The best way to troubleshoot these kinds of issues is to simplyfy the signal chain. It sounds like you are getting input to your Eventide, so the next step would be to see if you are getting output. I presume that you are taking two mono outputs out of the Eventide. Start bu running those outputs into your two amps and verify that you are getting sound at each. If you are not, then we need to look at how the Eventide is set up. If you are getting sound, then it is something else in your signal chain (after the Eventide) that is the problem.