I read some posts about setting the gain in an amplifier.
the gain on my older eclipse 3321 (OLD US MADE MODEL) ranges from .1 to 2V, I'm feeding it a signal from a CD5444 that has 5 volt pre-outs.
The amp gets louder as I turn the gain away from 2V towards the .1V mark. I'm not sure hwo to set it correctly, but was thinking about using the Multimeter Voltage Method?
If it's too much (wherever the gain is set) you could get a dual-ganged potentiometer and splice that directly into the RCA wire to turn the voltage down coming from the headunit.
For now, you'll probably have it more towards the 2V to keep it from clipping...