Interconnects Roller Coaster Ride


I purchased a pair of Morrow MA-1 interconnects, burned them in 24/7 for 500 hours. At present, I'm at about 550 hours. Each night I now listened to my system for about three hours. For two straight nights, the sound is gorgeous with the Morrows. Then the third night things sound bad. This pattern has repeated itself twice now. My assumption was that once the interconnects have been fully burned in, they will stabilize and will always sound good. Has anyone experienced this continued roller coster ride in good-to-poor sound from the Morrows?
kisawyer
Zd542, sorry my omission of "does not" sure ruined what I was trying to say.
Sorry for the delay in answering, but I've been having technical problems with posting this response.

All excellent comments.

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. The Morrow MA-1 interconnects are well shielded, I believe.

Most of my listening is at night between 9:00 p.m. — 12:00 midnight.

The suggestion that perhaps with the Morrows, I am becoming aware of some other problem that was not revealed before is food for thought.

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?

My preamplifier and amplifier are tubes (Audio Research SP-1C, and Dual 75). They are quite old, but were up to specifications last time they were checked out by ARC. The output tubes in the amp are at 200 hours.

My speakers are KLH Nines (double Nines), so I think I hear pretty much what is being fed them. With the Morrows, the sound has opened up even more. That's why I'm so frustrated. Once you hear how good the cables make things sound, you want that all the time.

Additional comments welcomed. Thank you all. I’ll keep you updated.

Yes, it is K.I. Sawyer Air Force Base in the UP, Michigan!
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