Digital Output Tweak, Those who doesn't use an outboard dac...

[clint e.]

Suddently i become with no outboard dac. One of the circuits in the pcb board is broken, but i'll try to fix it this weekend and than i'll post some pics.
...but i remember a good tweak i have done few years ago. This idea comes from a friend of mine in another forum. It's an oldie cheap tweak and sometimes the results are very good. I've done it again, this time with my nad cdp and i like it.

Solder a 75 ohm resistor between the signal and ground shield of a RCA male plug. I'm assuming your cdp digital output is RCA here. This resistor can be the tiny 1/8W. Bigger doesn't matter. If you have difficulties finding 75 ohm, then just parallel 2 pieces of 150 ohm. No need for WBT or audiophile approved resistors here.

Just like this:



Than plug plugged into digital output and listen....

The idea is to close an open circuit. I mean, if a low frequency signal reaches an open circuit, nothing happens but if a high frequency signal reaches an open circuit, it bounces back into the rest of the digital circuitry, causing jitter.
Terminate this unused digital output with a 75 ohm resistive load, and the reflections no longer occur, the transmission line has been terminated in it's characteristic impedance, and the backfeed has been reduced greatly or eliminated altogether. Less jitter, cleaner sound.

Try it yourself, it is quite easy and inexpensive to do, and there is no reason to not try it.

This post has been edited by clint e. on February 15, 2008 01:42 pm

[clint e.]

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