This Week on the Breadboard: The 'lectric Mama Flanger

Chuck D. Bones

Well-known member
I wanted to build something using the recently acquired V3207D and MN3102 chips, so here's the first pedal out of the gate. It's a flanger based on the EHX Electric Mistress, with some updates and mods. I remember tracing an Electric Mistress back in '77. The design is both minimalist and clever. Unlike most clock oscillators, the one in the EM modulates the period of the clock rather that the frequency. That means that the pitch shift is constant across the entire sweep. The LFO in the EM was too clever for words. While it worked pretty well, it varied considerably from unit-to unit. I deployed a more traditional LFO, including clicking prevention. The freq range runs from 0.07Hz to 9.2Hz. At the low end of the speed range, it's a chorus. At the top end of the range, it sounds like a ring modulator. The tone is quite smooth, despite the minimal filtering. These V3207D's rock! I added a balance trim to achieve the deepest notches. I never had much use for the FILTER setting, but it does come in handy when adjusting the timmers. Next, I'm going to try a sinewave LFO to see how that sounds.

'lectric Mama breadboard 03.jpg



'lectric Mama v0.2.png
 

Chuck D. Bones

Well-known member
Thanks!

C2 should be film, Q1 & Q2 can be any high-gain Si.

Not shown:
  • Anti-pop resistor on the input.
  • Power protection and filtering. Use 100uF & 100nF for filtering.
  • Switching and On/Off LED.
 
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lrgaraujo

New member
Awesome Work, Chuck! How do you like the more chorusy sounds of it?
I might have found just the project for the couple of 3207 and 3102 I've recently gotten
 

Chuck D. Bones

Well-known member
I have tried a sinewave LFO and I find the results much more sonically satisfying. The issue now is making a sinewave LFO that is tunable over at least 2 decades, fairly low distortion and reliable. I have one on the breadboard, but it does not really meet any of the criteria. I ran across a paper by noted Caltech professor Dr. R. D. Middlebrook that offers a solution. Once I get that working, I'll post an updated schematic.
 

cooder

Well-known member
I have tried a sinewave LFO and I find the results much more sonically satisfying. The issue now is making a sinewave LFO that is tunable over at least 2 decades, fairly low distortion and reliable. I have one on the breadboard, but it does not really meet any of the criteria. I ran across a paper by noted Caltech professor Dr. R. D. Middlebrook that offers a solution. Once I get that working, I'll post an updated schematic.
It gets really serious when Chuck checks out what another genius has to say... I'm twiddling thumbs and trying to grow new neuron connections in anticipation. ;)
 

Chuck D. Bones

Well-known member
I had the good fortune to attend a 3-day class that Dr. Middlebrook taught at my employer's about 20 years ago. It was a revelation.

Still working on the sine converter. It's a fine line between getting it right and going total OCD.
 
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