Sagging power cable at IEC outlet - any remedies?

I can suggest that you take the portion of the IEC male plug that goes into the IEC socket on you amp and wrap it with a couple of layers of electrical tape. It's not the prettiest fix, but it works.

In addition if you take an actualy roll of electrical tape, and turn it in its side , it can provide additional support, you may have to peel off some of the tape to get a good fit, and you just want a little support , not anything that will have too much pressure. I use both methods simultaneously.

Soliver, this is becoming a common problem due to some of these ridiculous, non-flexible cables hitting the market. You may find Velcro to help. A piece of "hook" attached on the BOTTOM of the component, directly BELOW the connector, with another piece of "hook" on the REAR of the component directly ABOVE the connector will provide two points of attachment for the use of two "loop" straps. These straps would be located at a point where they would be maintaining pressure along the back of the connector (one on each side of the cable), also retaining the connector in the socket.

Also, the "loop" material is very soft and won't scratch anything when applying/removing. Most Home Depot stores or the like, sell Velcro kits with a spool of hook and loop 1/2' wide. It is perfect for this application. Adhesion will always be enhanced with a thorough alcohol cleaning before applying the hook.

Hope this helps, Ed