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CA-800 Bias Problems After DOA Rebuild

Discussion in 'Yamaha' started by ekimezeerf, Jun 9, 2018.

  1. mbz

    mbz AK Subscriber Subscriber

    Messages:
    1,951
    Location:
    Melbourne, Victoria
    Good pickup

    The CA-800 is a nice amp, worth the effort.
     

     

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  2. ekimezeerf

    ekimezeerf New Member

    Messages:
    9
    Location:
    Michigan
    I removed the incorrect 4.7k ohm resistors R626 & R627 and installed the correct 4.7 ohm resistors. It's working!

    Class B Mode bias was set at 50 mV
    Class A Mode bias at 850 mV

    It sounds amazing, really. I've had a chance to listen to a lot of cool vintage sets and amps but this CA-800 is moving to the top of my favorites list!

    Thank you avionic and mbz for weighing in. I really appreciate the effort and the mental nudge.

    In case anyone else comes across this thread and is working on the CA-800 amp board, here's a little more detailed image of the components:
     
    Last edited: Jun 14, 2018
    zaibatsu, Mr. Yamaha, avionic and 2 others like this.
  3. mbz

    mbz AK Subscriber Subscriber

    Messages:
    1,951
    Location:
    Melbourne, Victoria
    Glad that it's working.

    The CA-800 is a good amp, the CA-1000 is better and the CA-1000II is slightly better again. All share the same basic mechanics=PITA to rebuild.
    Yamaha took a slightly different tact with the CA-1010 and 2010 (both same/easier rebuild) which are impressive but some people prefer the CA-1000
     
    avionic and ekimezeerf like this.
  4. avionic

    avionic " Black Knights " Subscriber

    Messages:
    41,605
    Location:
    Fort Dodge, Iowa
    Good job...:beerchug: Skál !
     
    Last edited: Jun 14, 2018
    ekimezeerf likes this.

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