Stereo & Electronics - Line Driver / Pre-Amp

Here is the issue:
I directly connected my Pioneer GEX-FM903XM to my Monsson headunit a while back. Using a CD Changer adapter and a IP-Bus adapter.

Here is how I did that for more info:
http://www.ls1tech.com/forums/showthread.php?t=194183

Well, the sound output is a bit low (softer/flatter than CD or FM, not dramatic or unbearable but noticeable). I was wondering if I can use a Line Driver / Pre-Amp to increase the gain (boost the output of the RCA OUTPUT).

This is what I bought from BestBuy's installation bay:
Install Edge IECALD Adjustable Line Driver "Pre-Amp"
http://www.installedge.com/products/product_details.jsp?productID=1113

I cant get it to work. It didnt come with any instructions and the website is no help either. It has a red wire and a black wire. I connected the red wire (it has a fuse) to the same switched 12v source as the XM receiver and connected the black wire to the same ground as the XM receiver. This causes the XM receiver to turn off and stay off while the Line Driver is connected to power. If I disconnect the Line Driver from power (disconnect either red or black wire), the XM unit turns on (this true regardless of RCA connection/orientation). The Line Driver / Pre-Amp also isnt labeled as to which side is IN/OUT. I tried connecting the RCAs to it without power and no sound travels through it no matter which way it is connected (which I figured would be the case). The funny thing is that the XM receiver's switched and constant 12V leads come from the back of the Monsoon headunit and it is not affected by any of this.

I have a basic knowledge of car audio and electrical engineering and figured this Line Driver / Pre-Amp would be an easy install. I was wrong. Any help would be appreciated.

A line out Amp SOULD be an easy install. It's weird that the ground is causing a problem. Try switch it to a different spot.

It looks like there are some POTS on it. try turning them all the way down. Might be over amplifying the signal. Threashhold exceeded might shut down the circuit to prevent damage.

At this point I'm thinking it might be a bad convertor. With the Phoenix Gold Line out Amps, I believe I saw it pass-through, but the Fosgate might Isolate the signal within the Transistor stage to limit noise. Coil to Coil to isolate noise more.

I tried turning the dual adjustment screws but nothing changed. My roomate suggested that I may be drawing to much power through that circuit. I am going to try connecting it in another place tomorrow to see if there is any difference. I am thinking that it may be defective.

I don't think it is drawing too much current. It is only a voltage configuration for the Transistors. You are only talking 1-4 volts input to 4-8 volts output. Only a 9 dB gain tranistor circuit. (max. 1 volt input 8 volts output. 9 dB) Current is very light Maybe something like 100-200 mA.


I'm starting to think bad box more than anything else. Why would the Pioneer XM box work with the ground you are using, but shut off when the convertor is hooked up? Sounds defective.

Thinking more about it. Disconnect it from under the Dash. Might blow out the Ground strap Fusable link on the pioneer board. It's causing the pioneer to shut down. Might be a defective circuit causing Power to go straight to ground causing both units to shut off

Hook it up by the battery. Hook only the +12v side up. Test for voltage comming out on the ground lead.

Also You said Engineering. Do you have a degree or just basic understanding. I typed all this out thinking you are an Engineer. I need to know if this is too advanced or right up your alley.

I have a degree in Computer Science and took some clases in engineering....you are not going over my head. I'll test the unit like you said but I wont get to it until tomorrow though.

Since I had trouble with the Line Driver, I removed it from the car. Its sitting on my desk now. It was only connected during testing.

The first thing I thought was that it might be shorting out, but the Pioneer gets its power from behind the headunit, therefore, shouldnt the headunit be affected as well?

Was it Grounded in the same spot as the radio? Also if it is hooked up to the ACC wire for the radio current can be ruled out because it should have popped the fuse.

The ground might be too weak. How is it all/was hooked up? I'll read your post but just incase I don't see it.

I tapped directly into the 12V Switched and Ground wires going to the XM Receiver.

I tapped directly into the 12V Switched and Ground wires going to the XM Receiver.

And you got the Power and Ground off the Radio Harness for the XM Receiver?

And you got the Power and Ground off the Radio Harness for the XM Receiver?

The Constant and Switched 12V come from the wiring harness behind the radio and the Ground is connected to the power antenna bolt (same place the power antenna is grounded).

The XM receiver and antenna are mounted in the rear.

Everything sounds right. It looks like it's the line-out driver.

I think thats what it is too. Thanks for the help. I'll try another one.

Sounds like a safe bet. If The Best Buy guy's in back have a clue, they will test it out for you.

I went to BestBuy and asked them to test it and give me a new one if it was deffective. They didn't know how to test it and just gave me a new one. This one cam with instructions. The Red wire goes to a Constant 12V and the black wire is only connected to ground if there is no sound output, otherwise leave the black wire disconnected. I connected it as per the instructions and it works. The sound is not as flat as it was before, but the clarity didn't increase (I wasnt sure if it would). I have it adjusted to about the middle of the range. Any more is too much and any less is too little.

I did some testing. If I connect it to the switched 12 and connect the RCA or ground the Black wire, the XM turns off. Now that I have it connected properly, I now see why the other one did not work. It possible that it was not deffective, but I have a new one now anyway.

Thanks for the help.

I went to BestBuy and asked them to test it and give me a new one if it was deffective. They didn't know how to test it and just gave me a new one. This one cam with instructions. The Red wire goes to a Constant 12V and the black wire is only connected to ground if there is no sound output, otherwise leave the black wire disconnected. I connected it as per the instructions and it works. The sound is not as flat as it was before, but the clarity didn't increase (I wasnt sure if it would). I have it adjusted to about the middle of the range. Any more is too much and any less is too little.

I did some testing. If I connect it to the switched 12 and connect the RCA or ground the Black wire, the XM turns off. Now that I have it connected properly, I now see why the other one did not work. It possible that it was not deffective, but I have a new one now anyway.

Thanks for the help.

That is wierd. I need to figure out what that Black wire does???