Motorola Car Kit Audio problem

I'm hoping one of you has a solution for problem I'm having trying to use a Motorola car kit audio output through my stereo system.

I've got the Motorola hands-free car kit ("brain" is SYN9760A), an Alpine 9855 head-unit, and an Alpine KCA-410 adapter. (Amps, etc seem irrelevant for the problem, so I'll exclude that.) The speaker output for the Motorola car kit connects to the line input on the KCA-410 via a custom "splitter" cable to allow the cell audio through the system. Everything works just fine at low system volume (1/4 or less), but at higher volume an odd thing happens: the car kit fails--as in smokes!

The first time it happened I didn't realize what was going on. I was driving with the windows open so the volume was up so I could hear. After a few minutes the audio started breaking down with pops and crackles, then the left channel cut out. Then I smelled the burning components. I pulled over immediately, panicked I was in for a big problem. Turns out it was just the car kit, and no big worries.

I realize the problem is likely/probably the splitter cable, but it doesn't make sense to me. If it failed all the time it'd be one thing, but the fact that it only fails at higher volume is the part I'm not getting. The output from the car kit is fixed--I am not adjusting the phone volume--and the input on the KCA-410 is adjustable but fixed. Unless the KCA-410 is varying it's input draw as the volume increases I can't see a volume-related variation. Maybe it does?

So, has anyone ever seen this, and, more importantly, does anyone have a suggested resolution that still allows me to have the cell audio through the system?

Thanks in advance!

~ Tony

hi,

does the "custom spilitter cable" isolate the speaker output electrically from the Alpine piece's input...... i.e. transformer-coupled input.  couldn't tell you why the car kit piece burns up as system volume is increased though...try a different source (dvd player/ walkman) on the aux-in to see if weird audio problems occur.  seems strange for a device connected as an input to fail as output is increased.  just extra input for you.

mark