Parallel LM3886 problem

[tb46]

Hi Y'all,

I was just think about building another LM3886 amplifier (after a long time) when I ran into this thread, thanks all, great stuff.

danielwritesbac,basically, you got it right.

In general the resistor at the non-inverting of an opamp is used to balance the dc offset. The rule of thumb for the value of this resistor is the parallel combination of the feedback resistors connecting output to inverting input to ground. This resistor is also a known noise source.

A capacitor connected in parallel to this resistor will not affect the dc performance, but will roll off (short out) the higher frequency signals at the positive input.

As a probably dumb question: "Has anyone tried this circuit with feedback components that are more in line with the values recommended by National Semiconductors, and reflected in standard implementations of the LM3886 as e.g.: the Elektor version?" It may well be that changing the design feedback components by an order of magnitude worsens the transient behaviour of this circuit. As Tom (gootee) seems to point out it is back to the seventies and all the fine discussions about slewrate and TIM.

Regards,