Enclosure not stated · 2 knobs
Shin Ei OB-28 Octave Box
Based on the Shin-ei OB-28 Octave Box· 1 other board clones it
- Category
- Octave / Pitch
- Controls
- Sensitivity · Volume
- Build
- Perfboard
- Layout
- Unverified · no build reported at Effects Layouts (blog) yet
- Tags
- Octave, Shin Ei
From the post
Here's a weird one for you–the Shin Ei Octave Box. It's apparently an all analog clean octave down effect. I'm not going to pretend to understand how it works, but there are a lot of transistors. Originals used 2SC644 and 2SC666 transistors, which I think were in the massive TO-3 package. I've drawn the layout for more modern replacements, BC547s and a BC557. Other transistors like the 2N3904/06 or 2N5088/87 would probably work as well. Socket and experiment with what you have on hand.
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 38 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 layout was not sure of
- SwB listed as the effect-control footswitch and SwA left out as the bypass: a guess from the wiring notes (SwA carries Vol 2 and a 1-4 jumper), the drawing does not say which is which
- D1-D3: no type printed on the board or in the legend
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 12 | ||||
| ×2 | 150Ω | 150 | read from the layout by eye | |
| ×2 | 1K | 1k | read from the layout by eye | |
| ×1 | 2.2K | 2.2k | read from the layout by eye | |
| ×4 | 3.3K | 3.3k | read from the layout by eye | |
| ×4 | 6.8K | 6.8k | read from the layout by eye | |
| ×7 | 10K | 10k | read from the layout by eye | |
| ×1 | 22K | 22k | read from the layout by eye | |
| ×1 | 33K | 33k | read from the layout by eye | |
| ×3 | 47K | 47k | read from the layout by eye | |
| ×9 | 100K | 100k | read from the layout by eye | |
| ×1 | 220K | 220k | read from the layout by eye | |
| ×5 | 470K | 470k | read from the layout by eye | |
| Capacitors 8 | ||||
| ×3 | 250pF | 250p | read from the layout by eye | |
| ×2 | 1nF | 1n | read from the layout by eye | |
| ×3 | 6.8nF | 6.8n | read from the layout by eye | |
| ×1 | 10nF | 10n | read from the layout by eye | |
| ×9 | 100nF | 100n | read from the layout by eye | |
| ×2 | 220nF | 220n | read from the layout by eye | |
| ×1 | 22uF | 22u | electrolytic; read from the layout by eye | |
| ×1 | 100uF | 100u | electrolytic; read from the layout by eye | |
| Diodes 4 | ||||
| ×1 | 1N4001 | 1N4001 | read from the layout by eye | |
| D1 | ? | ? | value not given; read from the layout by eye | |
| D2 | ? | ? | value not given; read from the layout by eye | |
| D3 | ? | ? | value not given; read from the layout by eye | |
| Transistors 11 | ||||
| Q1 | BC547 | BC547 | legend: BC547 or similar; read from the layout by eye | |
| Q2 | BC547 | BC547 | legend: BC547 or similar; read from the layout by eye | |
| Q3 | BC547 | BC547 | legend: BC547 or similar; read from the layout by eye | |
| Q4 | BC557 | BC557 | legend: BC557 or similar; read from the layout by eye | |
| Q5 | BC547 | BC547 | legend: BC547 or similar; read from the layout by eye | |
| Q6 | BC547 | BC547 | legend: BC547 or similar; read from the layout by eye | |
| Q7 | BC547 | BC547 | legend: BC547 or similar; read from the layout by eye | |
| Q8 | BC547 | BC547 | legend: BC547 or similar; read from the layout by eye | |
| Q9 | BC547 | BC547 | legend: BC547 or similar; read from the layout by eye | |
| Q10 | BC547 | BC547 | legend: BC547 or similar; read from the layout by eye | |
| Q11 | BC547 | BC547 | legend: BC547 or similar; read from the layout by eye | |
| Potentiometers 2 | ||||
| Sensitivity | B100K | B100k | Potentiometer | read from the layout by eye |
| Volume | A100K | A100k | Potentiometer | read from the layout by eye |
| Switches 1 | ||||
| SwB | DPDT | DPDT | footswitch; SwA taken as the bypass; read from the layout by eye | |
Other boards based on the Shin-ei OB-28 Octave Box
- Shin-ei OB-28 Octave Box Dirtbox Layouts