Folk Buffer

[HydrozeenElectronics]

Wow, Thanks for posting. I was wondering a while back about how to have variable input impedance and this answered my question to a T.

Thanks

[Greg]

Wow, Thanks for posting. I was wondering a while back about how to have variable input impedance and this answered my question to a T.

Thanks

viewtopic.php?f=28&t=7882&p=82559#p82559

Why not use a pot to ground so you can lower the input impedance ?

[HydrozeenElectronics]

Wow, Thanks for posting. I was wondering a while back about how to have variable input impedance and this answered my question to a T.

Thanks

viewtopic.php?f=28&t=7882&p=82559#p82559

Why not use a pot to ground so you can lower the input impedance ?

I was confused before about how that would react with a voltage divider, now I see you just throw a cap in front of the voltage divider and run your pot to ground before that.

Thanks all around though, I'm stoked about testing it out!

[earthtonesaudio]

That's a cool idea, but the execution could be improved.

The maximum input impedance is just over 85k, due mainly to the op-amp's low input resistance. If you want to vary the input impedance over a more useful range, a better approach would be to put the large value pot in series with the input (like in Soulsonic's Crackle Not Okay).

The diodes on the output... just for decoration?


Not dissing anyone; just expressing my opinion. I think a different (higher input impedance) op-amp would make more sense, and you could lose the output diodes.

[earthtonesaudio]

I think there is power protection in case something comes back through the output.

That makes sense. I thought that might be the reason, but second-guessed myself. I'm gonna check out the original thread to see if I need to eat any other of my words.