Can someone please explain to me how to use the Looper Preset as an actual looper? Or, can it be? If not, what is it for?
The name of this preset has nothing to do with its funcionality. It's simply 4000 ms delay.
If you want to use a real looper buy Xsonic ULooper. As far as I know this is the only looper suitable for modelling amps without effect loop interface (send/return).
