LM3886 Chipamp capacitor substituions

[vinay]

Can I sub out C1 and C2 for 1500uF, should be OK I think.

Also, if dont need mute function, can I leave out the mute resistor and cap. Also can pin 8 can be left open or it needs to be terminated in some way?

Regards, Vinay

 

[tomchr]

That's answered in the second line of the spec table in the LM3886 data sheet:

... and in the first paragraph of the Application Section of the data sheet:

In other words, if you want the amplifier to amplify, you need to take it out of the MUTE state. That's done by drawing at least 500 uA through pin 8. If you also want good performance, you need to add Cm as well.

Have a look here: https://neurochrome.com/pages/grounding#Mute

I don't see any C1 and C2 in your schematic. Are you referring to the supply bypass caps? You'll need at least 470 uF where the power enters the board and then a minimum of 10 uF || 100 nF at the IC pins. You can do better than that though.

My thoughts on LM3886 decoupling: https://neurochrome.com/pages/supply-decoupling

Tom

 

[jjasniew]

There's also a time constant implicit given the R and C in the mute circuit. Perhaps without these components, you get a power on thump when the switch is eliminated. Perhaps you'd get a mute thump with just the switch alone.