SOLVED Frajeelay question for those who have built it

[comradehoser]

I'm starting to suspect something might be amiss in the blend part of my circuit. But I am prone to thinking there is a problem with a pedal when it's just the way the pedal is supposed to be.

Full CW is very quiet, and the blend kind of drops off to clean pretty quickly after about 3:00, clean signal is fairly non-existent before.

Is this consistent with what you have?

 

[Robert]

The blend in the original was a little strange to me... The clean signal is fixed at around unity (maybe slightly below) and doesn't increase with the Drive. If you have the gain cranked the clean blend seems a bit anemic in comparison.

Does the dirt portion seem to behave as you'd expect with the blend rolled to 100% distortion?

Is the clean signal fairly close to unity with the blend rolled to 100% clean?

 

[comradehoser]

Dirt is as expected with 100% effected signal (Blend @ full CCW)

Clean signal is nowhere near unity with blend at 100% clean (Blend at or approaching full CW). Maybe 1/2? 1/4?

This remains the case through the full span of the gain knob past the "kick in" point (7:30 or whatever)

 

[comradehoser]

All components involved in the little excursion circuit at R2 to the tl074 and the blend pot are correct. Didn't check pot for in spec, but it's the correct label. At ic2.4, Pin 12 is getting 4.18v, and pins 13 and 14, 4.562v, which mirrors its twin on the other side of the blend pot, ic2.1, pins 1, 2 & 3.

No idea why the clean blend should be so low.

 

[comradehoser]

So here's a better question. How would I go about making more volume/gain on the clean side of the clean blend?

I can kind of wrap my head around basic fuzz circuits and mods that could affect tone or clipping.

No idea about blends. I assume it might be something with resistors around the pins 12/13/14

 

[DGWVI]

So here's a better question. How would I go about making more volume/gain on the clean side of the clean blend?

I can kind of wrap my head around basic fuzz circuits and mods that could affect tone or clipping.

No idea about blends. I assume it might be something with resistors around the pins 12/13/14

Lift pin 13 from the socket, add something like a 47k between the pin and socket. From this junction add lower value resistor, 4.7k for instance, and large-ish cap (1uf+) connected to ground

 

[comradehoser]

Alright, can try.

Thank you!

 

[comradehoser]

Like so?:

 

[comradehoser]

Lift pin 13 from the socket, add something like a 47k between the pin and socket. From this junction add lower value resistor, 4.7k for instance, and large-ish cap (1uf+) connected to ground

What am I doing, exactly? Decreasing the amount of signal shunted to ground by increasing resistance? Or increasing output by unbalancing the amplification stages? I guess I am missing what is happening within the tl074 and what the resistor/capacitor array does.

So basically, I need a class in electronics.

 

[DGWVI]

What am I doing, exactly? Decreasing the amount of signal shunted to ground by increasing resistance? Or increasing output by unbalancing the amplification stages? I guess I am missing what is happening within the tl074 and what the resistor/capacitor array does.

So basically, I need a class in electronics.

Basically, you're taking the non-inverting buffer and turning it into an amplifier- in this case a clean boost similar to an MXR Micro-Amp


The values I listed will give you a gain of 11 with a fairly flat frequency response

 

[comradehoser]

Rad.

Thank you so much for the explanation.

I will meditate on the weirdness of electricity and components a bit longer before I venture an attempt at explaining this to myself. It's very hard for me for some reason to grasp what components are actually doing individually and why it should result in a particular outcome (other than clipping and the big understanding of what each section does in a pedal). Like why the resistor to resistor and the capacitor to ground would result in a boost.

 

[comradehoser]

Basically, you're taking the non-inverting buffer and turning it into an amplifier- in this case a clean boost similar to an MXR Micro-Amp
View attachment 74666

The values I listed will give you a gain of 11 with a fairly flat frequency response

That solved it, 100%. Didn't have the right resistor values, ended up using 42k and 3.9k because that's what i had lying around, but it's a solid, balanced blend, now. Very useable.

Chapeau, monsieur!

Now I'm wondering if I didn't mess up the build somehow.