Orange amplifiers featured the first effects loop offered in an amplifier. They were designed for the effects of the day: stand-alone reverb units and tape echo delays. They do not work as well with modern effects. An effects loop is a means for inserting guitar effects into the signal path of the amplifier internally. Plug the send of your amplifier into the input of your effects using a guitar cable. Plug the output of your effects into to the return of the amplifier.