Just popped in to agree with the Mike27Oct = you should NEVER connect anything but a magnetic cartridge turntable to the "Phono" input of a Hi-Fi amp. Doing so can easily lead to damaging either the Phono circuit, or your speakers when the Echo suddenly (for whatever reason) starts to work as it should.
I take it you have tried increasing the volume setting on the Echo whilst it was connected to the "Aux" or "CD" inputs of your amp?
There is something not right as those ^^^ inputs should work just fine.
Maybe a faulty lead?
Try connecting a pair of ordinary wired headphones to the output socket of the Echo, you may have to ask the Echo to turn up the volume. This does work, I just tested it. If you can hear the sound OK through the headphones then it for sure should work on the Aux & CD inputs on the amp.
Let us know how you get on.
John