This Week on the Breadboard: The 'lectric Mama Flanger

Driz

New member
Awesome looking circuit! When applying this modulation section to another flanger, would the voltage supplied to pin 5 of the BBD need to be 9v as it is in yours? I've seen other flangers where the BBDs are being fed 5v at pin 5 i.e the ibanez FL5
 

Chuck D. Bones

Circuit Wizard
The 3207D will run on 5V or 9V. Higher voltage = more headroom. The BBD & clock driver have to be powered by the same voltage. When I used the 4KNOBFLANGE chip to provide the clock, I had to run the 3207D on 5V because the 4KNOBFLANGE runs on 5V.
 

Chuck D. Bones

Circuit Wizard
UPDATE: I added C17 from Vgg to GND in accordance with the V3207D datasheet. Schematic has been updated (no change to page 2 except for title block).

I believe I'm done. Spent some time yesterday reacquainting myself with Bill's Law. If all you want is a triangle wave from the LFO, then the WAVEFORM pot could be replaced with two resistors or a trimpot.

'lectric Mama v3.6.2 page 1.png

'lectric Mama v3.6.2 page 2.png


All resistors are 1% metal film.
All capacitors less than 1nF are silver mica.
All capacitors from 1nF to 1uF are film.
C17 is tantalum.
All other electrolytic capacitors are aluminum.
 
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Chuck D. Bones

Circuit Wizard
I tried MOSFETs and BJTs for Q1, they all sound the same. If you use a BJT, get one with a high HFE so it biases correctly and doesn't load the 3207.

I experimented with C29, which sets the clock freq range. Larger values of C29 gets this circuit into chorus territory. I went as high as 1nF.

The filtering is a compromise between being bright enough and filtering out charge pump noise from other pedals. The best solution for dealing with charge pump noise is to reduce it at the source. Easier said than done.

I spent some time studying the interaction between the BLEND and COLOUR controls. The two controls will always interact because the COLOUR control changes the peak amplitude of the wet signal. I configured this circuit so that when BLEND is dimed, the mix stays balanced for all COLOUR settings. When COLOUR and BLEND are set to zero, we get 100% dry signal. Advancing either control from zero adds in some wet signal. For high settings of the COLOUR control, BLEND changes the timbre more than it changes the mix.

If you don't have a scope, you can set the trimmers by ear and get close enough.
 

Chuck D. Bones

Circuit Wizard
Oh, so 6 knobs isn't enough? You guys want a toggle switch too? :rolleyes:

The RANGE control has a huge, well, uh, range. My advice is build it and see for yourself. You can probably find one capacitor value that does what you want.

do you have a clock range to bias with frequency measurements instead of a scope?
Not sure I understand the question.
 

benny_profane

Well-known member
I meant is the clock frequency range defined (i.e., min/max expressed in Hz). I misinterpreted what you meant when referring to setting up with the scope. I thought you meant setting up the clock.
 

Chuck D. Bones

Circuit Wizard
I can measure the min/max clock freq if you're interested. The clock freq is inversely proportional to C29 (for reasonable values of C29). The BBD delay is 512 / Fclk.
 
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