DIY patch cables - loss of volume

I recently shortened a couple of my patch cables, which have pancake connectors.

After re-soldering etc. both of them seem to be making my volume drop quite a bit.

Any idea what could be causing this?

Cheers

Alex

Have you got a multimeter to measure the resistance plug to plug,ground to ground and plug to ground on the cables?On the first two cases the meter should show zero ohm and on the third case infinity .Have you doublechecked your soldering joints? Bad solder joints are still the most common source of trouble.

if there is a bad (or non existent) ground connection between the cable and either or both of the plugs, could that cause these issues?

The cable has a shield which should be connected to the sleeve of the plug on both sides.
The cable also have a center conductor which is insulated from the outer shielded wire.That conductor should be connected to the tip of the cable at both ends.So,the sleeves of the plugs should be connected to each other (zero ohm) and the tips of the plugs should also be connected to each other(zero ohm).There should be absolutely no contact from any sleeve to any tip (infinite ohm).