1590BBS · 3 knobs
Event Horizon
Based on the Paul Trombetta Rotobone· 2 other boards clone it
Want a PCB? Naegele Audio laid out a PCB for this circuit and sells boards, as well as relay bypass and I/O boards: message PedalBuilder on the PedalPCB forum.
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- Fuzz
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From the vendor
Backstory Two of my first builds were Jordan Boss Tone derivatives, the PTD Mini-Bone/ Trumpeter and KMA Fuzzly Bear/ Teddy Rupture . Although the insides of the enclosures are far from my best work, they are still some of my favorite builds. Both of them offer a wide range of tonal options, from edge of breakup to all-out fuzzy madness. (Note: If you haven't built one yet, this is the build that you have been waiting for—only a few parts, none of which are unobtanium, and both boards are in stock. Go forth and build!) Despite being very similar circuits, i.e. Boss Tones with a voltage starve and modifications to the input/output capacitor values, their respective tonal ranges have much less overlap than you would think. The Fuzzly Bear is less compressed and works better for hard rock tones, likely due to the extra diodes in the clipping stage, while the Mini-Bone is much better at generating brassy/synthy octave overtones. My love for both pedals lead me to contemplate building my own take on PTD's Rotobone , which seems to be a Mini-Bone with rotary switches to select the input and output capacitors, and has additional switches for changing transistors/gain structure. About a year ago, when I first decided to experiment with my own PCBs, the first PCB that I created was meant to be a Rotobone with offboard switches for the capacitors, similar to what @coltonius did here . <a href="https://forum.pedalpcb.com/attachments/rotobone-v1-jpeg.76980/" target="_blank"> <img src="data:image/svg+xml;charset=utf-8,%3Csvg xmlns%3D'http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg' width='1501' height='2000' viewBox%3D'0 0 1501 2000'%2F%3E" data-src="https://pedalpcb-forum.nyc3.digitaloceanspaces.com/data/attachments/76/76999-a40285c397f44a8293932792a8abfc8b.jpg?hash=pAKFw5f0So" class="bbImage lazyload" style="" alt="Rotobone v1.jpeg" title="Rotobone v1.jpeg" width="150" height="200" /> <img src="https://pedalpcb-forum.nyc3.digitaloceanspaces.com/data/attachments/76/76999-a40285c397f44a8293932792a8abfc8b.jpg?hash=pAKFw5f0So" class="bbImage " style="" alt="Rotobone v1.jpeg" title="Rotobone v1.jpeg" width="150" height="200" /> Unfortunately, I made a couple mistakes with the circuit design (the gain structure switch should add an emitter resistor to Q1, not Q2/3; the 100k voltage control that was only useful for the first 2/3 of its rotation), transistor selection (the output of the BC108C overpowered Q2/3), and overall layout (side jacks!). I also concluded that the 1P12T switches offered more capacitor selections than I really needed, and had unpleasantly stiff mechanical action. So while I ended up with a cool pedal, it wasn't quite what I had in mind. So back to the drawing board. But life and other projects intervened, and it was quite some time before I was able to get back to the drawing board. Design Fast forward to December, and I found myself with some time on my hands, so I decided to restart my Rotobone project. I began by creating a list of the features that
Schematic
The schematic is in the post. Open it at Naegele Audio. No KiCad fragment has been drawn for this circuit yet.
Parts list 48 rows
Report a wrong parseGot parts in a drawer? See what you can build with them.
Check before you build · 2 values the reader of this schematic was not sure of
- R101: LED resistor drawn as 'CLR' with no value
- Energy, Structure and Element switch types are not printed; read from the poles drawn
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 9 | ||||
| R1 | 560k | 560k | read from the schematic by eye | |
| R2 | 150k | 150k | read from the schematic by eye | |
| R3 | 560k | 560k | read from the schematic by eye | |
| R4 | 18k | 18k | read from the schematic by eye | |
| R5 | 4.7k | 4.7k | switched in by Structure; read from the schematic by eye | |
| R6 | 1k | 1k | Energy switch; read from the schematic by eye | |
| R7 | 39k | 39k | Energy switch; read from the schematic by eye | |
| R8 | 1k | 1k | under the Gain pot so it never mutes; read from the schematic by eye | |
| R101 | ? | ? | LED current limiting resistor, drawn as CLR; read from the schematic by eye | |
| Capacitors 21 | ||||
| C1 | 10n | 10n | Gravity rotary; read from the schematic by eye | |
| C2 | 22n | 22n | Gravity rotary; read from the schematic by eye | |
| C3 | 68n | 68n | Gravity rotary; read from the schematic by eye | |
| C4 | 100n | 100n | Gravity rotary; read from the schematic by eye | |
| C5 | 220n | 220n | Gravity rotary; read from the schematic by eye | |
| C6 | 330n | 330n | Gravity rotary; read from the schematic by eye | |
| C7 | 470n | 470n | Gravity rotary; read from the schematic by eye | |
| C8 | 1u | 1u | Gravity rotary; read from the schematic by eye | |
| C9 | 22n | 22n | read from the schematic by eye | |
| C10 | 47p | 47p | read from the schematic by eye | |
| C11 | 10n | 10n | Density rotary; read from the schematic by eye | |
| C12 | 22n | 22n | Density rotary; read from the schematic by eye | |
| C13 | 68n | 68n | Density rotary; read from the schematic by eye | |
| C14 | 100n | 100n | Density rotary; read from the schematic by eye | |
| C15 | 220n | 220n | Density rotary; read from the schematic by eye | |
| C16 | 330n | 330n | Density rotary; read from the schematic by eye | |
| C17 | 470n | 470n | Density rotary; read from the schematic by eye | |
| C18 | 1u | 1u | Density rotary; read from the schematic by eye | |
| C19 | 1n | 1n | Bright DIP switch; read from the schematic by eye | |
| C20 | 2.2n | 2.2n | Bright DIP switch; read from the schematic by eye | |
| C101 | 100u | 100u | supply filter; read from the schematic by eye | |
| Diodes 4 | ||||
| D1 | 1N4148 | 1N4148 | read from the schematic by eye | |
| D2 | 1N4148 | 1N4148 | switched in series by the Clipping DIP switch; read from the schematic by eye | |
| D3 | 1N4148 | 1N4148 | switched in series by the Clipping DIP switch; read from the schematic by eye | |
| D4 | 1N4148 | 1N4148 | read from the schematic by eye | |
| Transistors 3 | ||||
| Q1 | 2N5088 | 2N5088 | hFE 330 in the post's build; read from the schematic by eye | |
| Q2 | 2N2907A | 2N2907A | silicon setting of Element; read from the schematic by eye | |
| Q3 | OC42 | OC42 | germanium setting of Element; the post's build used a GT310B (hFE 180); read from the schematic by eye | |
| Potentiometers 3 | ||||
| Gain | B100k | B100k | Potentiometer | read from the schematic by eye |
| Energy | B50k | B50k | Potentiometer | read from the schematic by eye |
| Level | B100k | B100k | Potentiometer | read from the schematic by eye |
| Switches 7 | ||||
| Gravity | 1P8T | 1P8T | SW1, input capacitor rotary; read from the schematic by eye | |
| Density | 1P8T | 1P8T | SW5, output capacitor rotary; read from the schematic by eye | |
| Element | DPDT | DPDT | SW3, silicon/germanium output transistor; read from the schematic by eye | |
| Energy switch | SPDT | SPDT | 1k or 39k in series with the Energy pot; read from the schematic by eye | |
| Structure | SPDT | SPDT | adds R5 to the Q1 emitter; read from the schematic by eye | |
| Clipping | DIP 2 | DIP 2 | internal DIP switch; read from the schematic by eye | |
| Bright | DIP 2 | DIP 2 | internal DIP switch; read from the schematic by eye | |
| LEDs 1 | ||||
| LED | LED | LED | status LED; read from the schematic by eye | |
Other boards based on the Paul Trombetta Rotobone
- Paul Trombetta Rotobone Dirtbox Layouts
- Trumpet Fuzz Naegele Audio · 1590BB2