Enclosure not stated · 6 knobs
EHX space drum
Based on the Electro-Harmonix space drum
- Category
- Ring Mod / Synth· Full Synths Drum Synths and Misc Synth
- Controls
- Start Freq · Stop Freq · Mod Depth · Mod Rate · Decay Time · Sweep Time
- Price
- see vendor
- Tags
- Full Synths Drum Synths and Misc Synth
Schematic
The schematic is the archived file. Open it at Experimentalists Anonymous, or browse its folder.
Parts list 43 rows
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Check before you build · 7 values the reader of this schematic was not sure of
- 330 series Mod Rate resistor: faint, could be 3K3 or 33K
- 33K dashed resistor: faint, could be 35K
- Zener: part number faint
- Q2: part number faint, looks like 2N5138
- Sens 1M trimmer: faint, dashed
- .1uF at right op amp could be 1uF
- 1048 x3: EHX house number, and the unlabelled op amp could be another section
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 15 | ||||
| R0 | 2M2 | 2.2M | decay RC in dashed circle near the VCO 1048; designator faint; read from the schematic by eye | |
| R4 | 10K | 10k | read from the schematic by eye | |
| ×1 | 10M | 10M | across the crystal mic; read from the schematic by eye | |
| ×4 | 10K | 10k | crystal-mic stage to 1uF; 1048 VCO input; Q1 emitter; output to ground; read from the schematic by eye | |
| ×1 | 33K | 33k | dashed (optional) resistor from the trigger 324 output; value faint; read from the schematic by eye | |
| ×2 | 27K | 27k | 1048 VCO pin 5; Q1 collector; read from the schematic by eye | |
| ×1 | 3K | 3k | VCO output to Q1 stage; read from the schematic by eye | |
| ×1 | 3K3 | 3.3k | deluxe modulation input; read from the schematic by eye | |
| ×6 | 47K | 47k | 1048 + input; 1048 pin 1; 1048 pin 5 bias; 1458 feedback; 2 x bias divider; read from the schematic by eye | |
| ×2 | 220K | 220k | Q1 base bias; right op-amp stage; read from the schematic by eye | |
| ×3 | 100K | 100k | deluxe 1458 stages; read from the schematic by eye | |
| ×1 | 22K | 22k | deluxe 1458 stage; read from the schematic by eye | |
| ×1 | 330 | 330 | in series with the Mod Rate pot; value faint, could be 3K3 or 33K; read from the schematic by eye | |
| ×4 | 2K2 | 2.2k | output 1048 stage; Decay Time and Sweep Time networks; zener feed; read from the schematic by eye | |
| ×1 | 2M2 | 2.2M | decay-switch network in dashed circle; read from the schematic by eye | |
| Capacitors 9 | ||||
| C11 | 0.1uF | 100n | drawn .1, in dashed circle with R0; read from the schematic by eye | |
| ×2 | 0.1uF | 100n | drawn .1, decay-switch network; read from the schematic by eye | |
| ×1 | 0.1uF | 100n | drawn .1uf to ground at the right op amp; could read 1uf; read from the schematic by eye | |
| ×2 | 1uF | 1u | crystal-mic stage; zener regulator; read from the schematic by eye | |
| ×2 | .22uF | 220n | input coupling to Q1; output coupling — .22uF; read from the schematic by eye | |
| ×3 | 10uF | 10u | 1458 input; Q1 stage to distortion trim; supply; read from the schematic by eye | |
| ×4 | 10uF | 10u | pairs of 10uF in the Decay Time and Sweep Time networks (deluxe); read from the schematic by eye | |
| ×2 | 100uF | 100u | 1048 pin 1 bypass; supply; read from the schematic by eye | |
| ×1 | 2.2uF | 2.2u | tantalum, deluxe modulation; read from the schematic by eye | |
| Diodes 3 | ||||
| D4 | Diode | DIODE | no part number given; read from the schematic by eye | |
| ×4 | Diode | DIODE | 3 in series under Stop Freq pot and 1 in the Mod Rate loop; no part number given; read from the schematic by eye | |
| ×1 | 1N4??? zener | 1N4??? ZENER | zener on the regulator, part number faint (looks like 1N4500/1N4600); read from the schematic by eye | |
| Transistors 2 | ||||
| Q1 | 2N5088 | 2N5088 | read from the schematic by eye | |
| Q2 | ? | ? | series-pass transistor on the 9V adapter input, number faint (looks like 2N5138); read from the schematic by eye | |
| ICs 4 | ||||
| ×1 | LM324 | LM324 | drawn 324, quad op amp, all four sections used; read from the schematic by eye | |
| ×3 | 1048 | 1048 | EHX house-numbered chip, three single sections drawn (pins 1-8); read from the schematic by eye | |
| ×1 | ? | ? | op amp with no number (right of the middle 1048); read from the schematic by eye | |
| ×1 | 1458 | 1458 | drawn 145B, two sections, deluxe model only; read from the schematic by eye | |
| Potentiometers 6 | ||||
| Start Freq | 10K log | A10k | Potentiometer | drawn 10K LOG; read from the schematic by eye |
| Stop Freq | 10K log | A10k | Potentiometer | R7, drawn 10K LOG; read from the schematic by eye |
| Mod Depth | 100K | 100k | Potentiometer | deluxe only; read from the schematic by eye |
| Mod Rate | 100K | 100k | Potentiometer | deluxe only; read from the schematic by eye |
| Decay Time | 100K | 100k | Potentiometer | deluxe only; read from the schematic by eye |
| Sweep Time | 100K | 100k | Potentiometer | deluxe only; read from the schematic by eye |
| Trimmers 2 | ||||
| Distortion Trim | 5K | 5k | read from the schematic by eye | |
| Sens | 1M | 1M | drawn faint near the crystal-mic op amp, labelled SEN... ADJ; read from the schematic by eye | |
| Switches 1 | ||||
| Decay Switch | SPST | SPST | read from the schematic by eye | |
| Other 1 | ||||
| ×1 | Crystal mic | CRYSTAL MIC | XTAL MIC trigger pickup; read from the schematic by eye | |