Enclosure not stated · 3 knobs
Ampeg A3 OverdriveVerified
Based on the Ampeg A3 Overdrive· 1 other board clones it
From the post
From UnofficialAmpeg.com: During MTI's ownership of Ampeg, everything was being built in Japan. Ampeg's most extensive line of pedals is no exception. In production during 1982 and 1983, the "A" series effects were housed in black steel boxes with brightly colored graphics in pinks, oranges, blues, yellows, etc., and included nine pedals and a "systems box".
From what i can tell from the prices i've seen - these are very collectible pedals. Might be a nice subject for building your own. The semiconductors are not mentioned (other than 4558 as opamp) on the schematic, but as the transistors are used as buffers, you should be fine with 2N3904, 2N5088 or similar. The clipper diodes are silicon, so 1N4148 should be very close to the original.
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 24 rows
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| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 9 | ||||
| ×2 | 1K | 1k | read from the layout by eye | |
| ×2 | 4.7K | 4.7k | read from the layout by eye | |
| ×6 | 10K | 10k | read from the layout by eye | |
| ×2 | 33K | 33k | read from the layout by eye | |
| ×1 | 47K | 47k | read from the layout by eye | |
| ×1 | 100K | 100k | read from the layout by eye | |
| ×1 | 220K | 220k | read from the layout by eye | |
| ×1 | 470K | 470k | read from the layout by eye | |
| ×2 | 1M | 1M | read from the layout by eye | |
| Capacitors 8 | ||||
| ×1 | 1nF | 1n | read from the layout by eye | |
| ×1 | 4.7nF | 4.7n | read from the layout by eye | |
| ×1 | 10nF | 10n | read from the layout by eye | |
| ×2 | 47nF | 47n | read from the layout by eye | |
| ×2 | 1uF | 1u | film; read from the layout by eye | |
| ×2 | 1uF | 1u | electrolytic; read from the layout by eye | |
| ×1 | 47uF | 47u | electrolytic; read from the layout by eye | |
| ×1 | 100uF | 100u | electrolytic; read from the layout by eye | |
| Diodes 2 | ||||
| ×3 | 1N4148 | 1N4148 | D1, D2, D3; read from the layout by eye | |
| D4 | 1N5817 | 1N5817 | read from the layout by eye | |
| Transistors 1 | ||||
| ×2 | 2N3904 | 2N3904 | or similar; read from the layout by eye | |
| ICs 1 | ||||
| IC1 | JRC4558 | JRC4558 | read from the layout by eye | |
| Potentiometers 3 | ||||
| Overdrive | A1M | A1M | Potentiometer | read from the layout by eye |
| Tone | B100K | B100k | Potentiometer | read from the layout by eye |
| Level | B50K | B50k | Potentiometer | read from the layout by eye |
Other boards based on the Ampeg A3 Overdrive
- Ampeg A3 Overdrive Dirtbox Layouts