Inverting Unity Gain or Non-Inverting Unity Gain for LFO Driver

[danfrank]

Hi everyone!
I'm looking to add a second channel (for stereo) to my crazy ADA flanger clone. I want to drive the second channel's LFO with the first channel's LFO, so they are in sync. I was wondering if there is an advantage to using an inverting vs. non-inverting unity gain op amp configuration. Please see attached pic. Phase is irrelevant as I can always add another op amp stage to invert phase.
I've seen non-inverting op amp stages used as a voltage reference but I'm assuming that they work well for voltages that change? My main goal is to not load the voltage output of LFO #1 and have the same voltage but low impedance driving the sweep of flanger #2. The 2 flangers are in different enclosures and will be connected by a 3.5mm jack/plug to carry over the LFO voltage.

[antonis]

I was wondering if there is an advantage to using an inverting vs. non-inverting unity gain op amp configuration.

Only input impedance difference..
(other than 0^o/180^o phase shifting..)
Your schematic isn't accurate 'cause for non-inverting configuration a Vref to Vin bias resistor is needed, which resistor sets the input impedance where 75k one sets the input impedance for inverting configuration..

[danfrank]

Thanks for the reply...
Hmm... I'm trying to understand what you're saying about Vref... Take a look at attached picture. What you're saying is to configure it as the top drawing and not the bottom drawing because this is a single polarity supply and not a split rail supply?
Thank you for your help.

[iainpunk]

i'd recommend the NON-inverting since it has higher impedance, and then an phase flipper to chose between in and out of phase.


cheers, Iain

[antonis]

For Inverting configuration, input impedance is R..
For Non inverting one, input impedance is the value of resistor going to Vref..

P.S.
AC amp coupling capacitors are omited for the sake of simplicity..

[danfrank]

Yeah, the non-inverting suits my needs better as the op-amp I'm taking the original signal from has the correct phase already.
There will be no coupling capacitors, audio will not be passing through this, just  a slowly varying DC voltage (which technically speaking, is an AC voltage. Lol!)