DIY patch cables; treble loss

[pb3000]

So I bought some wire and plugs to make my own effects box patch cables.  Canare g6, neutrik right angle plugs.  Should be decent stuff, right?

My first attempt is very depressing.  The 5" patch cable obviously kills treble from the signal, unlike my other POS $1 patch cables and cheap 10' instrument cables.

I cannot imagine what I did wrong as the soldering work is pretty simple and I make complicated effects boxes all the time...not a beginner to this type of thing.

I have isolated the problem to the patch cable and nothing else - even plugging the guitar directly into amp with it gives the same, dull sound.

Where could I have gone wrong?  Thanks for any help.