H90 output both stereo and mono?

No, this is not possible. If you only connect out of Output 1 the H90 automatically functions in mono, even if you were to use the stereo insert last in the chain.

If you will not be combining two algorithms per program, the workaround is using Dual Routing Mode and spitting your signal before the H90. Feed one to Path 1 (mono) and the other to Path 2 (stereo). Use the same algorithm for both.

Having the H90 function in mono naturally by only connecting Output 1 is always better than having an outboard device sum for you. The algorithms are designed to adjust for optimal performance when appropriate connections are made, and they have no way of detecting an external sum mixer. That said, in most cases, you will be okay summing externally, as in the case when your running a stereo rig but you can only connect in mono for a show or something. I’ve done it. Nonetheless, ask the pro rig builders and 100% of the time they will tell you, connect things in mono if that’s what you want, don’t sum externally.

Are you referring to a summing mixer that sums a stereo signal down to mono? There are plenty of boxes from Goodwood Audio (Output TX), JHS (Summing Amp), and Walrus Audio (Canvas).

So I just got my h90 and I’m running it stereo at the end of my pedal chain. I have the strymon Bigsky going in stereo into the H90 and stereo out the H90 into my Interface. For some reason I’m getting a wet signal on my left side but a very dry signal on my right, even while the H90 is bypassed. Am I doing something wrong??

Yes it’s only when I plug in my h90. I’ve Already plugged in with just the pedal itself and it works just fine and I am connecting my inputs and outputs 1 and 2 correctly as well. The weird thing is that my input and output 2 are getting signal but there’s very little sound coming through. I also tried the Dual routing mode and still no help.