DC Blocker Audio Grade Mains Filter - Built by EchoWars from AK

Description: DC Blocker Audio Grade Mains Filter - Built by EchoWars from the Audiokarma forums - Utility Boxes This was built for me by Glenn, aka EchoWars from the Audiokarma forums, in a pair of utility boxes. It solved my intermittent transformer buzzing issue with an audio amp that I was using at the time. The transformer buzzing was due to intermittent DC on my power line. As you will see from the photos, it was built to be out of sight behind my equipment cabinet. Built in 2006 with a cost to me of parts, his labor and shipping of $110.00. Where the DC comes from: Halfwave rectification devices (and PWM light controllers and dimmers) and source impedance of household wiring mean that you can have a volt of DC riding on the AC wires. It’s usually the fault of cheap appliances...blenders, hair dryers, dimmers, etc... If the house wiring was all 8ga wire, the DC would be nearly all sourced back to the panel, but in the real world that doesn’t happen. How the filter works: The filter works by using the diodes of the bridge rectifier to ‘chew up’ or block the DC. Since two diodes are used in either direction, the bridge can block about 1.1V of DC, and that is generally all that is needed. The AC voltage is passed by the large electrolytics, which is why the capacitance value must be so high, since these caps pass all the AC current they must be able to source all the AC current from the outlet. Comments on the build from EchoWars: Next order from DK I’ll get the caps on the way. The biggest that will fit are Panasonic T-UP 100,000µf 16V caps, rated at about 11.3A. The problem is getting a 40mm clamp. Michael Percy Audio has them, but I’ll have to wait till I order from them next to get ‘em. Just barely fit it all into the 4” x4” box. The whole assembly is two of these boxes bolted together...one box contains the caps and diode bridge (35A 800V bridge, and two 100,000µf 16V caps), and the other side is two of Cooper’s best 5-20R receptacles. There’s a 9’ 14ga cord, and a somewhat pedestrian power plug (the best I could find locally). All the box internal wiring is 16ga (a combination of solid and stranded) except for the incoming wire. There is no fuse...just wasn’t room for it. Was a real bitch getting those caps in there and getting them tightened down. The screws holding the cap clamps and the single screw on the diode bridge all had to be installed on the inside, with the nuts on the outside. Wish I could have done it the other way, but they are small, and besides...this unit is 100% functionality, and 0% aesthetics. Not that it looks horrid, but very industrial. It will block up to about 1.1VDC or so. After that, the excess gets through (but at least it is reduced by that amount). It would be unusual to have more than a volt of DC. Usually (from what I hear), 0.25 to 0.50 volts is the norm. No noise. No nuthin’. Pretty passive device. Caps are so large because I wanted to make sure that they could carry the ripple current of anything you could throw at it. Ought to be good to the 15A of your circuit breaker. The parts total is $65. $110 will get it packed and shipped to you.

Price: 65 USD

Location: Waterville, Minnesota

End Time: 2024-11-30T20:55:35.000Z

Shipping Cost: N/A USD