125B · 4 knobs
Decker
- Category
- EQ / Filter
- Price
- $10.00in stock
From the vendor
3-band passive EQ
Decker is a simple FMV EQ circuit similar to the tone stack found in many classic amps. A volume trim control is also available on the front panel to compensate for any loss or boost in volume caused by equalization. The op amp stages of this circuit can easily be tuned to provide a healthy amount of boost and/or overdrive if so desired. It can be built as a stand-alone pedal or as an add-on to a gain circuit in need of amp-like EQ. By adjusting values, a wide range of tonal options are available.
Sale is for PCB only. You must source the components and build the pedal yourself. To make foot switch wiring easier, we also suggest you buy the 3pdt utility switch.
Build documentation can be found here below. Please read before purchasing.
Decker Build Guide
For your convenience, a parts kit can be purchased here:
http://smallbear-electronics.mybigcommerce.com/kit-decker-pcb-not-included/
Share your work, get tips, ask questions and help troubleshoot at our Facebook Group. Don't forget to agree to the group rules if you wish to join. GCI DIY PCB builders group
NOT FOR COMMERCIAL USE
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 38 rows
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| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 12 | ||||
| CLR | 4.7k | 4.7k | 1/4 watt resistor 1k-10k Current limit | ing resistor for LED |
| R1 | 1M | 1M | 1/4 watt resistor 2.2M Pull down res | istor |
| R2 | 10k | 10k | 1/4 watt resistor | |
| R3 | 10k | 10k | 1/4 watt resistor | |
| R4 | 10k | 10k | 1/4 watt resistor 1k-47k Lower for mor | e output gain and op amp clipping. |
| R5 | 10k | 10k | 1/4 watt resistor 1k-47k Lower for mor | e input gain and op amp clipping. |
| R6 | 100k | 100k | 1/4 watt resistor | |
| R7 | 1k | 1k | 1/4 watt resistor | |
| R8 | 10k | 10k | 1/4 watt resistor | |
| R9 | 1M | 1M | 1/4 watt resistor | |
| R10 | 10k | 10k | 1/4 watt resistor | |
| R11 | 100k | 100k | 1/4 watt resistor | |
| Capacitors 12 | ||||
| C1 | 0.47u | 470n | Film cap See Duncan TS | C |
| C2 | 47n | 47n | Film cap 10n-0.1u Input cap. Fo | rms HPF with R9. |
| C3 | 100u | 100u | Electrolytic cap | |
| C4 | 0.1u | 100n | Film cap | |
| C5 | 100u | 100u | Electrolytic cap | |
| C6 | 1u | 1u | Film cap | |
| C7 | 4.7n | 4.7n | Film cap See Duncan TS | C |
| C8 | 0.33u | 330n | Film cap See Duncan TS | C |
| C9 | 2.2n | 2.2n | Film cap 1n-4.7n Forms input L | PF with R10. |
| C10 | 0.1u | 100n | MLCC | |
| C11 | 100p | 100p | MLCC 220p-1n Raise if usin | g smaller R4 values. |
| C12 | 1u | 1u | Film cap | |
| Diodes 1 | ||||
| D1 | 1n5818 | 1N5818 | Schottky diode 1n5817, 1n4001, bat41 Any suitable | protection diode for 9v. |
| ICs 1 | ||||
| IC | LM833 | LM833 | Dual Op Amp TL072, OPA2134, etc Any pin compa | tible dual op amp |
| Potentiometers 4 | ||||
| TREBLE | B25k | B25k | Potentiometers See Duncan TS | C |
| BASS | A100k | A100k | Potentiometers See Duncan TS | C |
| MID | B5k | B5k | Potentiometers See Duncan TS | C |
| SLOPE | A10k | A10k | Potentiometers See Duncan TS | C |
| Trimmers 1 | ||||
| TRIM | A100k | 100k | Potentiometers | |
| Switches 1 | ||||
| S | PAD | PAD | Send to PCB | |
| LEDs 3 | ||||
| LED | L1 | L1 | LED | |
| L+ | PAD | PAD | LED+ | |
| L- | PAD | PAD | LED- | |
| Other 3 | ||||
| R | PAD | PAD | Return from PCB | |
| V | PAD | PAD | 9v input | |
| G | PAD | PAD | Ground | |