Is +14V OK as remote turn on for amp requiring +12V?
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From: San Antonio
Is +14V OK as remote turn on for amp requiring +12V?
Well, I've had a few setbacks w/ my plan for adding an amp and speakers to my stock head unit. First of all, the JL Audio 300/4 amp I bought doesn't have a signal-sensing turn-on, like their monoblock amps do. So, now I have to run a remote turn-on lead from the fuse box, which will turn the amp on, whether or not the HU is on.
I've been thinking about another option, though. In looking through my S2K service manual, I saw that there's a wire that powers the antenna amplifier from the HU. This wire goes all the way to the antenna, which is already in the amp's neighborhood, i.e., the trunk. Having been told by a couple of people that the antenna amp wire would only be powered when the radio was on (not w/ the CD player), I figured that it wouldn't work too well as an amp turn-on source. But, I decided to test it anyway. And from what I can tell w/ my multimeter, the antenna amp wire sends +14V whenever the HU is on, regardless of which source is selected. So, can I just splice it (it turns into pretty thick wire right after leaving the HU), and send that voltage to my amp's turn-on terminal? Is +14V too much for an amp that, according to it's manual, "uses a conventional +12V remote turn-on lead"?
thanks,
gil
I've been thinking about another option, though. In looking through my S2K service manual, I saw that there's a wire that powers the antenna amplifier from the HU. This wire goes all the way to the antenna, which is already in the amp's neighborhood, i.e., the trunk. Having been told by a couple of people that the antenna amp wire would only be powered when the radio was on (not w/ the CD player), I figured that it wouldn't work too well as an amp turn-on source. But, I decided to test it anyway. And from what I can tell w/ my multimeter, the antenna amp wire sends +14V whenever the HU is on, regardless of which source is selected. So, can I just splice it (it turns into pretty thick wire right after leaving the HU), and send that voltage to my amp's turn-on terminal? Is +14V too much for an amp that, according to it's manual, "uses a conventional +12V remote turn-on lead"?
thanks,
gil
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From: middletown ohio
As a pro installer with 9 years under my belt I can tell you that 14 volts for the remote turn on line is no problem at all. One problem that you might have though is when you switch to the cd player the power amp on the ant. might shut off and thus your 300/4 also.
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From: San Antonio
Thanks, bobby. Regarding the shut-off when switching to the CD player, that's what I tested for. From what I can tell, the 14V was present anytime the HU was on... even w/ CD selected. When I turned the HU off, the 14V disappeared.
gil
gil
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From: Sydney
Most headunits have two switching lines, one for amp (on with headunit) and one for ant (on with radio). If your HU powers the ant whenever it is powered that is great.
The voltage it supplies is not regulated. It is the voltage of the battery. A good healthy car battery will have 14-15V across the terminals when running and that is what you are measuring. Products designed for 12V automotive use are fine with these sort of voltages.
The voltage it supplies is not regulated. It is the voltage of the battery. A good healthy car battery will have 14-15V across the terminals when running and that is what you are measuring. Products designed for 12V automotive use are fine with these sort of voltages.
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