Enclosure not stated
Holtek echo
- Category
- Delay· Delay Echo and Samplers
- Price
- see vendor
- Tags
- Delay Echo and Samplers
Schematic
The schematic is the archived file. Open it at Experimentalists Anonymous, or browse its folder.
Parts list 34 rows
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| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 13 | ||||
| R1 | 100K | 100k | read from the schematic by eye | |
| R2 | 120K | 120k | read from the schematic by eye | |
| R3 | 10K | 10k | read from the schematic by eye | |
| R4 | 47K | 47k | read from the schematic by eye | |
| R5 | 4.7K | 4.7k | read from the schematic by eye | |
| R6 | 10K | 10k | read from the schematic by eye | |
| R7 | 10K | 10k | read from the schematic by eye | |
| R8 | 82K | 82k | read from the schematic by eye | |
| R9 | 100K | 100k | read from the schematic by eye | |
| R10 | 560K | 560k | read from the schematic by eye | |
| R11 | 5.6K | 5.6k | read from the schematic by eye | |
| R12 | 150K | 150k | read from the schematic by eye | |
| R13 | 4.7R | 4.7 | VDD feed to the 41256 DRAM; read from the schematic by eye | |
| Capacitors 12 | ||||
| C1 | .22uF | 220n | read from the schematic by eye | |
| C2 | 10uF | 10u | electrolytic, output; read from the schematic by eye | |
| C3 | .1uF | 100n | read from the schematic by eye | |
| C4 | .01uF | 10n | read from the schematic by eye | |
| C5 | 3nF | 3n | read from the schematic by eye | |
| C6 | .1uF | 100n | read from the schematic by eye | |
| C7 | 10uF | 10u | electrolytic, 16V; read from the schematic by eye | |
| C8 | 10uF | 10u | electrolytic, 16V; read from the schematic by eye | |
| C9 | 100uF | 100u | electrolytic, 10V; read from the schematic by eye | |
| C10 | .01uF | 10n | DRAM decoupling; read from the schematic by eye | |
| C11 | 100uF | 100u | electrolytic, 10V; read from the schematic by eye | |
| C12 | 180pF | 180p | read from the schematic by eye | |
| ICs 4 | ||||
| U1 | HT8955A | HT8955A | Holtek echo/delay processor; read from the schematic by eye | |
| U2 | 41256 | 41256 | 256K x1 DRAM; read from the schematic by eye | |
| U3 | 4558 | 4558 | dual op amp (U3A/U3B); read from the schematic by eye | |
| ×1 | 78L05 | 78L05 | 5V regulator for VDD, no designator; read from the schematic by eye | |
| Potentiometers 5 | ||||
| P1 | 10K | 10k | Potentiometer | input level to the echo mix, unnamed; read from the schematic by eye |
| P2 | 10K | 10k | Potentiometer | echo/repeat level, unnamed; read from the schematic by eye |
| P3 | 500K | 500k | Potentiometer | wired as variable resistor, delay-time network on pin 2; read from the schematic by eye |
| P4 | 500K | 500k | Potentiometer | wired as variable resistor with R12 on pins 8/9; read from the schematic by eye |
| ×1 | 10K | 10k | Potentiometer | output level pot, no designator; read from the schematic by eye |