1590B · 4 knobs
MojoHand FX Iron Bell/Skreddy P19Verified
Based on the MojoHand FX Iron Bell/Skreddy P19· 1 other board clones it
From the post
For Fuzz Friday, here's another Big Muff based circuit to add to the collection. The Iron Bell is a variation of the Skreddy P19, the schematic of which was graciously posted by Marc from Skreddy a few years back. It's not based on any one classic Muff, but is Marc's unique blend of custom values, and features a boosted mids tone stack, with a switch to increase the mids. Shortly thereafter, the Iron Bell came out with a few mods, the biggest of which is the replacement of the Mids switch with a potentiometer and a few value changes. The layout below reflects the MojoHand iteration of the circuit, but the P19 can be built on the same board (see below for component changes). It's laid out for board mounted pots and should fit in a 1590B.
To make the Skreddy P19, made the following changes:
• Replace the Colour pot with an SPST on/off switch
• Change Q2-4 to BC550
• Change the following components indicated on the layout: * 200Ω ** 10k • 47nF •• 2.7k ‡ 6.8nF
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 36 rows
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Check before you build · 2 values the reader of this layout was not sure of
- 120Ω* (left column), 390Ω* (centre), 140Ω* (bottom centre): printed clearly with an asterisk, 140Ω is an unusual value; the footnote is not on the drawing
- 15K** (centre right) and 2K with two dots (right edge): printed clearly, footnote not on the drawing
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 13 | ||||
| ×5 | 10K | 10k | read from the layout by eye | |
| ×4 | 470K | 470k | read from the layout by eye | |
| ×3 | 100K | 100k | read from the layout by eye | |
| ×2 | 33K | 33k | read from the layout by eye | |
| ×1 | 56K | 56k | read from the layout by eye | |
| ×1 | 18K | 18k | read from the layout by eye | |
| ×1 | 15K | 15k | printed 15K**; read from the layout by eye | |
| ×1 | 2K | 2k | printed with two dots; read from the layout by eye | |
| ×1 | 1M | 1M | read from the layout by eye | |
| ×1 | 820Ω | 820 | read from the layout by eye | |
| ×1 | 390Ω | 390 | printed 390Ω*; read from the layout by eye | |
| ×1 | 140Ω | 140 | printed 140Ω*; read from the layout by eye | |
| ×1 | 120Ω | 120 | printed 120Ω*; read from the layout by eye | |
| Capacitors 10 | ||||
| ×4 | 560pF | 560p | read from the layout by eye | |
| ×5 | 100nF | 100n | read from the layout by eye | |
| ×1 | 2.2nF | 2.2n | read from the layout by eye | |
| ×1 | 6.8nF | 6.8n | read from the layout by eye | |
| ×1 | 10nF | 10n | read from the layout by eye | |
| ×1 | 33nF | 33n | read from the layout by eye | |
| ×1 | 56nF | 56n | printed with a dot; read from the layout by eye | |
| ×1 | 68nF | 68n | read from the layout by eye | |
| ×1 | 330nF | 330n | read from the layout by eye | |
| ×1 | 47uF | 47u | electrolytic; read from the layout by eye | |
| Diodes 5 | ||||
| D1 | 1N4148 | 1N4148 | legend: 1N4148 or mismatch; read from the layout by eye | |
| D2 | 1N4148 | 1N4148 | legend: 1N4148 or mismatch; read from the layout by eye | |
| D3 | 1N4148 | 1N4148 | legend: 1N4148 or mismatch; read from the layout by eye | |
| D4 | 1N4148 | 1N4148 | legend: 1N4148 or mismatch; read from the layout by eye | |
| ×1 | 1N4001 | 1N4001 | read from the layout by eye | |
| Transistors 4 | ||||
| Q1 | BC550 | BC550 | read from the layout by eye | |
| Q2 | 2N5088 | 2N5088 | read from the layout by eye | |
| Q3 | 2N5088 | 2N5088 | read from the layout by eye | |
| Q4 | 2N5088 | 2N5088 | read from the layout by eye | |
| Potentiometers 4 | ||||
| Colour | B100K | B100k | Potentiometer | read from the layout by eye |
| Gain | B100K | B100k | Potentiometer | read from the layout by eye |
| Tone | B50K | B50k | Potentiometer | read from the layout by eye |
| Volume | A100K | A100k | Potentiometer | read from the layout by eye |
Other boards based on the MojoHand FX Iron Bell/Skreddy P19
- 19 Bells Fuzz Fuzz Dog · 1590B · £36.00