James Dee wrote:My logic, albeit probably flawed, tells me that if the amp can get a signal then the iRig should too.
Nope, I reckon your logic is on point. As long as you're also turning the gain up on the iRig Pro I/O then you should be seeing signal.
Have you tried pluging your guitar direct into the iRig Pro I/O? This would confirm that the interface is working and you could then work backwards.
If you have and it is still the case that you can't hear/see signal, in case no one else chimes in here with advice or a solution the best thing to do is check the FAQs, via
https://www.ikmultimedia.com/contact-su ... ck=QUICKHWIf these do not resolve the issue, there is a link to the Technical Support form, for direct help from Official IK Support. They endeavour to reply within 2 working days, but obviously considering the current situation things may take longer than usual.
And, to help others who run into a similar problem, please let us know what you did to resolve the issues, but without directly quoting any correspondence from official support.