Csom sir!
i am pleased to inform you that project was a success! the volume controls are precisely where they should be.. and there is no heating/sparking or anything.. but there is a small problem... the sound is very less.. i mean my earphones sound higher! i guess this is because i didnt connect the bass-treble controls... i guess i should do that before coming to any conclusion as you yourself said it will not get proper gain without those pots.. anyhow thanks a ton for the help
i am pleased to inform you that project was a success! the volume controls are precisely where they should be.. and there is no heating/sparking or anything.. but there is a small problem... the sound is very less.. i mean my earphones sound higher! i guess this is because i didnt connect the bass-treble controls... i guess i should do that before coming to any conclusion as you yourself said it will not get proper gain without those pots.. anyhow thanks a ton for the help
Csom sir!
i am pleased to inform you that project was a success! the volume controls are precisely where they should be.. and there is no heating/sparking or anything.. but there is a small problem... the sound is very less.. i mean my earphones sound higher! i guess this is because i didnt connect the bass-treble controls... i guess i should do that before coming to any conclusion as you yourself said it will not get proper gain without those pots.. anyhow thanks a ton for the help
Csom, great piece of reverse engineering! Nice work.
Hugs!
Only "Som" is more than adequate
Thank you for your kind feedback
I am so happy for you!
Congratulations!!
Thank you so much quadtech!
It really hurts that some manufacturers really don't care about the customer/hobbyists and their hard earned money. It's hard to believe that an audio kit comes with absolute no reference
So sad.
indeed..! great reverse engineering..delivered very detailed and kindly(answering my noob questions.)
as for the sir part! i am half of your age. i guess i should call you that...
Bro, I came here to learn about audio ,just like you, from other great masters of audio in the fora
So we are co-learners.
Hugs
Bro, I came here to learn about audio ,just like you, from other great masters of audio in the fora
So we are co-learners.
Hugs
dear Som sir,
I noticed two things, the potentiometers given as BASS AND TREBLE have NO EFFECT ON THE OUTPUT WHATSOEVER also, connecting the bass and treble control has no effect on the output.. the output is still barely hearable...
Okay bro,
Checklist here:
First please check if every solder joint is okay or not.
then....
1. Check if the supply voltage is as per recommended value using a multimeter. And test the voltage at the collector of the transistors too (in the active tone control section).
2. Touch a screw driver at the pin 1 and 2 of the 5 pin connector ( that goes to the input pin 2 of the ICs. If everything is okay you should hear a louder hum if your system is powered with AC 12 Volts using a step down transformer.
3. Make sure everything is wired as per the connection. Touch at each input of the Bass and Treble you will notice some noise/hum.
4. If that fails, the problem might be in the active tone control section.
In that case, please study the following tone control circuits using Transistor so that you can understand how it works.
http://www.electronicecircuits.com/electronic-circuits/bass-treble-tone-control-circuit
Bass Treble Controller Circuit Diagram For Amplifier | Electronics Circuits For Students
5. The potentiometers should ideally be 100K . But 47K works too with a compromise in some cases.
Hope you have not missed the Filter Cap, c19 I guess. ( please check previous posts)
Please make sure the LA4440 Ics are running properly. The rest can be solved easily.
Checklist here:
First please check if every solder joint is okay or not.
then....
1. Check if the supply voltage is as per recommended value using a multimeter. And test the voltage at the collector of the transistors too (in the active tone control section).
2. Touch a screw driver at the pin 1 and 2 of the 5 pin connector ( that goes to the input pin 2 of the ICs. If everything is okay you should hear a louder hum if your system is powered with AC 12 Volts using a step down transformer.
3. Make sure everything is wired as per the connection. Touch at each input of the Bass and Treble you will notice some noise/hum.
4. If that fails, the problem might be in the active tone control section.
In that case, please study the following tone control circuits using Transistor so that you can understand how it works.
http://www.electronicecircuits.com/electronic-circuits/bass-treble-tone-control-circuit
Bass Treble Controller Circuit Diagram For Amplifier | Electronics Circuits For Students
5. The potentiometers should ideally be 100K . But 47K works too with a compromise in some cases.
Hope you have not missed the Filter Cap, c19 I guess. ( please check previous posts)
Please make sure the LA4440 Ics are running properly. The rest can be solved easily.
Last edited:
Now you will enjoy the true DIY spirit.
Don't be frustrated. This trouble shooting is the fun part in a DIY situation.
It is a very very simple circuit. Study the datasheet over and over again.
Keep your cool. Don't make haste. It happens in the life of every hobbyist.
Please wear a protective eye glass and always be careful with the polarity of the evil electrolytic capacitors while fault finding your amp.
You yourself will figure the problem out in no time, I am confident.
All the very best.
Don't be frustrated. This trouble shooting is the fun part in a DIY situation.
It is a very very simple circuit. Study the datasheet over and over again.
Keep your cool. Don't make haste. It happens in the life of every hobbyist.
Please wear a protective eye glass and always be careful with the polarity of the evil electrolytic capacitors while fault finding your amp.
You yourself will figure the problem out in no time, I am confident.
All the very best.
Bro,
From your this post, one thing that comes to my mind is the speaker connections as I guessd from your photos are not right ( although I am right as per datasheet reference). Perhaps, thats why tone control has no effect.
I was studying some LA4440 circuits and PCBs on net. And I found a board where the speaker wires are directly connected to PIN 10 and 12.
Please see this link: LA4440 Amplifier Circuit ~ CircuitsTune ( FIG:2)
and this , for PCB reference.
LA4440 audio amplifier in Bridge mode | CircuitsDIY.
But to my utter surprise I have not found such an example in the Datasheet that I studied.
And more I am not sure about the value of the caps used in your circuit.
But I think you should carefully study the links that I gave and take a decision.
All the very best.
Attachments
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.