TASCAM DX-40 / dbx I Professional Noise Reduction 1980 - with marks

The Tascam DX-40 

is a vintage 4-channel DBX Type I noise reduction system produced in the 1980s. It was engineered specifically to expand headroom and eliminate tape hiss on professional analog multi-track reel-to-reel tape recorders.

Key Features and Specifications

• Noise Reduction Protocol: Uses professional DBX Type I encoding/decoding, which provides up to 30 dB of noise reduction.
• Channel Configuration: A single unit handles 4 discrete channels (simultaneous record or playback processing).
• Scalability: Studios frequently paired two DX-40 units together to handle 8-channel tape machines like the legendary Tascam 38.
• Target Compatibility: Designed to integrate with vintage 4-track and 8-track decks, including the Tascam 34, 34B, 22-4, and 48-OB.
• Hardware Interlocking: It relies on a specific multi-pin Foot Valve (FV) remote control circuit. It must either receive a signal from a matching Tascam deck's 6-pin square socket or have the circuit manually bypassed to activate.