Enclosure not stated · 6 knobs
Gretsch Expandafuzz
Based on the Gretsch Expandafuzz
- Category
- EQ / Filter
- Build
- Vero· 26×22· 42 cuts, 20 links
- Layout
- Unverified · no build reported at Dirtbox Layouts yet
- Tags
- Eq, Fuzz, Gretsch
From the post
Here is an old forgotten old cat... It is basically a Controfuzz followed by three seperate channels for the Treble, Bass and Mid controls. The fuzz can be bypassed so it can serve as an EQ pedal only as well. Some improvements had to be done to make it more practical. 1. An onboard voltage inverter is added for the required bipolar power supply. 2. Bypass switching. 3. A Master volume control at the output. 4. The ancient 14 pin uA748 single op amps is replaced with dual channel op amps. 1458 op amps has the closest spec to the original but it is worth experimenting with higher fidelity op amps for the EQ section and the summing amp (IC2 and IC3).
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 Dirtbox Layouts. No KiCad fragment has been drawn for this circuit yet.
Parts list 36 rows
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Check before you build · 1 value the reader of this layout was not sure of
- 5nF at column 9 rows Q-S: printed clearly, unusual value
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 12 | ||||
| ×5 | 10K | 10k | read from the layout by eye | |
| ×5 | 1K | 1k | read from the layout by eye | |
| ×4 | 100K | 100k | read from the layout by eye | |
| ×2 | 220K | 220k | read from the layout by eye | |
| ×1 | 100Ω | 100 | read from the layout by eye | |
| ×1 | 680Ω | 680 | read from the layout by eye | |
| ×1 | 3.3K | 3.3k | read from the layout by eye | |
| ×1 | 33K | 33k | read from the layout by eye | |
| ×1 | 47K | 47k | read from the layout by eye | |
| ×1 | 330K | 330k | read from the layout by eye | |
| ×1 | 1M | 1M | read from the layout by eye | |
| ×2 | ? | ? | LED resistor, value not given; read from the layout by eye | |
| Capacitors 8 | ||||
| ×5 | 100nF | 100n | read from the layout by eye | |
| ×2 | 470nF | 470n | read from the layout by eye | |
| ×2 | 220pF | 220p | read from the layout by eye | |
| ×1 | 1nF | 1n | read from the layout by eye | |
| ×1 | 5nF | 5n | read from the layout by eye | |
| ×3 | 10uF | 10u | electrolytic; read from the layout by eye | |
| ×2 | 100uF | 100u | electrolytic; read from the layout by eye | |
| ×1 | 2.2uF | 2.2u | electrolytic; read from the layout by eye | |
| Diodes 2 | ||||
| ×2 | 1N4001 | 1N4001 | D1, D2; read from the layout by eye | |
| D3 | 1N5817 | 1N5817 | read from the layout by eye | |
| ICs 4 | ||||
| IC1 | 1458 | 1458 | legend: 1458, 4558 etc. (6x UA748 in original); read from the layout by eye | |
| IC2 | 1458 | 1458 | legend: 1458, 4558 etc. (6x UA748 in original); read from the layout by eye | |
| IC3 | 1458 | 1458 | legend: 1458, 4558 etc. (6x UA748 in original); read from the layout by eye | |
| IC4 | ICL7660S | ICL7660S | legend: ICL7660S/MAX1044; read from the layout by eye | |
| Potentiometers 6 | ||||
| Boost | B10K | B10k | Potentiometer | read from the layout by eye |
| Distort | B10K | B10k | Potentiometer | read from the layout by eye |
| Treble | B10K | B10k | Potentiometer | read from the layout by eye |
| Mid | B10K | B10k | Potentiometer | read from the layout by eye |
| Bass | B10K | B10k | Potentiometer | read from the layout by eye |
| Master | A250K | A250k | Potentiometer | read from the layout by eye |
| Switches 4 | ||||
| Fuzz Sw | 3PDT | 3PDT | footswitch; read from the layout by eye | |
| Treble Sw | SPDT on/on | SPDT ON/ON | toggle; legend: or DPDT footswitches; read from the layout by eye | |
| Mid Sw | SPDT on/on | SPDT ON/ON | toggle; legend: or DPDT footswitches; read from the layout by eye | |
| Bass Sw | SPDT on/on | SPDT ON/ON | toggle; legend: or DPDT footswitches; read from the layout by eye | |