input voltage for a lm3886

[Gaston]

i looked on the spec sheet but didn't see were it said how much input signal voltage it can take. i measered the output from my computer and it doesn't even hit .2 volts. i had to put at least one volt to get 30 out of the amp. i would guess that i need a preamp. thats why i was wondering how much voltage to design the preamp to output. or does anyone have a preamp design already?

 

[Russlk]

The gain is determined by the ratio of Rfi to Ri as shown on the datasheet. The datasheet circuit gives a gain of 21, if you want more, make Rfi larger than 20K ( like 100K). You shouldn't need a preamp.