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Discussion Starter #1
I'm not impressed with the output of my new amp (PDX-1.600) with my ID 8v3D4 sub that I have. I figured that I'd be turning the gain all the way down and still pushing it hard. I'm just not getting that kind of output.

I have it wired to 2 ohms so it should be getting oodles of power, but it's very weak. I have the gains turned up to almost 3/4 and I'm getting the same output or less than what I was getting when it was connected to two channels on my 4.100 @ 4 ohms.

I don't think the issue is at the sub, but I also had to change a few things when I added the second amp. For one, my HU only has one RCA output. So my RCA goes to the 1.600 first and then preamp outs to the 4.100. The only other thing is that the amp is very close to my ECU, but I'm not getting any noise really. I do hear a weird buzz when I first turn the key on, but then it stops completely when the HU starts up and plays music. I can put it on a silent track on my test disc and turn it up to 40 and get nothing...It is clean clean.

I am experiencing one other very strange thing. The 4.100 now seems to be turning on and off if the signal is low...Well, it doesn't turn off, it just seems like it is detecting a low signal and not outputing anything. Ok, let me give you an example. I turn eveything on, start playing a CD, volume is at 0. I begin turning up the volume and I hear the sub start playing immediately (lets say vol @ 5-10), then around 15 - 18 I hear the left speaker, then at 20 -22 I start hearing the right. Obviously at this point it's pretty loud. I can then turn it down no problem and it all works fine, but its not "turning on" until it's getting a big signal.

Here is the setup:



You can see more pictures in my build thread if you need more detailed pictures.

Any ideas? on these two issues? I know I need to do some testing to figure out the issue most likely, but I'd love to be able to test things that don't require me to completely tear apart my truck again....:(

Thanks DIYMA
 

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I think your problem is that is not a sub! Its a case of beer! JK....did I understand that you are running the sub amp off of a line output off the other amp?

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Discussion Starter #3
I think your problem is that is not a sub! Its a case of beer! JK....did I understand that you are running the sub amp off of a line output off the other amp?

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Nope, you got that backwards...I'm running my highs off the line output from the sub amp. The PDX-1.600 has a pre-amp out, the PDX-4.100 does not. So I'm passing through the sub amp.

Like this:

 

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Maybe try splitting the signal off prior to the amps with a y harness (just for giggles) maybe it will improve overall output..... and if you have a signal sensing switch on the amps, set it to off and give it a remote wire. I had an amp a few years ago that had a signal sensing thingy in it and it did odd things like that, only turn on at certain volumes etc etc. I ran a remote to it and problem solved.
 

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I was also going to ask if you had both remote turn on wires run back to the HU to trigger the amps on. Or if it was a signal sensing turn on. You could always add a simple electronic crossover also to split the signal to the two amps.

As far as the output on the sub......hmmmmm???? Maybe try the input gain selector switch. Or your phasing, switch +/- at the amp. It is designed to put out 600W into 2 or 4 ohms....its regulated.

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Discussion Starter #6
The alpines have no signal sensing that I know of. I ran power turn on wire to one amp and then to the other.
 

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Discussion Starter #8
I got it. The gain switch on the amplifier I had set to 1 V to 8 V. This I would assume is the correct setting since my head unit has 2 V RCA outputs. However when I switched it to .0 V to .8 V the output was much much better. I had to turn the gain setting to about one quarter which is what I was expecting from the beginning. Needless to say, it's painfully loud (not distorted, clarity is amazing). Now all I need is time alignment since center and no processing makes the driver seat experience not ideal.
 

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Discussion Starter #9
Oh, I am running a Alpine CDE – 100. It is a very basic head unit but it works well for what I'm wanting to do. It also does not look very complex so it's probably less likely to be stolen.
 

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Discussion Starter #10
Thanks Erik for your help. I would love to check out your FJ sometime and get some advice on next steps for my truck since I have a base foundation setup completed.
 

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Thanks Erik for your help. I would love to check out your FJ sometime and get some advice on next steps for my truck since I have a base foundation setup completed.
Sure thing! I had a sneaky suspicion about the gain selector! I live out on the NW side of town and work by the Galleria, so, we can hook up sometime for sure.

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Sure thing! I had a sneaky suspicion about the gain selector! I live out on the NW side of town and work by the Galleria, so, we can hook up sometime for sure.

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I'm pretty close to the Galleria, maybe I could meet you for a drink or a burger one day after work or something...On me of course. :D
 

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I'm pretty close to the Galleria, maybe I could meet you for a drink or a burger one day after work or something...On me of course. :D

Sure! Maybe sometime the week after turkey day. I will send you a PM, I start a new job on the 28th so I will see what my schedule is like.

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