Hyper Fuzz blend mod

[Grubb]

Hi folks,

One of the projects I am currently working on is an FZ-2 clone with some modifications. In particular, rather than having a switch between the two fuzz modes, I would like to have a pot for blending the modes. At one extreme, it would have the full midrange fuzz; at the other, it would be the scooped fuzz. In between, there would be some blended tones. As usual, I am working beyond the range of my limited understanding, which I find helpful for learning new things.

The two fuzz voices run on parallel paths, as per this section of the schematic from PedalPCB:


Ignoring the Boost path, which I have no interest in, what is the best way to blend these two fuzz paths in place of the switch? Would a simple pot wired to R26 and R27 at either end and with the centre lug passing the signal to R28 etc work? Or do I need a buffered blend circuit here, such as the Paralyzer?

Thanks as always for lending me your expertise.

[idy]

I think your solution will work. A pot with R26 and 27 on 1 and 3 and the wiper going towards R28. I think the two opamp stages feeding it will buffer enough. Surely worth a try.

[Grubb]

What value would you make the potentiometer for this application? Would B50K be appropriate?

[idy]

It might work as low as 10k. If 50k is what you have try it. Linear (B) taper.

[Grubb]

Thanks for the help so far. I will try the Blend pot. Another mod I would like to add is the ability to blend in some of the HM2 EQ section, as this tone is complementary to the FZ2 (thinking of bands like Monolord here, or Tony Peper's Humongous Fuzz pedal).

I have placed the HM2 EQ after the regular EQ section, and have split it off after a buffer, returning it to the main signal path via another blend pot. I would love some feedback or correction on this, as I'm still at the block diagram level of understanding and am putting circuit sections together in this manner.

Here is the schematic from the first blend pot from my original post, up to the end of the circuit:


And here is the EQ section that I want to blend in through a blend pot I'm labelling "Grind":


Is this an OK way to do it? Have I missed something important? What would you change?

[antonis]

And here is the EQ section that I want to blend in through a blend pot I'm labelling "Grind":

Is this an OK way to do it? Have I missed something important? What would you change?

Maybe I'm confused but, as it is, it blends nothing..

[Grubb]

I can guarantee I'm the one who is confused

I've probably drawn it up wrong, but the idea is that the signal would split somewhere here and the parallel branch would have the HM2 gyrators impart their tone:

[antonis]

To make things more comprehensible..

You want part of IC4.1 output signal to go  to GR_SND, pass through an EQ and come back to GR_IN to blend with its origin via GRIND pot, yes..??

[Grubb]

Yes, pretty much. I want the signal to branch out after the circuit's original EQ section, pass through a secondary EQ section, and be able to blended in (or out!) with a potentiometer. The diagram at IC4.1 is my attempt to do this.

[Nitefly182]

Hi folks,

One of the projects I am currently working on is an FZ-2 clone with some modifications. In particular, rather than having a switch between the two fuzz modes, I would like to have a pot for blending the modes. At one extreme, it would have the full midrange fuzz; at the other, it would be the scooped fuzz. In between, there would be some blended tones. As usual, I am working beyond the range of my limited understanding, which I find helpful for learning new things.

The two fuzz voices run on parallel paths, as per this section of the schematic from PedalPCB:


Ignoring the Boost path, which I have no interest in, what is the best way to blend these two fuzz paths in place of the switch? Would a simple pot wired to R26 and R27 at either end and with the centre lug passing the signal to R28 etc work? Or do I need a buffered blend circuit here, such as the Paralyzer?

Thanks as always for lending me your expertise.

Blending between the two paths is unnecessarily complex for the goal in mind.

Lift the ground side of C14 and wire in a 10K linear pot between the cap and ground. This pot will control the depth of the mid scoop. You can eliminate the "non-scoop" mode from the pedal now because the resistance between the mid notch and ground can completely remove the notch and produce the same sound. If you change the value of C14 you can move the notch center to different frequencies.

[Grubb]

You want part of IC4.1 output signal to go  to GR_SND, pass through an EQ and come back to GR_IN to blend with its origin via GRIND pot, yes..??

So what do you think? Does it work? Or is there a better way to do this?

[antonis]

As long as both blend signals are in phase, why not..??

Just connect Low & High pots lugs 3 to IC1.6 inverting input..
(or better, inverse pots orientation and connect lugs 1 to IC1.6 pin 2)

[Grubb]

Just connect Low & High pots lugs 3 to IC1.6 inverting input..

Oh whoops, they were supposed to be connected already. This is why I shouldn't draw up schematics late at night