Description
High-Output 70W+70W Stereo Audio Power Amplifier Module
The STK4211II is a heavy-duty thick-film hybrid integrated circuit from Sanyo's legendary "Series II" family. Delivering a continuous 70 Watts per channel, this module was a staple in high-end stereo receivers and integrated amplifiers. It is engineered for audiophile-grade performance with a balanced analog sound and a Total Harmonic Distortion (THD) of 0.4%.
The Series II architecture features an internal constant-current circuit to ensure high stability and a built-in muting circuit to suppress power-on/off "shock noise." This makes it the ideal choice for technicians performing precise restorations on premium vintage audio equipment.
Key Technical Features:
- Continuous Power Output: 70W + 70W (at 8Ω, 20Hz to 20kHz, THD = 0.4%).
- Configuration: 2-Channel Stereo in a standard 22-Pin SIP (Single In-line Package).
- Built-in Muting: Integrated on-chip muting to protect speakers from pop/shock noise.
- Thermal Excellence: Built on Sanyo's Insulated Metal Substrate Technology (IMST) for superior heat dissipation.
- Frequency Response: Full-range high-fidelity from 20Hz to 50kHz.
- Operating Voltage: Recommended supply of ±42V (Absolute Maximum ±60V).
Installation & Technical Guide:
As a 140W total output module, the STK4211II generates significant heat. It must be securely mounted to a large, 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 Note: Before installation, verify that the power supply rails are symmetrical and discharge all filter capacitors. We recommend verifying the health of the output emitter resistors (typically 0.22Ω to 0.47Ω) and the speaker relay, as these are common failure points alongside the IC.