Enclosure not stated · 3 knobs
Dunwich Amplification Hybrid Cthulhu - 3 knob versionVerified
Based on the Dunwich Amplification Hybrid Cthulhu - 3 knob version
From the post
Another Dunwich trace by evilarsen, AlexS and fuzzhead. I believe this one was made on custom order and/or was a on/off product. However, compoent values varied over time but we added some notes at the bottom of the layout and schematic for the most significant changes that is worth experimenting with: Input capacitors connecting to the input cap blend control (Depth) varied quite a bit. I ended up with a 15nF for C2 and an 1uF for C1 with a 100kC Depth control. The other thing is one of the clipping diodes at Q4. Most units had a germanium diode but a few had a silicon transistor in TO-18 casing wired as a diode. Both layouts bellow have slots for both components but remember to use one of them, NOT both. Two layouts, one normal and one with 1.5W carbon comp resistors. Both is verified.
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 28 rows
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Check before you build · 3 values the reader of this layout was not sure of
- 845Ω next to Q2 (column 7): printed clearly, unusual value
- Q5 / D3: legend reads 'Q5: NPN Si, TO-18 case (wired as diode) or D3 germanium diode' - both are drawn on the board, probably only one is fitted
- 470nF at column 11 is drawn as a small ceramic disc; printed clearly as nF
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 8 | ||||
| ×1 | 27K | 27k | read from the layout by eye | |
| ×1 | 845Ω | 845 | read from the layout by eye | |
| ×2 | 100K | 100k | read from the layout by eye | |
| ×1 | 33K | 33k | read from the layout by eye | |
| ×1 | 470K | 470k | read from the layout by eye | |
| ×1 | 1M | 1M | read from the layout by eye | |
| ×1 | 100Ω | 100 | read from the layout by eye | |
| ×1 | ? | ? | LED resistor, value not given; read from the layout by eye | |
| Capacitors 8 | ||||
| ×2 | 100nF | 100n | read from the layout by eye | |
| ×1 | 820pF | 820p | read from the layout by eye | |
| ×1 | 470nF | 470n | read from the layout by eye | |
| ×1 | 1uF | 1u | read from the layout by eye | |
| ×1 | 10uF | 10u | electrolytic; read from the layout by eye | |
| ×1 | 100uF | 100u | electrolytic; read from the layout by eye | |
| C1 | ? | ? | value not given; legend: values between 33nF to 2,2uF; read from the layout by eye | |
| C2 | ? | ? | value not given; legend: values between 1nF-15nF; read from the layout by eye | |
| Diodes 2 | ||||
| D2 | 1N5817 | 1N5817 | read from the layout by eye | |
| D3 | Germanium | GERMANIUM | alternative to Q5; read from the layout by eye | |
| Transistors 5 | ||||
| Q1 | 2N2219A | 2N2219A | read from the layout by eye | |
| Q2 | 2N1306 | 2N1306 | read from the layout by eye | |
| Q3 | BS170 | BS170 | MOSFET; read from the layout by eye | |
| Q4 | 2N2219A | 2N2219A | read from the layout by eye | |
| Q5 | NPN Si | NPN SI | TO-18 case, wired as diode; or D3 germanium diode; read from the layout by eye | |
| Potentiometers 3 | ||||
| Fuzz | C1K | C1k | Potentiometer | read from the layout by eye |
| Depth | B100K | B100k | Potentiometer | read from the layout by eye |
| Volume | B100K | B100k | Potentiometer | some units have B1M; read from the layout by eye |
| Trimmers 1 | ||||
| ×1 | 10K | 10k | read from the layout by eye | |
| LEDs 1 | ||||
| D1 | 3mm red LED | 3MM RED LED | on board; read from the layout by eye | |