Thanks for the info.
Using Insert routing, connecting to an amp in PRE POST is possible using one of the inserts. Connect the guitar to In 1 of the H90. From the Out 3, connect to the front of the amp. From the amp’s effects send, connect to In 3 on H90. From Out 1 of the H90, connect to the amp’s effects return. In this example, the aim is to have one effect in front and another in the loop. The signal goes into the pedal and into the first algorithm. Then, it travels out of the insert send to the front of the amp through its preamp section. After the preamp section, the signal travels back to H90 via the insert return and through the second algorithm. Finally, the pedal’s output gets returned to the amp through the effects return to be heard through the speaker. Because we are using an insert on H90 to route signal to the amp, we can position algorithms anywhere in the signal chain; we can have two effects in front on one Program, two effects in the effects loop, or one in front and one in the back. We can even introduce another outboard effect anywhere in the chain with the second H90 insert. The downside to using the global Insert routing mode is if we bypass the insert providing the connection to the front of the amp, we may lose the signal completely. Similarly, if we employ the second insert and the external effect goes down or gets disconnected, we can also lose the signal. It makes things more challenging to troubleshoot. For this reason, it may be best to use the global Dual routing mode for PRE POST connections.