I put a clipping indicator LED circuit on one of my home amplifiers and it rarely flashes when I am using the amplifier. But it flashes all the time when my wife uses the amplifier.

 

I put a clipping indicator LED circuit on one of my home amplifiers and it rarely flashes when I am using the amplifier. But it flashes all the time when my wife uses the amplifier.

Because you don't set the input to its maximum it doesn't have clipping, but your wife does, right?

 

Well, I think it's distortion.

For any serious work analyzing audio amps an oscilloscope and various size dummy loads are priceless.

 

For any serious work analyzing audio amps an oscilloscope and various size dummy loads are priceless.

Thank you for your advice, but I think at this time, that is all I can do. But as soon as I can, I will make more measurements.

 

Because you don't set the input to its maximum it doesn't have clipping, but your wife does, right?

Your live playing has no "compressor circuit " but my recordings playing has a compressor circuit in the recording studio. Therefore your peak levels produce clipping when you strum your guitar hard but my recordings do not produce much clipping.

Does anybody "set the input (volume control) to maximum"? The fixed gain of an amplifier is always too much so that a low level input signal can have the output be turned up to normal level. Then normal and high input levels MUST be turned down to avoid clipping distortion.

I understand about clipping and turn down the volume control to eliminate it but maybe my wife thinks that clipping distortion is already in the recordings.

 

Thank you for your advice, but I think at this time, that is all I can do.

I would suspect that once you get the chip mounted on a pc board it will be fine.

 

Well, I just finished the schematic of the circuit. Is there anything should I change to make it better? Hope to get you guys advice.
I will attach the datasheet of the IC and module I use here:
DFPlayer: DFPlayer Mini Mp3 Player - DFRobot Wiki
AMS1117: AMS1117.PDF

 

Looks OK to me. The important thing is the pcb design, keeping all the audio input signal grounds separate from the power ground.

 

Looks OK to me. The important thing is the pcb design, keeping all the audio input signal grounds separate from the power ground.

I mean to pour a polygon for the PCB with the net GND, but I will set the polygon clearance large, like 3mm for instace. Is that okay? Or I shouldn't pour with the net GND but with another net. Hope to hear your advice!

 

I would need to see the pcb design before making any comments.

 

I would need to see the pcb design before making any comments.

Alright, I think it will take a while to finish it. When I finish, I will send it here. Thank you so much!

 

Looks OK to me. The important thing is the PCB design, keeping all the audio input signal grounds separate from the power ground.

Not related but I wonder if is there any way that I can add the Mosfet and BJT to my circuit. They can make the circuit have more functions or just replace the components or parts that aren't needed. Hope you can give me some ideas or hints to make it possible.

 

What mosfet and bjt are you speaking of?

 

What mosfet and bjt are you speaking of?

Oh, my bad, I mean that if is there any way that I can add a MOSFET and a BJT to my circuit? Just any kind of MOSFET and BJT.

 

Possibly using a P channel mosfet to replace the relay but personally I like using the relay it's simpler.

 

Possibly using a P channel mosfet to replace the relay but personally I like using the relay it's simpler.

Ok, I will give it a try. Thank youu!

 

Possibly using a P channel mosfet to replace the relay but personally I like using the relay it's simpler.

I still keep the relays, but there's a problem, when I use the 12VDC jack, it's fine. But when I take it out, the circuit uses the battery power, and then it starts to vibrate and make noise. When I measured the voltage has dropped down to 1.6 V, but with no load, it was 11.42V. When I used the output of the relay of the battery go through a 1k R and LED, it didn't vibrate and made a noise. I also tried to use the NC of the relay (from the battery) to power the circuit and it works. Do you know what is the problem?

 

and then it starts to vibrate and make noise.

What exactly starts to vibrate and make noise, the relay?
Think the contacts on the relay are not wired correctly.

 

Your voltage and relay vibration is probably because your tiny 9V battery is severely overloaded. It is made to operate a low current smoke alarm for 1 year.

 

What exactly starts to vibrate and make noise, the relay?
Think the contacts on the relay are not wired correctly.

Yes, the relay. I will check it again, but yesterday, I measured the output of the relay when I plug the jack and when without and it looked correct.