Inverting amp, not inverting..at a loss

[chicago_mike]

Lastly..those 1000p caps. Should those stay at 1000 or am I doing wrong by changing those values?

Thats more a curiosity.

[amptramp]

The 1000 pF cap in parallel with a 1000 ohm resistor gives a lowpass at 159235.7 Hz.  It is good for stabilizing the stage and does not get in the way of any audible signal.  The resistors seem a little low for an op amp stage, but if it can swing the current, there is no problem.

[R.G.]

I saw a schematic like that...

The invert was tapped off pin 1, and it fed to a 10k, with a 10kfeedback resistor.

The gain of both opamps / outputs  would be more or less matched.

More importantly, the first amp does whatever fancy stuff it does, and the second amp ONLY inverts what the first one does. The second amp output is "matched" because whatever the first amp does, the second amp inverts it.

[chicago_mike]

Thats what I thought. 

I felt like trying to create a whole new "stage" just to invert a signal was overboard.

159235.7 Hz   ... wow.

[chicago_mike]

the outputs are almost perfectly matched.

I used a 3k3 for gain and 2 x 11K1% matched for the inverter.

should I remove pin 5 resistor to ground and just wire it with a jumper?

[R.G.]

the outputs are almost perfectly matched.
...
should I remove pin 5 resistor to ground and just wire it with a jumper?

Great!

The pin 5 resistor to bias (that's how the ground to pin 5 is being used in this thing) is somewhat arbitrary. Strictly speaking, it should be the same as the parallel combination of the feedback and input resistors, or about 5.5K for best DC accuracy. For lowest thermal noise from the resistance, it should be a jumper. For lowest ground-noise pickup, it should be some medium value. On top of that, DC accuracy is of almost no concern here because of the +/- 15V power supplies and the trivial amount of gain and offset, as well as the almost nonexistent bias currents that would degrade DC accuracy anyway.

Mostly - it doesn't matter much. Leave it there. If there's noticeable hiss in the inverter output that's not in the straight output, swap it for a 10K (about) carbon film. Or a jumper. I suspect it won't make much difference.