|
Remove the 100 ohm resistors to improve crosstalk. Install a 100 uh inductor to trap rf. Replace the 10 pf feedback caps with 50 to 100 pf, stability will improve as the noise gain of the sum amp rises with the number of inputs summed. This also degrades the phase margin and can affect stability. If you use a low bias, low offset opamp like a Linear Tech LT1358, you can remove the coupling caps. Put the transformer in a box so you can choose whether you want the flavor or not.
Jim Williams
Audio Upgrades
|