Hi Rograt,
What do you mean ‘moved effects in from or after the amp’s preamp using Loop 7 and 8’?
You can move any loop on the ES-8 into any position relative to the amps FX loop, which I presume is using the ES-8 volume loop. For example you can have loop 8 right at the start of the chain this:
7-6-5-4-V-3-2-1-8
In this example 8 is first and loops 4,5,6 and 7 are in the amp FX loop.
If we talk about the H90 in this above example, and if you used it in dual mode using ES-8 loops 7 and 8, you could have a pitch effect first and a delay or reverb last. It’s easy.