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    Ground loop

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    Tube Nube

    Posts : 653
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Ground loop

    Post by Tube Nube on Wed Nov 23, 2016 11:00 pm

    This time I'm here to offer a solution i stead of a problem.

    Recently I developed a pesky problem of an apparent ground loop. From all I read about the symptoms, that was the diagnosis.

    It seemed to be associated with the phono stage. No hummmmmmm with hi level inputs.

    Following standard advice from the web, getting all components fed from one outlet didnt help. Lifting the ground on the phono and/or pre amp with a cheater plug didn't help. Making a star ground for all components didn't help. (Darn, it worked so well with my ham gear!)

    I'd recently purchased a high quality interconnect, and thought I'd put it where it would do most good: between step up transformer and phono stage. This, in plac of a Blue Jeans interconnect ( shielded coaxial cable by Belden manufacture ).

    So I've already tipped my hand here.

    I put a Blue Jeans cable back there, and moved the new unshielded cable to go between phono stage and pre amp. "Ground loop" cured!

    My conclusions are that, while the fragile low level signal input to the phono might have benefitted from the fancy new cable, its low levelness was swamped by interference from all the power cables, power supply magnetism etc back behind the rack because of it being unshielded.

    Perhaps there are other explanations. But information on the web about how to resolve hummmmm is woefully inadequate. If ypu have this problem, begin by reading everything you can on the net, but be prepared for frustration when it doesnt work.

    Get all your gear on one outlet. Next, make a star ground. Next, unplug your cable tv router. Next, disconnect you interconnects to try to isolate the culprit. Next--here's a new one--consult a ham radio operator. Why? Because they have these problems all the time. Because they have technical training you don't... Often to an extraordinary extent. Because, as a group, they are cheap soms of guns who take pride in scrounging and, as a result, performing miracles with scraps. Because they collectively embrace an ethic of charitable service to the community-- i.e., so you're essentially consulting a lay electrical, or even actual engineer, who will be happy to help you for free!

    Maybe not least, but surely last, hire an electrician to consult.

    Tube Nube

    Posts : 653
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: Ground loop

    Post by Tube Nube on Wed Nov 23, 2016 11:07 pm

    P.S. You offer most hams, as their reward, a chance to near a tube amplified stereo system with the suggestion it'll probably be the best system they ever heard, regardless of modern silicon technology... Well, you'll not only see him drool, he'll probably be the one bringing the beer! If I'm wrong about that...then I'll buy the beer. I'm tellin' ya!

    sKiZo

    Posts : 1327
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Ground loop

    Post by sKiZo on Thu Nov 24, 2016 1:27 am

    If I ever end up with a ground loop due to an interconnect, I'm screwed ... clown


    Kentley

    Posts : 355
    Join date : 2015-03-06
    Age : 64
    Location : Worcester, MA

    Re: Ground loop

    Post by Kentley on Thu Nov 24, 2016 2:53 am

    You have hereby blown your cover. We now know beyond a shadow of a doubt that you are running the NSA, for this is obviously a flimsily-encoded diagram of the entire military/industrial/security operation. Turn in your badge.
    And if you should ever develop a ground-loop issue, whole third-world countries are doomed. I hope you're happy. bom


    Last edited by Kentley on Thu Nov 24, 2016 2:49 pm; edited 1 time in total

    pmarcin

    Posts : 132
    Join date : 2009-01-20
    Age : 69

    Re: Ground loop

    Post by pmarcin on Thu Nov 24, 2016 12:49 pm

    Lol, sire.

    Tube Nube

    Posts : 653
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: Ground loop

    Post by Tube Nube on Thu Nov 24, 2016 1:16 pm

    "Loop" is not the word for what is going on in sKiZo'S sYsTeM. "Loop-y" maybe, but not "loop."

    deepee99

    Posts : 1358
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Ground loop

    Post by deepee99 on Fri Nov 25, 2016 5:01 am

    Tube Nube wrote:P.S. You offer most hams, as their reward, a chance to near a tube amplified stereo system with the suggestion it'll probably be the best system they ever heard, regardless of modern silicon technology... Well, you'll not only see him drool, he'll probably be the one bringing the beer! If I'm wrong about that...then I'll buy the beer. I'm tellin' ya!
    Here's to the 6146A. If I could build a hi-fi out of those bad boys I would.

    pichacker

    Posts : 17
    Join date : 2016-08-01
    Age : 52
    Location : Near to London - UK

    Re: Ground loop

    Post by pichacker on Fri Nov 25, 2016 5:38 am

    Aye, I've seen pictures of audio amps built using QQV06-40A's as the outputs. That's a UHF transmitter valve. But it looks good Smile

    Tube Nube

    Posts : 653
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: Ground loop

    Post by Tube Nube on Fri Nov 25, 2016 9:24 am

    Ahhh 6148A's. Many happy memories of those, Dave.

    deepee99

    Posts : 1358
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Ground loop

    Post by deepee99 on Fri Nov 25, 2016 9:37 am

    The 6146As gave me my first serious lessons about proper biasing, and I still have the burn-scars to prove it. We all dove head-long into converting our Collins S-Line pwr supplies to solid state, but no-one in my kindergarten school taught me about the impact on the xmtr tubes of doing so. A well settled-in series of 6146s did not appreciate the power supply mod and let you know in a hurry. Collins built a cage around them for a reason. It was to keep people, not cats, away, and even if lightning didn't shoot out, somebody would pounce on your first CQ about your splattering signal.

    Tube Nube

    Posts : 653
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: Ground loop

    Post by Tube Nube on Fri Nov 25, 2016 4:52 pm

    I continue to have Collins Envy, and may one day acquire some of that gear. It sounds so good when I hear it!

    deepee99

    Posts : 1358
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Ground loop

    Post by deepee99 on Fri Nov 25, 2016 4:57 pm

    Tube Nube wrote:I continue to have Collins Envy, and may one day acquire some of that gear. It sounds so good when I hear it!
    I know a guy who knows a guy.. . . big-time S-Line dude.

    tubes4hifi
    Admin

    Posts : 1299
    Join date : 2008-11-30

    Re: Ground loop

    Post by tubes4hifi on Sat Nov 26, 2016 3:13 pm

    skizo,
    alot of nice equipment, and no speakers . . . .

    sKiZo

    Posts : 1327
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Ground loop

    Post by sKiZo on Sat Nov 26, 2016 9:29 pm

    ooPs ... clown

    Front channels - McIntosh XR16's

    Rear channels - Bose 201, 161, and Gekko GK114 in a modified Hafler array. The Gekko flat panels are to the side and mid wall, the 161's just behind the comfy chair at the ceiling, and the 201's about 10 feet back mid wall for ambiance ...

    Just had the McIntosh completely restored and have usable SPLs down to around 14hz ... guess that will have to do ... ;-}






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