1590B
5-Band-EQ
- Category
- EQ / Filter
- Price
- €4.89in stock
From the vendor
A compact slimline 5-band graphic EQ built around the Rohm BA3812L gyrator chip. Each band has ±12 dB of boost or cut via its own 100 kΩ slider, with frequency centres at 100 Hz, 300 Hz, 1 kHz, 3 kHz and 10 kHz — the classic hi-fi reference set. A compact 5-band graphic equalizer built around the Rohm BA3812L — a single-chip gyrator-based EQ that integrates five bandpass filters and a summing amplifier in one 20-pin SIP package. Each band has ±12 dB of boost or cut via its own 100 kΩ slider/pot, with frequency centres set entirely by external capacitor pairs. Each tuned by two caps (C0 and C). Change the caps to move any band anywhere in the audio range — there's no hidden RC network to figh
Schematic
The schematic is in the vendor's build document. Open the build document. No KiCad fragment has been drawn for this circuit yet.
Parts list 14 rows
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| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 2 | ||||
| R1 | 6k8 | 6.8k | Set the gain of the pre-amp and output stage paths around the chip | |
| R2 | 6k8 | 6.8k | Set the gain of the pre-amp and output stage paths around the chip | |
| Capacitors 5 | ||||
| C1 | 100µF | 100u | Supply decoupling (C1) and chip bias decoupling (C4) — 16 V or 25 V rated, observe polarity | |
| C4 | 100µF | 100u | Supply decoupling (C1) and chip bias decoupling (C4) — 16 V or 25 V rated, observe polarity | |
| C2 | 10µF | 10u | Input (C2) and output (C3) AC-coupling — 16 V or 25 V rated, observe polarity | |
| C3 | 10µF | 10u | Input (C2) and output (C3) AC-coupling — 16 V or 25 V rated, observe polarity | |
| C5 | 1n | 1n | Box film cap. The original prototype used 1µF here and worked fine — 1nF is the recommended value but the chip is tolerant. | |
| Diodes 1 | ||||
| D1 | 1N4001 | 1N4001 | Reverse polarity protection — observe cathode band orientation | |
| ICs 1 | ||||
| IC1 | BA3812L | BA3812L | Rohm 5-band gyrator EQ chip, SIP-20 package — obsolete part, see notice above | |
| Other 5 | ||||
| F1 | 100k B | 100K B | 9 mm Alpha PCB-mount, B-taper (linear). Centre-detent versions strongly recommended | |
| F2 | 100k B | 100K B | 9 mm Alpha PCB-mount, B-taper (linear). Centre-detent versions strongly recommended | |
| F3 | 100k B | 100K B | 9 mm Alpha PCB-mount, B-taper (linear). Centre-detent versions strongly recommended | |
| F4 | 100k B | 100K B | 9 mm Alpha PCB-mount, B-taper (linear). Centre-detent versions strongly recommended | |
| F5 | 100k B | 100K B | 9 mm Alpha PCB-mount, B-taper (linear). Centre-detent versions strongly recommended | |