There are many DC blockers available, at different price points. PS Audio used to make a popular one, occasionally available used. Audio by Van Alstine, Emotiva, and Isotek all have models.
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.
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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- 107 posts total
@jea48 , this is a large electrical contractor in Philadelphia. I’ve been with them since they were a small family business. Now their prices are high and using younger techs. My guy, a master electrician who knew audio and owned a nice system is no longer with the company. He did test for DC offset and polarity when he upgraded my power 3 years ago. This morning line voltage was 124VAC on my monitor I keep in one of the duplexes. That’s high, it’s been steady at 122V for years (using a Furman conditioner with voltage display). I’ll test voltage on the amp line as you suggested. I know Ralph uses a DC blocker in his amps. Many thanks, Jim. |
@twoleftears Thanks. I'm aware of the Van Alstine as an inexpensive solution... https://avahifi.com/products/humdinger-dc-line-blocker The Isotek looks great with its ability to rebalance the AC sine wave, but it's expensive. https://www.musicdirect.com/power/IsoTek-EVO3-Syncro-Uni-Sine-Wave-Rebalancing-Unit-C19?variant=AISO... I used to own the Emotiva when I was having ground faults. I guess about five years ago, and there was never any DC on the mains. As I stated earlier, this issue is a recent occurrence, but a very real problem. |
- 107 posts total