Hello, i wanted to power my amplifier wich is working, with dc power. The amplifier has a power supply on it, but i wanted to power it from a battery or from a other power supply, i figured out what the gnd and vcc traces are, i connected a power supply on it, it worked but the subwoofer maked strange sounds.I upload photos so you can see the pcb, when someone aks where the amplifier comes from, its from a speaker system from Trust gxt 38 tytan 2.1. Now i need help, i hope someone can help me, Thanks.

 

We need to see the schematic.

 

We need to see the schematic.

Srry but i cant find anyone, thats the problem.

 

U have a SMPS as a PSU in that amp PCB
I presume it has the feeble TDA2010 or TDA 2030 chips.
U can use two 12V 5A SLA in series to supply ±12V.
Might need an additional regulator to provide any auxiliary supply if the SMPS has any.

 

by the way, if the sub-woofer is making noises, try replacing it's amp chips

 

by the way, if the sub-woofer is making noises, try replacing it's amp chips

Thanks for the reply, the subwoofer is working when i use the pcb power supply. but when i use the externel power supply then the subwoofer makes strange sounds. And the power supply is feeding the amplifier with 30V and 3A, and i used the exact same voltage and ampere on the external power supply.

 

U need to supply ± Voltages.
Measure the PCB positive and negative rails.
I don't think a single ended supply is used originally.

Give me the Subwoofer IC number first

 

From ur image it seems u are measuring 30V across -V and +V.
U need to use the ground line which is the 0V reference.
In the image I have marked the 0V line



U need ±15V for this amp.
±12V will also do, if you wanna use batteries. But do use two fuse for the voltage rails. One for -Ve and one for +Ve

 

From ur image it seems u are measuring 30V across -V and +V.
U need to use the ground line which is the 0V reference.
In the image I have marked the 0V line

View attachment 162783

U need ±15V for this amp.
±12V will also do, if you wanna use batteries. But do use two fuse for the voltage rails. One for -Ve and one for +Ve

Hello, i measured again the rails, there where you marked the 0v rail there are 15V and the other one i marked are 30V. The problem is the subwoofer line is connected to 2 ics, The first one is LM1875 and the other one is TDA2030A.

 

Try googling how to measure
dual supply rails with DMM

 

Try googling how to measure
dual supply rails with DMM

I powered the traces with 15V and 30V with exact same power supply, but its still makes strange noises.

 

Draw a detail diagram of u connected power and show us

 

And also show us a pic of ur psu