low-level output on stock system

[DouglasABaker]

Originally Posted by UKenGB

In which case the radio module could drive a third party amp without having to fool it into believing the OEM amp is connected.

There is still the issue regarding the output varying with volume depending on whether it's a DSP amp or other, but if this is true there's no need for any Speaker->LineOut converter. There would just be the DC bias to take care of. Not sure if that's better or not.

Could do with the experts offering their insight on this one.

There is no question that the factory radio unit will drive any aftermarket amplifier - it will do so with no issue. The only question in this case is whether or not the amplifier can handle the signal being provided to it. When there is no DSP amplifier attached to the factory radio it will provide a balanced +- 5V signal (note that this is the same as a 10V signal). This is a considerably higher voltage than most "low level" inputs are designed to accept, so you may need LOC's. If you amp also has "high level" or "speaker level" inputs, then you can just provide the signal directly to those instead of LOC's.

There is a question as to whether the factory radio module can drive a speaker load. I would say the answer is "Not for very long" since speaker impedance is so much lower than amplifier impedance (and therefore higher current which will fry the radio unit circuit). Having said that, I've never tried. And for clarity, I am referring specifically to the radio unit mounted in the trunk. You, apparently, have a headunit that drives speakers without an amp. By definition then, your headunit is capable of driving both amplifiers and speakers.

d-