Goofybastard

would this solution work for a CD deck with 2 rca outputs instead of a PC. i want to add and amplifire with subs and i dont want to lose the wattage to the speakers by replacing the HU. if this isnt the solution for me does any one have any links/suggestions?

Bugbyte

Yes, this will work.

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Goofybastard

Thanks you made my day!

ducati321

I've wired everything as stated in the faq - everything works, except the turning off of the monsoon amp. (2001 golf).

When I disconnect the 12v power that goes into the 5v regulator, and shut the car off - the music continues to play. I have to disconnect the 2nd harness (the one I didn't muck with that goes into the monsoon) for the monsoon to cut off. I then have to reconnect the 2nd harness and apply the 12v power to the 5v regulator again to get it started up.

has this happened to anyone else?

Thanks folks!

qkslvr

Did you take the key out of the ignition after you turned the car off? I know in stock form the music won't turn off until the key is removed from the ignition.

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ducati321

Yes, I did remove the key. Music still goes... and even if I shut off the music, obviously, the amp remains on.

Lazyflip

I was wondering how a regular head unit turns on the monsoon amp. I currently have a head unit right now but the remote turn on isn't connected. Can someone explain?

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kb1gtt

I connected an isolated power supply to my left front speaker - and ground, then I found the amp turns on at +3V and off at -.5V. Current draw was less then 10ma. I suspect the -.5V may be caused by some voltage on the ground wires, perhaps increased as age increases resistance, ect. Any one experimented with a means of putting a slightly negative signal on the wire to make sure the amp turns off? The ground loop isolator may offer a means of doing that with an inductive spike.

2001 Jetta 1.8T AWW

kb1gtt

I guess I'll reply to myself. It appears that my problem is that when I turn off the radio, my radio goes from driving the speaker lines, to floating, rather then driving them to ground. When they float, some times, but not always, the lines end up at around 2-3V or higher. When this happens the Monsoon doesn't fully turn off. Causing a dead battery.

So my solution, which is under test now and has had good results so far, is to put a 1K ohm resistor between gnd and the left front - line. Here's the reasoning for using a 1K resistor. My radio claims 50W output for 4 speakers each with 4 ohms, or say 12.5 watts per speaker. I'll assume that's RMS not peak, even thought the real power is probably closer to 8-9 watts RMS. With P = V X I and I = V / R plus a little algebra we get P = V^2 / R or (P X R)^.5 = V = (12.5 X 4)^.5 = 7.07V. Resistors typically come in 1/8 watt or 1/4 watt so I'll choose look to drive it to ground with an 1/8th watt resistor. So we do V^2 / R = P --> R = V^2 / P = (7.07^2) / .125 = 39 ohms. But lets say it can do up to 12V we get (12 X 12) / .125 = 1152 or about 1K. So I chose 1K because you don't have to worry about the power rating of the resistor.

kbyrd

Did you read this thread? The OEM head unit applies 5V to the speaker signal, that acts as the amp on/off switch.

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kb1gtt

Well it's been about 2 weeks now and no dead battery. Appears to have worked.

ducati321

I've been reading this thread and working on my golf for the passed few months (very little time).

I have succesfully turned on the amp with my 5v injected into the audio system, but can not for the life of me turn it off.

if I leave the car running, and physically take off the positive wire running into the regulator - nothing happens. if I take out the key, nothing happens.

does anyone have an idea about this?

kb1gtt

Yes I've had the same problem. Ground the LF- line and the amp will turn off. I found a 1kohm resistor from LF- to GND works well as a permanent fix. The resistor won't affect your speaker level audio signal but will pull the line to 0V and turn the amp off when the radio doesn't drive the LF- hard enough.

Your problem is that some voltage is getting on the LF- line keeping it above about 3V. This can be caused by radio signals and long wires picking up the voltage out of the air, it can be caused by small amounts of leakage current from a number of electrical devices, or it can happen because it wasn't given a chance to go somewhere else. A meter is basically a resistor with a meter across it, so if you put a volt meter across LF- and GND, the meter will probably cause enough of a pull to ground to make the amp turn off.

It's now been several weeks, and we have had no problems with a dead battery.

ducati321

Thanks very much for this. this has helped extremely. I've been able to avoid having to put in the resistor, and the amp shuts off - albeit, with a 3 second delay. I believe it is as you said, a small amount of current left over from the other devices and is leaking back into the 12v+ line of the amp turn on wire. I don't care if the music plays for 3 seconds after I remove the key. The amp is turning off, and the delay is kind of cool actually.


Thanks for the reply,

regards, Jay

kb1gtt

I'd like to raise some caution about the 3 second thing. I had the same sequence when I originally installed my head unit. What I found is that once in a while, usually once a week, it would last longer then 3 seconds. When it lasted longer it generally didn't turn off until the battery was dead. At first we avoided a dead battery by pulling the fuse. The fuse how, ever is not intended to be a switch and can wear out. If it does wear out, what a bear that can be. In the end we needed the resistor to make for a consistent turn off, as well as a permanent fix.

Good luck.