Car Stereos: Headphone jack setup, headphone jack, rca plugs

Question
I have a 1993 BMW K110LT motorcycle with a factory stereo unit in it.  It has a 3.5mm headphone jack built into it.  I use a patch cable from it to go to my on board communication system.  The communication system then feeds the helmet speakers.  I am going to replace the factory stereo with an aftermarket CD/receiver that does not have a headphone jack.  Can I simply tap a jack into the speaker wires or do I have to do something else?

Answer
Hi Jeff,

Just about all after-market head units include line-level pre-amp outputs at the rear.  This would probably be a better choice for the connection to your motorcycle's communication system.  It will simply be a pair of RCA jacks rather than a headphone jack.

A typical headphone jack uses separate left and right audio conductors, with a common "ground" conductor.  A high-powered head unit's speaker outputs aren't compatible with this type of setup, but the low-level RCA pre-outs will match up perfectly.  Patch cables with RCA plugs at one end and a stereo 3.5mm mini plug on the other are very easy to find at any electronics store.

Hope this helps!

Brian