Left Channel Blues

Mea culpa . . rip, Kent Maze.  He always took the time to speak with me on any question regarding his products.  A very nice man. 

If you have another set of speakers (alternate pair), hook up

those speakers and if you hear the sound you can eliminate a speaker (main pair) problem.

This is a tube amp.  You should always suspect a bad tube first when the gremlins visit.  Lots of options for swapping components.

I'd probably just swap left and right channel tubes.

If the problem moves, then it is a tube.  I'd then swap tubes back one tube at a time...until I identified the bad tube.  

Or just do some swapping out with new tubes.

Jerry

Swap the speaker cables on back of amp, so left is now right etc. If the issue now occurs on the right channel then you know it is the amp and not the speakers, of don't forget to swap cables back. Then swap the left an right valves over on the amp etc.

You just have to go through the process of finding the criminal. This does sound like an electronics issue and tubes will do this sort of thing. Next time it goes out tap the tubes lightly with a screwdriver.

I had a similar problem not long ago. No matter what I switched around the left channel was weak. I thought something in the crossover had gone south. I eventually used my phone to measure the speaker outputs, and BAM, they were exactly the same! Turned out my left hearing aid was malfunctioning.

Sounds like you have a broken connection in your Mac.  When it gets warm a connection expands and separates.

Call Mac.

Gotta be the amp.  Vanishingly unlikely you have an intermittent cable connection.

Thank you all for your responses !

And, MarkMuse, May I never be there !

As an retired electronics repair tech, iso the problem one step at a time. Starting at the far end of the chain and working backwards. Speaker, speaker connection, speaker wire, termination at the amp and so on. Always keep in mind that just the act of handling these links in the chain can cause the problem to disappear, therefore the isolation must be verified at least twice. Guessing or assuming is not allowed. Any link in the chain can go belly-up at any time. This is one of the more perplexing and time consuming troubles to pinpoint. Guessing and checking one thing here then one thing there is a time waster. Regards    AB

Follow-Up

Left channel lost volume and got crackly after 2 hours of CD playing again . . . hadn’t done that for at least 4 months  

This time, DUH, I switched to Unbal 2 input and listened to Spotify through my Mc MB50 streamer and No problems. 

So, unplugged both ends of my AQ 1m interconnect and cleaned and dusted it and replugged it . . problem appears solved. 

Also (mind games) but left channel seems louder and cleaner now?

Would not have thought that leaving this ic plugged in for nearly 4 years could cause this problem.  And why only left channel?

Anyway, will update if problem returns again. Wtf, over !