Enclosure not stated · 2 knobs
D*A*M GB-83 GreaseBox
Based on the D*A*M GB-83 GreaseBox· 3 other boards clone it
From the post
This is the silicon version of the GB-80. The darlington pair of transistors in the GB-80 aren't needed as silicon transistors have enough gain, and the rest of the circuit has just been tweaked for the silicon transistors. One problem people seemed to have cloning this circuit over on FSB was biasing the transistors properly. The 260k resistor from the base of Q1 to ground could either be socketed and experimented with to get the right value, or replaced with a 500k trim pot to dial in the right sound. The transistors in the originals are BC series, but socket and experiment. Anything in the 300 hfe range should work for Q1 and 400 hfe for Q2.
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 18 rows
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Check before you build · 1 value the reader of this layout was not sure of
- 260K resistor at row G, left column of the resistor stack: printed clearly, unusual value
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 8 | ||||
| ×1 | 1M | 1M | read from the layout by eye | |
| ×1 | 10K | 10k | read from the layout by eye | |
| ×1 | 22K | 22k | read from the layout by eye | |
| ×1 | 8.2K | 8.2k | read from the layout by eye | |
| ×1 | 470K | 470k | read from the layout by eye | |
| ×1 | 260K | 260k | read from the layout by eye | |
| ×1 | 2M | 2M | read from the layout by eye | |
| ×1 | 4.7K | 4.7k | read from the layout by eye | |
| Capacitors 5 | ||||
| ×1 | 100nF | 100n | read from the layout by eye | |
| ×1 | 22nF | 22n | read from the layout by eye | |
| ×1 | 10nF | 10n | 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 1 | ||||
| ×1 | 1N4001 | 1N4001 | printed 4001; read from the layout by eye | |
| Transistors 2 | ||||
| Q1 | BC547B | BC547B | read from the layout by eye | |
| Q2 | BC337 | BC337 | read from the layout by eye | |
| Potentiometers 2 | ||||
| Sustain | B100K | B100k | Potentiometer | read from the layout by eye |
| Volume | A500K | A500k | Potentiometer | read from the layout by eye |
Other boards based on the D*A*M GB-83 GreaseBox
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