Help - Hissing sound after installing Amp

[Tane0019]

Need help

 

Got an old working amp from a friend & fix it up onto my new Altis.

At the same time, also change the front speaker to 2 components + rear to 6x9 coaxial.

 

Now, when ever I start up my car (even without power on my factory fitted HU), there is a loud hissing sound coming out of the speakers (I think from the front). Once in a while, there will also be some spark sound coming out of the speakers when I start-up my car.

 

The Amp : JBL Grand Touring GTO75.4 (4x104W RMS 4 Ohms <=1% THD +N).

 

Because my factory fitted HU do not have any pre-out + my amp have high level input : the set up was done with speaker outputs from the HU directly into the amp.

 

Was told that the only way out of this is to replace the HU with one with pre-out. True ?

 

Is there any other way to remove the un-wanted hisiing noise other than replacing the HU ??

 

[Roverboy]

most likely is workmanship problem,redo the wiring.

my stock headunit install amp and speaker also got unwanted sound,sent to another installer to redo the wiring and it slove the problem

[Galantspeedz]

Need help

 

Got an old working amp from a friend & fix it up onto my new Altis.

At the same time, also change the front speaker to 2 components + rear to 6x9 coaxial.

 

Now, when ever I start up my car (even without power on my factory fitted HU), there is a loud hissing sound coming out of the speakers (I think from the front). Once in a while, there will also be some spark sound coming out of the speakers when I start-up my car.

 

The Amp : JBL Grand Touring GTO75.4 (4x104W RMS 4 Ohms <=1% THD +N).

 

Because my factory fitted HU do not have any pre-out + my amp have high level input : the set up was done with speaker outputs from the HU directly into the amp.

 

Was told that the only way out of this is to replace the HU with one with pre-out. True ?

 

Is there any other way to remove the un-wanted hisiing noise other than replacing the HU ??

 

 

happened to me....

 

1st time.... they had to 'de-tune' my amp.....

2nd time... was my HU short circuit... changed new HU...

 

 

[Tane0019]

most likely is workmanship problem,redo the wiring.

my stock headunit install amp and speaker also got unwanted sound,sent to another installer to redo the wiring and it slove the problem

 

 

Which installer ?

How much does it cost you ??

[Patience]

my installer also told me to change my HU...

after changing, the hissing was solved

[Beehive3783]

My installer did a hi-lo converter set up on my friend's factory HU. Same without any pre-outs. I wonder how TS's installer managed to hook up directly to the amp without installing a hi-lo converter in between.

 

My suggestion is to check the the wiring. And also turn down the gain level on the amp first.

[Tane0019]

My installer did a hi-lo converter set up on my friend's factory HU. Same without any pre-outs. I wonder how TS's installer managed to hook up directly to the amp without installing a hi-lo converter in between.

 

My suggestion is to check the the wiring. And also turn down the gain level on the amp first.

 

My amp has a high-low input (converter built in).

[Beehive3783]

My amp has a high-low input (converter built in).

Ah I see.. then most likely should be wiring problem. Worst case is amp or head unit up lorry.. go back to the shop and get them to fix the problem.

[Subarugt]

wiring issue... they will detune the amp power to reduce the hissing sound

[Beehive3783]

wiring issue... they will detune the amp power to reduce the hissing sound

it might also be the amp problem.

[Roverboy]

foon garage,not cheap

[Tane0019]

Tomorrow going down to [Autoimage, the original installer] to get the tuning done up.

Hopefully, no need to replace the HU & spend more $$.

Wish me luck.

[Beehive3783]

Tomorrow going down to [Autoimage, the original installer] to get the tuning done up.

Hopefully, no need to replace the HU & spend more $$.

Wish me luck.

ok, good luck then

[Tane0019]

Hissing sound reduce. He also teach me where & how to tune the amp. Might try one of the day to see possible combination.

[Beehive3783]

Hissing sound reduce. He also teach me where & how to tune the amp. Might try one of the day to see possible combination.

try reducing the gain.. might reduce noise from the system.