The JRC2701D is a dedicated analog audio processing integrated circuit. It is designed to expand the perceived acoustic soundstage of stereo systems. By utilizing precise internal phase-shifting and simultaneous multi-channel sampling networks, the chip synthesizes natural, wide 3D ambient sound effects from a generic left/right audio input, even when the placement distance between the physical output speakers is restricted.

Specification

• Product Number: JRC2701D ("D" designates the through-hole plastic DIP package)
• Package Profile: DIP-14
• Operating Voltage Range: 4.7V to 13 V (Typical: 12.0V single supply)
• Supply Current (Icc): Approx 5.8mA typical in Stereo mode (8.9mA maximum)
• Maximum Input Voltage (VIM): Approx 0.8Vrms (in Stereo mode at THD = 3%)
• Total Harmonic Distortion (THD): High-fidelity characteristics optimized for consumer line-level paths
• Internal Routing Modes: Bypass, Stereo 3D Surround, and Monaural (Mono-to-Stereo Synthesis)
• Technology Architecture: Monolithic Bipolar Linear IC

Features

• Dual Mode Operations (Stereo & Mono): Features both a Stereo Mode that spreads out a normal left/right mix while keeping a stable center vocal image, and a Monaural Mode that synthesizes a simulated spatial stereo field out of a single mono input line.
• Adjustable Surround Control: Allows manual or digital tuning of the spatial expansion level by varying external resistance or control voltages on its dedicated surround pins.
• Built-in Mode Switching Logic: Contains internal electronic mode control switches. By applying logic levels to its control pins, you can jump seamlessly between Bypass, Surround, and Mono modes without adding mechanical relays or noise.
• Simultaneous Channel Alignment: Its internal dual-path analog engine samples the left and right audio channels simultaneously. This eliminates internal timing delays, protecting phase alignment to yield an accurate spatial position.

Common Applications

• Compact Multimedia Speakers: Integrated into portable desktop computer speakers, desktop bookshelf systems, and smart home sound docks to give them a wider acoustic presence.
• Retro Boomboxes & CD Radio Cassettes: Serving as a vintage spatial expansion module in portable high-fidelity audio gear.
• CRT and Flat-Panel Televisions: Employed inside consumer televisions to project sound fields outward past the narrow physical bezel of built-in speakers.
• DIY Audio Effect Boxes: Used by hobbyists to construct custom hardware expanders, mixer master inserts, and pre-amplifier modification projects.

Professional Usage & Deployment Tips

• Isolate Your Power Supply: The 3D audio synthesis relies heavily on minor phase adjustments. If there is ripple on your power rail, it will manifest directly as audio hum or cross-channel noise. Always solder a 0.1uF ceramic capacitor directly adjacent to the power pin (V+) to ground, backed up by a bulk 10uF to 47uF electrolytic capacitor to smooth out power supply fluctuations.
• Maintain Trace Length Symmetry: Keep the passive resistors and capacitors connected to the left and right feedback filter loops physically identical and arranged symmetrically on your PCB layout. Asymmetrical traces change trace capacitance, which can skew the phase processing and ruin the accuracy of the 3D center image.
• Mind Input Signal Attenuation: The maximum input voltage threshold maxes out around 0.8Vrms in full surround expansion mode before clipping occurs. If you are driving the JRC2701D from a heavy line-level source (like a standard 2.0Vrms DAC or CD player output), you must use a passive resistor divider network on the input pins (LIN / RIN) to attenuate the incoming signal to avoid harsh overdrive distortion.

Datasheet