Linkwitz lm3886 circuit

[srfranci]

Im building his Orion speakers at the moment and am searching for an amp to power them. Stumbled across this
Lm3886 amp circuit
Im in a basic linear circuits course right now, and Im trying to figure out the purpose of some of the parts on his design that I don't normally see on the ones on this forum. BTW, the input to this is an active crossover.

1. The 100pF capacitor across the feedback resistor.

2. The Ci capacitor

3. The 1k 19.6k voltage divider at the input with the 1.5nF capacitor

4. The 220pF capacitor across the input terminals of the opamp

Been browsing the forums for a couple months and havn't seen these, save #4, on other designs. Any ideas?

[Mr Evil]

1) Increases feedback at high frequencies, rolling off frequency response.

2) DC feedback capacitor, ensures gain of 1 at DC, rolling off frequency response at the low end.

3)The 1K resistor at the input forms a low-pass filter along with the 1.5n capacitor. I think the fact that it is also a voltage divider with other the input resistor is a side-effect only.

4)For RF suppression.

I'm sure you'll come across all four being used again, none of them are that uncommon, in fact I'm sure most of them are in the LM3886 datasheet.