ER-ADSR-555-01

Eurorack ADSR Module

Features

• Attack-DeCay-Sustain-Release Eurorack ADSR Module
• Takes in Gate signal, generates CV to VCA
• Attack, decay, and release pots control speed
  • Attack, decay, and release times can range from 200ms to 16s
• Sustain pot sets the sustain voltage level
• LED dims to level
• 3U tall, 6 HP wide
• 555 Based design
• Benjie Jiao MiniADSR
  • Original was based on Barry Klein design
  • As built by schmitzbits design - "The Fastest Envelope in the West"
• Benji's build has a three card stack-up and is 4 HP wide
• This card is wider but uses 2 cards

Rev 1 Checkout

• Ordered wrong (earlier) version of the board
• Re-create ordered board in Rev 1 folder
• Annotated schematic

• Drive with Erica Synths EDU Sequencer
  • GATE Out output
  • At slowest speed, ~2Hz
• My schematic symbols are Schottky but installed 1N4148 like schmitzbits schemati
• Using 1 M linear pots instead of 2.2M log pots
  • A, D, R pots should have been log pots
    • FAKING A LOG POT
  • Controls are are "touchy"
  • Sustain pot is linear as it should be and "works" but is backwards
  • All of the pots are backwards
    • A, D, S pots should be CCW for no delay
• ADR series resistors are 220 Ohms but should be 100 Ohms per schmitzbits note
• C3 is 4.7 uF
• Log pot curves

• Does not have 1M that is dashed line on schmitzbits schemati
• ADSR controls
  • A pot full CW
  • D pot full CW
  • S Pot mid
  • R pot full CW

• Back off Attack just a tiny bit from CCW
• Rounds over the attack like it should but it is very "touchy"

Issues

Rev 1 Issues

• Silkscreen has "DELAY" should be "DECAY"
• A, D, S, R pots are all backwards
• A, D, R pots should be A1M
• Made 2nd card

Cuts

• Cuts before build
• Cuts to RV1 (pins 2-3)

• Cuts to RV2 (pins 2-3)

• Cut to RV3 (pins 1, 3)

• Cuts to RV4 (pins 2-3 and pin 1)

Change Pot Series Resistor Values

• 220 Ohms on A, D, R pots s/b 100 Ohms
  • Change R7 to 100 Ohms (A pot)
  • Change R8 to 100 Ohms (D pot)
  • Change R10 to 100 Ohms (R pot)

Add wires

• Add wire RV1-2 to RV1-1 (back side view)

• Add wire RV2-2 to RV2-1 (back side view)

• Add wire R10 left side to Sustain pot, RV3 right side (back side view)
• Add wire U2-7 to Sustain pot, RV3 left side (back side view)

• Add wire D3-K to RV4-3 (back side view)
• Add wire RV4-1 to RV4-2 (back side view)

Add Release Resistor

• Add 1M resistor

Assembly Sheet

ER-ADSR-555-01 Rev 1 Assembly Sheet