Thump sound

[sharma]

Hi,

I recently got a new jbl amplifier. Previously i have had cheaper amplifiers such as Pyle. Anyways i must say the sound quality is definately better.

When i turn my car on its fine however if i have the radio on or turn my car off and dont take the key out (so the radio is still on), and then i turn my car on, there is a thump sound.

Basically if you have the radio on the sound appears as soon as the car is turned on. This did not happen with my old amplifiers. Does anyone know why this is? Could it be a faulty amplifier?

Thanks.

 

[AndyMac]

I take it you are using the stock Audi head unit?
If this is the case then the thump is normal. It's caused by the bizarre way Audi HU's mute the line outs going to the rear amp. So when you first turn the HU on you get a slight thump. The amount of thump depends on the amp you are using, the quality of its input circuitry and how quickly it switches on. JBL are not particularly good amps, although admittedly better than Pyle. If you used an Alpine V12 or similar decent quality amp then the thump would be much less pronounced or completely gone.