Question on fuzzy tone from one half of IC

[Hout]

Hi there!
I am new to this forum, and quite new to building stompboxes. I started with building the splitter-blender circuit from runoffgroove.com, to fit in a wah housing. I made a pcb and wired it all up, but ran into an issue:

In the return section below, when the phase flip switch (S1) is engaged I get a clear tone, but when I open it, I get a mild distortion. Any idea what could cause this? Did I fry the opamp with to much heat or something?

[duck_arse]

hello Hout, and welcome.

might we see what you have built? and can you provide the voltages measured around the circuit, please?

[Hout]

Sure can!
Here's the housing left and right:




The idea is I have an input, which is split into two effect loops, one of which has a bypass switch. The return of the  two signals and can be blended with the expression pedal.
The phase switch is in case a phase inverting pedal is used somewhere one of the chains. I kind of directly copied the schematic, with the addition of a led for the phase flip.
Here's the original schematic, I do not have my schematic available from my phone. Will add it later.

And a spaghetti picture:


Up measuring just now I think I figured out one thing I screwed up. I suppose I added the led wrongly as it causes the bias voltage to drop significantly.  It drops from 3,8v to 1,5v.
Only one of the channels (the Green from the above schem) has the distorted tone without the led engaged.

Apart from fixing the led issue, should I lower the overall bias voltage? Is the 2N5457 likely to cause cause the issue?

[Fabeii]

Unrelated thing: socket for ICs are a very nice things, you can swap them and don't worry about it. I think you did not use them looking at the pictures.

Related thing: how and where did you add the led? The quickest way to add a led would be to leave the phase circuit untouched, use a DPDT switch and wire the phase wires on one side and the led wires on the other. Don't forget the Current Limiting Resistor for the LED.

[Hout]

Nope, did not use sockets for the ic's, even though I do have them lying around.. I did for the transistor though..

You are right about the led, I did use a dpdt switch but I connected the led, with a limiting resistor, to the Vbias. I realise now this is obviously not right way. Not sure solving this will solve my issue though.

[anotherjim]

The Vref/Vbias is "just some voltage" and not a power supply. This is because it is generated by the relatively high-value resistor divider network (33k). In the circuit, the current draw from the bias network is expected to be negligible, a few uA. Excessive current will pull the bias voltage up or down bringing the amplifiers closer to clipping. Returning a LED through the bias would do that.