High Frequency Tone, Blown Tweeters.

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  • VSAT88
    VSAT88 Posts: 1,260
    https://www.youtube.com/watch?v=mQFL-NLh0O8
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  • VSAT88
    VSAT88 Posts: 1,260
    Hell, I hope not !
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  • tonyb
    tonyb Posts: 32,983
    Sorry to hear that, the amp is certainly at the age of needing some updating.

    Anyway....I hope you checked all the simple things first. If using bare wire speaker cable ends, make sure nothing is touching another post creating a short. Make sure none of the metal ends of any IC's used are touching either. Sometimes larger plugs and real close in/outputs can be a pain. Damaged power cables, etc. Good luck to you.
    HT SYSTEM-
    Sony 850c 4k
    Pioneer elite vhx 21
    Sony 4k BRP
    SVS SB-2000
    Polk Sig. 20's
    Polk FX500 surrounds

    Cables-
    Acoustic zen Satori speaker cables
    Acoustic zen Matrix 2 IC's
    Wireworld eclipse 7 ic's
    Audio metallurgy ga-o digital cable

    Kitchen

    Sonos zp90
    Grant Fidelity tube dac
    B&k 1420
    lsi 9's
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  • VSAT88
    VSAT88 Posts: 1,260
    tonyb wrote: »
    Sorry to hear that, the amp is certainly at the age of needing some updating.

    Anyway....I hope you checked all the simple things first. If using bare wire speaker cable ends, make sure nothing is touching another post creating a short. Make sure none of the metal ends of any IC's used are touching either. Sometimes larger plugs and real close in/outputs can be a pain. Damaged power cables, etc. Good luck to you.

    Thanks Tony I agree. It was made in 1988 so that is a long stretch. Equipment was made well back in those days well, a lot of it was still well made. I really like the amplifier and I will restore it soon after repairs to get it back up and running.
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  • VSAT88
    VSAT88 Posts: 1,260
    For posterity's sake I found the problem and wanted to post it. Thought I already had but guess I did not. The wires coming out of the transformer are solid copper. They run up thru the bottom of the rectifier PCB's on each side of the amp. These PCB's are mounted on top of the filter caps. Where the wire from the transformer comes up and solders to the board I found a tiny crack in the solder joint. Soldered all that back after cleaning it all up with new Kester solder and have had not one problem with the amp since. Look at the image where the arrows point to the board in those areas.
    e0nhtavw59lq.jpg

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  • msg
    msg Posts: 10,140
    Wow! Nice find!
    This is great information, thank you for posting back. I have B&K amps, too, and still have my first one, which is the EX-442 Sonata in bronze. I'll better check mine out, too.
    I disabled signatures.
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  • txcoastal1
    txcoastal1 Posts: 13,306
    Nice update and glad you found the issue
    2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
    Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
    Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
    Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC

    erat interfectorem cesar et **** dictatorem dicere a
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  • VSAT88
    VSAT88 Posts: 1,260
    I love my amplifier. I like it enough that I have went completely thru it. New electrolytes all the way through including the main filters. New switch, 30 A. New larger power cord. Anything that may have been needed is done. I have a McCormack DNA 1 a PS Audio 200 cx and a few other power amplifiers that are well regarded. The only one I would not sell is the B&K.
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  • audioluvr
    audioluvr Posts: 5,603
    VSAT88 wrote: »
    ... The only one I would not sell is the B&K.

    Agreed
    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
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