Handmade PCB layout works?

Thread Starter

TieBravo

Joined Aug 21, 2021
50
Hey its me again ☹ and this time with LA4440. Have a look at the pcb diagram, and i tried to mimic the diagram using cardboard and copper wire strips (2 resistance would be added later). The copper wire strips i took is from The leftover of a thick electric cable that's used in my home's main switch terminal and we're also using these as a fuse wire on our wall boards. My question is, would that cause any resistance issue to my circuit? I mean those strips might heat up and change the circuit's total impedance?
 

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shortbus

Joined Sep 30, 2009
8,880
we're also using these as a fuse wire on our wall boards.
Won't comment on your posts real question. But the quote above causes a concern. What exactly do you mean? Wire is not a fuse or circuit breaker, if that is what your using it for, a fire could be in your future.
 

BobTPH

Joined Jun 5, 2013
3,812
I have to congratulate your ingenuity, but I think cardboard is not the best material due to it's lack of strength and rigidity. Couldn't you get your hands on a perfboard? You could lay it out the same way on the more stable base.

Edit: Oh, and what are currents? That wiring should be fine for up to 1A. Anything more, use more copper.

Bob
 

Thread Starter

TieBravo

Joined Aug 21, 2021
50
Won't comment on your posts real question. But the quote above causes a concern. What exactly do you mean? Wire is not a fuse or circuit breaker, if that is what your using it for, a fire could be in your future.
Sorry for misunderstanding, i tried to say im using the same wire strip which has been used as our wall socket fuse wire. I mentioned that just to make the viewers understand the connector wire's thickness.
 

Thread Starter

TieBravo

Joined Aug 21, 2021
50
I have to congratulate your ingenuity, but I think cardboard is not the best material due to it's lack of strength and rigidity. Couldn't you get your hands on a perfboard? You could lay it out the same way on the more stable base.

Edit: Oh, and what are currents? That wiring should be fine for up to 1A. Anything more, use more copper.

Bob
Thank you, i felt it's unreliability too, that is why i would be securing it on a box and make sure this don't wiggle around. But the wire i used would cause any problem? Is it too thin?
Another question, should i ground the heatsink?
 

Yaakov

Joined Jan 27, 2019
3,602
I have to congratulate your ingenuity, but I think cardboard is not the best material due to it's lack of strength and rigidity. Couldn't you get your hands on a perfboard? You could lay it out the same way on the more stable base.

Edit: Oh, and what are currents? That wiring should be fine for up to 1A. Anything more, use more copper.

Bob
Even laminating the cardboard would provide a better substrate, but I would be worried about fire resistance even if it was more structurally sound.
 

KeithWalker

Joined Jul 10, 2017
1,938
The problem with using cardboard is that it will absorb water in a humid atmosphere. That would cause it to loose its physical strength and its insulating properties. It would work much better if you first sealed it with lacquer or varnish.
Look up copper wire tables. They will give you the resistance per unit length of the wire you are using. You will find that the resistance of such short lengths of wire is so low that it will have very little resistance even at several amps and will generate negligible heat.
 

Thread Starter

TieBravo

Joined Aug 21, 2021
50
The problem with using cardboard is that it will absorb water in a humid atmosphere. That would cause it to loose its physical strength and its insulating properties. It would work much better if you first sealed it with lacquer or varnish.
Look up copper wire tables. They will give you the resistance per unit length of the wire you are using. You will find that the resistance of such short lengths of wire is so low that it will have very little resistance even at several amps and will generate negligible heat.
Thanks for the reply, should i ground the heatsink
 

Thread Starter

TieBravo

Joined Aug 21, 2021
50
Hello i made the layout using cardboard and copper wire.
All the components are new, I'm using a 12v transformer and tested its ampere using multimeter settings 200u (knob is at ampere side ) and it showed .5
Problem is humming noise when amplifier is idle, and the noise is increasing when i insert the jack on my smartphone, humming sound doesn't get effected when i increase or decrease phone's volume. I tried connecting the heatsink with the on board gnd and both negative end of the speakers to my home's wall socket's 3rd pin. Doing this the humming noise is reducing just a bit (but the cones are still vibrating) while idle, but this got no result when i connect the amp with my phone (same increased humming noise).
I also tried connecting it with a 9v transformer (both got diode bridge rectifier) with amp value .2 using amp settings 200u. But no result, no humming noise when idle but connecting aux causes problem.
Here is the back side of the pcb diagrams.
I need help.
Update: touching the phone's screen causing a slight "ssssss" noise whenever i touch it, it stays there for less than a second even after taking finger away. And after sometime when im playing songs now the buzzing noise seems to me minimised some how. Vocals and music can clearly be heard when when the song stops i can still here the buzzing (maybe persists when the song is playing its just the song that's overlapping it).
 

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Thread Starter

TieBravo

Joined Aug 21, 2021
50
Test with a 12V battery and see if the hum goes away.
Thanks for the useful reply no humming or buzzing when i connected with a 6v battery, stereo working fine both channel. Even though i have diode rectifier with my transformer what's the reason the circuit still got some ac in it ?
 

MrChips

Joined Oct 2, 2009
24,441
One diode after an AC transformer makes a half-wave rectifier. You need a full-wave rectifier using four diodes.
Use a 4700μF reservoir capacitor to smooth out the output ripple voltage.

1630672985498.png
 

Thread Starter

TieBravo

Joined Aug 21, 2021
50
Please tell me why on earth my handmade amplifiers are not working like it should after 2-3 days?
I made an amplifier based on 4440 ic and it worked pretty good (but bass distortion when i volume it up). After 3 days the right channel sounded lower than the left channel, ic was warming up as it should, no sudden heat.
Same thing happened to my CD6283 handmade amplifier.
I used new components and didn't heat up (max 6secs) the components much while soldering, no chance it would be a heat damage.
Below i added the 4440 diagram that i followed.
I would be grateful if any of you share a stereo amplifier schematic based on 4440 or any other amplifier ic that can be handmade. I am trying gift this to my grandpa and i love making these.
 

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