Not the best amp for cranking tunes

Being a Kenwood fan, I bought this 4 channel amp brand new and dirt cheap off eBay. I soon realized that it would cut out when I got into the volume. There is no fan or heat sink in it, so it goes into thermal protect mode after a few minutes at high volume. If you keep the volume below medium high levels, it works fine. My volume level goes to 35. If I keep it below 29, it sounds great. Needless to say, I was very disappointed when I would try to crank AC/DC, Metallica, or other hard rock CD's. I replaced it with a Kenwood Excelon KAC-X541 4 channel amp and I couldn't be happier. In my opinion, I'd stick with the top of the line Excelon equipment, if you want the REAL quality from Kenwood.