New stereo/ Univolt ?

[treeair]

Got the new car stereo today. Sony single cd, tuner, w/ a front aux port. Put the speakers in Sun. Decided to go adjacent to the control panel instead of below. Used the spreaker covers that came w/ but hope to find something that blends in better. So, took stereo and elec tools out to the trailer and hooked up some temp connections to see whats what. I had pulled the control panel and seperated the original wiring harness. After looking at the wiring diagram, located the 12v + and - leads. Clipped my alligator clips to corresponding wires. Buzzzz was all I got. No lights or any sign of life from the stereo unit. Remembered I had the univolt plugged in and after unplugging shore power and reattaching wires she fired right up. Sounds great! but what gives w/ the 12v when attaced to shore power? Should I pull power off a different lead? We always boondock but would like to understand whats going on bfore making permanant connections. Also, was going to put another 12v outlet in line w/ the acc wire to charge the ipod or whatever. Any insight would be appreciated.

[68 Overlander]

Old Univolts do not have filtered DC output. You will always need to have a battery in the system to filter the dirty DC output of the old univolts.

[shermybaby]

You may be able to add a capacitor to your stereo to filter the dirty dc output of the univolt. Talk to you local stereo shop about the capacitor size best for the stereo you have. I should think if it is just the stereo and two speakers that a small one should do fine.

[treeair]

Bought a 35amp, 1000microfarad capacitor on the advice of a car stereo tech. Installed pre stereo w/ one leed to + and one to -(series ?). No effect w/ same buzzing of head unit itself. For kicks, tried putting capacitor in line w/ + leed pre stereo (parallel ?) and it fired right up for a few minutes until capacitor went pop and fluid discharged. Fun science in the streamer. Glad I'm wearing safety goggles. Seriously, any of you EE's want to give a rudimentory lesson hear it would be greatly appreciated.

[vswingfield]

Just another reason to get rid of the Univolt and go with a modern converter. In addition to taking better care of the batteries, they have a clean 12 volt output.