ROG Splitter-Blend - Bypass Switch Pop

[Slade]

Hi,
I just built a runoffgroove's Splitter-Blend.
I made it with BYPASS switch and 2 switcheable BLEND pots.
I used shielded cables and I used 50k pots for both blend controls (I made it just by switching pin 2 of both pots to the output). Everything else is as per schematic.

I'm getting a big pop with both switches, when I turn it on/off and when I switch between both blend controls.

Could be the 50k pots I'm using that's causing it? I tried using a 2M2 pull-down resistor at the input with no change.

Has anybody else experienced this?

Here's my build...



Thank you.

Fernando.-

[Slade]

Removing the output 1M resistor I have no popping when switching Blend pots.

But I'm still getting the big bypass pop.

[B Tremblay]

If you are switching two different Blend pots (to provide two presets, I'm guessing) then there is a moment when the output of each loop is hanging.  If you add pulldowns after the 10u output cap of both, that may do the trick.

Nice box!

[Slade]

Hey, Brian, thanks. I think that would only solve the blend switching pop, but not the bypass switch pop, isn't it?

[Slade]

IT COMPLETELY SOLVED IT!

Thanks a lot, Brian, using two 1M pulldown resistors before the blend pots worked perfectly.

Cheers!

[B Tremblay]

Woo hoo!  That's great news.  I'm glad I was able to help.

[Slade]

In fact the bypass pop is still there, but for only a few seconds, or a few 'switchings' and then it's entirely gone, but now it works exactly as I imagined!

I'm thinking that the next one(s) will have two separate opamps for the "returns", because when I tried with distortions there was an audible bleeding through from LOOP A even with the blend pot completely to LOOP B. I used shielded wires in almost all the circuit, so it must be happening into the dual opamp used for the returns.

[Yonatan]

Hi Slade,

I am going to build this next, and I really like your design.  Can you explain how you modified the original circuit to solve the popping?  This is what I understood from the thread:

1. You removed the 1M resistor connecting the output to ground?
2. You added a 1M resistor after each output cap?  What does this mean actually, that you connected one leg of the resistor to the output leg of the cap and the other end of the resistor to ground?

Thanks!
Yonatan