Difference between revisions of "ER-VCA2-01"

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* [http://musicfromouterspace.com/analogsynth_new/DUALVCA/DLLVCA001.html Dual Log/Linear VCA] - Article by Ray Wilson
 
* [http://musicfromouterspace.com/analogsynth_new/DUALVCA/DLLVCA001.html Dual Log/Linear VCA] - Article by Ray Wilson
 
** Has adjustment procedure
 
** Has adjustment procedure
 +
* [https://electricdruid.net/design-a-eurorack-vintage-vca-with-the-lm13700/ Design a Eurorack “Vintage VCA” with the LM13700] - Electric Druid
 +
-
  
 
== Video ==
 
== Video ==

Revision as of 22:41, 12 January 2023

Tindie-mediums.png

ER-VCA2-01 SET P1080800-720PX.jpg

Features

  • Eurorack card
    • 3U tall
    • 6HP wide
    • 3 card set
  • Dual Voltage Controlled Amplifier (VCA)
  • LM13700 based
  • Pots adjust between input and Mod jacks
    • CW - output is fully controlled by MOD jack
    • CCW - output is not controlled by MOD jack
  • +/- 12V Power, 10-pin power connector

Credits

Connectors

J1 - Daughtercard Pots

ER-VCA2-01-DB J1.PNG

  • POT1 = RV1 = Modulation Adjust Channel 1
  • POT2 = RV2 = Modulation Adjust Channel 2

J2 - Daughtercard Eurorack Power

ER-VCA2-01-DB J2.PNG

J3 - Daughtercard Control Card Jacks

ER-VCA2-01-DB J3.PNG

  • Controls card J3 = OUT1 (bottom left jack)
  • Controls card J4 = OUT2 (bottom right jack)
  • Controls card J5 = MOD1 (middle left jack)
  • Controls card J6 = MOD2 (middle right jack)
  • Controls card J7 = IN1 (top left jack)
  • Controls card J8 = IN2 (top right jack)

Reference

-

Video

Checkout

Rev 2

  • Updated Controls card
  • Using Rev 1 Analog daughtercard
  • Headers line up
  • Tested as set
  • View from rear side

ER-VCA2-01 SET P1080806-720PX.jpg

  • Output clipping below 0V, missing 510K resistors between LM13700 out and Transistors set
    • Add 510K on back side U2-12 to U2-13
    • Add 510K on back side U2-4 to U2-5
    • Works much better, no clipping

Rev 1

  • Headers between cards do not line up
    • Fix on Controls card
      • Make Rev 2 Controls card
      • Move down bottom header J2 to match daughtercard
    • Cut off 0.1" of controls card using vice/hacksaw
    • Use female headers on bottom of daughtercard
    • Use right angle pin header pins to connect to pads (remove plastic)

ER-VCA2-01-CTRLS CONN RWK.png

Assembly Sheet

  • Two revs of Daughtercard
    • Rev 1 shipping (ships on Tindie starting 2022-11)
    • Rev 2 future version which will incorporate resistor rework
  • Two revs of Controls card
    • Rev 2 ships (Tindie)

Rev 2 Daughtercard, Rev 2 Controls Card

Rev 1 Daughtercard, Rev 2 Controls Card

Rev 1 Daughtercard, Rev 1 Controls Card