125B · 2 knobs
OberonVintage Distortion
Based on the Jordan Bosstone· 5 other boards clone it
- Category
- Distortion· Boost / distortion
- Controls
- Attack · Volume
- Difficulty
- Beginner
- Price
- $12.50in stock
From the vendor
Originally a module that plugged directly into the guitar, this early distortion unit was one of the first effects to use diode clipping.
The Oberon Vintage Distortion is based on the original Jordan Boss Tone Model 1000, originally designed in 1966 by a company who was better known for making medical equipment and consumer Geiger counters for a post-WW2 atomic world.
The Boss Tone (also stylized as Bosstone) was one of the first fuzz or distortion units to use diode clipping. The Astrotone Fuzz predates it, but not by much. The Astrotone was released in 1966, and the Boss Tone was shown at the NAMM show in July 1966, but does not appear to have been commercially available until early 1967.
The two circuits are somewhat similar. The biggest difference is in form: the Jordan is meant to be plugged directly into the guitar, like the Vox Distortion Booster or Dan Armstrong effects, while the Astrotone is a floor pedal. These plug-in boxes were trendy for awhile in the late 1960s, but since they were incompatible with the Stratocaster and other recessed-jack guitars, this format of effect unit had largely disappeared by the early 1970s.
Inside the boxes, the Jordan has two cascaded transistor gain stages before the diode clipping while the Astrotone only has one. The Astrotone has a tone control, though not a terribly effective one in the stock configuration, and the second transistor only serves as a buffer to isolate the clipping diodes from the tone control. Both circuits control gain the same way, with an input potentiometer that is functionally the same as a guitar volume knob.
The Boss Tone was released in five different versions. The first three use two NPN transistors and are called the “California” versions since Jordan Electronics was based in California. The last two use one NPN transistor and one PNP, and are called the “Nashville” versions since Jordan licensed production of the circuit to the Sho-Bud company in Nashville. Each of the five versions sounds different, but the California-Nashville transition between V3 and V4 was the most drastic change.
The Oberon is directly based on the original California versions of the Boss Tone, with the NPN-NPN version of the circuit. We have added a toggle switch that selects between two sets of clipping diodes or disables them altogether, but otherwise, it’s a faithful reproduction of the original circuit.
Schematic
The schematic is in the vendor's build document, page 5. Open the build document. No KiCad fragment has been drawn for this circuit yet.
Parts list 30 rows
Report a wrong parse| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 8 | ||||
| R1 | 33k | 33k | Metal film resistor, 1/4W | |
| R2 | 6M8 | 6.8M | Metal film resistor, 1/4W | |
| R3 | 100k | 100k | Metal film resistor, 1/4W | |
| R4 | 470R | 470 | Metal film resistor, 1/4W | |
| R5 | 560k | 560k | Metal film resistor, 1/4W | |
| R6 | 10k | 10k | Metal film resistor, 1/4W | |
| R7 | 100R | 100 | Metal film resistor, 1/4W | |
| LEDR | 10k | 10k | Metal film resistor, 1/4W | LED current-limiting resistor. |
| Capacitors 6 | ||||
| C1 | 22n | 22n | Film capacitor, 7.2 x 2.5mm | |
| C2 | 220pF | 220p | MLCC capacitor, NP0/C0G | |
| C3 | 22n | 22n | Film capacitor, 7.2 x 2.5mm | |
| C4 | 22n | 22n | Film capacitor, 7.2 x 2.5mm | Power supply filter capacitor. |
| C5 | 100uF | 100u | Electrolytic capacitor, 6.3mm | Power supply filter capacitor. |
| C6 | 100n | 100n | MLCC capacitor, X7R | |
| Diodes 5 | ||||
| D1 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D2 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| D3 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| D4 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| D5 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| Transistors 2 | ||||
| Q1 | 2N3903 | 2N3903 | BJT transistor, NPN, TO-92 | |
| Q2 | 2N3903 | 2N3903 | BJT transistor, NPN, TO-92 | |
| Potentiometers 2 | ||||
| ATTACK | 100kB | B100k | 16mm right-angle PCB mount pot | Linear taper. |
| VOLUME | 100kA | A100k | 16mm right-angle PCB mount pot | Audio (log) taper. |
| Switches 2 | ||||
| CLIP | SPDT cntr off | SPDT CNTR OFF | Toggle switch, SPDT on-off-on | |
| FSW | 3PDT | 3PDT | Stomp switch, 3PDT | |
| Jacks & sockets 3 | ||||
| IN | 1/4" stereo | 1/4" STEREO | 1/4" phone jack, closed frame | Switchcraft 112BX or equivalent. |
| OUT | 1/4" mono | 1/4" MONO | 1/4" phone jack, closed frame | Switchcraft 111X or equivalent. |
| DC | 2.1mm | 2.1MM | DC jack, 2.1mm panel mount | Mouser 163-4302-E or equivalent. |
| Hardware 2 | ||||
| BATT | Battery snap | BATTERY SNAP | 9V battery snap | Optional. Use the soft plastic type—the hard-shell type will not fit. |
| ENC | 125B | 125B | Enclosure, die-cast aluminum | Can also use a Hammond 1590N1. |
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- Jordan Bosstone Experimentalists Anonymous
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