I have an ALPINE deck that gets fairly warm when I play it for an extended period of time. Now I understand they generate heat because they are putting out watts to the internal speakers. However, I have my internals running off of an amp, as well as my subs, so the only out put from my HU are RCA signals, and as I understand it RCA outputs put out a very low amount of volts/current. Should this still cause the HU to get hot??? I have never had any problems but a buddy of mine's HU does not get nearly as warm and he has a similiar setup. Anybody else runnig dual RCA outs with an ALPINE and having it get warm let me know.
There might be a way to turn off the internal amplifier so it can run cooler.
Also, keep in mind the heatsink in your buddy's car might get better cooling because there is better circulation around his unit due to differences in cars...