Optional Resistors in GGG Octavia

[fogwolf]

Hi,

I'm building the Octavia project from GGG (http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=128&Itemid=26) and had a question. JD lists the 2 1.5M resistors as optional. 1 is at the input and 1 is at the output. He has 2 schematics up, one that includes a pre-gain input pot and one without. Both schematics have the output 1.5M resistor present but the schematic *with* the pre-gain pot does *not* have the input resistor. So, my question is, what's the difference if I leave these out or put them in? Are they both there to help with capacitor/switching popping? Does the input resistor also contribute to the input impedance? If so (or even if not), should I put this resistor in if I'm also including the input pre-gain pot?

Thanks!

[petemoore]

I'm building the Octavia project from GGG (http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=128&Itemid=26) and had a question. JD lists the 2 1.5M resistors as optional. 1 is at the input and 1 is at the output. He has 2 schematics up, one that includes a pre-gain input pot and one without. Both schematics have the output 1.5M resistor present but the schematic *with* the pre-gain pot does *not* have the input resistor. So, my question is, what's the difference if I leave these out or put them in? Are they both there to help with capacitor/switching popping? Does the input resistor also contribute to the input impedance? If so (or even if not), should I put this resistor in if I'm also including the input pre-gain pot?
  Pulldown resistors drain the caps, slow enough so that drain isn't loading the signal [so much], 1.5meg specified.
  I didn't see R1 where I expected to, and the pregain pot is more than small enough to drain small DC charges from the input cap [instead of the switch, which causes pop, the pulldowns are for preventing the charge from building up]. A 1.5 input pulldown R isn't necessary, and would be parallel to the already much smaller input gain pot settings resistance [signal path to ground.
  On the output capacitor, a pulldown resistor should insure the capacitor doesn't discharge DC into the switch when activated..

[natalio]

They seems to be to avoid the "pop" when switching the effect on off.
There is so much topics talking about it, ..

[slacker]

Those resistors are to try and stop pops that are caused by any DC voltage might leak out through the input cap, they do this by providing a path to ground for that voltage. If you build the circuit with the pregain control then the pot does the same job so you don't need the resistor.

[fogwolf]

That's what it seemed like but still new, so wanted to make sure. Thanks for all the responses.

Those resistors are to try and stop pops that are caused by any DC voltage might leak out through the input cap, they do this by providing a path to ground for that voltage. If you build the circuit with the pregain control then the pot does the same job so you don't need the resistor.

[fogwolf]

Removed - different subject so moving to new post.

Those resistors are to try and stop pops that are caused by any DC voltage might leak out through the input cap, they do this by providing a path to ground for that voltage. If you build the circuit with the pregain control then the pot does the same job so you don't need the resistor.