Left channel fading in and out

What Almarg said.
With reference to Zd's idea, I cannot imagine how "knocking" the cartridge out of alignment could produce the phenomenon that you described, but you're going to find out whether the cartridge is the cause by swapping channels all the way up the chain.

Unfortunately, IME, when one has an intermittent problem such as this it typically fails to reveal itself when one is hunting for it. I have been trying to find out for 8 months what is wrong with my Sony CDP. It malfunctions in my house but not on Bill Thalmann's workbench, except for a brief moment which allowed us to confirm that I am not imagining things.

Lewm,

"I cannot imagine how "knocking" the cartridge out of alignment could produce the phenomenon that you described."

It can easily do that. The groove in a record is shaped like a V. The info for the right and left channels are on each side of the wall. If the cart is not aligned properly, it may not be fully able to touch both walls the amount it needs to produce full resolution, causing an intermittent problem. I also said "or something similar". Things like not having enough tracking force, anti skating and SRA, can also contribute as well. If the problem is alignment related, it can very well be a combination of the above. Or, like you say, it may be something else entirely.

As far as your CD player goes, that seems like an interesting problem, as well. I think you need to find out what is different about Bill Thalmann's workbench than your equipment rack. (I know that sounds like a smart ass remark, but its not.) There really may be some difference you are not aware of that is causing the problem. It could even be temperature related. Just by taking it out of your system for a while may let it cool long enough for to work.

Actusreus, everything Al said -- try. Got a funny feeling though you've got a weak or failing tube. Nevertheless, follow Al advice. Please let us know how your detective work fares.

Good luck.

Thank you all for good advice.

Can anything be eliminated as a potential culprit? I was going to ask whether tubes could be crossed off the list, but just saw Bifwynne's post...I was also going to suggest the speaker since I'd think any damage would be fairly obvious, not as subtle.

I will recheck the cartridge alignment. I actually checked the VTF that very same night before I started hearing the problem, and it was as intended. I probably have about 1000 hrs on my Delos.

Actsreus, I still think whatever Al says is good advice. But try this short cut. Switch speaker cables left/right. See if the fading problems moves. If not, in some goofy way I do not understand, it could be the speakers. If yes, moving downstream, check the bias of the power tubes on your amp. Btw, how many hours on the tubes? If your pushing to the outer edge of the envelope on tube life span, I'd be looking to retube regardless. After these quick checks, back to what the folks above said.

Any problems I've had with my gear -- which have been few -- were tube related.