newbie here - hope u can help

[tuckj]

Just finished replacing a defective “Panasonic” cd player with a new Alpine. Everything works great except when the deck is turned on. There is a fairly loud thump coming from the sub. It wasn’t there with the old deck

D461 MTX amp

12” ExPlod

Alpine deck CDE-9845.

Simple system – but this sound scares me……..thanks a million.

Click to read more...

 

[vasilios 10+ year member]

check the grounds/connections???

 

[jsloan10 10+ year member]

This is the full technical guide to repair the problem-

Replace the words processor and equalizer with head unit as this is the cause of the thump.

2.2 My system "pops" when I turn it off. What is happening and how

can I get rid of it? [JD]

=====================================================================

This kind of problem is often caused by transients in the signal

processor as it powers down finding their way into the signal path,

which the amplifier then transmits to the speakers.

Usually this can be solved by adding a little turn-off delay to the

processor. This allows the processor to stay powered on for a short

time after the amplifiers have powered down, thus preventing the pop.

Many components sold today (such as crossovers, equalizers, etc) have

delays built-in. Read your manual to see if it is possible to set this

delay on your piece of equipment or be sure to look for this feature

during your next car audio purchase.

If your processor does not have this feature, you can build your own

delay circuit with a diode and a capacitor. Add a 1N4004 diode in

series with the processor's turn-on lead, striped side towards the EQ.

Then add a capacitor in parallel, the (+) side of the cap connects to

the striped (processor) side of the diode, the (-) side of the cap goes

to ground (not the radio or EQ chassis - connect to the car chassis).

Experimenting with the cap value will give you the right amount of delay

before the EQ shuts off. You don't want it too long, just long enough to

make sure the amp is off before the EQ powers down. 220 - 1000 uF is

about right, and make sure the cap is a polarized electrolytic, 16V or

higher. Also keep in mind that the diode will introduce a 0.7V drop on

the remote wire, which can cause the processor to power down before the

rest of the system.

Edit- in the event of a turn on pop/thump the amplifier turns on before the head units rca's turn on. When the the head units RCA's energize the amp will pop/thump the speakers this is why most amps have a soft turn on curcuit that delays powerup to allow the headunits to turn on first, If your amplifier is turning on before the RCA's on the head units turn on then you need to delay the remote turn on leads signal.

 

[BeanII 10+ year member]

check the grounds/connections???

wow! what great advice............ He said he's new. what should he check for? that they're still there?

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[wingnut691983 10+ year member]

Check to be sure that the grounds are good, if you dont get a good ground you can end up with noise like that, and its not good for your components.

 

[Chevyaudio 5,000+ posts]

to check the grounds he means....Make sure the place where the amp is grounded is bare metal, if not sand off all of the paint, rust, or any other material. Also make sure that the ground connection is tight.

 

[gnet158 10+ year member]

I thought the thump problem was more common with component amps? I too just added a sub/amp (check the sig) combo and have had ZERO problems. Recheck everything, grounds (head unit and amp), RCA’s, remote turn no wire. Good luck!

 

[tuckj]

Thanks all !!!!!

Been away from computer for awhile.......lots of good advice to try.........I know the grounds are AOK, and will key on "head unit delay"

Thanks

Great forum //content.invisioncic.com/y282845/emoticons/veryhappy.gif.fec4fed33b4a1279cf10bdd45a039dae.gif