Looking For Digital Octave up

PedalPCB

Admin (Robert)
Staff member
Clean sounds fuzzy and pitch shifted up sounds pingy and electronic.

It shouldn't be fuzzy. Definitely look into the things phi1 suggested, especially the (possibly?) missing volume pot.

The pitch shifting may never meet your expectations. Like I mentioned back in post #6, it's far from perfect, but it shouldn't be fuzzy.
 

RobertJay

Member
All very interesting. I have the same performance with and without the pots. This circuit is for a multi effect box and one of them being an octave up w the dry out too. So, pitch 1 is off, pitch 2 is max, blend is set for the pitch 2. I used my meter and then gave the terminals to same as if I had the pots. 0 ohms where fused and Infinity where I left open. No? Does it not work like that? Because my removal of the pots changed nothing. It did exactly what I wanted it to do. It sounded pingy and weirds anyway.
That's an interesting question though... Can I remove pots if they are just gonna sit at max or min. All or nothing... So just solder it like t hat.... That's what we have here.
 

RobertJay

Member
Couple things I noticed,

-the volume area seems weird. More Resistance between lug 1 & 2 boosts the output. Since you don’t have lug 1 connected, you Have infinite resistance, which would boost the op amp to being unstable I think. Unless you have it connected some way underneath the board.

-not having the control pots connected may do weird things to some of the patches. I don’t know exactly how it would behave, but I would look into that. For control 2 & 3 you only have 2 pads connected. Connecting all three pads to a potentiometer is the normal way (voltage divider sets the voltage going to the fv-1 pin).
Yeah those pots are either all the way min or all the way max, set it and forget it. So I jumped the 2 pads that give me 0 ohms and left the one that was infinity. Maybe not that simple? Made total sense to me the other day. haha
 

RobertJay

Member
It shouldn't be fuzzy. Definitely look into the things phi1 suggested, especially the (possibly?) missing volume pot.

The pitch shifting may never meet your expectations. Like I mentioned back in post #6, it's far from perfect, but it shouldn't be fuzzy.
And the vol pot, in particular actually confused me. It never did anything. It had no control or changed a thing with this build.
 

zgrav

Well-known member
try connecting the unused control pins to ground and see if that changes anything. what is your expectation for the pitch shift function with the fv-1? if you are hoping for a real-time pitch shift the chip cannot deliver. it is good for shifting any delayed repeats but falls a bit short for real-time shift.
 

phi1

Well-known member
For the vol pot area, the resistance that matters is between lug pad 1-2. Lugs 2-3 are connected together. If you don’t want to adjust the volume, you can put a resistor between lugs 1-2 (experiment to find the value resistor for the volume you want).

for the control pots, I didn’t know if leaving them unconnected would make a difference, just seems like bad practice to leave them open. Link either lug pad 1-2 (control at minimum) or lugs pads 2-3 (control at maximum). I think that’s maybe what you described.
 
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