Interconnects Roller Coaster Ride

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

KiSAWYER.....are you near an airport/military base??.... I had a similar problem that I traced to radar interference....... I moved, you probably can't.

Thanks to all for your responses.

As I mentioned, the output tubes in the power amp have about 200 hours on them. I am able to check the bias often, and keep them within specifications. 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.

I'll look into the line voltage issue and see if I can check that out with the volt meter as suggested.

The same components were used during both the burn in and listening sessions. The burn in was through my CD player to the preamp (which was turned off), as recommended by Morrow. I simply reconnected the CD player into the system for the actual listening sessions.

I do live near an Air Force Base. Not K.I. Sawyer in Michigan, but Luke AFB in Arizona.

Thanks to all for the great suggestions. I'll keep everyone informed on further listening and what I ultimately find out.

Has anyone experienced this continued roller coster ride in good-to-poor sound from the Morrows?

FWIW, I have used both MA-1's and MA-3's from Morrow and I have not noticed the effect you are describing. Anything is possible, but I think variations in line voltage is a much better hypothesis, and easily tested.

Bryon

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