Yes well I have done that.
Even though my Marshalls went long ago I can slave my Nano 1/2 watt through my huge 5 watt load resistor into a H&H keyboard amp that I picked up.
I'm going to put a clip up of the Echoplex in front of the amp because there are people posting about unnatural noise levels when the Echoplex is in front of the amp which to me means that their gear is not 100% or how they are setting it up is not 100%.
I've just got to set up my recording stuff which I currently don't have set up and track down mp3 convertors and whatnot which I don't use.
I used to use a stereo Ibanez CS9 chorus (which I sold long ago) back in the 80s when chorus was big and I just recently bought an original Ibanez CS9 chorus from the 80s and it's way noisier than the Echoplex and I used to use the Ibanez Chorus in front of the amp with a TS9 Tubescreamer as well and there were no problems with noise.
Another reason for the Echoplex in front of the amp is the very high impedance that the guitar signal hits which can influence the guitar volume turn down muddiness syndrome.
Ed is just about always able to turn down the volume and be very clear even on the 1976/77 boots where he's using different pickups so it points to not really being a pickup or volume pot thing but something else.
If there is a high impedance FET buffering the guitar signal before the amp then this buffers what's coming from the guitars volume pot (through other effects bypassed or not) and if the FET is after the first amp then this effect just doesn't happen in the same sort of way as the FET is then buffering the first amps output.
Black signal lead in black and white footswitch lead in blue.