All of the amp output wires have 0.03V - 0.04V DC voltage whether or not test signal is playing. RF+ and LR+ (the ones that had no AC voltage) do read 1-5 Ohms to each other (basically 0 because the test leads together report this as well).
EDIT: Just realized you meant ALL the wires (4) that had no AC voltage, not just positives (2). Yes, they all have NO resistance to each other (1-5 Ohms). This is without a test signal playing. Does one need to be?
Thanks so much for your help. Ready for the next step.
EDIT: Just realized you meant ALL the wires (4) that had no AC voltage, not just positives (2). Yes, they all have NO resistance to each other (1-5 Ohms). This is without a test signal playing. Does one need to be?
Thanks so much for your help. Ready for the next step.
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The FGA is (it appears) to use an OEM head unit with a common ground speaker system. The capacitors are needed to block the DC (OEM head units typically have 1/2 B+ on all speaker wires) from reaching the speakers. The DC voltage would destroy the speakers.
I'd install a 5 amp fuse in the amp and confirm that it will power up and play to a reasonable level with that fuse, driving speakers normally.
What's the resistance from the RF+ to ALL of the other 0v speaker terminals?
The next step depends on the answers above.
I'd install a 5 amp fuse in the amp and confirm that it will power up and play to a reasonable level with that fuse, driving speakers normally.
What's the resistance from the RF+ to ALL of the other 0v speaker terminals?
The next step depends on the answers above.
You should check the resistance with the amp off and disconnected from speakers.
1-5 ohms could be important. I'd like to hear that all read the same (essentially 0 ohms) which would tell us that there is only one secondary ground in the amp.
Confirm that the amp will function with a 5 amp fuse.
1-5 ohms could be important. I'd like to hear that all read the same (essentially 0 ohms) which would tell us that there is only one secondary ground in the amp.
Confirm that the amp will function with a 5 amp fuse.
Yes they all measure about 1.5 Ohms to each other. My test leads to each other measure the same. The value changes a bit if I reinsert my leads into the multimeter so I think that's the problem and they are actually 0. What does this mean? That I may not need the FGA and can splice all the negatives together into my common ground (or rather, all of the ones that test 0V AC)? Is this what you mean for me to try with a 5 amp fuse in the amp?
I want you to confirm normal operation and wiring with the 5 amp fuse so that we can use the 5 amp fuse when you're connecting the common ground system. The lower value fuse will help protect the amp in case of a mistake.
I think it's OK to connect all 0v wires if they are all reading the same.
I don't think the FGA will serve a purpose here.
If the amp works (wired to a normal set of speakers with the 5 amp fuse, I'd try connecting the two channels that had signal on the positive terminals to the common ground system. Confirm that the balance and fader work normally for those two speakers.
If so (initially), connect the two amp speaker wires to the common ground speaker wires that normally go to the positive speaker terminals. Recheck balance and fader.
With the speakers connected as above, you will likely have some bass cancellation because two speakers will be out of phase. If everything else works OK, reverse the speaker wires at the speakers for the two channels that had signal on the negative speaker wires at the amp output.
I think it's OK to connect all 0v wires if they are all reading the same.
I don't think the FGA will serve a purpose here.
If the amp works (wired to a normal set of speakers with the 5 amp fuse, I'd try connecting the two channels that had signal on the positive terminals to the common ground system. Confirm that the balance and fader work normally for those two speakers.
If so (initially), connect the two amp speaker wires to the common ground speaker wires that normally go to the positive speaker terminals. Recheck balance and fader.
With the speakers connected as above, you will likely have some bass cancellation because two speakers will be out of phase. If everything else works OK, reverse the speaker wires at the speakers for the two channels that had signal on the negative speaker wires at the amp output.
Awesome, I just want to confirm I understand correctly:
1) Confirm normal operation with a 5 amp fuse with the FGA still attached.
2) Remove the FGA completely and wire in only the amp LF and RR to the common ground system. I assume this means amp positives to their respective vehicle positive, and the negatives together to the vehicle common ground?
3) Check balance / fade.
4) Wire in the amp RF and LR to the common ground system: amp negatives to their respective vehicle positive (since they're swapped for these channels), and positives together to the vehicle common ground?
5) Check balance / fade.
6) Swap the speaker connections on RF and LR to bring them back in phase with the others.
1) Confirm normal operation with a 5 amp fuse with the FGA still attached.
2) Remove the FGA completely and wire in only the amp LF and RR to the common ground system. I assume this means amp positives to their respective vehicle positive, and the negatives together to the vehicle common ground?
3) Check balance / fade.
4) Wire in the amp RF and LR to the common ground system: amp negatives to their respective vehicle positive (since they're swapped for these channels), and positives together to the vehicle common ground?
5) Check balance / fade.
6) Swap the speaker connections on RF and LR to bring them back in phase with the others.
1. No. Connect to normal speakers directly using a normal speaker connection to the amp. No FGA (for anything from this point)
2, 3, 5. Yes
4. The negatives for these channels. Yes
All after making sure the amp works normally with the 5 amp fuse.
2, 3, 5. Yes
4. The negatives for these channels. Yes
All after making sure the amp works normally with the 5 amp fuse.
How do I confirm "normal" operation with a 5 amp fuse? I don't have another set of speakers to connect to the amp.
No test speakers? No old set of home speakers (nothing expensive)?
The reason I want you to confirm 5 amp fuse operation is because the inrush alone could blow the fuse. The test speakers would simply be to make sure that everything is working. Doing this via text AND trying to do no damage takes a lot more effort than being there.
The reason I want you to confirm 5 amp fuse operation is because the inrush alone could blow the fuse. The test speakers would simply be to make sure that everything is working. Doing this via text AND trying to do no damage takes a lot more effort than being there.
Nope, no other speakers on hand. Thanks man I appreciate it! What if I only connect one speaker? That way it's kind of "normal" since there's only one positive and one negative.
I also don't have a 5A mini fuse like the amp takes. I do however have a normal sized 5A I could put in place for the power running this whole system. It's no longer running off the car 12V, but lithium house batteries (that also use vehicle's ground for negative). Will that work?
I also don't have a 5A mini fuse like the amp takes. I do however have a normal sized 5A I could put in place for the power running this whole system. It's no longer running off the car 12V, but lithium house batteries (that also use vehicle's ground for negative). Will that work?
You're a genius. I have the front 2 speakers going so far and the balance / fader works. They also seem to get way louder (like when the FGA was grounded with only 2 working speakers). And that's still with them out of phase.
Oh my goodness. Got all the speakers hooked up and it all works!
Dude please send me a DM with your Venmo or PayPal so I can thank you.
Dude please send me a DM with your Venmo or PayPal so I can thank you.
Well I am beyond grateful. I posted this across three different forums and you're the only one who came through. Everyone else just said run new wiring.
Another question! I've noticed there's a tiny bit of static with the engine running. I believe the FGA can also act like a ground loop isolator and stop this? There was no static when I had it hooked up, although I'm not sure if this is because I was using it without its input ground connected. My old FGA did not prevent the static. If the new one does indeed prevent the static (I'll check), is there any downside to using it? I.e. will it reduce the signal or change its quality in any negative way?
You're not going to use an FGA with this system. Why is there a question about it?
Static? Ticking would likely be from the ignition system. An engine RPM related whine would be alternator. Which do you have?
Static? Ticking would likely be from the ignition system. An engine RPM related whine would be alternator. Which do you have?
Neither! It's just a very faint amount of white noise when nothing is playing. The question about the FGA is in the case that it eliminates this noise, which it did seem to do previously, albeit when its input ground was not connected so I can't confirm that it would when wired with the correct signal wires that we discovered yesterday and its input ground connected to the headunit chassis. However if there's any chance adding the FGA would reduce sound quality or output volume, I really don't care to add it as the system plays with the engine off 99% of the time and the static is only audible when nothing is playing.
There are several possible issues.
It's a class D and that can be noisier than a linear type amp.
The amp may have a regulated power supply and with the engine running, the supply voltage could drive the internal power supply into regulation and that can sometimes induce noise.
There are no gain controls. With most amps, you can reduce the gain to reduce the hiss. That's not possible here.
I doubt that the FGA would do anything beneficial.
If you disconnect the lithium battery's positive wire from the vehicle charging system, is the amp noisy with the engine running?
Side note:
A search for the following had a fair number of people complaining about hiss.
Alpine KTP noise hiss
It's a class D and that can be noisier than a linear type amp.
The amp may have a regulated power supply and with the engine running, the supply voltage could drive the internal power supply into regulation and that can sometimes induce noise.
There are no gain controls. With most amps, you can reduce the gain to reduce the hiss. That's not possible here.
I doubt that the FGA would do anything beneficial.
If you disconnect the lithium battery's positive wire from the vehicle charging system, is the amp noisy with the engine running?
Side note:
A search for the following had a fair number of people complaining about hiss.
Alpine KTP noise hiss
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