Enclosure not stated · 3 knobs
From the vendor
Tim Escobedo's take on the Mini Booster: two J201 JFETs stacked, the top one as a current source with a 100k trimmer and the bottom one as the gain stage with a 2M gain pot, running on 3V from two AA batteries at about 25uA. Fairly clean at minimum gain and pleasantly 'syrupy' at maximum; he uses it as an overdrive.
Can run on 3V to 9V; 3V from two AA batteries and the 22k source resistor are what make it stand out. Set the 100k trimmer to the sweet spot; several different JFETs all worked.
Schematic
The schematic is in the post. Open it at Revolution Deux. No KiCad fragment has been drawn for this circuit yet.
Parts list 9 rows
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| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 1 | ||||
| R1 | 22K | 22k | Q2 source; read from the schematic by eye | |
| Capacitors 2 | ||||
| C1 | 22u | 22u | electrolytic, supply; read from the schematic by eye | |
| C2 | 100n | 100n | output; read from the schematic by eye | |
| Diodes 1 | ||||
| D1 | 1N4001 | 1N4001 | read from the schematic by eye | |
| Transistors 2 | ||||
| Q1 | J201 | J201 | current source; read from the schematic by eye | |
| Q2 | J201 | J201 | read from the schematic by eye | |
| Potentiometers 3 | ||||
| Trim | 100K | 100k | Potentiometer | trimmer; read from the schematic by eye |
| Gain | 2M | 2M | Potentiometer | read from the schematic by eye |
| Volume | 100K | 100k | Potentiometer | read from the schematic by eye |