Interconnects Roller Coaster Ride

Just curious, but what leads you to conclude that the Morrows are responsible for the fluctuations you are perceiving? How do you know that it is not something in one of your components, such as tubes, or fluctuations in AC line voltage or noise conditions, or any of many other conceivable causes?

Regards,
-- Al

Regarding line voltage, there is no way I personally know of for testing that. But I have noticed a halogen lamp in my adjacent room cycling in brightness for periods of time some evenings while I am listening. Would that be an indication of line voltage variation?

Yes, it certainly could be. According to this Wikipedia writeup on Halogen lamps, their light output is approximately proportional to a voltage change, expressed as a ratio, raised to the third power. Meaning that a 5% increase in voltage would cause about a (1.05^3) = 16% increase in light output. That is slightly less than the effect that a similar voltage change would have on the output of a regular incandescent bulb, where the light output is approximately proportional to the voltage ratio raised to the 3.4 power, resulting in a 5% voltage increase causing an increase of about (1.05^3.4) = 18% in light output.

Regards,
-- Al

Kisawyer 04-06-13
I purchased a pair of Morrow MA-1 interconnects, burned them in 24/7 for 500 hours.

Kisawyer 04-08-13
I suspected the Morrows because once I installed them and heard how well they sounded I immediately knew what to listen for during my sessions. When the sound degraded, I suspected the cables. The cables have never been moved during this entire process.

If I understand correctly, you therefore burned them in 24/7 for 500 hours using one or more of the components in the system.

In addition to AC line conditions, tubes, and several of the other possible explanations that have been suggested, that seems to me to cast suspicion on whichever component or components were being operated for those 500 hours. Especially if the component(s) that were operated for those 500 hours are of comparable age to those that are listed in your system description.

Personally, I see no reason to suspect the cables, and lots of reasons to suspect many other things.

Regards,
-- Al

The other smaller tubes in both the power amp and preamp have more hours on them but according to ARC, need only to be changed after two cycle changes of the output tubes. That is, about 4,000 hours.

Keep in mind that any electronic or mechanical component, be it a tube, a capacitor, a CD transport mechanism, or anything else, can develop a problem (intermittent or otherwise) at any time. While admittedly that stands a greater chance of occurring at times that are either early or late in the life of the part or component, compared to in between, the multitude of possible explanations that have been suggested should be weighed against the likelihood that the sonic effects of an interconnect cable would fluctuate to the extent you have described, after 500 hours. I'll add, btw, that I've had brand new small signal tubes abruptly fail after as little as 2 hours.

Given that you used the CD player for burn-in, yet another possibility, in addition to those suggested in the posts above, would be dirt accumulation affecting its optical mechanisms, and/or wear and tear on its optical or mechanical mechanisms. Either of those possibilities could conceivably affect electrical noise conditions in the player, jitter, or the need to utilize interpolation to correct read errors. Perhaps intermittently.

Interesting input from Stringreen. As someone having significant experience with radar equipment, and although most radars transmit at frequencies well into the gigahertz region, I wouldn't rule out the possibility.

In any event, good luck with the investigation.

Regards,
-- Al