Equi=Core Hum & Other Issues

Send an email to Underwood HiFi as they bought out Equi=Core and are now manufacturing and marketing newer version. 

The Equi=Core is balanced power, therefore, we all get the indicated inverted polarity. I suggest you phone or email Walter, I'll bet he will repair or replace the unit. underwoodwally@aol.com

Hi Lowrider,

DC offset on an AC power line can't be measured with an ordinary multimeter, or with the device you purchased. Although after looking at the description of the device I'm not sure why it indicated an overload. Apparently it automatically senses whether the voltage is AC or DC, and I would have expected it to illuminate the LED corresponding to 120 volts AC.

It might be possible to measure DC offset to some degree of accuracy with an oscilloscope. But a better way would be to construct a low-pass filter that would remove the 60 Hz content, and use that in conjunction with a multimeter. If that might be of interest to you or anyone else reading this thread see the posts by Jea48 and me on page 2 of the following thread (assuming you have the posts sorted oldest first):

https://forum.audiogon.com/discussions/dc-offset-blocker-killer-where-to-buy-in-the-usa?page=2

In any event, good luck in getting the issue resolved.

Best regards,
-- Al

@ lowrider57

I agree with testpilot and lak , send the unit in for repair.


As for measuring DC on the mains. You cannot measure DC on the mains by connecting a regular DVM directly across the AC mains at the wall outlet. You would need to connect a low pass filter between the DVM leads and the wall outlet.
The Klien tester you bought is not a DVM by the way.

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.

Stop using the Equi=Core..... Get it repaired.

You need to hire an electrician to have the 20 amp breaker in the electrical panel replaced. That is a must!... Repeated tripping and resetting of the breaker has damaged the thermomagnetic trip unit in the breaker. In many cases the breaker just gets weaker, will trip with less of a connected load than the 20 amps it is rated for and or will not be able to handle inrush current that the breaker used to be able to handle before the repeated tripping and resetting of the breaker.

Worse case that could, can, happen now if it trips due to a high inrush current or a short circuit event of the Equi=Core unit the 20 amp breaker in the electrical panel will not trip when you try to reset it again and the breaker may explode causing major damage to the electrical panel but may also explode outward through the front of the breaker casing burning your fingers, hand, arm, and possibly your face and eyes.
Yes a defective 20 amp breaker could, can, do that........

You should never face,look, at a circuit breaker when resetting a tripped breaker. Always turn your face away from the breaker and electrical panel when pushing the breaker handle back to the ON position. In fact your body should not be in front of the electrical panel. You should be off to the side with your arm and hand extended. 

Jim

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Thanks @lak  for that valuable information.

@almarg , I've been reading that thread.
The Klein device does register 120VAC, but the Overload LED is lit. The polarity LED's indicate normal AC, maybe the overload is due to high DC. Overload is >25vDC.
And I know not to use a multimeter, that's why I bought this device. Thanks.

@jea48 , I think I should call the electrician to address the breaker situation. The 20A breaker being tripped at every powerup has never happened before this week.
Would he be able to measure DC offset?