T-amp turns off after ten mins?

I have a Lepy LP2020A, it's turning off after ten minutes - is there anything non-obvious that could cause this? It's only doing it on a particular pair of Denons, has been fine on some Sony speakers for months. Both the speaker cables and the Denon speakers themselves have changed since it was used on the Sonys. Thank you!
 
Hi
can you look at your speakers label on the back side and tell us the specification what you can read. i guess the denons are with less impedance e.g. 4ohms and your sony were e.g. 8R. therefore the amp chip draw more current --> get hot.

chris