C-80 Score!

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Recently picked a mint Nikko set up; Alpha 220, Beta 20 pre. Liked the way it sounded at higher volumes but the pre amp lacked the variable loudness or any loudness. Ended up on e-pay one night, bidding on a mint C-80 with issues. One channel was louder than the other. My hope was the hidden balance control. Openned the package and sure enough the balance was off center. Finally got around the giving it a test listen. It appears both channels work fine.

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ah yes, the ole' hidden balance control trick...

great pre!
 
Recently picked a mint Nikko set up; Alpha 220, Beta 20 pre. Liked the way it sounded at higher volumes but the pre amp lacked the variable loudness or any loudness. Ended up on e-pay one night, bidding on a mint C-80 with issues. One channel was louder than the other. My hope was the hidden balance control. Openned the package and sure enough the balance was off center. Finally got around the giving it a test listen. It appears both channels work fine.

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Congrats!

I've fallen for that setting once myself. One evening when turning on my system for the first time in a week or more I noticed that one channel was not as loud as the other. After some troubleshooting I realized that the balance control had been 'adjusted'. Duh -oh.

At least I didn't sell it ;)

Cheers,
John
 
Is there some way I could check L & R output? I have a Fluke 77IV.

I would like to verify before installing into my system.

http://en-us.fluke.com/products/digital-multimeters/fluke-77-iv-digital-multimeter.html

Do you have a audio signal generator ? Need to apply a equal signal (1khz) to both the left and right Tape,tuner or CD input. Then monitor both (normal) pre-amp outputs with a RMS AC voltmeter(Fluke) while varying the volume control.They should be pretty darn close to the same RMS voltage out.
 
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C-80 adjustments...

There also may be internal adjustments regarding a few aspects of the pre.
The service manual has setting adjustments for the MC area called "DC Offset".

Paul
 
There also may be internal adjustments regarding a few aspects of the pre.
The service manual has setting adjustments for the MC area called "DC Offset".

Paul

This is a bit weird. Regardless of the adjustment the DC servo will always try to come close to ±0V. The only side effect is that the amp will produce more heat if not adjusted properly. Anyway, this adjustment does not affect channel balance.
 
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