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    M125's + Bucker Update

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    LeGrace

    Posts : 262
    Join date : 2016-08-07
    Location : Ontario, Canada

    M125's + Bucker Update

    Post by LeGrace on Tue Jul 31, 2018 11:22 am

    Follow on post updating results; closing in on 6 months now since I built and started using a bucker transformer with my M125's. Have experienced zero issues with either M125 during this time frame. My first few months of M125 ownership the path was littered with blown rectifier and power tubes, also witnessed multiple red plate events. Little did I appreciate how much house voltage commonly varies. I checked it once and it was 120 so I figured I’m good. Wrong! In my case actually varies anywhere from 118 to as high as almost 123. The latter is where all the fun (not!) would begin.

    The bucker drops my incoming @3.5 volts. Now I turn the amps on without worry anymore. They just sit there glowing calmly. No more buying fuses in bulk! No more nervously eyeing the amps every few minutes for evidence of the onset of a red plate. No more dead amp syndrome. Not it's just kick back and enjoy. sunny
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    sKiZo

    Posts : 1508
    Join date : 2013-04-01
    Location : Michigan USA

    Re: M125's + Bucker Update

    Post by sKiZo on Tue Jul 31, 2018 2:09 pm

    Yup ... same thing happened here when I first fired up. A bucker adds an extra level of protection for any tube amps. I'd think the power tubes blowing would be a result of additional stress when the rectifier blows. My ST120 has piled up a boatload of hours on the same tube set, and is quite happy and reliable operating at around 117vac.
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    CletusB

    Posts : 194
    Join date : 2018-02-11
    Age : 63
    Location : Trinidad & Tobago

    Re: M125's + Bucker Update

    Post by CletusB on Tue Jul 31, 2018 3:44 pm

    Line voltage here is anything from 109V through 120v and my ST-120 has no problem operating under those conditions. Right now my monitor is reading 111V @ 2.12A
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    sKiZo

    Posts : 1508
    Join date : 2013-04-01
    Location : Michigan USA

    Re: M125's + Bucker Update

    Post by sKiZo on Tue Jul 31, 2018 6:29 pm

    I'd think 111vac would be a bit low. Brownout can be just as hard on amps as overvoltage ...

    PS ... you can wire a bucker up to BOOST line voltage as well ... nudge nudge ...
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    CletusB

    Posts : 194
    Join date : 2018-02-11
    Age : 63
    Location : Trinidad & Tobago

    Re: M125's + Bucker Update

    Post by CletusB on Tue Jul 31, 2018 6:50 pm

    sKiZo wrote:I'd think 111vac would be a bit low. Brownout can be just as hard on amps as overvoltage ...

    PS ... you can wire a bucker up to BOOST line voltage as well ... nudge nudge ...
    Works a treat  ....don't fix it if it ain't broke! Very Happy

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