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    GFI Unexpected Benefit

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    LeGrace

    Posts : 92
    Join date : 2016-08-07

    GFI Unexpected Benefit

    Post by LeGrace on Fri Aug 26, 2016 2:36 pm

    Been planning on getting one of these ever since seeing Deepee's thread. Turned out even greater then I expected.

    You see I've always had to tolerate a bit of hum. Not speakers mind you, talking amp hum. Always had this with my Marantz. The M125's the same thing. Coming from the power transformers. Transformers hum so I figure this is simply part of the ownership experience.

    Finding a manual reset model wasn't easy. The one I got is meant for contractors. Some things you just don't want to unexpectedly start up again, like a rip saw! affraid

    So I plug it and the magic happens - all of a sudden no hum whatsoever coming from any of the amps! I'm over the moon. Thanks Deepee!! santa

    deepee99

    Posts : 1333
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: GFI Unexpected Benefit

    Post by deepee99 on Fri Aug 26, 2016 3:39 pm

    I think Bob and Roy ought to just add $20 to the price of their stuff and toss in a manual-reset GFCI. It really is required equipment, whether you're running toobs or solid state.
    I wouldn't expect a GFCI to resolve hum, but who knows? My first guess would be that there's an imbalance in your fuse-box downstairs. I have a dedicated breaker and circuit to the amps and the other audio stuff here, and try to keep the breaker panel balanced, which requires the work of an intelligent electrician. I run a 20-amp dedicated circuit to the electronics, with a Furman that helps with the frequent power bumps around here. We live in a mining district here, so when one of those 2,000 horsepower hoists or compressors on our grid kick on or off, the lights blink, the computers puke. Ditto with lightning strikes. So far, so good, never lost a tube with the GFCI in line.

    LeGrace

    Posts : 92
    Join date : 2016-08-07

    Re: GFI Unexpected Benefit

    Post by LeGrace on Sat Aug 27, 2016 3:16 pm

    I have old wiring in my house, maybe that has something to do with it. One thing I've learned is if your GFI comes with a test button test it with a lamp, not the amps. The GFI instructions say test at least once a month, which I just did. One of my tube rectifiers promptly flashed a light show. Its totally fried now, and of course the fuse blew.

    But the story has a happy ending. I live in a tiny Canadian town and the odds of finding any tube replacements here I figure is on a similar scale as winning the lotto. But unbelievably I did. The shop owner figured he had them in the back of his shop for at least 20 years, and the condition of the boxes sure reflected it! I just got my first NOS tubes! And a heck of a deal, he said they probably weren't any good anymore so he sold them to me super cheap. They work perfect!!

    deepee99

    Posts : 1333
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: GFI Unexpected Benefit

    Post by deepee99 on Sat Aug 27, 2016 3:35 pm

    LeGrace,
    You ought to take your tube guy out for prime rib and beer. You just made a killing.
    I bought some new old-stock Tung-Sol 6550s for $8.50 apiece from a TV repairman because that was what he had marked them up to back in the early 1960s. But that doesn't happen very often to many of us anymore.
    Again, I would encourage you to spend the $100 or so on a certified electrician to check the balance on your fuse-box or breaker box, as well as its ground. Your tubes and your refrigerator will love you for it.


    Dale Stevens

    Posts : 77
    Join date : 2014-07-06
    Age : 67
    Location : Loris, SC

    Re: GFI Unexpected Benefit

    Post by Dale Stevens on Sat Aug 27, 2016 5:33 pm

    Dave, define balance on your fuse box. Dale

    deepee99

    Posts : 1333
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: GFI Unexpected Benefit

    Post by deepee99 on Sat Aug 27, 2016 7:54 pm

    Dale,
    I'm not a certified electrician, though I play one on TV.
    There are two sets of rails on the typical breaker box. Go downstairs or wherever and look. Each rail hosts a stack of breakers.
    If one rail of breakers is hauling a lot more amps than the other, you will have an imbalance. In an old house like mine, it's not unusual. Add a room here or there, or a lighted porch, or especially some 220v for a water heater or clothes dryer, it can throw things askew.
    Whether that generates hum in tube equipment, I dunno. I'd be looking for ground issues for starters, especially in an old house. Could be LeGrace's GFI simply resolved a local ground loop, too.
    But if you're living in a 100-year-old Dumpster, as I do, it's worth checking out at the breaker panel level - especially the grounding.

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