Description
High-Output 70W Mono Audio Power Amplifier Module
The STK4040II is a versatile thick-film hybrid integrated circuit from Sanyo's trusted "Series II" line. Delivering a continuous 70 Watts of power, this module is an essential replacement part for high-performance vintage receivers, dedicated center channels, and active speaker systems.
The STK4040II is engineered for split-power supply systems and features an internal constant-current circuit designed to reduce supply switch-on and switch-off shock noise ("thump"), ensuring your speakers are protected during operation. It offers a balanced performance profile, combining high-output power with excellent thermal durability.
Key Technical Features:
- Continuous Power Output: 70W Minimum (at 8Ω, 20Hz to 20kHz, THD = 0.4%).
- Configuration: Mono (Single Channel) in a compact SIP-ZIP package.
- Thermal Reliability: Series II architecture optimized for low thermal resistance (1.5°C/W).
- Frequency Response: Full-range audio capability from 20Hz to 50kHz.
- Operating Voltage: Recommended ±42V (Absolute Maximum ±60V).
- Pin Compatibility: Member of the STK4024II series (20W to 100W) for flexible repair options.
Installation & Technical Notes:
The STK4040II generates significant heat during operation and must be securely mounted to a flat heatsink using high-quality thermal silicone grease. Operating this module without a heatsink—even for a brief functional test—will cause immediate and permanent internal substrate failure.
Technician's Tip: Before installation, verify that the power supply filter capacitors are fully discharged. Since this module is often used in receivers that have aged, we recommend checking the output emitter resistors and the speaker protection relay to ensure a stable environment for the new IC.