Peavey TubeFex Operation Manual page 13

4. Using the Tube Fex in the effects loop of a separate preamp.
In this case, the Tube Fex is used as an outboard effects processor of your preamplifier. To hook up:
preamp, respectively.
Note: For mono operation use only the Left/Mono jacks in the steps above.
To Signal Input of preamp
To Loop Return
From Loop Send
Tube Fex
From Audio Output
.
Chapter 7 Setup