Trobleshooting a faulty amplifier

3 years ago I bought a car amplifier. Lately one of the 2 channels is
producing cracking noise. Not hiss noise, but inconsistent cracking.

1. The noise doesn't go away and remain the same even when I turn down the volume to zero.

2. The noise remain there even I unplug the RCA from my amp.

3.
When I turn up the volume, the noise will go away sometimes. I'll then
turn down my volume. After a few minutes, the noise will come back.

4.
I have remove the amplifier and replaced with another amplifier, the
noise is gone (with the new amp). But when I install back the old amp,
the noise comes again.

5. The cracking noise level doesn't change when I adjust the "gain" on my amp.

Base on the above finding, I could draw the following condition:
1. The problem is not with the head unit (noise remained even RCA cables are unplug)
2. The problem is not with the grounding (noise only from one channel)
3. The problem is not with the power cable or other common components (external and internal)

Mostly
like my amp is faulty. I do not plan to replace it. I'd like to fix it
if possible. Is anyone out there be able to help? I don't practice EE
so I have no idea what component in the amp need to be replaced.

Hi Kelvin.

I normally deal with repair of power amplifiers and home hifi amplifiers, but car amplifiers also produce almost the same electronic faults.

Does your car amplifier produce noise when you move or press your volume control. If it does, then the problem with your amplifier is with the volume control.

If your amplifier does not make any noise when you move the volume control, then the problem is most likely with the capacitors starting to leak.

With Regards,
Edmund Jude

Hi Edmund, thanks for the input. The amplifier produces noise even with the RCA cable removed from the Input. And the noise doesn't change when adjusting the "Gain" on the amp. I do suspect it's capacitor problem.

I had sent the amp for repair and hopefully it doesn't cost too much.

Btw, I have a NAD Integrated Amplifier which is also producing crack noise on and off on the right channel. I'll give you a call and see if you can help me on that since you do provide repair service.

Thanks again.

kelvinyam wrote:Hi Edmund, thanks for the input. The amplifier produces noise even with the RCA cable removed from the Input. And the noise doesn't change when adjusting the "Gain" on the amp. I do suspect it's capacitor problem.

I had sent the amp for repair and hopefully it doesn't cost too much.

Btw, I have a NAD Integrated Amplifier which is also producing crack noise on and off on the right channel. I'll give you a call and see if you can help me on that since you do provide repair service.

Thanks again.

Hi Kelvin,
I can repair the cracking noise problem on your NAD. I have repaired many NAD units before with this problem and mostly its caused by the capacitors.
Please feel free to contact me at 012-2174777.

With Regards,
Edmund