LM3886 unussual pcb

[yd1cvj]

Hi, does anybody use this PCB for LM3886. I'm going to build 2 parallel/pcb. PCB it self for stereo and thickness of pcb 2.6mm.

Just wonder if I can use same componen value as it's printed. And input line are + and - instead L and R. The + and - goes to same pin number, so I conclude it is not bridge.

[madtecchy]

Do you have a schematic for this PCB??????

[AndrewT]

Attach a higher resolution pic.
Then we can open the pic and see the detail more easily.

[yd1cvj]

@madtecchy : I do not have the schematic.

@AndrewT : some of copper line is covered black paint, I will try to get good camera.

[s3tup]

or use document scanner, they are great for PCB "photographing"

[picowallspeaker]

Why shouldn't it be a bridged module ?
As I see, the ICs are held parallel to the board, because there are no trough holes made for the ICs.

Send me four

[yd1cvj]

The black paint is very perfect to hide some copper track even scanner can't "see" it . I draw the scheme and use multimeter to trace connection of some point and get this:
(Sorry the R18K and C 1uf is connected to pin no 8 not to output)


I build one channel w/ 30 volt+/-DC and result is good, eventhough I do not put the C = 1 uf.

[yd1cvj]

I have qustion about feedback R=100k, and biased R=4.7k . I saw other scheme ussualy feedback R=20K.

[AndrewT]

Originally Posted by yd1cvj

I have qustion about feedback R=100k, and biased R=4.7k . I saw other scheme ussualy feedback R=20K.

biased R=4.7k what does that refer to?

Link to a schematic and use the schematic component labeling to make clear what you are talking about.

[yd1cvj]

Originally Posted by AndrewT

biased R=4.7k what does that refer to?

Link to a schematic and use the schematic component labeling to make clear what you are talking about.

Andrew T,
Sorry . Actually I'm refer to the 4.7K in my drawing scheme.

Also I wonder is the elco =1uf is really needed ?