DAC drops out when Furnace starts or stops. HELP

Follow up to this thread.

I later contacted the OP, through the Agon message system, with a question about the problem he had with drop outs. I asked him if he was still using the same 1.5M Grover Huffman digital cable. He responded no he had bought a new 1M Grover Huffman digital cable and was not experiencing any drop out problems with the 1M Grover Huffman cable.

Conclusion? Not all S/PDIF 75 ohm digital coaxial cables are created equal.
Was it the RCA connectors used? Do the ends used by Grover Huffman have a closer better 75 ohm characteristic than the ones used by Audio Envy?

Was it how the RCA connectors were connected to the coax cable?

Was it the 75 ohm coax cable Audio Envy used?

Or was it ???

Is it the length of the cable that could be the culprit or is it the design/construction differences?

Or was it ???

-The characteristic impedance of the cable. That is why length is immaterial.

If the characteristic impedance of the cable is incorrect, there will be reflections that cause errors. This can lead to an inability for the DAC to lock onto the signal. The right cable is all that's needed. Not all high end cable manufacturers understand this, so you see a lot of variance. One cable manufacturer that does get this right is Purist Audio.

Hope there are still audiophiles smarter than me still interested in commenting about dropouts because I ran into a similar problem for which I need help with when I introduced the Yggdrasil dac into my system running off a Grover Huffman digital cable (as recommended in this stream) connected to the digital out of my CD player.  I was hearing occasional dropouts which I subsequently was able, thru experimentation, to duplicate/induce by switching on or off a nearby fluorescent fixture or a clothes dryer in an adjacent room. Incandescent switches in the room have no affect. 
Not clear to me yet whether these components share a conmmom AC line.  I have tried several lesser cost different digital cables both coax and xlr with no difference. And, oh yes, the CD player need not be spinning. I can see the sample rate indicators on the Yggdrasil flashing off momentarily when I hit the fluorescent switch