1590BBM · 7 knobs
Socialist Jr. V1.1
- Category
- Distortion
- Controls
- Distortion · Response · Loudness · Level · Clip · Mid · Dark
- Price
- $10.00in stock
From the vendor
Distortion
The spiritual successor to the one that started it all, Socialist Jr. does the "Brutalist Jr. thing" but with a number of improvements and additional options built right into the PCB. If you're planning on building a highly modified Brutalist Jr., the Socialist Jr. will get you there faster. Here's a quick summary of the changes:
• Moved I/O pads for easier wiring.
• 2nd op amp stage converted to non-inverting to improve bias and make it tolerant to a wider range of dual op amps.
• Gain converted to a dual pot to control two gain stages simultaneously resulting in a much wider range of useable gain settings. (cleans up better) Values scaled to make this work well with readily available, B100k dual pot.
• "Response mod" pot built in.
• "Clipping mod" switch built in.
• Deeper mid-cut with Loudness fully engaged.
• Less volume drop when Loudness is set at minimum. (tone-stack bypass)
• "Mid Shift" switch built in.
• "Bright Switch" added. This was not a common mod in the Brutalist Jr. but it's useful for removing sizzle when loudness is fully engaged.
Sale is for PCB only. You must source the components and build the pedal yourself. Photo of completed pedal is for reference only. Enclosure shown in the completed pedal, courtesy of Acid Rain Pedalworks.
Build documents can be found here. Please read before purchasing.
Socialist Jr. V1.1 Build Guide
Note: V1.0 and V1.1 are mostly compatible. The values shown in V1.1 more closely resemble the original Brutalist Jr. circuit.
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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 64 rows
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| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 22 | ||||
| CLR | 4.7k | 4.7k | 1/4 watt resistor | |
| R1 | 1k | 1k | 1/4 watt resistor | |
| R2 | 2.2M | 2.2M | 1/4 watt resistor | |
| R3 | 10k | 10k | 1/4 watt resistor | |
| R4 | 10k | 10k | 1/4 watt resistor | |
| R5 | 1M | 1M | 1/4 watt resistor | |
| R6 | 2.2M | 2.2M | 1/4 watt resistor | |
| R7 | 10k | 10k | 1/4 watt resistor | |
| R8 | 1k | 1k | 1/4 watt resistor | |
| R9 | 10k | 10k | 1/4 watt resistor | |
| R10 | 22k | 22k | 1/4 watt resistor | |
| R11 | 120k | 120k | 1/4 watt resistor 68k-180k Affects mid f | requency. Lower value = lower frequency. |
| R12 | 100k | 100k | 1/4 watt resistor 4.7k-33k Affects outpu | t volume. Smaller = more volume. May cause clipping |
| R13 | 1k | 1k | 1/4 watt resistor 470R-3.3k Affects gain and bass in 2nd | stage. Smaller = brighter and gainier. |
| R14 | 1k | 1k | 1/4 watt resistor | |
| R15 | 100R | 100 | 1/4 watt resistor | |
| R16 | 2.2k | 2.2k | 1/4 watt resistor | |
| R17 | 10k | 10k | 1/4 watt resistor | |
| R18 | 2.2k | 2.2k | 1/4 watt resistor | |
| R19 | 100k | 100k | 1/4 watt resistor 12k-220k Affects output volume. Bigge | r = more volume. May cause clipping |
| R20 | 12k | 12k | 1/4 watt resistor | |
| R21 | 10R | 10 | 1/4 watt resistor | |
| Capacitors 21 | ||||
| C1 | 2.2u | 2.2u | electrolytic cap 1u-4.7u Forms HPF wit | h R13. Bigger = more bass/mud. |
| C2 | 0.1u | 100n | MLCC | |
| C3 | 2.2n | 2.2n | film cap 1n-4.7n Forms input L | PF with R1. Bbigger = mud, smaller = possible RF. |
| C4 | 22n | 22n | film cap | |
| C5 | 100u | 100u | electrolytic cap 47u-220u power filter | cap |
| C6 | 100u | 100u | electrolytic cap 47u-220u power filter | cap |
| C7 | 10u | 10u | electrolytic cap 4.7u-22u Forms HPF wit | h R16. Bigger = more bass/mud. |
| C8 | 1n | 1n | MLCC 680p-2.2n Smooths high | frequencies related to clipping of ssecond stage. |
| C9 | 47n | 47n | film cap | |
| C10 | 27n | 27n | film cap | |
| C11 | 300p | 300p | MLCC | |
| C12 | 0.22u | 220n | film cap | |
| C13 | 1n | 1n | film cap 470p-2.2n Switchable sy | stem LPF |
| C14 | 270p | 270p | film cap 100p-470p System LPF | |
| C15 | 1.5u | 1.5u | film cap 1u-2.2u Forms HPF wit | h R15 and Response. Bigger = more mud. |
| C16 | 0.1u | 100n | film cap | |
| C17 | 1u | 1u | film cap | |
| C18 | 1u | 1u | film cap | |
| C19 | 120p | 120p | MLCC 47p-470p Smooths high | frequencies related to clipping of first stage. |
| C20 | 470p | 470p | MLCC | |
| C21 | 270p | 270p | MLCC | |
| Diodes 5 | ||||
| D2 | Yellow | YELLOW | 3mm LED | |
| D3 | 1n4148 | 1N4148 | Si diode | |
| D4 | 1n4148 | 1N4148 | Si diode | |
| D6 | 1n34a | 1N34A | Ge diode | |
| D7 | 1n5818 | 1N5818 | Scottky diode 1n5817, 1n4001 Any suitable | polarity protection diode |
| ICs 2 | ||||
| IC1 | MC1458 | MC1458 | dual op amp TL072, TLC2272, LM833 Pin compatibl | e dual op amp |
| IC2 | TL072 | TL072 | dual op amp TLC2272, NE5532, OPA2132 Pin compatibl | e dual op amp |
| Potentiometers 4 | ||||
| DISTORTION | B10k | B10k | DUALGANG 16mm pot | |
| RESPONSE | C1k | C1k | 16mm pot | |
| LOUDNESS | B1M | B1M | 16mm pot | |
| LEVEL | A100k | A100k | 16mm pot | |
| Switches 4 | ||||
| CLIP | SPDT.PINS | SPDT.PINS | on/off/on 3 position switch! | |
| MID | DPDT.PINS | DPDT.PINS | on/on 2 position switch! | |
| DARK | SPDT.PINS | SPDT.PINS | on/on 2 position switch! | |
| 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 | |