Noise Generator on ER-PROTO-01

Features

• Eurorack 6HP, 3U module
• Noise Generator
  • Based on Moritz Klein's Designing a white, pink & blue noise generator from scratch design
  • White, Pink, Blue noise outputs
  • Outputs are all buffered
• Built on ER-PROTO-01 card
• 10 pin Eurorack power connector

Noise Generator

• Credit Moritz Klein's Designing a white, pink & blue noise generator from scratch design

• Noise Generator

• White/Pink/Blue noise

• High Pass Filter (Blue Noise)

• Low Pass Filter (Pink Noise)

Build

White Noise Generator

• Voltage Gain = 148
• Switched from TL074 to TL084
  • Output seems pretty quiet (~200 mV)

• Offset errors = about 500 mV
  • Gain = 148, 500mV = 3.5mV offset voltage
  • Add offset voltage trimmer
  • Circuit from here

• Add offset adjust and gain to the optput

• White Noise Scope capture
• 100 mS / div

• 5 mS / div

• 200 uS / div

• 20 uS / div

• FFT, 25HKz range

Blue Noise Generator

• FFT 1mS scope setting

• Amplitude is too small
  • Added amplifier to the output stage

Pink Noise Generator

Jacks

Connectors

J1 - White Output

• +/- 7.5V swing

Eurorack Power

Build

On Controls Card

• Install J1, J3, J4
• Wire J1-S to J3-S
• Wire J3-S to J4-S

On Daughtercard

• Transistor Noise Source wiring

• Opamp wiring

• Wire J38-3 or J38-5 to nearby GND
• Install U1 14 pin socket near "middle of card
  • Pin 4 goes towards +12V
• Add 10 Ohm resistor U1-4 to +12V
• Add jumper U1-11 to GND
• Add jumper U1-8 to U1-9 (Blue loopback)
• Add jumper U1-6 to U1-7 (White loopback)
• Install R16 1K J1-8 to Open bus row (J1-T) - White noise out
• Install R15 1K J3-6 to Open bus row (J3-T) - Blue noise out
• Install R14 1K J4-4 to Open bus row (J4-T) - Pink noise out
• Install 100K from U1-13 to U1-14
• Install 22K from U1-13 to GND
• Add wire U1-8 to R15 (new row)
• Add wire U1-14 to R14 (new row)
• Add wire U1-7 to R16 (new row)
• Add wire U1-1 to U1-5 (NOISE_WB)
• Rest per schematic

Debug

• 60 Hz noise on U1-1