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Equi=Core Hum & Other Issues

I’ve owned a Core Power Tech Equi=Core 1800 for 6 months. Recently the transformer has started to hum inside the chassis. It happens when components are on and also when sources are powered down. The transformer hum is intermittent. It ranges from multiple times per day to 3 or 4 days without any hum. I never had DC on my dedicated lines before, so I picked up a Klein Tools AC/DC tester... https://www.kleintools.com/catalog/electrical-testers/electronic-acdc-voltage-tester-12-240v-ac-15-2...
and when plugged into wall receptacles it indicated overload. Line voltage is steady at 122VAC and always has been.
What am I doing wrong, and how should I test for DC on the power line?

I discovered another problem when testing the Equi=Core duplex receptacles; they indicate inverted polarity. All house outlets measure correct polarity.
I’m looking for some assistance in diagnosing this hum. I’m not sure if it’s due to DC offset or if the torroid itself is vibrating in its mounting.

I know this is becoming a long thread, but I must mention that the Equi=Core now trips the breaker at the panel when powered on. It trips several times in a row, eventually allowing power-up. This is a 20A dedicated line from a subpanel which I’ve had for years.
Any advice is much appreciated.


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almarg
9,670 posts
 
@Millercarbon, as someone who has been here for not much more than a year you may not be aware that over the course of many years it has become abundantly clear to long-time participants that Jim (Jea48) knows more about electrician-related matters than pretty much the rest of the membership combined.

I suggest that in the future you think twice before directing insulting and completely unconstructive comments toward highly respected members (and others as well), as you have done on numerous occasions.

Regards,
-- Al

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amg56
887 posts
 
Hear, hear 😝
lowrider57's avatar
lowrider57 OP
5,411 posts
 
Thank heaven for @jea48 (Jim) and @almarg .
Thank you for all you do,
Jim S.
robert_vnn
2 posts
 
I just have a balance transformer installed in my listening room at the third floor of my house, where run a separated line from the main inlet. Whenever I turn on my pow-amp, the transformer causes a "buzz" but nothing wrong happened, I enjoy the music perfectly. One day I heard a hum noise very noticable, stop for a while, and again. I go around to check and detect that hum noise caused by the hairdryer of my wife from the first floor. Now I know every single time when she use her hairdryer.
Another, balance transformer have two "live" polarity, there is no "neutral" polarity any more.
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lowrider57 OP
5,411 posts
 
Hairdryers are notorious for contaminating the AC line.

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