no sound undulator

I believe the issue came from putting the H9 into the effects loop of my amp AND having the volume very low.   I’ve duplicated the symptoms with three different H9s using the same amp, cables and setup.   The symptoms are: most (if not all) other effects such as chorus, flange and delay work fine – but when you switch to the Undulator algorithm that effect isn’t triggering (there is sound, but no Undulator effect) and when you turn the intensity up to 99 there is no sound.  Fixing the issue (for my amp) is to turn up the volume of my amp enough to trigger the Undulator algorithm – then, the Undulator effect works as expected.  

I’ve got a weird issue with my H9.  Other effects work as expected – but my Undulator effect just does not work.  I hear sound with the effect on – but the undulator sound doesn’t come through and if I set the intensity to 99 then all sound is turn off.    Any idea what could be the issue?

Have you tried reinstalling the software and doing a factory reset?

Not sure how to reinstall the software.   The same issue seems to occur with two H9s and it’s only the undulator algorithm that has the issue.  Weird.   I’ve used the undulator algorithm a lot in the past. Not sure why it would suddenly go away – on two H9 pedals.  I thought maybe there was some general setting that was wrong – but, I’m not really sure.