Do not run the STK411-240E without a heatsink. Even at idle, it dissipates ~15W due to class-AB bias.
Use these search strings (avoid -240E unless verified):
[ A_v = 1 + \fracR2R4 = 1 + \frac150010,000 = 1.15 \text (non-inverting) ] Wait — this seems low. Correction: In the standard STK application, the feedback is from output (pin5) to inverting input (pin2) via R2. But pin2 also has R4 to ground. Actually, the correct gain formula for an inverting configuration? No — the STK411-240E is typically used in the non-inverting configuration with: Stk411-240e Circuit Diagram
ceramic) close to the power pins to prevent parasitic oscillations.
Because the original Sanyo datasheets are becoming harder to find, and many hobbyists are restoring vintage amplifiers, the is a critical resource. This article provides a complete breakdown of the internal schematic, the typical application circuit, pinout details, and practical tips for building or repairing an amplifier using this module. Do not run the STK411-240E without a heatsink
| Pin No. | Symbol | Description | |---------|--------|-------------| | 1 | IN+ (CH1) | Non-inverting input, channel 1 | | 2 | IN- (CH1) | Inverting input, channel 1 | | 3 | GND | Signal ground | | 4 | COM | Common (power ground) | | 5 | OUT (CH1) | Output, channel 1 | | 6 | +Vcc | Positive power supply (+35V typical) | | 7 | -Vee | Negative power supply (-35V typical) | | 8 | COM | Common (power ground) | | 9 | OUT (CH2) | Output, channel 2 | | 10 | +Vcc | Positive power supply (connected internally to pin 6) | | 11 | BOOT (CH2) | Bootstrap capacitor connection, channel 2 | | 12 | IN- (CH2) | Inverting input, channel 2 | | 13 | IN+ (CH2) | Non-inverting input, channel 2 | | 14 | GND | Signal ground (internal to pin 3) | | 15 | BOOT (CH1) | Bootstrap capacitor connection, channel 1 |
While modern ICs outperform the STK411-240E in efficiency and distortion, the thick-film hybrid sound remains beloved by audiophiles for its warm, robust character. Use this guide to bring your old amplifier back to life or to build a faithful reproduction of a 1990s stereo power amp. Correction: In the standard STK application, the feedback
Add : 2.5A slow-blow on each supply rail and mains input.
The power output stage is a Class AB configuration, comprising transistors Q5, Q6, Q7, and Q8. This stage is responsible for driving the speaker loads and delivering high-quality audio power.