Ignition noise, Toyota/JBL with JVC head unit

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quadsearcher

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I had this DVDA JVC in a different car using the JVC internal amps, worked great. Then moved it to a newer Toyota Camry 2006 with JBL system (powered speakers, no idea where the amp is), using line level outs. Have a problem with ignition noise. Classic symptom, a whine that gets more high-pitched the faster it revs, constant volume no matter the volume control setting. Tried chassis ground instead of harness ground, no change. Here's the kicker: I tried a pair of stereo ground-loop isolators and the noise persisted.

Anyone have experience eliminating ignition noise? I asked a local install shop if they sold any power filters, they looked at me like I was from another planet and said there would be no noise if they had done the install, they never had that problem.
 
I had this DVDA JVC in a different car using the JVC internal amps, worked great. Then moved it to a newer Toyota Camry 2006 with JBL system (powered speakers, no idea where the amp is), using line level outs. Have a problem with ignition noise. Classic symptom, a whine that gets more high-pitched the faster it revs, constant volume no matter the volume control setting. Tried chassis ground instead of harness ground, no change. Here's the kicker: I tried a pair of stereo ground-loop isolators and the noise persisted.

Anyone have experience eliminating ignition noise? I asked a local install shop if they sold any power filters, they looked at me like I was from another planet and said there would be no noise if they had done the install, they never had that problem.

Try a ferrite choke you can put them on all the lines, power, gnd, audio. No guarantees on stopping it, but they do work in certain situations.
https://www.amazon.com/s/ref=nb_sb_...ke&sprefix=ferrite,aps,563&crid=1U7T60ME5G6ZR
 
Try a choke first, but if that doesn't work, you may have to get technical. Problem with modern cars is they lack the big radio noise suppressors (condenser) on their alternators because generally, they are not needed anymore with OE equipment.

That's what happens with aftermarket equipment. It's made to fit everything, so winds up being compatible with nothing.

An alternator produces AC current, which is rectified into DC. The problem is the rectification is not perfect. The DC output will have a small AC signal riding on it. That AC signal will have 9 cycles for each revolution of the alternator. Suppose your engine is idling at 600 RPM and the drive pulley ratio to your alternator is 1:3. At that engine speed your alternator is turning 1800 RPM, which is 30 rotations per second. Each rotation gives you 9 cycles of AC. Do the math and you get a 270 Hz sinusoidal (not a perfect sinusoidal but close enough). Cruise down the road at 2000 RPM and you get a 900 Hz sinusoidal riding on your DC power supply.

In the old days, we'd use a 4700 uF 35V capacitor from Radio Shack hooked to the output of the alternator. That would cure most noise.
 
Try a choke first, but if that doesn't work, you may have to get technical. Problem with modern cars is they lack the big radio noise suppressors (condenser) on their alternators because generally, they are not needed anymore with OE equipment.

That's what happens with aftermarket equipment. It's made to fit everything, so winds up being compatible with nothing.

An alternator produces AC current, which is rectified into DC. The problem is the rectification is not perfect. The DC output will have a small AC signal riding on it. That AC signal will have 9 cycles for each revolution of the alternator. Suppose your engine is idling at 600 RPM and the drive pulley ratio to your alternator is 1:3. At that engine speed your alternator is turning 1800 RPM, which is 30 rotations per second. Each rotation gives you 9 cycles of AC. Do the math and you get a 270 Hz sinusoidal (not a perfect sinusoidal but close enough). Cruise down the road at 2000 RPM and you get a 900 Hz sinusoidal riding on your DC power supply.

In the old days, we'd use a 4700 uF 35V capacitor from Radio Shack hooked to the output of the alternator. That would cure most noise.

Ya and I would put them on every single line of the head unit, and the power. speaker lines audio interconnects, and even on the gnd.
I once a VW Rabbit fast little shit! I won every race but for Vettes. That sucker had no ability for a radio, no matter what I did the noise was there, it was ignition line you could hear it as I revved the motor. It was just a dud of a electrical system. But we had no Amazon then and even the RS trick failed where I have seen it work.
 
Try a choke first, but if that doesn't work, you may have to get technical. Problem with modern cars is they lack the big radio noise suppressors (condenser) on their alternators because generally, they are not needed anymore with OE equipment.

That's what happens with aftermarket equipment. It's made to fit everything, so winds up being compatible with nothing.

An alternator produces AC current, which is rectified into DC. The problem is the rectification is not perfect. The DC output will have a small AC signal riding on it. That AC signal will have 9 cycles for each revolution of the alternator. Suppose your engine is idling at 600 RPM and the drive pulley ratio to your alternator is 1:3. At that engine speed your alternator is turning 1800 RPM, which is 30 rotations per second. Each rotation gives you 9 cycles of AC. Do the math and you get a 270 Hz sinusoidal (not a perfect sinusoidal but close enough). Cruise down the road at 2000 RPM and you get a 900 Hz sinusoidal riding on your DC power supply.

In the old days, we'd use a 4700 uF 35V capacitor from Radio Shack hooked to the output of the alternator. That would cure most noise.

I'll try a choke, ferrite doughnut, when I find one, I know there's one around here somewhere. I would think that both positive and ground would need to be wrapped together three or four turns around the core.

A capacitor is the conclusion I came to as well. Good to hear 35v could handle the spikes.
I wonder if it would be as effective across + and ground locally right behind the head unit?
 
Or you could just go to Amazon and type in 12volt power conditioner and purchase 2 of them. 1 for the hot battery (yellow) and 1 for the hot ignition (red). It's a shot in the dark, They are about $10 each. If that doesn't work then you are going to have to locate the factory amp and rewire and or replace. Which is probably where your trouble is coming from in the first place. Trying to connect an aftermarket head unit to a factory amp usually produces bad results. Look under passenger seat, or under dash in front of passenger seat, 2 most common locations.
 
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