measuring voltage in RCAs

[mattj 5,000+ posts]

Im trying to test the RCA Preout voltage in my car with a voltmeter and im not sure how to do it. Ive put pos in the RCA preout of my deck and grounded the neg and tried putting pos and neg in each R and L input. Im not sure if my deck is all ****ed up (alpine cda-7894) or something. but how do i measure voltage from it?

Click to read more...

 

[maylar 10+ year member]

You'll need a test CD that gives a sine wave at 0dB reference. Measuring with music ain't gonna tell you anything useful without a 'scope. The Autosound 2000 Disk 4 is good for that, it has a 1000 Hz tone. You could also use the Bass Mekanik CD on one of the 30-99 Hz tracks. Your HU should be set to flat response.

Put your DVM on AC volts and connect it to one of the RCA jacks. One meter lead in the hole, the other on the outer ring. Turn your HU up to about 3/4 volume and take a reading.