the effect loop normally is after the preamp. It sends a signal only to the power section of the amp avoiding any unwanted gain and colorations. The one pictured i would asssume by the controls is a parallel loop allowing control of the send and return signals. This lets you mix how much of the loop signal is mixed with the original signal being sent through the amp. This is sending a preamped signal out to your loop through whatever device in the loop and back to the power section of the amp while at the same time sending the original non processed signal through amp.
A normal set up is Guitar > wah> input of amp> loop send > effects(processor)>loop return.
VGB
A normal set up is Guitar > wah> input of amp> loop send > effects(processor)>loop return.
VGB
