The Roland SRA-540 is a vintage 2-channel professional power amplifier known for its robust build and reliability. It delivers high-fidelity stereo output and is designed for heavy-duty studio, or sound reinforcement applications. This unit was gently used to power the PA system of a church for approximately 20 years.

Specs:

Power Output & Performance:

- Stereo @ 8 ohms: 240W at 2 (1 kHz, 1% THD) or 200 W x 2 (20 Hz to 20 kHz, 0.1% THD)
- Stereo @ 4 ohms: 425W at 2 (1 kHz, 1% THD) or 400 W x 2 (20 Hz to 20 kHz, 0.1% THD)
- BTL (Bridged) @ 8 ohms: 850 W (1 kHz, 1% THD) or 800 W x 2 (20 Hz to 20 kHz, 0.1% THD)
- Frequency Response: 10 Hz to 50 kHz ( 0/-1 dB, at 1 W/8 ohms)
- Total Harmonic Distortion (THD): 0.01% or less (stereo, 8 ohms, 1 kHz, half power)
- Signal-to-Noise Ratio: 105 dB or greater
- Damping Factor: 150 or greater (8 ohm load, 1 kHz)
- Channel Separation: 80 dB or greater

Inputs & Outputs:

- Input Connectors: Balanced/Unbalanced XLR and 1/4" TRS phone jacks
- Input Impedance: 10 k\(\Omega \) (Balanced/Unbalanced)
- Speaker Terminals: Heavy-duty binding posts

Operation & Protection:

- Modes: Stereo / BTL (Bridged) switchable
- Protection Circuits: Power ON/OFF muting, DC protection, Thermal protection, and PC limiter
- Cooling: Thermal-switched two-speed fan

Physical Specs:

- Dimensions (W x D x H): 482 x 442 x 88mm (Standard 19" Rack Mountable, 2U)
- Power Consumption: 750W

For full schematics and service schematics, you can reference the Roland SRA-260/540/800 Service Manual on Scribd:

https://www.scribd.com/document/732211866/Roland-SRA-260-540-800-Power-Amp-Service-Manual