Digital Cables

@jimf421 Great article! Thank you! 

Glad you all liked the article.

I had an Iris and found it very sensitive to cables.  The HDMI, USB and power cord each cost more than the Iris did.  I've moved on from the Iris, Terminator Plus and HDMI.  I found HDMI was better than USB with the Iris but ultimately there was something with the Terminator Plus that I found unsettling.

I now use S/PDIF with BNC.  I wish my DAC had AES/EBU or Ethernet inputs.

These are situations for which the impact of EMI/RFI on the digital conversion process will be audible if error recovery is not instantaneous as well as potential impacts on analog output stages. 

The following digital impacts (#1 and #3) are errors in digital-to-analog conversion, not in transferring bits for which any errors can be resolved with error checking and a buffer. A buffer doesn't help in these situations because EMI/RFI is affecting the validity of the output from the digital-to-analog conversion process.

1. Clock Instability creating Jitter

• How it happens: EMI/RFI couples into the DAC’s master clock circuit, nudging the timing of when each sample is converted.

• Effect on conversion: The DAC still outputs the correct voltage levels, but at slightly the wrong instants in time.

• Audible impact: Treble glare or “etchiness”, Flattened stereo image, Loss of spaciousness

2. Coupling into the Analog Output Stage

• How it happens: After the DAC chip outputs a small analog voltage, it’s sent through op-amps or discrete analog stages. These are high-gain, wide-bandwidth circuits — practically antennas for EMI/RFI.

• Effect on conversion: Adds a noise floor “haze”, Can cause intermodulation distortion (high-frequency interference folding down into the audible band)

• Audible impact: Graininess, Fatigue in longer listening sessions, Reduced warmth and realism

3. Reference Voltage Pollution

• How it happens: Every DAC chip uses a precise voltage reference to decide, for example, “this bit pattern equals 0.734 V.” EMI/RFI sneaking in via the power supply or ground can modulate this reference.

• Effect on conversion: The DAC’s internal scale is wobbling, so each sample isn’t output at the exact intended level.

• Audible impact: Subtle distortion, Loss of microdetail, “Gray” or veiled background instead of black silence

@calvinandhobbes Very Interesting indeed! Thank you!!