Amplifier Thump/Pop Sound Power On/Off: How To Fix

A simple 555 timer and relay circuit delays the amplifiers from turning on allowing all the other components to power up before the amps/subs do.

UPDATE: The solution for my application, Yours may vary. The LCQ1 grounding jumper needs to be set to 200 ohm to ground to prevent the amplifier thump noise. It seems that the signal ground and power ground need to be connected together with a 200 ohm resistance. See Fitfreak thread for more details. This negates having the need for the delay relay, but is still a great component to have for an aftermarket application.

*****A note on the 555 timer. Some of the earlier versions had an issue of the chip failing. This looks to be corrected. The solution is to ground or lift pin 6 of the chip. It is the threshold pin, and because the voltage is so close to the operating voltage it would cause the relay not to activate. You can either cut the pin with a small pocket knife, or if you are good with a chisel type soldering iron lift the pin.

[SuperSportAudioProduction]

Even though I don't have a lc1 so my problems different as it's coming from the head unit but great job explaining everything man we need more directional people like you when it comes to directional videos lmao.

[davidosburn]

if this dude saw my wiring hed spit in my eye

[vielle]

Thanks for your advice. I had a similar problem; a loud "thump" from the subs when the system turned off. I don't have an LCQ-1 like you but there is an EQ connected between the head unit and the amps, and this was causing the noise when shutting down. I followed your suggestions and made a simple delay circuit on the control line to the EQ, and it now shuts down a few seconds after the amps are off and so the noise isn't audible. My circuit is just a switching transistor, with a cap and a resistor that adds a delay to the base, but it works fine. Thanks again for posting your video. Good stuff !

[colbyjohnson]

I solved my loud thump at turn off by switching my amps remote wire to the red acc on the head unit. That way my amp shuts off at the exact same time as the head unit not seconds after like when hooked to the blue/white remote wire.

[rayzdavolume]

This is also a sign that your gains are not properly set from the signals off your head unit. before you add relays back down the gain and try turning off and on till you hear it go away. simple fix. Too many people putting the to full blast gain knob thinking that gives more power.

[williejones]

Have a question. How do you wire it up. I have power off popping

[DIYAudioGuy]

Your link to the relay module does not seem to work.

[bobbymathiwathanan]

Looks like I finally found the solution of my speakers popping everytime I switch off the car. My vehicle is BMW E46, since I want to keep the factory head unit, I installed a DSP between speakers and the head unit, sound quality is amazing but, can't get rid of this pop noise.

[leion]

I have a glitch I'm trying to figure out. All my speekers are repeatedly thumping when the sterio is on. It was working fine for about a year. Hopefully I can find the issue

[dapbubba]

Great video. I get the part about delay at start up, but my issue is at ignition turn off after a few minutes of use. I have 2017 Audio A4 and installed a Rockford powered sub in the trunk. I tapped powered directly from battery in the trunk, used speaker inputs from original OEM sub connections coming from factory amp, and used a remote pwr source from the cigarette 12vdc aux power outlet also located in the trunk. When I shut down the ignition, there's a terrible hum/buzz from the powered sub for about 2-3 secs. Will the time delay relay you recommend help with instant shut down as well? I'm confused why the 12vdc from the trunk aux outlet does not immediately drop at ignition off to kill power to the sub instantly as well? Is it because I used the speaker input after the OEM amp vs before from OEM head unit? Does it have anything to do with gain setting too high? Thanks for you help.

[SolidBatcorp]

I have a problem where my lcq1 bass knob is controlling the bass output on my speakers also. It seems this unit is defective.

[juanacosta]

Can you provide wiring instructions please

[charlescox]

Just switched the ground jumper on my LCQ-1 to the 200ohm setting and it fixed my turn off pop I was getting before thanks for this excellent advice, I have the GTO off and running an accessory wire to the remote turn on. I wonder if switching to the GTO auto sense will work too? I have not tried that yet.

[ThirdCoastCrypto]

Clean and concise solution, thanks for this.

[hh]

I put my remote out from head unit to a relay and connected my amp and line driver to that. I think this may be causing the issue. Should I go to amp, then daisy chain to relay? Or is it being caused by the line driver like in your case... ac7i or whatever rhe model is is similar to a line driver. Mine is audiopipe 3001-rmt.

[magic]

Can you wire the remote turn on straight to the accessory or cigarette lighter. I have the same issue with my amp and sub

[ntechsolutions]

If com and vcc are connected together from where I'm getting ground cable to amplifier?I have popping sound when turning off and I want to add delay timer relay.

[TracyBoyer-pncn]

I dont know how to explain my issue but there is a constant thumping static sound every 1-2 seconds after the car is OFF. It only happens wheb the car is not running and everything is off, its been hoing on for hours ... Would a bad stereo fuse cause this? Everything works fine wheb car is running

[camachopaul]

Please help !! So if you connected the remote out cable from the head unit to VCC in put you had to cut it right ?? What did you do with the other end of the cable that actually feeds power to the rest of accessories? Where do I connect that to meet power to the rest of the accessories ? Thank you

[luismercado]

Do you have to use the common to? on the out put, I want to use it to delay the remote on the amp