amplifier unstable problem

[sametkarakoyunlu]

Hello,

i made a guitar amplifier. But i have a problem. I add a video and schematic link.

video : https://drive.google.com/file/d/1UWhGdim6vpIAbIJum5EPUE7MTuyZL0RR/view?usp=sharing

schematic: https://drive.google.com/file/d/1ybwzHHtpqFBV5gKnsvlcSiusPlCdJg0P/view?usp=sharing

mail : snkmuhendislik@gmail.com

 

[jan.didden]

If you don't clearly explain what the problem is, under what conditions, you will get a lot of views and very few replies.
Your video doesn't tell me anything.

Jan

 

[sametkarakoyunlu]

I made a guitar amplifier as shown in the diagram, but when nothing is connected to the input of the amplifier, popping and crackling sounds come from the speaker for no reason. I couldn't quite figure out where and why the problem was. The yellow and blue probes connected to the oscilloscope in the video represent the signals at the power stage input of the amplifier. If you want, I can also send you the altium designer file.

 

[rayma]

Never test an amplifier with an open input.
Either insert a shorting plug into the input socket, or connect it to a source.

 

[sametkarakoyunlu]

Hello, if you look at the schematic, you can see that the audio inputs are connected directly to the ground line when the guitar is not connected.

 

[Mark Tillotson]

Crackling can be either a faulty component or a poor intermittent connection (such as dry solder joint). Tracking down the culprit can be done with an (insulated) prodding stick or a freeze-spray. Since this is down powered-up you need to do it safely if the mains power is accessible.

 

[sametkarakoyunlu]

This problem does not always occur. It usually happens when I first turn on the amplifier and it stops on its own. Then it reappears at an undetermined time.

 

[gorgon53]

Fake components easely turn into faulty components, look into that possibility also