Enclosure not stated · 2 knobs
WEM Pep BoxVerified
Based on the WEM Pep Box· 2 other boards clone it
From the post
Here's a cool vintage fuzz circuit from the mid 60s–the WEM Pep Box. It's probably best known its use by John Lennon during the Revolver sessions. There are two versions of this effect, the first using germanium transistors and the later using silicon. I've drawn up layouts for both iterations of the circuit, as there are slight variations between the two. The originals used a 500k Level pot with a 56k resistor in parallel. This equates to a 50k pot, so the layouts reflect that. Also, if the effect is to thick for your tastes, try reducing the 2 electro caps down to 10µ. It seems both values were used.
If you're building the germanium version, the layout shows positive ground on the perf side (original transistors were PNP), and the PCB side shows negative ground (for use with NPN germaniums). Since the original ACY41 transistors are pretty scarce now (especially outside the UK), socket and experiment.
Here's a demo of the germanium reissue:
And a demo of an original silicon unit:
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 15 rows
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Check before you build · 1 value the reader of this layout was not sure of
- 16K below the 820K, left of the 1.5K: printed clearly, unusual value
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 7 | ||||
| ×1 | 100Ω | 100 | 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 | |
| ×1 | 16K | 16k | read from the layout by eye | |
| ×1 | 470K | 470k | read from the layout by eye | |
| ×1 | 820K | 820k | read from the layout by eye | |
| ×1 | 1M | 1M | read from the layout by eye | |
| Capacitors 3 | ||||
| ×1 | 3.3nF | 3.3n | read from the layout by eye | |
| ×2 | 22uF | 22u | electrolytic; read from the layout by eye | |
| ×1 | 47uF | 47u | electrolytic; read from the layout by eye | |
| Diodes 1 | ||||
| ×1 | 1N4001 | 1N4001 | read from the layout by eye | |
| Transistors 2 | ||||
| Q1 | ACY41 | ACY41 | germanium PNP; read from the layout by eye | |
| Q2 | ACY41 | ACY41 | germanium PNP; read from the layout by eye | |
| Potentiometers 2 | ||||
| Effect | A10K | A10k | Potentiometer | printed 10K Log; read from the layout by eye |
| Level | A50K | A50k | Potentiometer | printed 50K Log; read from the layout by eye |
Other boards based on the WEM Pep Box
- Pep Box Fuzz Dog · 1590B · £26.40
- WEM Pepbox Tagboard Effects