With the 4-cable method, a multi-effects device is connected to a guitar amplifier with a total of 4 cables. The prerequisite is that both the amplifier and the multi-effects device have an effects loop (FX loop), which can be identified by jack sockets labeled " SEND " and " RETURN ".

With the 4-cable method, the guitar is connected to the input ( INPUT ) of the effects device ( cable 1 ). Here, the signal passes through so-called pre-effects, i.e. effects that are usually placed by the amplifier, such as compressor, overdrive/distortion or wah wah.

From there, the signal is output via the SEND socket of the effects device and sent via cable 2 to the guitar input of the amplifier ( INPUT ). It passes through the preamp of the amp and is tapped with cable 3 at the SEND of the amplifier to be fed back via the RETURN of the effects device.

The so-called loop effects (e.g. modulation effects, reverb, delay) are then run through in the effects device before the signal is sent via cable 4 from the OUTPUT of the multi-effects to the RETURN socket of the amp. From there, the amplifier's power stage is controlled.