Trikbox UnDeD Flanger

[Kipper4]

Following some experiments with the Zombie Chorus.
Some encouragement from Tom and Rob and a few great suggestions.
Decided to hack it and try to make a cheap easy to make, low parts Flanger.
Thats just what it is. It aint no Electric Mistress. But worth the parts if you just want simple.

Main changes
the 50pf timing cap CD4046 pin6>pin7 I read suggestions its not worth trying a smaller cap unless you buffer the lfo output as Hollis did for the ultra Flanger.
I tried 50pf (not47pf) and 100pf both work.
Pin 11 R=10k>GND
Pin 12 R=1M2

Then as well as the 10k feedback in the zombie.
Tom suggested filtering the output and feeding it back to input inverting input on a pot. (see Regen pot)
This is where the flanging feel comes in.
Tested caps from 1nf-22nf (C9 my drawing) It changes the tone of the feedback, found values much above 7nf started to get noisy.

If using a transistor PSO you'll need a 100k resistance between its output and pin 9 or it gets thumpy.


Haven't tried the LFO Range cap mod.

Heres the drawing.

[Kipper4]

And the mods.
Some are untested, Just coppied and pasted from a previous project but dont see why it wouldnt work.
Not sure if they have any value in this project maybe I'll try the depth mod and see if i can get it so theres no depth when playing and the depth increases as you stop playing and get a flange sound when sustaining notes at a phrase ending.

I'm sure it would be ok in the Zombie chorus too.
Enveloped Chorus.

Try it if you want.

[Kipper4]

https://youtu.be/q4iXx_T3Bfc

[Kipper4]

No need for R7. Largely superseded by the regen network.

[ElectricDruid]

No need for R7. Largely superseded by the regen network.

Those bits look back-to-front to me. Correct me if I'm wrong but...

R7 is supposed to take the buffered input signal to the output to mix together with the wet signal. So it should be connected to pin *1* of the input buffer, not pin 2.

Regen is supposed to mix the wet signal back into the input mixer, so it should go from pin7 of the output filter, not after that 10K, where it's also feeding dry signal back to the input.

??

[Scruffie]

No need for R7. Largely superseded by the regen network.

Those bits look back-to-front to me. Correct me if I'm wrong but...

R7 is supposed to take the buffered input signal to the output to mix together with the wet signal. So it should be connected to pin *1* of the input buffer, not pin 2.

Regen is supposed to mix the wet signal back into the input mixer, so it should go from pin7 of the output filter, not after that 10K, where it's also feeding dry signal back to the input.

??

You're right on the first part, but on the second, you can do a pure wet or a 50/50 mix for Regen, has different effects on the notches and is personal preference.

[ElectricDruid]

You're right on the first part, but on the second, you can do a pure wet or a 50/50 mix for Regen, has different effects on the notches and is personal preference.

Thanks Scruffie. I think I must have tried it when I was doing the Flangelicious design, since I remember doing a lot of messing about with the feedback paths and doing experiments with inversions and so on. But it was a while ago, and I've forgotten.

[Kipper4]

Tried a few suck it and see experiments on the breadboard and to be fair its doing a good job.
Some useful sounds too.

Key things to note.
The R7 feed network is back.
The global feeback has a new R value besides the pot  4n7- 33k+6k8 series. just tames the feedback some at higher settings.
That feedback network is now on a switch. in an additive/subtractive style.
Maintained the clone switch.
Have a choice of R to pin 12 220k or 3M3.
Added a seperate bias network for the lfo.
Changed the min R(r52) in the lfo speed from 4k7 to 33k. Its still plenty fast for what i need.
I tried a pair of back to back diode to Vb after the input buffer but it just added more distortion, so they got binned off.

Happy days and nights modding and learning.

Thanks guys

[Kipper4]

Above schematic (flanger 2) is missing a 100k bias R to pin2 IC2 A.
Didn't spot it on the breadboard sorry guys