2008 TSX w/navi:

I have everything installed and sounding pretty good. I'm running Mercman's harness to a JL 450/4v2 amp and JL C5 components up front. Nothing in the rear doors and nothing in the rear deck. Uncald4's enclosure with a JL 10W3v3in it.

I'm using the method explained in the amp owners manual to set the gains with an AC voltmeter and having a 1 kHz sine wave tone playing. According to the guide in the manual I should reach 17.3 volts for the front components, but I just can get past 11 volts. It doesn't matter if I swith back and forth between high and low input voltage. Do you know why this might happen? It worked perfectly fine for channels one and 2 which are bridged for the sub. I can't figure it out. Any advice?

 

This is normal.
The JLs use a sensing circuit that adjusts the power supply rail voltage to match the lowest impendence the amp will see. The bridged channels will see the lowest (I assume 2 ohm for the sub) and the fronts see 4 ohm. The amp sets up for the 2 ohm so that you get max power with minimum distortion into that load. This will result is less power to the fronts. The other thing is bridged set up doubles the power out the rears so that also reduces the power to the front because the power supply is producing more current and less voltage swing because of the 2 ohm load. If you followed the JL procedure for the setup you will achieve the lowest distortion.

Basically you will get twice the voltage on the bridged channels as you will on the Stereo channels. This is normal for any amp but the JLs power supply adds a little more bias to the low impedance channel, this not only protects your ears but the amp as well.

Set the voltages in the sub-optimum configs for your speaker impedances and don’t worry.

jeff

 

Thanks for the reply. Channels 1 and 2 are bridged for the sub. Bridged, it's 300 watts x 1 and 3-8 ohm. The sub is a 4 ohm sub. Channels 3 and 4 are for the front. They are 75 watts each and 1.5-4 ohm. They are 4 ohm components.

So you're saying for the fronts I should just get it as close to the 11 volts that I can and forget about the 17.3 that the manual recommends? The only thing is that I don't see 11 until the gains are turned all the way up. I don't think that's very safe is it?

 

Anyone? Now I also have a new problem. When listening at around volume 18, the nav screen starts getting all crazy. Blurry horizontal lines start going across the screen. What could this be?