Nakamichi 620 Power Amp


1970’s Japanese Class B power at its very best.


Hi-Fi Engine Description

Nakamichi’s Complete Mirror design brings a level of performance to class B amplifiers that was formerly associated only with class A amplifiers.

The 620 is closer to a pure class B amplifier than anything else that has gone before. The first stage of the 620 is a differential amplifier with “current mirror” loading. The final section of the amplifier is a four stage push-pull circuit.

All four stages are full complementary direct coupled, and each stage employs a unique double NPN/PNP combination for the positive and negative halves. This design eliminates the errors inherent in even the most carefully matched pairs of NPN/PNP output devices. These errors, furthermore, are eliminated without the use of bias diodes, bias adjustments and high idle currents.

The 620, in fact, idles at approximately 1/20 the current of conventional class B power amplifiers of comparable output power.

This new approach takes full advantage of class B efficiency with the freedom from switching and crossover distortions that was once thought possible only with class A amplifiers.


Power output: 100 watts per channel into 8Ω (stereo)

Frequency response: 5Hz to 100kHz

Total harmonic distortion: 0.005%

Damping factor: 100

Signal to noise ratio: 120dB

Semiconductors: 3 x ICs, 46 x transistors, 41 x diodes

Dimensions: 400 x 189 x 248mm

Weight: 12.5kg


It would be our pleasure to demonstrate this product in store for you, contact us to arrange an appointment

Available for UK & EU shipping, please get in touch to arrange EU shipping

All vintage and used equipment that we supply is sold with a full one year warranty

Please contact us if you own Nakamichi gear that you’d like to sell, or that would benefit from service / repair

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