[quote name='ambient' timestamp='1371933213' post='2119874']
I gotta say, I thought a jack was a jack was a jack .
[/quote]
Nah, that'd be easy and make perfect sense and we certainly can't be having with that.
What generally happens with some of these posh leads is they have a different shaped tip which pushes the socket 'tip' connector back further than it should.
It's great to begin with - it makes a really firm connection against the tip connector.
However, that excessive back and forth motion you get, when you insert and remove the jack plug, eventually weakens the springiness and it can then lose contact with the tip of the plug - especially if you decide to change to a different type of lead with a differently shaped tip.
On the open 'skeleton' type sockets you can tease the spring back into place with a pair of long nose pliers, but if your bass has a sealed barrel type jack socket then it's pretty much a write off straight away.