Back in 2010, i have a pioneer car stereo model; 6950 with HPF and LPF (for sub output with different cut off frequency, ganda kaya ng sub pag dito kumuha ng signal, ang lalim at ang ganda ng drive) then fed to a car power amplifier (made in japan, sa Pier nabili), I used a computer power supply 12v dc( a bit noisy). As they say, not as clean sounding as compared to a hi fi gear and messy to look at the wiring. Everytime I Plug and turn on the power, I always set the desired equalization , loudness, etc., Then after less than a year, I change my system to a home hifi gear bought also in Pier (Manila), made in japan amplifier. This is my short little story about using a car amp as pre amp..