plz check my bais

[electro samurai]

its a 20w amp based on a ic, lm1876.
im not sure its properly baised, plz check me.
thx 2 all that reply.
[IMG]C:\Documents and Settings\roey prat\My Documents\electric data\complete 20w amp.bmp[/IMG]

[electro samurai]

i hope u can c it this time...

[runebivrin]

Aaahh, don't quite know where to start.

Doing a quick calculation on the voltage divider you use to get ground from single power supply:

40Vac * 1,4 = 56Vdc = 28V / resistor

Ir = 28/2.5 = 11.2A

Pr = 28 * 11.2 = 313.6W / resistor

So, you're looking at burning 627W just to get 20W output power.

I suggest that you either replace the resistors with something like 100 ohms parallell with 2200uF, or place a 4700uF cap on the output. Or better, get a centre tapped transformer.

Rune

[GregGC]

Originally posted by runebivrin
Aaahh, don't quite know where to start.

Doing a quick calculation on the voltage divider you use to get ground from single power supply:

40Vac * 1,4 = 56Vdc = 28V / resistor

Ir = 28/2.5 = 11.2A

Pr = 28 * 11.2 = 313.6W / resistor

So, you're looking at burning 627W just to get 20W output power.

I suggest that you either replace the resistors with something like 100 ohms parallell with 2200uF, or place a 4700uF cap on the output. Or better, get a centre tapped transformer.

Rune

Yes, Do it right with the proper transformer and put a 22k res. from +in to GND and an 10uF input cap (depending where you connect the input to).

Otherwise you might as well connect the IC as a single supply configuration with an output cap.

/Greg