Audiophile-designed STK433-760 thick-film vocal Hi-Fi amplifier kit / finished board – why still bother with the LM1875

1. Set of parts: 58 yuan is the spare parts that need to be welded by yourself.

2. Finished plate: The finished plate is 73 yuan, and the welded plate can be directly installed.

Sanyo STK is commonly known as Sanyo Thick Film. Under the control of the tuned sound and high-precision semiconductor process production process, it is not the level that ordinary amateur DIY players can achieve. In addition to better sound field and resolution, the low-frequency strength is much stronger, which is completely the difference between professional athletes and ordinary players! These thick film circuits have always been customized products for big brand audio manufacturers. In the early days, many famous factories used them to make power amplifiers, such as K + H, Sony, Panasonic, Kenwood, Jervis, Shanshui, Sharp, Pioneer, Aihua AIWA, etc. Almost all Japanese audio manufacturers used them, and they have been used for more than 20 years. It has influenced a generation, and it is also a sound with a strong brand of the times that our entire generation heard when they were young. It is always unforgettable. Sanyo, a company specializing in the production of power amplifier modules, was later acquired by ON Semiconductor of the United States. After the acquisition, it integrated Sanyo's traditional craftsmanship, coupled with ON's unique design, and the later products were even more outstanding. They are still used by large companies in the United States, such as BOSE and Genelec in Europe!  

I was fortunate to encounter the power amplifier module STK433-260 produced by Sanyo SANYO in the later stage of batch new inventory. It is said that this earth trademark package gray shell is the product after ON semiconductor (ON Semiconductor) acquired Sanyo's production line. Among them, ON Semiconductor's design and process were integrated. The appearance of the products produced at that stage changed the tradition of the original black ugly shell of the old Sanyo, becoming exquisite and meticulous, and the internal workmanship was also greatly improved. The objective hearing is far beyond the old Sanyo. It is a pity that only a few of the products at that time can still be seen today. At that time, with the vigorous development of the Internet and the large-scale popularization of various portable devices (especially large-screen touch-screen mobile phones), many people gradually forgot about these high-performance desktop devices. Those former well-known audio manufacturers had to change their product direction, making these customized products dusty in the original SANYO packaging factory warehouse in the Philippines for more than ten years.

After getting the test, it was found that this module still has a relatively large potential, and the actual power is also 50WX2@6 Ω, THD = 0.2%. The module was originally a three-channel design, and this circuit only uses two of them. The recommended working voltage is plus or minus 37V, and the maximum working voltage should not exceed plus or minus 40V.

The main filter capacitor of this product is the original "Nitsu" in Japan. Nitsuko used disassembly brand capacitor 63V7000UF

The components and ports on the kit PCB are clearly marked, and as long as they are installed correctly, it is basically a success.

Power supply voltage AC: AC dual 22-28V,

Dimensions: width 133, height 41, depth 73mm

Product weight: about 123g

Output power: 50W measured

Wiring diagram, take STK433-760 as an example:

Detail display: