Enclosure not stated · 3 knobs
ProCo Fat RatVerified
Based on the ProCo Fat Rat
- Category
- Distortion
- Controls
- Distortion · Filter · Volume
- Build
- Vero· 17×15· 20 cuts, 8 links
- Layout
- Verified · Dirtbox Layouts marks it as built and working
- Tags
- Distortion, ProCo
From the post
Pretty much a stock Rat with two additional switches. The clipping switch selects between the stock silicons and a assymetric MOSFET/Shottky pair. A Earlier units is supposed to have a 1N270 germanium diode in place of the Shottky The Fat switch toggles between stock mode and Fat mode by adding a 6,8uF cap at one of the RC filters and a cap to ground at the gate of the output buffer.
....and a demo by MR. Ian Sheridan.
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 30 rows
Report a wrong parseGot parts in a drawer? See what you can build with them.
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 8 | ||||
| ×2 | 47Ω | 47 | read from the layout by eye | |
| ×1 | 560Ω | 560 | read from the layout by eye | |
| ×2 | 1K | 1k | read from the layout by eye | |
| ×1 | 1.5K | 1.5k | read from the layout by eye | |
| ×1 | 10K | 10k | read from the layout by eye | |
| ×2 | 100K | 100k | read from the layout by eye | |
| ×3 | 1M | 1M | read from the layout by eye | |
| ×1 | ? | ? | LED resistor, value not given; read from the layout by eye | |
| Capacitors 11 | ||||
| ×1 | 33pF | 33p | read from the layout by eye | |
| ×1 | 100pF | 100p | read from the layout by eye | |
| ×1 | 1nF | 1n | read from the layout by eye | |
| ×1 | 2.2nF | 2.2n | read from the layout by eye | |
| ×1 | 3.3nF | 3.3n | read from the layout by eye | |
| ×2 | 22nF | 22n | read from the layout by eye | |
| ×2 | 1uF | 1u | electrolytic; read from the layout by eye | |
| ×1 | 2.2uF | 2.2u | electrolytic; read from the layout by eye | |
| ×2 | 4.7uF | 4.7u | electrolytic; read from the layout by eye | |
| ×1 | 6.8uF | 6.8u | electrolytic; read from the layout by eye | |
| ×1 | 100uF | 100u | electrolytic; read from the layout by eye | |
| Diodes 3 | ||||
| ×2 | 1N4148 | 1N4148 | D1, D2; read from the layout by eye | |
| D3 | BATxx | BATXX | BATxx or 1N270; read from the layout by eye | |
| D4 | 1N5817 | 1N5817 | read from the layout by eye | |
| Transistors 2 | ||||
| Q1 | 2N5458 | 2N5458 | JFET; read from the layout by eye | |
| Q2 | BS170 | BS170 | MOSFET; read from the layout by eye | |
| ICs 1 | ||||
| IC1 | LM308 | LM308 | LM308 or OP07; read from the layout by eye | |
| Potentiometers 3 | ||||
| Distortion | A100K | A100k | Potentiometer | read from the layout by eye |
| Filter | A100K | A100k | Potentiometer | read from the layout by eye |
| Volume | A100K | A100k | Potentiometer | read from the layout by eye |
| Switches 2 | ||||
| Fat Sw | DPDT on/on | DPDT ON/ON | toggle; read from the layout by eye | |
| Clip Sw | SPDT on/on | SPDT ON/ON | toggle; read from the layout by eye | |