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Nikko Alpha III

Stereo Power Amplifier (1978)

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Nikko Alpha III


Power output: 80 watts per channel into 8Ω (stereo)

Frequency response: 20Hz to 20kHz

Total harmonic distortion: 0.008%

Damping factor: 80

Input sensitivity: 1V

Signal to noise ratio: 115dB

Semiconductors: 3 x IC, 18 x transistors, 4 x FET, 23 x diodes, 7 x zener diodes, 27 x LED

Dimensions: 492 x 130.5 x 325mm

Weight: 16kg


service manual   English -

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Reviewed Apr 06th, 2014 by T.H.

Nikko Alpha III stereo power amplifier (1978-1982)
I bought this 2 channel MOSFET DC power amplifier in the spring of 2014 in my favorite vintage and second hand audio shop ‘Studio 107' in The Hague, The Netherlands for only 229 euro's. Combined with my old JK acoustics Passive 5-II preamplifier, the Nikko Alpha III performs beyond belief. The Nikko Alpha III is one of the rarely found amplifiers which, in my opinion, finally reproduces music instead of producing HiFi. It is a highly enjoyable amplifier and it just makes you want to listen to it all day long. It is a truly versatile and ‘all-round' amplifier: rock, jazz, vocals and all sorts of classical music sounds equally good/realistic. The sound is clean but not least cold or ‘technical', and neutral but not the least dull. The overall performance can be described as ‘luxuriant' and smooth but the music never disappear under a ‘warm blanket'. The sound is dynamic but never fatiguing. If needed the Alpha III can reproduce the sound of a earthquake and make your room shake, but is also can be extremely subtle and refined. The 3-d soundstage of this 2 channel amplifier is how it should be: breathtaking. Over the years I have been listening to many different amplifiers. For me the Nikko Alpha III proofs again that a good MOSFET power output stage is the best choice if you like ‘music' instead of ‘HiFi'. A good MOSFET power amplifier like the Alpha III combines the best of both worlds: the musical performance of tube amplifiers and the fast and powerful performance of traditional transistor amplifiers. Special for the Nikko Alpha III is that it has a ‘normal' input (AC) and also a ‘direct' input (DC). Since the JK acoustics Passive 5-II preamplifier which I use is has an AC and a DC output, it matches perfect with the Alpha III. Connected via DC output/input, especially the bass is more defined, tight and realistic than with the ‘normal' AC output/input combination.
So good news, but what are the contra indications for this amplifier? In theory the damping factor (80) should have been higher in my opinion and, depending on the sensitivity of your loudspeakers, de power output of 80 watts could have been 100 watts. In daily practice however I don't miss anything. I is just a very good sounding power amplifier. Of course, than there is the fact that it is an old amplifier so you never know how long it will last. But bearing in mind the price I paid this is not really a problem. So, my advice is: if you see a Nikko Alpha III power amplifier in good working condition for sale around 100-250 euro's, buy one. Maybe the vintage look, size and weight (16 kg / 35.2 lbs), will not appeal to everybody but the sound quality is equal to power amplifiers costing 1000 to 1500 euro's, and maybe even more than that.
T.H., The Netherlands, spring 2014.



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