Enclosure not stated · 3 knobs
Death by Audio Robot
Based on the Death By Audio Robot· 6 other boards clone it
- Category
- Octave / Pitch
- Controls
- Input trim · Control · Volume
- Price
- see vendor
- Tags
- freestompboxes.org trace
From the vendor
A lo-fi 8-bit pitch shifter built around the Holtek HT8950 voice modulator chip, with a TL072 input gain stage and output stage and a split supply from two 3.6V zeners. The Control knob bends the pitch (or sets the arpeggiator speed), and a rotary switch selects normal, octave down, octave up and arpeggiator modes by grounding the chip's SW0-SW2 pins.
Instead of the 4P3T rotary switch, wire three SPST switches that ground HT8950 pins 1, 2 and 3 (SW0-SW2) to select modes independently and get more range; the datasheet's switching table shows the combinations.
Schematic
The schematic is in the post. Open it at Revolution Deux. No KiCad fragment has been drawn for this circuit yet.
Parts list 30 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
- The mode-select rotary switch wiring to SW0-SW2 is not drawn.
- The 1M variable resistor at the input stage is not named; it is listed as a trimmer.
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 12 | ||||
| R1 | 27K | 27k | read from the schematic by eye | |
| R2 | 10K | 10k | read from the schematic by eye | |
| R3 | 1.5K | 1.5k | read from the schematic by eye | |
| R4 | 43K | 43k | read from the schematic by eye | |
| R5 | 5.6K | 5.6k | read from the schematic by eye | |
| R6 | 100K | 100k | read from the schematic by eye | |
| R7 | 330 | 330 | read from the schematic by eye | |
| R8 | 10K | 10k | read from the schematic by eye | |
| R9 | 27K | 27k | read from the schematic by eye | |
| R10 | 430K | 430k | read from the schematic by eye | |
| R11 | 43 | 43 | supply; read from the schematic by eye | |
| R12 | 43 | 43 | supply; read from the schematic by eye | |
| Capacitors 10 | ||||
| C1 | 330n | 330n | input; read from the schematic by eye | |
| C2 | 330n | 330n | read from the schematic by eye | |
| C3 | 100n | 100n | read from the schematic by eye | |
| C4 | 2.2u | 2.2u | electrolytic, Vref; read from the schematic by eye | |
| C5 | 100n | 100n | read from the schematic by eye | |
| C6 | 330n | 330n | read from the schematic by eye | |
| C9 | 470p | 470p | read from the schematic by eye | |
| C10 | 330n | 330n | output; read from the schematic by eye | |
| C7 | 33u | 33u | electrolytic; read from the schematic by eye | |
| C8 | 33u | 33u | electrolytic; read from the schematic by eye | |
| Diodes 2 | ||||
| Z1 | 1N5227 | 1N5227 / 3V6 | 3.6V zener; read from the schematic by eye | |
| Z2 | 1N5227 | 1N5227 / 3V6 | 3.6V zener; read from the schematic by eye | |
| ICs 2 | ||||
| U1 | TL072 | TL072 | read from the schematic by eye | |
| U2 | HT8950 | HT8950 | voice modulator; read from the schematic by eye | |
| Potentiometers 3 | ||||
| Input trim | 1M | 1M | Potentiometer | variable resistor in the input stage; read from the schematic by eye |
| Control | B500K | B500k | Potentiometer | read from the schematic by eye |
| Volume | A100K | A100k | Potentiometer | read from the schematic by eye |
| Switches 1 | ||||
| Mode | 4P3T | 4P3T | rotary; read from the schematic by eye | |
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