Upgrading B&K M200's

Has anyone here ever done anything to these or similar B&K amps? These things are 26 years old and I'm concerned that could be an issue. They sound superb by the way but I'd like to keep them that way. There seems to be NO information on the internet regarding bias settings or schematics.

Thoughts?
Gustard X26 Pro DAC
Belles 21A Pre modded with Mundorf Supreme caps
B&K M200 Sonata monoblocks refreshed and upgraded
Polk SDA 1C's modded / 1000Va Dreadnaught
Wireworld Silver Eclipse IC's and speaker cables
Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)


There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus

Comments

  • gyosa
    gyosa Posts: 751
    Here ya go .....

    I had my ex442 serviced last spring... gave this info to the tech.

    It says the m200 is the same as ex-442 with an exception on the schematics page ....
    Here’s The offset and bias instructions .....

    I have a few more pages , if you’re interested .....

    BK



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    PS Audio S300 , WiiM Ultra , Yamaha wxc-50 , Salk SuperCharged Songtowers , Kimber Kable 4TC, Sony 42” - BEDROOM

    B&K EX-442 ( it will go in my casket when I die ... ) , PS Audio 4.6 preamp ( old school , but it still jams on ... ) , Eversolo DMP-A6 , Boston Acoustic voyager 7’s - POOL

    Parasound A21, Eversolo DMP-A8 , Kimber Kable 4vs , Ascend Acoustics ELX Ribbon Towers , Sony XBR-A8F 65” OLED - DEN , MAIN system

    Onkyo TX-nr609 , Polk atrium 7 , Boston acoustic sound ware (4) , Boston acoustic sub , B&W center , Sharp 65” TV - PATIO
  • gyosa
    gyosa Posts: 751
    Oh .... of note ,
    I purchased my 442 new in 1990 , sat in my closet for 10 years - took it in for a checkup and all it needed was offset and bias adjusted ....
    Still works great !

    BK
    PS Audio S300 , WiiM Ultra , Yamaha wxc-50 , Salk SuperCharged Songtowers , Kimber Kable 4TC, Sony 42” - BEDROOM

    B&K EX-442 ( it will go in my casket when I die ... ) , PS Audio 4.6 preamp ( old school , but it still jams on ... ) , Eversolo DMP-A6 , Boston Acoustic voyager 7’s - POOL

    Parasound A21, Eversolo DMP-A8 , Kimber Kable 4vs , Ascend Acoustics ELX Ribbon Towers , Sony XBR-A8F 65” OLED - DEN , MAIN system

    Onkyo TX-nr609 , Polk atrium 7 , Boston acoustic sound ware (4) , Boston acoustic sub , B&W center , Sharp 65” TV - PATIO
  • audioluvr
    audioluvr Posts: 5,601
    gyosa wrote: »
    Here ya go .....

    I had my ex442 serviced last spring... gave this info to the tech.

    It says the m200 is the same as ex-442 with an exception on the schematics page ....
    Here’s The offset and bias instructions .....

    I have a few more pages , if you’re interested .....

    BK

    Sweet! Could you send all the info you got to my email address? PM sent.
    Gustard X26 Pro DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)


    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
  • gyosa
    gyosa Posts: 751
    Done ...

    BK
    PS Audio S300 , WiiM Ultra , Yamaha wxc-50 , Salk SuperCharged Songtowers , Kimber Kable 4TC, Sony 42” - BEDROOM

    B&K EX-442 ( it will go in my casket when I die ... ) , PS Audio 4.6 preamp ( old school , but it still jams on ... ) , Eversolo DMP-A6 , Boston Acoustic voyager 7’s - POOL

    Parasound A21, Eversolo DMP-A8 , Kimber Kable 4vs , Ascend Acoustics ELX Ribbon Towers , Sony XBR-A8F 65” OLED - DEN , MAIN system

    Onkyo TX-nr609 , Polk atrium 7 , Boston acoustic sound ware (4) , Boston acoustic sub , B&W center , Sharp 65” TV - PATIO
  • audioluvr
    audioluvr Posts: 5,601
    Thanks! Had the bias reset. One was a little low. Offset was good though. Interesting this amp was Sonic Frontier's first delve into solid state. Built like a tank. It's the same internals as your amp only L & R channels paralleled into one channel giving it twice the reserve amperage capacity. Not sure if that matters or not. Really simple design though.
    Gustard X26 Pro DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)


    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
  • gyosa
    gyosa Posts: 751
    Yeah ,
    I've had my 442 since new in 1990 or so ....bought it to drive my sda 1c's which I still have .....
    I truly love it
    PS Audio S300 , WiiM Ultra , Yamaha wxc-50 , Salk SuperCharged Songtowers , Kimber Kable 4TC, Sony 42” - BEDROOM

    B&K EX-442 ( it will go in my casket when I die ... ) , PS Audio 4.6 preamp ( old school , but it still jams on ... ) , Eversolo DMP-A6 , Boston Acoustic voyager 7’s - POOL

    Parasound A21, Eversolo DMP-A8 , Kimber Kable 4vs , Ascend Acoustics ELX Ribbon Towers , Sony XBR-A8F 65” OLED - DEN , MAIN system

    Onkyo TX-nr609 , Polk atrium 7 , Boston acoustic sound ware (4) , Boston acoustic sub , B&W center , Sharp 65” TV - PATIO