Help: depth pot on Phasers/Flangers/Chorus/etc (DC offset also)

[savethewhales]

Hey!

I've been working in a phaser pedal for a while, but I've been stuck in one thing here: I designed a LFO (which all I want it to do is output a nice triangle wave, no matter voltage or offset), but I wanted to be able to regulate the depth of the triangle wave (separately) to a voltage range of 0.8 Volt, which is what I need, followed by a DC offset for me to get the voltage range in the right offset (meaning I want the maximum depth to be 0.8 volt range, being from 3.4 to 4.2 Volt). However I designed this circuit for that:



And I'm realizing that the "DC offset" is affecting the amplitude of the wave, and it's not separating stages at all.. Can somebody help me doing a DC offset that doesn't affect the rest?

This is the simulation with the probe on the end of "each stage". Notice that the DC offset end is pratically the same of the depth end...



I know this should be way easier than what I'm doing... Anyway thanks in advance.

[PRR]

[savethewhales]

Ok, I guess that it's a inverting amplifier with the DC injected to the positive pin?
I just don't know what the middle 1k3 does.. And isn't it supposed to have a capacitor to filter any DC that comes in the input?