Description
High-Quality 40W+40W Stereo Audio Power Amplifier Module
The STK4171II is a classic thick-film hybrid integrated circuit from Sanyo's dependable "Series II" lineup. Delivering a continuous 40 Watts per channel, this module was a staple in high-fidelity bookshelf stereos, mid-sized receivers, and active speaker systems throughout the 1990s. It is renowned for its durability and its ability to reproduce a clean, musical analog sound.
The STK4171II features an internal constant-current circuit designed to suppress power-on "shock noise," protecting your speakers from damaging pops. Its robust Series II architecture ensures stable operation and a respectable Total Harmonic Distortion (THD) of 0.4%, making it the ideal choice for restoring vintage gear to its original glory.
Key Technical Features:
- Continuous Power Output: 40W + 40W (at 8Ω, 20Hz to 20kHz, THD = 0.4%).
- Configuration: 2-Channel Stereo in a standard 18-Pin SIP (Single In-line Package).
- Distortion Performance: 0.4% THD at full rated power; 0.3% typical at 1.0W.
- Frequency Response: Full-range high-fidelity from 20Hz to 50kHz (+0, -3dB).
- Operating Voltage: Recommended supply of ±32.5V (Absolute Maximum ±48V).
- Thermal Reliability: Guaranteed operation up to 125°C substrate temperature.
Installation & Safety Guide:
The STK4171II produces significant heat during operation and must be securely bolted to a clean, flat heatsink using a fresh layer of high-quality thermal silicone grease. Operating the module without a heatsink—even for a brief functional test—will cause immediate and permanent internal substrate failure.
Technician's Note: Before installing, verify that your power supply rails are healthy and discharge all filter capacitors. Always check the output emitter resistors (typically 0.22Ω to 0.47Ω) for signs of heat stress, as external shorts are the most common cause of the original module's failure.