ER-ADSR-555-01

Eurorack ADSR Module

Features

• 3U tall, 6 HP wide Eurorack module
• Attack-Decay-Sustain-Release 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
• 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
  • Missing 1M decay fix resistor
• Re-create ordered board in Rev 1 folder
• Annotated schematic

• Drive IN jack with Erica Synths EDU Sequencer
  • GATE Out output
• My schematic symbols are Schottky but installed 1N4148 like schmitzbits schemati
  • A, D, R need to be log (Type A) pots
• All of the pots are backwards (rework below)
  • A, D, S pots should be CCW for no delay
  • S pot should be CW for full output
• ADR series resistors are 220 Ohms but should be 100 Ohms per schmitzbits note
• Attack overshoots
• May need > 100 ohms
• C3 s/b 1 uF for the pots to have a good range
• Updated Pl for above
• Log pot curves

• Scope capture

Schematics

• Rev 1 Schematic
• Rev 2 Schematic

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 assembling parts on card
• 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 (PL below is updated already for this)
  • 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 R9 left side to Sustain pot, RV3-1
• Add wire U2-7 to Sustain pot, RV3-3

• 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