The AB-32 was the debut creation of Shengya’s founder He Zhuojian. It was also China’s first separate tube pre & power amplifier. Even today, its exterior styling and circuit design remain timeless. The model designation stands for 32 watts output in Class AB. Back then it retailed at 5,000 RMB, an amount equivalent to hundreds of thousands of RMB in today’s value.

Long before founding Shengya Audio, He Zhuojian developed a passion for radio technology back in his secondary school days. He enjoyed taking apart circuit boards and experimenting with small electrical appliances. Later, with the help of a relative in Hong Kong, he enrolled in a correspondence course on radio technology offered by Columbia University in the United States. The training gave him solid, in-depth technical know-how while sharpening his language skills. Edwin Armstrong, the father of radio, was also an alumnus of Columbia University, whose radio program enjoys a world-renowned reputation.

When He Zhuojian went into business, his first profitable product was a practical TV signal booster, followed by voltage stabilizers — both closely linked to what he had learned. With sufficient capital at hand, he turned his passion into reality. Drawing on circuit diagrams from magazines and sourcing a wide range of electronic components, he went through repeated rounds of development and refinement until he built a pure tube amplifier.
After listening to it, his friends were amazed by its tonal quality. One of them suggested that joy is better shared, and that he should introduce this amplifier to fellow audio enthusiasts. At that moment, He Zhuojian, who was looking for a new business direction, stepped into the Hi‑Fi industry with his tube amplifier.
In May 1991, He Zhuojian co-founded Shengya Audio and released his self-branded tube amplifier: the AB-32, China’s first separate tube pre & power amplifier. This landmark unit laid the foundation for Shengya’s long-term focus on Hi‑Fi equipment.

Its eye-catching gold-plated copper panel and knobs were exquisitely crafted. Four Shuguang KT88 tubes per channel glow with warm orange light, a design that still holds up well even today. The power stage uses 12AU7 tubes for input and drive, delivering an output of 32 watts. The preamplifier employs dual triodes 6DJ8 and 12AX7, with a 6N6 tube for high-voltage regulation. It is said that once fully warmed up and paired with British loudspeakers, this amplifier produces a smooth and enchanting sound.

On the eve of the Mid-Autumn Festival, the Chen Jia – "Jia" & Full Moon Concert was held at the Shengya flagship store in Zhongshan, where the 30th Anniversary commemorative tube amplifier was unveiled.

Back then, the AB-32 tube amplifier was displayed at Nanfang Building Mall, one of the landmark buildings along the Pearl River in Guangzhou. It was Guangzhou’s first high-rise building with reinforced concrete structure and once the most dazzling department store in South China, holding precious memories of modernity for the older generation of Guangzhou residents. The tube amplifier, priced at nearly 6,000 RMB, was showcased in a large street-side shop window, with advertisements widely published in newspapers. It was only natural that it created quite a stir.

Accompanied by a group of industry veterans, renowned audio pioneer Mr. Tian Shouyu travelled to Zhongshan to visit this student he had never met before, curious to see how a small local factory could produce such an extraordinary tube amplifier. Nevertheless, a price tag of 5,000 RMB for one set of pre and power amplifier was simply astronomical for ordinary wage earners, whose average monthly salary was merely 300 RMB at that time. Hardly anyone could afford it. Shengya’s tube amplifiers were widely praised yet poorly sold, putting He Zhuojian in a difficult dilemma.

Founder Mr. He Zhuojian and singer Chen Jia unveiled the A30 tube amplifier together.

Due to immature technology, unstable components and other factors, production of the AB-32 pre and power amplifier was discontinued one year later. Mr. He recalled that he lost almost all his savings in this venture. To seek a new direction, He Zhuojian carried out extensive market research and analysis. By chance, he came across products from Japan’s Luxman and drew inspiration from them.

Luxman launched the D-107U in 1992, a pioneer Compact CD Player equipped with vacuum tube amplification. Two 6CG7 dual triodes were visible through a small window on the front panel, and an output transformer was used at the output stage. Its Sony transport and Burr‑Brown 18‑bit DAC chip represented top-tier specifications at that time.

Around the same period, Luxman also released the LV-107U hybrid integrated amplifier to match it. Similarly, two 6CG7 dual triodes for pre-stage gain were displayed behind a small glass window on its black panel, while MOSFET transistors were adopted for the power stage, delivering an output power of 80 watts into 8Ω.

Nevertheless, the sound of Luxman amplifiers of that era was relatively soft and restrained. He Zhuojian aimed to adopt the concept of hybrid tube-and-transistor circuitry, designing an amplifier that delivers refined sound, high resolution, along with warmth and musicality. The VL-250 integrated amplifier was thus born.

Mr. He introduced the design features of the A30. He stated that it embodies and sums up the experience accumulated over the past thirty years.

Launched in 1992, the VL-250 was once again China’s first hybrid amplifier with tube pre-stage and solid-state power stage. Priced at 600 RMB, it cost only one-tenth of the AB-32 tube amplifier. With this model, Shengya scored its first remarkable market breakthrough.

The VL-250 delivers an output power of 150 watts. Four vacuum tubes handle the preamplification, while each channel is equipped with four Toshiba power transistors for the power stage. It adopts dual-transformer power supply. The design retains the rich tonal flavour of tube amplifiers, while avoiding the reliability issues associated with high-power vacuum tubes. It is robust, durable and affordably priced.

This “tube-input, solid-state output” amplifier was an instant hit. After auditioning it, Mr. Tian Shouyu published an article titled Rivaling Luxman in a magazine, singing high praises for the VL-250.

Driven by strong market response, Shengya’s sales climbed steadily. Later, the brand rolled out the revised VL-260, as well as the LS-1 / D-150 separate pre & power amplifier set. Its preamplifier uses two vacuum tubes, and the power stage features four vacuum tubes plus three pairs of power transistors per channel. Shengya also began exporting its products overseas.

Over the years, Shengya has kept upgrading its hybrid tube-and-solid-state products and also released several solid-state amplifiers, yet He Zhuojian has never lost his passion for tube amplifiers. On the occasion of Shengya’s 30th anniversary, the brand rolled out the PSM-300T monoblock hybrid power amplifier, A-238 Mark II hybrid stereo power amplifier, CV-3 Tube Stereo Preamplifier and other models. Due to pandemic restrictions, the official launch of the new A-30 Tube Stereo Integrated Amplifier was delayed until now. Right up until the day before the unveiling, final voicing tuning was still underway, and the product was kept strictly confidential from the public. According to He Zhuojian, the whole R&D process spanned two years.

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Key Features of the A30

Simply put, the A30 is a new-generation all-in-one tube stereo integrated amplifier. It features no output transformer, delivers high output power and incorporates an on-board DAC chip.

Shengya has released multiple Compact CD Players in the past and is well versed in digital circuitry. This year’s CV-1HD Tube Stereo Preamplifier also comes with built-in decoding circuits. The CV-1HD marks Shengya’s first preamplifier with DAC functionality. Its decoding capability keeps pace with modern standards and supports a wide range of audio sources, catering to young digital streaming enthusiasts. It adopts the popular XMOS USB receiver solution paired with the premium ESS9038Q2M DAC chip, supporting PCM up to 32Bit / 384kHz as well as DSD512.

Full specifications of the A30 have not yet been officially released. It is speculated that its digital decoding section will be similar to that of the CV-1HD, making it an excellent value proposition!

Mr. He Weilin, the second-generation successor of Shengya, is also an alumnus of the Hong Kong Polytechnic University.

Since the A30 is a tube amplifier without an output transformer, why does its output stage employ eight high‑power Toshiba transistors? Let’s clarify this.

Both OTL (Output Transformerless) and OCL (Output Capacitorless) topologies represent the ultimate challenge for tube amplifier designers. The most well‑known OTL circuit design was pioneered by Julius Futterman, a self‑taught New Yorker, back in 1954. His OTL architecture delivered outstanding performance and reliable stability, creating a sensation worldwide at that time.

For more than half a century, mass‑produced OTL tube amplifiers have remained rare. The American brand Counterpoint once built an OTL amplifier based on 6LF6 tubes, yet it suffered from many drawbacks. Japan’s Luxman launched the MQ36 OTL amplifier using 6336A tubes; it only produced 25 watts, limiting its application. The Italian brand Graaf’s GM20, designed by engineer Giovanni Mariani, adopted both OTL and OCL principles. Equipped with two 6C33C dual triodes per channel, it outputs 65 watts and is renowned for its fine sound.

In conventional vacuum tube amplifiers, the power tubes are coupled to the loudspeakers via an output transformer. It serves two purposes: primarily impedance matching between high-impedance tubes and low-impedance speaker loads, and secondarily DC isolation to protect the loudspeakers.

Nevertheless, the output transformer has long been the biggest bottleneck limiting tube amplifier performance. It is inherently a compromise device. Unlike power transformers designed for a single frequency, it must deliver a wide frequency response, ideally covering at least 20Hz to 20kHz. To achieve solid bass impact together with crisp treble penetration and resolution, the primary winding must have sufficient inductance while keeping inter-turn stray capacitance as low as possible. Yet such a structure inevitably introduces phase shift. These conflicting requirements lead to many trade‑offs in material selection, winding techniques and parameter tuning.

For typical power tubes, OTL tube amplifiers would present an excessively high output impedance to drive loudspeakers. Therefore, specially made low-impedance tubes are usually connected in parallel to lower the output impedance. This solution, however, is costly, power‑hungry and prone to stability issues.

For OCL and OTL tube amplifiers, power tubes are required to feature low internal resistance and tight consistency. Examples include Soviet types: 6C33C, 6082, 6336/A/B, 7236, 7241, 6080, 6AS7G (6N5P / 6N13P), and the domestic Chinese 6C19. All are low‑internal‑resistance triodes, and rigorous screening is mandatory to guarantee uniform performance.

“Relaxation is all that matters right now” has become the slogan of the Shengya flagship store.

For the A30, the front stage uses an ECC83 (12AX7) dual triode for input amplification, and a 6N11 vacuum tube for second‑stage voltage amplification. Four KT88 power tubes operate as the Class‑A drive stage, rather than coupling directly into an output transformer. Mr. He explained that tubes sharing the same pinout, such as the KT88, 6550 and EL34 (6CA7), are interchangeable without extra adjustments, letting users explore different tonal flavours.

According to data from GE, the developer of the KT88, its plate resistance reaches roughly 15kΩ when operated in pentode superlinear mode. For typical push‑pull circuits, the load impedance of the output transformer falls between 4.3kΩ and 7kΩ. For pentodes, higher load impedance yields greater output power — a characteristic opposite to triodes. Such high plate resistance and load impedance make it extremely difficult to implement in an OTL topology. Shengya chose the KT88 for the A30 as a tribute to its pioneering AB‑32. Faced with this technical hurdle, He Zhuojian devised an innovative workaround. He adopted Toshiba metal‑oxide‑semiconductor field‑effect transistors (MOSFETs), a device familiar to him, to replace the transformer load. The KT88 thus functions as a driver stage instead of the power stage. This arrangement preserves the warm tonal signature of tube amplifiers while harnessing the formidable power of transistors, bypassing the limitations imposed by traditional output transformers.

How does this rare circuit topology sound? The concert venue covered approximately 180 square metres and could accommodate dozens of guests. On stage was a pair of ATC SCM‑7 bookshelf loudspeakers, the smallest model from ATC, driven by the A30 operating in Class AB1. The result astonished nearly everyone. This compact speaker with only a 5‑inch woofer delivered rich, full‑bodied sound with abundant energy and immense dynamic scale. The A30’s rated 200 watts (8Ω) delivers on its promise. It boasts wider bandwidth, faster transient response, a more expansive soundstage and tighter control than conventional KT88 tube amplifiers. During playback of Tutti! from Reference Recordings at high volume, the ATC bookshelf speaker performed with remarkable poise, rendering a massive, dense presentation alongside powerful, well‑defined bass. Tutti is a musical term meaning tutti, “all together”. This recording captures the overwhelming power of orchestral ensemble performance and is a benchmark recording. Paired together, the A30 and ATC SCM‑7 reproduced the music with an almost live‑in‑the‑room sensation.

What distinguishes the A30 sonically from traditional tube amplifiers is its cleaner, more transparent presentation. Treble carries greater density and penetration, while bass is firmer and better controlled. Still, it differs from true OTL tube amplifiers that omit output transformers entirely. A well‑executed OTL amplifier produces sound that is light, fluid, open, swift and natural with no artificial colouration. Once you hear a fine OTL amplifier, conventional poorly designed tube gear may sound murky and congested by comparison. OTL amplifiers offer excellent resolution, clean layering across the frequency spectrum, springy bass, fine air and refined, luxurious timbre. The A30 shares a similar aesthetic, yet delivers fuller, more substantial bass and stronger drive capability.

Mr. He also tested the A30 with B&W 802D loudspeakers, though he was uncertain of the outcome. My impression is that the pairing is less than ideal; in particular, the definition of its two 8‑inch woofers lacks clarity. Few would expect a 20,000‑renminbi Tube Stereo Integrated Amplifier to drive a large floor‑standing speaker costing hundreds of thousands. A more suitable recommendation is to match the A30 with most bookshelf loudspeakers. The result yields sweet, engaging tonality, relaxed and ample low frequencies, and a wide, open soundstage.

Mr. He Weilin, second‑generation successor at Shengya, remarked that while the A30 distills decades of his father’s experience, it marks not an end, but the start of another thirty‑year chapter. We applauded and await what lies ahead.