Primary Voltage: 33-0-33V AC
Secondary Voltages: 17-0-17V AC & 14-0V AC

About SANYO Semiconductor (an ON Semiconductor Company)

SANYO Semiconductor Co., Ltd. (an ON Semiconductor company) is a semiconductor manufacturing company with excellent power device technologies, such as miniaturized packaging, high-efficiency switching, and high-density packaging, as well as world-class analog technology. Its analog-related assets include extensive process technologies, analog design expertise, skilled analog engineers, and specially designed and manufactured energy-saving and environmentally friendly devices, such as hybrid integrated circuits for inverters. SANYO Semiconductor’s core devices include discrete circuits, general-purpose analog LSIs, ASSPs, and hybrid ICs, widely used in various products like personal computers, printers, cable TV systems, mobile phones, audio-visual equipment, gaming devices, car audio systems, and air conditioners.

About SANYO STK (Thick-Film Integrated Circuits)

The SANYO STK series is commonly known as “SANYO Thick-Film.” Its meticulously tuned sound performance and the high-precision control in its semiconductor production process are levels that ordinary amateur DIY enthusiasts simply cannot achieve. Beyond offering better soundstage and resolution, its bass impact is significantly stronger—it’s like the difference between a professional athlete and an average player! These thick-film circuits were always custom products specifically made for major audio brands. In the past, many famous manufacturers used them to build power amplifiers. Nearly all major Japanese audio brands of the era adopted them—such as K+H, Sony, Panasonic, Kenwood, JVC, Sansui, Sharp, Pioneer, Aiwa, and more—and continued their use for over twenty years. They influenced an entire generation and represent the quintessential sound of that era, etched deeply into the memory of those who grew up with it, a sound that is unforgettable upon every listen. The SANYO division specializing in amplifier modules was later acquired by the American company ON Semiconductor. Post-acquisition, the integration of SANYO’s traditional craftsmanship with ON’s unique design made subsequent products even more outstanding. They continue to be used by major American and European companies today, such as Bose and Genelec.

About the SANYO STK412-530-E Module

We were fortunate to encounter a batch of brand-new, old-stock SANYO STK412-530-E amplifier modules from SANYO’s later production period. It is said that the versions with the “globe” logo and grey casing are products from after ON Semiconductor acquired SANYO’s production lines. These modules incorporated ON Semiconductor’s design and craftsmanship. Products from that phase broke from the traditional, aesthetically unappealing black casing of older SANYO modules, becoming more refined and delicate, with significant improvements in internal build quality as well. Objectively, in terms of listening experience, they far surpass the older SANYO modules.

Unfortunately, very few products from that time can still be found today. That period coincided with the rapid rise of the internet and the widespread adoption of various portable devices (especially large-screen smartphones), which gradually led many to forget about these high-performance desktop components. Many once-prominent audio manufacturers were forced to shift their product directions, leaving these custom-ordered modules forgotten in the warehouse of the original SANYO packaging plant in the Philippines for over a decade.

It wasn’t until late last year that a friend from Shantou connected us with this batch of products. At the time, we couldn’t find any reference material for this product online. With the help of our friend A Liang, we managed to find only a single application screenshot on a foreign website, which gave us the confidence to acquire the entire batch.

After testing, we found this module still holds considerable potential. Its actual power output exceeds that of the STK412-430, and it utilizes a high/low voltage supply. Lacking official documentation, we provisionally rate its power at 200W x 2, recommend an operating voltage of ±45V DC, with the maximum operating voltage not exceeding ±52V DC. (The schematic indicates it requires dual voltage supply; a reference schematic is available via the link in the product description.)

Product & Sales Information

Product Version: This is a tested prototype version. Each unit is installed and tested before shipping.
Included Heatsink: The finished board includes a heatsink as shown in the pictures. For high-power operation, this may be insufficient. Users should add additional cooling based on their actual usage.
Main Filter Capacitors: These are second-hand, salvaged Rubycon capacitors.
Availability: Only available as a finished board. No kit version is offered, and components are not sold separately.
Warranty: Warranted to be functional upon arrival. Damage due to overvoltage is not covered. The finished board carries a 3-month warranty.

Key Specifications

Power Supply Voltage: AC dual 24-36V
Recommended Transformer Power: 300W or above
Output Power: 200W x 2
Impedance: 4-8 Ω
Dimensions (W x H x D): 120 x 55 x 140 mm
Weight: 0.45 kg

Guaranteed functional upon arrival. Damage caused by overvoltage is not covered.
The finished board comes with a 3-month warranty
Power Supply: AC dual 24-36V
Recommended Transformer: 300W or above
Filter Capacitors (Default Rating): 63V
Output Power: 100W x 2 @ 4Ω | 80W x 2 @ 8Ω
Impedance: 4-8 Ω
Dimensions (W x H x D): 125 x 49 x 68 mm

Guaranteed functional upon arrival. Damage caused by overvoltage is not covered.
The finished board carries a 3-month warranty.
Power Supply: AC dual 24-35V
Recommended Transformer Power: 300W or above
Filter Capacitors (Default): Rated at 50V
Output Power: 200W x 2
Impedance: 4-8 Ω