|
Most digital equipment radiates digital some digital signal (hash) through its power supply back down the powercord. This
signal can then get into the rest of the system and cause degradation of the sound. The digital filter shown here was designed
by Jon Risch and first posted at Audio Asylum.
The filter is contructed from two 24V center-tapped transformers which are wired with their secondaries/ connected back-to
back. A capacitor connected across the two secondaries serves to filter out the digital noise keeping it from entering the
powerline. The size of the capacitor is dependent on the power rating of the transformers. Since some of the AC voltage is
"wasted" due to the reactance of the capacitor, the output voltage will be somewhat reduced if the capacitor is too large.
Transformers rated for less than 2 Amps will probably not function in this circuit as their output voltage will be too greatly
reduced by the capacitor.
Some transformer capcitor combinations may have a tendency to oscillate. In these cases, a 250 Ohm 10W resistor is added as
shown.
If you have a separate transport and DAC, try the filter with both the Transport and DAC plugged into the filter and also
with only the DAC plugged into the filter and the Transport plugged into the same wall outlet as the filter. My ART DI/O sounds
best using this latter configuration. Using this digital filter to remove the "hash" from the DAC powerline resulted in a
much darker backgroud and increased resolution when used with my ART DI/O.
|
