Aftermarket amplifier turn-off pop/click/thump...The Answers

[darkrider01]

History:
As some of you may know, I have been fighting quite a battle with a pop/click/thump (henceforth referred to as p/c/t) when I turn off my radio. I have a long history of car stereo installation (amateur and professional) and I have an associates degree in electronics engineering. I am currently employed as a commercial electrical designer. I know my way around electricity and have a pretty decent grasp of electronics.

I have had issues with turn-off p/c/t in the past, but it was always a grounding issue, and it was always with aftermarket radios/amps/eq's.

When I installed my amp and sub into my camaro, I googled the Boston Amp wiring diagram which eventually lead me to these forums. I found the wiring diagram and began hacking away at my factory harness. Originally, I had an Alpine 3527S and my Rockford T1000-1BDCP. The Alpine was running mids/highs (all car speakers, including center channel) with the Rockford handling sub duty. It sounded pretty damn good. I was smiling ear to ear, until I turned it off.

When I turned it off, there was a p/c/t. It wasn't super loud - I didn't expect it would destroy speakers or anything, but it was very noticeable. I was mostly worried about it damaging my amps. Now I had just spent over $1000 and it was like a stick that poked me every time I turned off my car. Being proud of my car and my high-end (to me anyway) equipment, I was embarrassed by the p/c/t.

I started a little troubleshooting - having my wife operate the keys while I watched how the amps and sub reacted when the keys were removed. I noticed that after the keys were removed, the amps stayed on for roughly 2 seconds. When they turned off, there was the p/c/t. So I looked around for something that would change the sequence of operation. I found 2 things I thought might work - the Metra Axxess Trigger and the P.I.E. EIS-PS2 (pop-stopper). Now the Metra Axxess Trigger I'm pretty sure was expensive and mostly unavailable when I first started looking - I'm sure I remember seeing it on ebay for $90+ . So I figured I'd try the P.I.E. EIS-PS2 since it was only $25 and it's a pop-stopper - win, right?! It provided a 2 second turn-off delay. I figured that if the amp stayed on after the signal dropped, it would not pop. Wrong.

So next I tried removing the amp remote as soon as my wife removed the keys. Viola! No pop! Now I was getting frustrated because I figured that no one made anything that would disconnect the remote at that second. I figured that the factory radio was sending a mute to the factory amp through the mute wire and that the amp was disconnecting the inputs when it got the mute signal. I couldn't think of anything that would do that for me, so after living with the p/c/t for several months, I finally had a breakdown and removed all of my aftermarket equipment and returned it to stock. Yes, I threw a hissy-fit.

I was pretty sad. I love my car, but I missed my overkill sub. I started looking for answers on the internet, on these forums, everywhere. I started asking questions, and thought several of the answers had merit and were worth at least trying. $1000 worth of stereo sitting in boxes in my garage annoyed me. I wanted to use it again, so I started trying anything and everything that I thought might work. Then I tried some things that I didn't think would do anything to help. I figured that honestly, if nothing else, what I learn could at least help others that might have the same problem. I was determined to find the answer.

Below, I will detail the causes some said were causing the p/c/t and some things I tried and the solution that is semi-working for me. As a note, none of the solutions are perfect. My opinion is that the only perfect solution is replacing the factory radio, since the p/c/t is all it's fault,

[darkrider01]

Possible Causes

Remote Voltage Too High:I was told several times that the problem was that the remote turn-on voltage was too high. That is incorrect. I have used 12V direct from the battery in past, through a dash mounted switch, to turn amps on and off, with no pop. I have read somewhere that certain Ford factory amplified systems had an issue like this.

Groud Loop: I thought I had pretty good grounding, but figured I would try the ground loop isolator anyway. The consensus is that there is DC riding on the low level outputs coming from the radio. A ground loop isolator would in theory remove the DC from the line. I still don't know what to make of this. See Ground Loop Isolator below.

Line Output Converter A line output converter takes a high level speaker signal and converts it to a low level RCA output that can be used to connect to an amp. Some amps have this already built-in and you can plug high level inputs directly into them. None of my amps have this feature. That could be a reason some people do not have the p/c/t. Some manufacturers have adapters for their amps that basically are just speaker cable wired directly to an RCA. In those cases, the amplifier must be able to accept high and low level inputs via the RCA connections.

Gains Too HighSetting all gains at 0 did not eliminate the p/c/t. It did reduce it to a low level, so gain has an effect on the p/c/t.

[darkrider01]

Possible Solutions

A Little Turn-off Pop is Normal: I didn't accept this answer. I'm not going to call anyone out on this, but dropping thousands on a system to have "a little pop" is unacceptable - for me anyway.

Precision Interface Electronics EIS-PS2: As detailed in history, no effect.

Ground Loop Isolator: I tried 3 different models. One Stinger, one AudioPipe, and generic. It seemed like it made the p/c/t less severe, but did not eliminate it. As a note, my original Alpine 3527S did not need ground Loop Isolators but my Alpine MRV-F357 goes into protect without them (when fed low-level radio output directly). My RF T1000 didn't need it either.

Line Output Converter (LOC): I just knew this would do it. The consensus about the DC and removing it pointed to a LOC being the best bet at getting rid of the DC. I went and bought the best LOC I could find - and AudioControl LC6i. I tried the LC6i in front of and behind the BA amp. It did not remove the p/c/t. I was devastated. There was speculation that it might actually cause a p/c/t itself, so upon direction of Steve @ ********, I tried his AudioPipe LOC. Honestly, I didn't think it would work, but I figured I would give Steve a shot. Well, it didn't remove it, but it did reduce it to a very low level (probably because it reduced everything to a very low level).

Resistors Across Low Level Inputs: One person said placing a resistor across the low level inputs should remove the DC, but the p/c/t did not go away. I used a 10 ohm - 10 Watt resistor. The p/c/t was greatly reduced, but not eliminated. I believe the signal volume was also reduced, but I don't 100% recall.

Relay: I had an idea that if I used a single-pole double-throw relay to break the remote going to the amp by using the mute, it would kill the p/c/t. I tested the voltage of the mute and I believe it was around 6V. I went to RadioShack and purchased around $20 in materials (blank board, 5-7V SPDT relay, new soldering iron, etc). The plan was to use the Radio-Mute to actuate the coil, thereby breaking the remote and turning off the amp as soon as the mute went active. Turns out that the Mute only provided 1.9mA of current, and the mini-SPDT relay required 56mA to operate. I had a good laugh at that. This would have been the simplest solution - of course it wouldn't work.

[darkrider01]

The Actual Solutions

Metra Axxess Trigger: A "guy at Metra" sent me a Metra Axxess Trigger to try. When he told me he was going to send it to me, I figured it would probably work because it was the one solution I originally passed on (I didn't know this person worked at Metra until after I PM'd him to ask him if he needed my first born or soul as payment). So, I looked it up online again, and they can be had in the $30-40 range now. In the description of the device, it says "GMLAN Aftermarket Amp Turn-On provides an amp turn on LAN vehicles for adding an aftermarket amp". Truth in advertising. It does just what it says, but there is a caveat. My relay, had it worked, probably would have done the same. When you first turn on the radio, or if you press the mute on your steering wheel controls, it turns off the amp. Therefore, there is a 2-3 second delay when turn on the radio or un-mute the radio. I can deal with it.......for now.

Use Accessory Outlet Power (Cigarette Lighter) As Remote Source: This will work, to an extent. The caveat of using this remote source is that when you turn off your car, your amps turn off as well. Normal operation is that you can open the door of your Camaro and turn on the radio, without the key in the ignition. If you use the cigarette lighter, you have to turn the key on to accessory for your amps to come on.

Replace Factory Radio: Yeah, this should definitely fix it, but I wanted to keep the factory radio and all of it's functions.

Did I miss anything?

[darkrider01]

reserved

[jeepguy_1980]

Originally Posted by darkrider01

The Actual Solutions


Did I miss anything?

The remote amp control line on the back of the stock HU.

[darkrider01]

Originally Posted by jeepguy_1980

The remote amp control line on the back of the stock HU.

Actually, that is how I had it hooked up originally, and it does cause the p/c/t. I guess I didn't state it clearly enough.

The amp control line = amplifier remote = Orange Wire on X3 connector. The amp control line stays on for around 2-3 seconds after the radio is turned off or key is removed.

I was told that some amps do not have this problem, and that's great. But, a lot of us do have this problem.

[Iwantone2]

I applaud all the steps you have taken and your great documentation.

[Jason@JacFab]

I wonder if this has something to do with the Boston system... Of all the threads I've come across with people talking about this problem, it seems they all have the Boston system... I was pretty concerned with this issue when I went to install my system, but I do not have the BA option in my car.

I used a PAC SOEM-T LOC and tapped into the rear speakers to get the signal. I chose the SOEM-T because also provides the signal to the remote wire, as I didn't want to try to run a wire to somewhere else in the car with keyed power to try and get the remote signal to the amp. IIRC the SOEM-t can detect as little at .5v through the speaker wires and provide the remote signal to the amp... Although it seems like a good idea, it also seems that there is always at least that running through the speaker wires even when the radio is off... So even with I turn off the radio, my amp is still powered on. Is this a big deal? I don't think so, but I don't personally know if it will damage something eventually.

Long story short, I do not have the BA system, and the p/c/t I was so concerned about going into this installation is not present, so I am happy. Like I mentioned, the only thing wrong with this set up is that the amp is always powered on with the ignition is on, even with the radio off... But with the ignition off, the amp is off, until the radio is turned on and then it powers up... No big deal... I think?

My system install thread is here: http://www.camaro5.com/forums/showthread.php?t=191938

[Soundplus]

So in a nut shell

Buy the Metra Axxess Trigger.. install it. get power from the cig light in the center console. and problem solved??

[jeepguy_1980]

Originally Posted by Soundplus

So in a nut shell

Buy the Metra Axxess Trigger.. install it. get power from the cig light in the center console. and problem solved??

I'm sure I sound a bit like a broken horse here, but I put my DMM up to pin 43 (the wire circled in blue below) and it will save you the trouble and money of using the trigger. It's free to try and certainly just as easy as opening up the center console.

It has a delayed turn off already. When the radio is powered down, the line holds voltage on it for a few seconds and then slowly bleeds down to 0v over the course of another 5 or so seconds. If you use that line, you will not hear a pop.

Originally Posted by jeepguy_1980

I made a mistake, which may have actually been a good thing. I cut the wrong blue wire. I wound up cutting the wire that is annotated in blue in the documents below. I really meant to cut the wire annotated in yellow. All of my testing was with the blue wire, which seems to work as I would have hoped. Though, the real test will be tomorrow when I install my amp.

[Steve@Subthump]

Everyone needs to keep in mind that this is totally dependent on the amp being installed. Different amps use different internal power supplies and there is no simple formula to know in advance. Just because one amp does it, doesn't necessarily mean the next one will. I know all the JL amps we have tried, they don't seem to need anything because they just plain don't do it. The kicker amps we have tried, do it slightly but the ground loop isolator on the input signal takes care of it completely.

With that said, there will still be times when certain amps need a ground loop isolator or a line converter just to make them work. This is because of the way they are built. A small percentage of amps will go into protect mode without these devices regardless of the trigger mechanism. This is why we recommend the ground loops because it solves that problem for many amps, and also minimizes the thump in a lot of other amps.

There are just to many different amps guys are using to say one solution is universal. The axxess trigger may work fine for a subwoofer amp installation, but keep in mind that if you replace the boston amp and try to use the axxess trigger on a multi-channel amp, there will be a rather lengthy delay in how quickly it powers up to play the chimes. What I mean is: The boston amp actually powers up really fast in order to play the chime sounds thru your speaker when you open the door. Aftermarket amps typically turn on a little bit slower--so you actually miss the first and second chime. Add 2-3 seconds of delay on top of that and you will already be seated in the car before the amp powers up and starts playing the chime sounds. Or worse, you might not even hear the chime becuase you'd have the door closed already. Either way, this may or may not be an acceptible solution because of the possible side effects.

My recommendation would be to see how your amp responds first and go from there. I still think the ground loop is good insurance if you don't know if your amp can handle the dc. But now that we have some other documented solutions, guys will know what to do in the event they have a persistent p/c/t. I actually have a metra account, I will call my rep and see what the pricing would be should anyone need one.

[darkrider01]

Originally Posted by jeepguy_1980

I'm sure I sound a bit like a broken horse here, but I put my DMM up to pin 43 (the wire circled in blue below) and it will save you the trouble and money of using the trigger. It's free to try and certainly just as easy as opening up the center console.

It has a delayed turn off already. When the radio is powered down, the line holds voltage on it for a few seconds and then slowly bleeds down to 0v over the course of another 5 or so seconds. If you use that line, you will not hear a pop.

The wire you are referring to is the one I started with. The delayed turn-off part is the problem. The Orange wire is the Amp Mute signal wire.

[darkrider01]

Originally Posted by Steve@********

Everyone needs to keep in mind that this is totally dependent on the amp being installed. Different amps use different internal power supplies and there is no simple formula to know in advance. Just because one amp does it, doesn't necessarily mean the next one will. I know all the JL amps we have tried, they don't seem to need anything because they just plain don't do it. The kicker amps we have tried, do it slightly but the ground loop isolator on the input signal takes care of it completely.

With that said, there will still be times when certain amps need a ground loop isolator or a line converter just to make them work. This is because of the way they are built. A small percentage of amps will go into protect mode without these devices regardless of the trigger mechanism. This is why we recommend the ground loops because it solves that problem for many amps, and also minimizes the thump in a lot of other amps.

There are just to many different amps guys are using to say one solution is universal. The axxess trigger may work fine for a subwoofer amp installation, but keep in mind that if you replace the boston amp and try to use the axxess trigger on a multi-channel amp, there will be a rather lengthy delay in how quickly it powers up to play the chimes. What I mean is: The boston amp actually powers up really fast in order to play the chime sounds thru your speaker when you open the door. Aftermarket amps typically turn on a little bit slower--so you actually miss the first and second chime. Add 2-3 seconds of delay on top of that and you will already be seated in the car before the amp powers up and starts playing the chime sounds. Or worse, you might not even hear the chime becuase you'd have the door closed already. Either way, this may or may not be an acceptible solution because of the possible side effects.

My recommendation would be to see how your amp responds first and go from there. I still think the ground loop is good insurance if you don't know if your amp can handle the dc. But now that we have some other documented solutions, guys will know what to do in the event they have a persistent p/c/t. I actually have a metra account, I will call my rep and see what the pricing would be should anyone need one.

Everything Steve has said here is 100% accurate and goes well in line with everything I have learned. My document was meant more of as "if you have p/c/t, here are some work-arounds". I did note in my document that the Trigger gives a 2-3 second delay on amp turn-on, but for me, it is so much better than that p/c/t.

Also, thanks again for working with me on this Steve.