2019/05/24

Nakamichi CA-5

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I just got the Nakamichi CA-5 pre amplifier !

The Nakamichi CA-5 was a legendary product when Nakamichi entered the high-end amplifier markets in 1985.

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This pre amp was released under the product names CA-5 for North America, CA-5E for Europe, and CA-50 for Japan. In addition, there were the top model CA-7 and the power amplifier PA-7/PA-5 products.

These amplifiers were commercialized in a technical partnership with Threshold Electronics. The PA-7/PA-5 power amp was developed with STASIS technology. And the CA-5 pre amp was also designed by Mr. Nelson Pass at Threshold.

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This amp seems to have been treated very carefully and the front panel is almost flawless.

Well the problem is inside the amp, so I tried to open it before turning on the power.

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There is no dust inside because of the sealed structure. There seems to be no swelling of electrolytic capacitors. This condition is unbelievable as it was over 30 years ago.

I looked closely at the circuit and found that in fully discrete components configuration no OP amps or ICs were used. It is a very simple circuit configuration of the MC phono preamplifier, the MM phono preamplifier, the RIAA phono equalizer and the line-level amplifier. Left and right channel circuits have been completely isolated in pure copper bus bar, so it was “dual mono” circuit board design. The phono stage seems to be a very sophisticated circuit. In addition, six giant film capacitors has mounted as coupling capacitors.

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I turned on the power in this state and looked at the state of the internal parts for a while, but there are no parts that generate heat. I tried measuring the voltage of the line output with a tester, but there seems to be no DC leakage.

Then I connected the CD player and the power amplifier and tried to play music.

The playback sound was output with noise mixed in the left channel. I think that it is a high possibility of poor signal contact, so I will try to repair it carefully.
posted by toons at 03:31 | Audio