it's probably not a hose, the LP air is constant, so if you're turning up the HP then the hosing isn't under any more stress.
It's probably the cup seal on your valve.
If you know what you're doing, then just strip, clean and rebuild. If you don't then try the following.
1) Unscrew both HP and LP reg caps, clean the pistons and springs, relube and reassemble
2) take out the ram cap, clean the ram tube as well as you can with tissue or long handled cotton buds
3) holding the gun so the barrel is pointing at the floor, drop 5 or so drops of gun oil down the ram tube.
4) relube the ram and slide that in, then replace ramp cap and bolt - all while keeping the gun pointed at the floor.
5) Using the bolt (hold the bolt pin), push the ram down so it hits the valve and then open the valve by pushing the bolt. Do this several times. This allows the oil you put in to work past the valve and onto the cup seal side.
6) unscrew your regs and set them from scratch (you should do this every day anyway)
Once you've done that. Change the battery for good measure and check you haven't snaffled the dwell setting too.
