This is a single channel power amplifier board designed for use in a dual channel (stereo) system. Key features and benefits Dual channel operation in a stereo setup: a single board is designed to be used as part of a twoboard, dualchannel configuration for full stereo playback. Flexible and wide power supply: supports a dual DC supply of / 20 to 90 V. The upgraded version includes optimized circuit and parts. For safety and reliability, do not apply voltages above 90 V. Tubebased signal path with proven designs: input/drive topology uses A970 and C2240 voltage audio pair tubes in a dual differential arrangement; voltage amplification uses A1145 and C2705; the midpower driver stage feeds the A1837 and C4793 pair tubes; the output stage uses the power A1943 and C5200 pair tubes. drive capability and bass power: with adequate power, the board can deliver up to about 200 W, providing strong drive and sound quality that supports large speakers, including 15inch woofers, with confident bass and dynamic range. Clear, engineerfocused design: emphasis on reliable voltage tube performance and a straightforward signal chain from input to output. Specifications and compatibility Board type: singlechannel power amplifier board (designed for dualchannel use in a stereo pair). Power supply: DC ±20 to ±90 V. The upgraded version features circuit and component optimizations; avoid voltages above 90 V. Tube configuration: Input differential stage: A970 / C2240 voltage audio pair tubes Voltage amplification: A1145 / C2705 Driver stage: midpower pair tube A1837 / C4793 Output stage: power pair tube A1943 / C5200 Performance note: with sufficient supply, capable of delivering strong output suitable for demanding speakers, including large 15inch models. Use scenarios and applications Home stereo system: install two boards for a complete left and right channel pair to achieve a fidelity tubebased stereo with robust bass and dynamic range. DIY tube amplifier project: integrate into a vintage or modern speaker setup that benefits from a voltage tube signal path and strong output capability. Small venue or rehearsal space: employ a matched pair of boards in a compact power tube amplification chain to provide clear, powerful sound with good headroom for live or playback use. This description preserves the original brand and component models while presenting the information in a customerfriendly, concise format.