Enclosure not stated · 1 knob
Escobedo Idiot WahVerified
Based on the Escobedo Idiot Wah· 1 other board clones it
- Category
- EQ / Filter
- Controls
- Freq
- Build
- Vero· 10×10
- Layout
- Verified · Tagboard Effects marks it as built and working
- Tags
- Filter, Wah
From the post
Request.
The Idiot Wah is a simple building block Bridged/Twin T filter giving a resonant low pass response. It's specifically designed for electric guitar, for simplicity and useability, making it a bit different from similar designs. The input resistor helps the input from loading down and attenuates the input signal. The Darlington transistor has enough gain to keep the output at about unity. Biasing helps keep the distortion down. And most unusual, the unequal capacitors in the T network give a more useful, more musical range than the typical matched values.
VR can be a pot, an LDR, or any type of variable resistive element. Being a resistor to ground allows many different schemes to be used to control the cutoff frequency for the filter.
A quick example of the idiot wah being controlled via an LDR rather than a pot:
Schematic
This is a board layout, a drawing of where each part goes, and the post may link the schematic it was drawn from. Open the layout at Tagboard Effects. No KiCad fragment has been drawn for this circuit yet.
Parts list 12 rows
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Check before you build · 3 values the reader of this layout was not sure of
- 680p ceramic right of Q1: tiny text, could be 660p
- 500K resistors (two, upper left): printed clearly, unusual value
- 5n capacitor at upper right: printed clearly, unusual value
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 4 | ||||
| ×2 | 500K | 500k | read from the layout by eye | |
| ×2 | 10K | 10k | read from the layout by eye | |
| ×3 | 1M | 1M | read from the layout by eye | |
| ×1 | 100K | 100k | read from the layout by eye | |
| Capacitors 5 | ||||
| ×1 | 220p | 220p | read from the layout by eye | |
| ×2 | 100n | 100n | read from the layout by eye | |
| ×1 | 680p | 680p | read from the layout by eye | |
| ×1 | 5n | 5n | read from the layout by eye | |
| ×1 | 22u | 22u | electrolytic; read from the layout by eye | |
| Transistors 1 | ||||
| Q1 | MPSA13 | MPSA13 | read from the layout by eye | |
| Potentiometers 1 | ||||
| Freq | 50K | 50k | Potentiometer | no taper stated; read from the layout by eye |
| Switches 1 | ||||
| Resonance | SPST | SPST | toggle; read from the layout by eye | |
Other boards based on the Escobedo Idiot Wah
- Escobedo Idiot Wah Effects Layouts (blog) · 1590A