Quick Question on Audio Splitter Circuit

[dastuff]

I have made a voltage follower circuit using a popular TL072 IC. I send a passive guitar signal into each op-amp on the TL072 and these drive two different signal chains. My question, with 1M of input impedance (via voltage divider for single power supply) in front of the two op-amps, is this good enough for a passive guitar signal to drive the input of (2) op-amps on the TL072? Or am i going to have to use a third op-amp as a buffer to the other two op-amps? Do i need higher impedance? I read that 1M is a rule of thumb for guitar signals.

[Steve Conner]

You can use the same voltage divider to bias both op-amps. Just connect their non-inverting inputs together.

As an aside, if you have a voltage divider of two 1M resistors, the input impedance is 500k. Don't blame me, blame Thevenin.

I'm not sure about input impedance, given that most vintage amps effectively have an input impedance of 130k, if you only use one input, because of the 68k resistors on the twin input jacks, and the fact that the jacks short when there's no plug inserted. Putting an empty jack plug into the other input increases it to 1M. (Well, I guess 1,068k to be pedantic.)