Enclosure not stated · 3 knobs
Blue MagicVerified
Based on the Blue Magic
From the post
Here's an overdrive I stumbled across while browsing the Free Information Society site. It was designed by Jake Nagy and was quite popular in the DIY world at while back. Here's what he had to say about it:
Blue Magic is a very low to medium grit, tube-like, overdrive pedal that is based on a MOSFET (BS170) pushing a JFET (J201) into distortion. Voltage at the JFET drain should be about 4.7, but tune by ear. [The 22k resistor] smooths out the sound, but at the cost of sounding less “open.” Thus, reduce [it] for a more open sound. Also, experiment with the coupling caps and the source bypass caps.
I've increased the power filter cap and added polarity protection. You can board mount pots using right angle PCB mount pots from the solder-side of the board.
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 Effects Layouts (blog). No KiCad fragment has been drawn for this circuit yet.
Parts list 28 rows
Report a wrong parseGot parts in a drawer? See what you can build with them.
Check before you build · 1 value the reader of this layout was not sure of
- 530pF (bottom left, column B): printed clearly, unusual value
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 9 | ||||
| ×2 | 4.7K | 4.7k | read from the layout by eye | |
| ×1 | 4.7M | 4.7M | read from the layout by eye | |
| ×1 | 1K | 1k | read from the layout by eye | |
| ×1 | 6.8K | 6.8k | read from the layout by eye | |
| ×1 | 22K | 22k | read from the layout by eye | |
| ×2 | 2.2M | 2.2M | read from the layout by eye | |
| ×1 | 470K | 470k | read from the layout by eye | |
| ×1 | 68K | 68k | read from the layout by eye | |
| ×1 | 1.5M | 1.5M | read from the layout by eye | |
| Capacitors 10 | ||||
| ×1 | 47nF | 47n | read from the layout by eye | |
| ×3 | 1nF | 1n | read from the layout by eye | |
| ×1 | 100nF | 100n | read from the layout by eye | |
| ×1 | 530pF | 530p | read from the layout by eye | |
| ×2 | 470pF | 470p | read from the layout by eye | |
| ×1 | 22nF | 22n | read from the layout by eye | |
| ×1 | 4.7nF | 4.7n | read from the layout by eye | |
| ×1 | 6.8uF | 6.8u | electrolytic; read from the layout by eye | |
| ×1 | 10uF | 10u | electrolytic; read from the layout by eye | |
| ×1 | 47uF | 47u | electrolytic; read from the layout by eye | |
| Diodes 2 | ||||
| ×1 | 12V | 12V | Zener, printed 12v; read from the layout by eye | |
| ×1 | 1N4001 | 1N4001 | read from the layout by eye | |
| Transistors 2 | ||||
| Q1 | BS170 | BS170 | MOSFET; read from the layout by eye | |
| Q2 | J201 | J201 | JFET; read from the layout by eye | |
| Potentiometers 3 | ||||
| Drive | B500K | B500k | Potentiometer | read from the layout by eye |
| Tone | B50K | B50k | Potentiometer | read from the layout by eye |
| Volume | A100K | A100k | Potentiometer | read from the layout by eye |
| Trimmers 1 | ||||
| ×1 | 50K | 50k | read from the layout by eye | |
| Switches 1 | ||||
| Mids | SPST | SPST | toggle; read from the layout by eye | |