The STK428-640 model is a high-end product launched by SANYO in 2000. Although it is a Class D circuit, it is carefully crafted in strict accordance with SANYO's traditional tuning style of Class AB circuits. The sound is warm and pleasant to listen to, with extended low and high frequencies, maintaining the sound characteristics of SANYO's thick-mode circuits without the digital taste of modern digital amplifiers. Moreover, it boasts an actual power output of 200W x 2 @ 4 ohms. According to its PDF file, each channel can achieve 200W of power under a 4 ohm load, with a distortion (THD) level of only 0.8%. This model features high efficiency, low heat generation, high power, and excellent sound quality, meeting more than 99% of audio amplification needs.
The STK428-640 module adopts a PWM CMOS logic level audio input method. This audio input mode effectively reduces noise, distortion, and interference, greatly enhancing audio clarity, dynamic range, and fidelity, thereby providing users with an even more superior auditory experience.
This product is a pure power amplifier, which can be used with pre-amplifier and other devices according to your needs. The power output of the amplifier is very strong. The measured continuous output power of 200W without distortion is more powerful than TPA3255, IR2092, and other products on the market. It can easily drive medium to large bookshelf speakers and floor-standing speakers, and its power output is much larger than the music power of several kilowatts claimed online.
Digressing a bit, the first digital amplifier, TRIP ATHTA2022, which made waves in the market since 2010 and became widely known, appeared ten years later than SANYO's STK428-640. However, its power output is merely 20W x 2, which is one-tenth of SANYO's thick-film technology. The STK428-640 was only featured in a two-thousand-yuan-level combination stereo system. Unfortunately, it was born at the wrong time and encountered the wave of the Internet, which quickly made the combination stereo market lose its popularity. It's a pity that such a good circuit design was overlooked. After acquiring all of SANYO's inventory, we went through more than four years of repeated testing and design modifications to produce the current version. Its stability and actual performance are beyond doubt
Basic Parameters:
Output power: 200W+200W4 Ω 130W+130W8 Ω measured RMS power
Supply voltage: AC dual voltage 22V~36V
Amplifier type: Class D thick film
Distortion THD: 0.8%
Frequency response: 20Hz-25KHz
Magnification factor: 24 times
Static power consumption: 6W
Input impedance: 10K Ω
Input sensitivity: 0.9V
Output impedance: 4-8 Ω
Dimensions: 110 wide * 50 high * 140 deep mm
Whole board weight: approximately 420g
