Attack/release circuits tailored to frequency content
• Modular card-based unit design (Cat. No. 22 card)

Legacy & Evolution

The Dolby 361 became an essential tool in multitrack analog recording. Engineers sometimes misused it creatively — for instance, by decoding unencoded signals to enhance transients and presence, an effect revived today through emulations.

Key Specs

• Release Year: ~1969
• Noise Reduction: Dolby A four-band companding
• Inputs/Outputs: Line level (balanced/unbalanced)
• Form Factor: Rack-mounted with removable cards
• Power: AC-powered