DIATONE DA-U750 (1975)

 

The Diatone DA-U750, released by Mitsubishi in 1975, was one of the company’s top integrated amplifier and one of the finest examples of 1970s Japanese amplifier engineering. Although Diatone is best known for its loudspeakers, the DA-U750 demonstrated the brand’s serious commitment to high-end amplifier design, incorporating technology later used in the separate DA-P10 and DA-A10 series. One of its most distinctive features was the dual-block internal construction, with the preamplifier and power amplifier sections physically separated at the front and rear of the chassis. The power amplifier block was independently shielded to minimize heat and magnetic interference from the power supply, improving stability, reliability, and long-term performance. The fully direct-coupled pure complementary OCL power amplifier used carefully matched transistor pairs in both the driver and output stages to reduce distortion and preserve dynamic range, delivering 90W + 90W into 4Ω. The equalizer amplifier employed proprietary ultra-low-noise transistors developed using Mitsubishi’s low-concentration diffusion technology, achieving improved noise performance and excellent phono sensitivity. Diatone also designed the amplifier using simulated cartridges and speakers to optimize real-world dynamic performance rather than relying only on laboratory measurements. Additional features included precision tone and presence controls with selectable turnover frequencies, a high-accuracy 22-contact attenuator, multiple low-cut and high-cut filters, extensive input and tape dubbing facilities, and beautifully machined solid metalic knobs. Combining advanced engineering with luxurious construction, the DA-U750 remains one of the most respected vintage Diatone integrated amplifiers. Size (W/H/D) 425x148x387mm | Weight 17kg | Original sale price in Japan ¥ 98,800

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