Thump/Pop when system turned on/off

[Bear80]

I've looked around for any info on my problem but it seems all I come up with is the typical issues.

Ok, so what I did was add an aftermarket amp inplace of my stock OEM amp. The stock head unit has a severe crackel at power on and a bad thump at power off. I assume a delayed remote turn on signal will help with the power on crackel. BUT what can I do about the power off thump?? -- the power off thump is NOT from the new amp.

The head unit has a mute signal that runs to the stock amp, which I assume sends a signal just prior to power on/off to prevent the noise. So is there anyway I can adapte this signal to mute my aftermarket amp. Or is there any aftermarket amp that can use this signal.

Is there anything else I should disclose? I'll add that I simply took the low level signals from the headunit spliced into it and ran them to the new amp with RCA plug ends. Then the remote turn on from the headunit to the stock amp was diverted to the new amp.

Thanks,

Benjamin

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[J31Rob 5,000+ posts]

Turn on bump.. your amp may lack the 'soft turn on' feature.

 

[Bear80]

Yep that was my first assumption, but I don't want to go buy another amp. Even so, will an amp with this feature help with the power off noise?

 

[NewToTheGrounds 10+ year member]

i dont think it will help with the power down its a soft on wich just means the amp waites a few secs to turn on so the deck and everything is on before it turns on, wont help with the shut down.

 

[Bear80]

So is there any power amp on the market that can use a mute input signal? I think pretty much all power amp chips have the mute feature built into them. I'm thinking that some amps that do not pop when turned off *might* use a similar built in mute to prevent that pop. If so I'm thinking I might be able to trigger that mute from my headunits signal...maybe.

Am I out of the league of typical market amps, and more into the custom engineered setup?

Anyone with input?

 

[Vegas WRX 10+ year member]

one way to tell if its the amp or the headunit. Run a 12volt power to the amp turn on (either from the battery or find a 12volt contant power source). Touch the wire to the remote wire lead on the amp, should turn the amp on, now take the wire off of the amp, should turn the amp off. If you hear a thump, then its the amp. If you dont hear the thump the amp is fine.

Now if you dont hear the thump, just throw a switch inline with the 12volt power wire and just turn the amp on and off when you choose. A good idea anyhow for the times when you just dont want any bump in the trunk.

 

[Rich B 5,000+ posts]

If all else fails, David Navone sells a delay on his website-

N-66 TURN-ON POP DELAY

N-66 Now $16.50

(was $19.50)

Order N-66 .:| Here |:.

The N-66 was designed to eliminate amplifier turn-on pops by delaying the turn-on of a pre-amp level device until the power amp is on. The fixed delay time of the N-66 is 2.5 seconds. There are only three wires needed: An input wire, and output wire, and the connection to the chassis ground. The N-66 can be used for alarm applications, window roll up or down, interior light delays

http://www.davidnavone.com/

 

[Bear80]

Ok, I got some things sorted out on the setup.

The crackle at power on isn't an issue. I had the remote power jumpered from the main power on the amp for testing. Duh, that pretty much by-passes the soft power on of the amp and so it's no wonder I got a bad crackle from the head unit. Properly tapped on to the head units remote turn on, I no longer have a power on issue.

However, the excessive pop with power off is what I've really been after. Toyota seems to like the use of the mute signal from the deck to the amp, it's on pretty much all early 90-current units with external amps. This mute signals at power on, off and FM scanning. Of course with the use of an aftermarket amp this mute feature is not possible, so I've found out. Mute is usally a feature built right into the power transitor chipset.

Well playing around with my bass link's remote level control I notice something. If I turned the gain down on the sub prior to turning off the headunit, no thump. Another DUH! If the gain is adjusted down, it will not amplify the signal as much. SO I adjustted the gain on my new amp to the minimum setting. This made a HUGE improvement in the power off pop, now it's still there but nothing like it was when the gain was set midway. This also caused the adjustment in the deck volume to increase. Meaning I will have to turn it up more by the nob but still having enough adjustment to reach a level beyond my ear comfort. In doing so it also gives me more variable control with the volume. Win-Win.

I would like to delete the power off pop all together since this is a "luxury" suv but I can live with the minor pop now.

Thanks guys for all the ideas and input, hopefuly what I have to add helps someone else.

PS. I assumed since factory decks are becomming more intergrated with the dash what I've tried would be more common and that a possible mute solution would be out there, guess not. Either way, turing the gain on the amp down makes for a world of difference.