Quote Originally Posted by msrance
But still do you feel - getting this one tested out - or getting a new one made from some local small time electronics repair chap will not be of any help for the time being - till i can get something better?
The way you describe it (flimsy and homemade) tells me that it's most likely at fault. It's difficult to do a good job soldering such connectors. A precision manufacturing facility will do a much better job, ensuring solid electrical connections, sturdy construction and adequate insulation. Rather than getting another "Y" cable, get one of these type connectors that F1 linked to:

This should last a lifetime and is virtually indestructible. Cables are much more vulnerable to damage (pinching, failure due to flexing, etc.), so if a "Y" cable fails, you have to search for another one. With the connector pictured above, a common RCA cable is the weak point, and they're relatively easy to find in a variety of lengths and quality.
Quote Originally Posted by msrance
did I paint too pessimistic a picture of myself?
Not at all. I trust that my little "normal people" and "medical school tools" comments were taken as just funning with you!

Incidentally, there's ONE test that you can make pretty easily. Just flip the RCA connectors going into your Yamaha (left/right). Instead of the left channel humming, I bet the right channel will hum. All that will prove is that the Yamaha is NOT at fault. The problem still could be with the "Y" cable or the adapter. Swapping the connections won't give a definitive answer over which is faulty, but it eliminates one possibility.