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Discussion Starter #1
I recently got my hands on a JBL GTO 4000 amp and a matching JBL 1000w sub, i have two sets of 6x9's and a set of 5" tweeters also. it's the same amp as pictured but brand
new/never been used. i can get all the speakers, sub included running off the lower "rear" channel but can't get anything running off the upper "front" channel. i've tried just hooking up one set of 6x9's to the rear and just the sub in bridged mode and single channel mode to the front but still nothing. i can run just the sub on its own on the rear and filter it properly but can't get anything out of the front channel in any configuration. is there some way to switch it to three/four channel mode to get power out of the front? am i doing something wrong or is it just that the amp is cabbaged?
thanks in advance!
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What are the speakers that you're using? That is a 4 channel amp, and if you're using 2 channels for the sub, that means that you're trying to run 6 speakers off of the remaining 2 channels, I am guessing that's the problem right there. It's possible that you have the speakers wired to too low of an impedence, and the amp can't handle the load. There are plenty of other possibilities for why you are having issues, be we need to know the specific speakers that you're using, and how you have the amp wired. up.

Regardless, it sounds like you're trying to use an amp for a purpose that it's not designed for.
 

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Discussion Starter #3
i have 2 sets of pioneer TS G6930F 6x9's wired in series and one set of pioneer TS A1370F, that was the setup all running great prior to getting a subwoofer, the subwoofer i just got is a JBL GT4-12 Series which the previous owner had running on the exact same model of amp with a set of 6x9's. As i mentioned i've tried just running one set of speakers on the rear and the subwoofer on the front or even just the subwoofer on the front and still getting no sound out of it. In short, previous owner had the same amp with a set of 6x9's running off the rear and the sub running off the front but i've wired up in the same way and it doesn't want to work for me
 

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Having a hard time following your wiring scheme. Can you sketch a picture? Also, does this amplifier have any crossovers that might be filtering out the wrong signal?

Ge0
 
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Having a hard time following your wiring scheme. Can you sketch a picture? Also, does this amplifier have any crossovers that might be filtering out the wrong signal?

Ge0
Good question from Geo, you may have a filter set. I'm also having a tough time visualizing your wiring. If you have your 6x9's in series, then the 5 1/4 also in series, you have a 12 ohm load, so you can count on getting almost no power from the amp.

Not to sound discouraging, but 4 6x9's, 2 5 1/4's, and 6 tweeters is going to sound pretty bad, I'd consider rethinking the plan a bit. A car should have 2 tweeters, not 6, you're going to have a hell of a time getting it to sound decent. Even if you had a strong DSP, and an experienced tuner, getting 6 tweeters to sound good in a car is a huge challenge.
 

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Discussion Starter #6
as i said, that was the previous setup before i got the subwoofer and it actually sounded great. The top input line of the amp will not run with just the subwoofer or any other speaker plugged in. i'm only trying to run the sub and two 6x9's at this stage but the two channels won't run simultaneously.

In short, previous owner had the same amp with a set of 6x9's running off the rear and the sub running off the front but i've wired up in the same way and it doesn't want to work for me
 

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as i said, that was the previous setup before i got the subwoofer and it actually sounded great. The top input line of the amp will not run with just the subwoofer or any other speaker plugged in. i'm only trying to run the sub and two 6x9's at this stage but the two channels won't run simultaneously.

In short, previous owner had the same amp with a set of 6x9's running off the rear and the sub running off the front but i've wired up in the same way and it doesn't want to work for me
I don't know what else to tell you. Take a picture of how it's wired, or at least describe in detail exactly what wires are connected where, and where all of the knobs and switches are set to, or nobody can help you. Saying that it's "wired up in the same way" tells us literally nothing.
 

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Discussion Starter #8
ok, the bottom row of speaker inputs i have one 6x9 wired into the left and one 6x9 wired into the right the hp/lp filters both work as they should and ive tried the various positions, gain and db knobs are adjusted half way, also played around with these. In short, the 6x9's on the bottom row are working fine and as they should. Ive also tried just the sub into one side on the bottom row and it works as it should with hp filter etc.

I've tried with one set of 6x9's wired into the bottom row as described and played around with settings while the sub is wired into the top row, i've tried both sub into the right, sub into the left and bridged mode which i believe is - on one side and + on the other, ive tried both variations of left and right and played around with settings but no sound out of the sub whatsoever.

ive tried just one 6x9 into the left and one 6x9 into the right on the top row but no sound whatsoever.

ive tried just the sub on its own into the top row but no sound whatsoever.

no sound from the top row of inputs whatsoever no matter what configuration.

i think thats about as plainly as it can be explained, does that make sense?
 

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Discussion Starter #9
the positive terminals are going to the positive inputs and the negative terminals are going to the negative inputs
 

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Sounds like you may have a few blown channels. Do you have somewhere that could test your amplifier?

Ge0
 

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I’d check for a blown fuse. Do you have a separate set of RCA’s plugged into the front channel input? What if you hook one of your 6x9 speakers to a front output and switch the RCA’s?
 

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Discussion Starter #17
Fuses are good, first thing i checked obviously. i'll play around with the RCA's when i get a chance
 
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