Enclosure not stated · 4 knobs
Fred Briggs E11even
Based on the Briggs' E11even· 1 other board clones it
- Category
- Overdrive
- Price
- see vendor
From the vendor
Fred Briggs' Marshall-flavored booster/overdrive (plexi and JTM45 tones), the last of his Fender/Vox/Marshall themed series. It is a single BS170 MOSFET booster with a Body pot in the input filter that sets the bass content (at 470k it is close to the classic Marshall mid/high boost filter), a Gain pot in the source leg, and a pair of BAT41 clipping diodes fed through a Bias pot that acts as a saturation control: high for headroom and a smoother drive, low for a grittier tone.
Suggested mod: put the Bias (saturation) control over one diode only for asymmetrical clipping. The protection diode can be a 12V zener or a red LED. The author uses a 470k linear pot for Body; a log taper may suit some players.
Schematic
The schematic is in the post. Open it at Revolution Deux. No KiCad fragment has been drawn for this circuit yet.
Parts list 15 rows
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Check before you build · 1 value the reader of this schematic was not sure of
- The Gain pot (1K) has no taper on the drawing; the second clipping diode is drawn with a different symbol and is assumed to be a BAT41 like the first.
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 3 | ||||
| R1 | 2.2M | 2.2M | gate bias; read from the schematic by eye | |
| R2 | 10K | 10k | drain; read from the schematic by eye | |
| R3 | 1M | 1M | gate to ground; read from the schematic by eye | |
| Capacitors 4 | ||||
| C1 | 22n | 22n | input; read from the schematic by eye | |
| C2 | 470p | 470p | read from the schematic by eye | |
| C3 | 4.7n | 4.7n | drain to ground; read from the schematic by eye | |
| C4 | 100n | 100n | output; read from the schematic by eye | |
| Diodes 3 | ||||
| D1 | BAT41 | BAT41 | clipping; read from the schematic by eye | |
| D2 | BAT41 | BAT41 | clipping; read from the schematic by eye | |
| D3 | ? | ? | protection diode: 12V zener or red LED; read from the schematic by eye | |
| Transistors 1 | ||||
| Q1 | BS170 | BS170 | MOSFET; read from the schematic by eye | |
| Potentiometers 4 | ||||
| Body | B470K | B470k | Potentiometer | drawn 470K; the post uses linear; read from the schematic by eye |
| Gain | 1K | 1k | Potentiometer | source to ground; read from the schematic by eye |
| Bias | B10K | B10k | Potentiometer | saturation of the clipping diodes; read from the schematic by eye |
| Master | B100K | B100k | Potentiometer | read from the schematic by eye |
Other boards based on the Briggs' E11even
- Briggs' E11even Tagboard Effects