Description
High-Output 50W+50W Stereo Audio Power Amplifier Module
The STK4191II is the flagship thick-film hybrid integrated circuit from Sanyo's prestigious 4101II series. Engineered for split-rail power supplies, this module provides a consistent 50 Watts per channel, making it the definitive replacement part for flagship vintage receivers, high-power bookshelf systems, and integrated Hi-Fi amplifiers.
The "Series II" architecture features an optimized internal constant current circuit that ensures low harmonic distortion (0.4% THD) and high thermal stability. This module is prized by audio technicians for its ruggedness and the classic, musical warmth it brings to restored audio equipment.
Key Technical Features:
- Continuous Power Output: 50W + 50W (at 8Ω, 20Hz to 20kHz, THD = 0.4%).
- Configuration: 2-Channel Stereo (18-Pin SIP Package).
- Frequency Response: Full-range high-fidelity from 20Hz to 50kHz (+0, -3dB).
- Operating Voltage: Recommended supply of ±35.5V (Absolute Maximum ±53V).
- Built-in Muting: Integrated circuitry to suppress power-on/off shock noise ("pops").
Technician's Installation Guide:
Due to its high 50W+50W output, the STK4191II generates significant heat during operation. It must be securely mounted to a large heatsink using high-quality thermal silicone grease. Running this module without a heatsink—even for a few seconds of testing—will result in immediate and permanent internal substrate failure.
Pro Tip: Before installation, verify that the power supply rails are symmetrical and the filter capacitors are fully discharged. Always check the output emitter resistors for signs of overheating, as a previous speaker short is the most common cause of the original chip's failure.