Connecting a "virtual" to "real" ground circuit on the same supply? Is that OK?

[merlinb]

BUT you'll have to keep voltage divider resistor values (for Vbias) as low as possible (max affortable current consumption)..

Actually you want them to be fairly large to minimise noise and current consumption. Typically they can be 100k or even 1Meg when using a TL0xx opamp.

[antonis]

Actually you want them to be fairly large to minimise noise and current consumption. Typically they can be 100k or even 1Meg when using a TL0xx opamp.

In such a case, there shouldn't be need for "extra" bias resistor..

[duck_arse]

with an electro at C2, you deffo want a pull-down resistor (100k? 220k?) on its (-) leg to ground. maybe a high-value pulldown on the input cap as well?

[diffeq]

Thanks everyone for the input.

with an electro at C2, you deffo want a pull-down resistor (100k? 220k?) on its (-) leg to ground.

Now that you mentioned it, I see pull-down resistor at the output a lot in various pedal schematics. Completely forgot about that!

maybe a high-value pulldown on the input cap as well?

Should be high enough then (1-10M is what saw in several input buffers). Again, how much noise will 10M introduce? Seems like quite a large value.

[samhay]

>Should be high enough then (1-10M is what saw in several input buffers). Again, how much noise will 10M introduce? Seems like quite a large value.

You aren't thinking about the system:
What do you plug into the input?
Does this additional circuit have some impedance to ground?
If so, is it << 10M.
If so, does the additional resistor's resistance make any difference seeing as it is parallel to this impedance?

[PRR]

The 1Meg bias resistor is ||in parallel|| with your source. Source is say 50K, and can't be changed. The result is 95% of signal with a 47.6K hiss equivalent resistance. NOT "1Meg". Things are even better with 10Meg (as Merlin says).

We usually pick the two divider resistors 100K or less, because... why not? Higher values seem to reduce the size of the capacitor at the junction, but <100K allows a cheap electrolytic instead of a costly film cap.