Sony TA-N88 (1978–1981)
The TA-N88 was Sony's flagship pure class A power amplifier of the late 1970s — a no-holds-barred statement piece from the company's golden age of high-end audio. Introduced in Japan in May 1979 at 350,000 yen, it remained in production through roughly 1981 and formed part of Sony's ES series of premium components.
What made the TA-N88 distinctive was its uncompromising circuit design. It ran as a genuine pure class A amplifier with a bias current of 3.3A through the output stages, which demanded a massive power supply: a 1.5kVA toroidal transformer and four 33,000µF capacitors (132,000µF total). The amplifier circuit itself used a "straight" topology with no positive or negative feedback, and Sony mounted the power transistors vertically in a unique arrangement to handle the heat. The result was an amp rated at 80W + 80W into 8 ohms in pure class A — though some sources cite 100W + 100W — with a frequency response reaching from 0Hz to 200kHz and a signal-to-noise ratio of 120dB. Power consumption was enormous, up to 600W, and the unit ran extremely hot by design. It weighed 24kg.
Sony's own advertising emphasized the pulse width modulation angle in early coverage; HiFI-Stereo (April 1978, p.26) reported on the "switching" amplifier approach at the Winter CES in Las Vegas, and DB-Magazine (August 1978, p.28) noted the remarkably lightweight (22 lbs.) yet efficient design made possible by the V-FET circuitry handling the 500kHz signal. The TA-N88 was well received by Japanese audio magazines, earning top awards, and the family (including its successor) sold over 100,000 units in Japan. The Absolute Sound later called it "a superb amplifier with a warm, inviting, three-dimensional sound that at times seems almost tube-like in its liquidity and ease."
There is, however, a well-documented flaw. The TA-N88's bias setting drifted with room temperature, and its idle current could rise high enough to damage the output stages. Sony attempted a fix by installing a battery on the circuit board to stabilize the bias — but the battery eventually discharged, creating a new problem. Sony addressed this with the TA-N88B, introduced around 1980, which corrected the bias stability issue. Collectors should also know that the vertically mounted power transistors are difficult to source today.
- Pure class A stereo power amplifier, 80W + 80W (some sources cite 100W + 100W into 8 ohms)
- THD: 0.005%
- Frequency response: 0Hz–200kHz
- S/N ratio: 120dB
- Damping factor: 100
- Dimensions: 430 × 165 × 464mm (or 485mm deep, depending on source)
- Weight: 24kg
- Power consumption: 600W
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