Audio Volume Relay Attenuator with IR Control

Circuit-Zone.com - Electronic Projects

Posted on Tuesday, March 24, 2009 • Category: Audio Attenuators

The circuit provides both audio volume and input channel selection. A stepwise volume control is implemented with a set of tiny relays and RN60D / RN55D Dale resistors. In a high-end audio system, a noticeable sound improvement over potentiometers is obtained, also compared to 'audio grade' potentiometers. Its IR remote control provides convenience over solutions with stepped attenuator rotary switches. The sealed relays will maintain contact quality over a practically endless lifetime. The design represents a audio 'preamplifier' of top-class sonic quality, in a compact and affordable implementation. Compact and simple circuit with just 6 tiny relays implement a 64-step logarithmic stereo attenuator. The 64 steps of 1.0dB together span a 63dB audio attenuation range. By avoiding any active electronics, a very clean and open sound is maintained. An IR receiver allows remote control. The IR 'eye' and a numeric display are on a small front-mount printed circuit board, separate from the relay board. The device can learn and store your favorite key codes. The controller understands the popular Philips 'RC5' protocol, Philips' newer 'RC6' protocol, and Sony's SIRC protocol. This also ensures interoperability with all 'generic' IR-controllers.

Digital Potentiometer with Memory

Audio Volume Relay Attenuator with IR Control

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