Car Stereos: adding ampd sub to GM Delco rear speakers, line output converters, rca plugs

Question
Hi, since the sub amp expecpts (I think) more of a 'line out' than the voltage levels used to drive the rear 6x9", I', cooncerned that I need a pair of 'high-to-low (ie stepdown transformer before feeding the amp RCA input...
agree? or is it OK to drive that high a voltage into sub amp?? if need xformer, whats suggested? 10x step-down? any ideas as to where to find like radioShack
I'll try Crutchfield but yhey can get expensive for small part matching items like this..
thanx!
--George--

Answer
Hi George,

Some amplifiers include "high-level" inputs in addition to the normal RCA inputs.  If yours is so equipped, you can connect the high-level inputs directly to the factory speaker wiring, instead of using the line-level RCA plugs.  A few amplifiers (notably Kicker) allow you to connect speaker-level inputs directly to the RCA plugs.  Check your amplifier's owner's manual.

If you don't have the high-level inputs, then you'll need a device called a line-output converter.  Essentially, this is a step-down transformer set like you're thinking of (although some very cheap models just use resistors).  Line-output converters are extremely common in today's car audio industry, and you should be able to find one at any car audio store (or certainly at Radio Shack).  Most converters will include a built-in level adjustment dial, so you don't have to worry about the step-down ratio; just wire it up and adjust it as needed.

Hope this helps!

Brian