Dual TBridge Percussion

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The TBridge circuit was used in some famous analog drumcomputers. It is possible to create different drumsounds like bassdrums, toms, claves and more. The circuit was developed during the Homemade summercamp 2014 in Fou de Fougerette by Uwe Schueler, Tamara Wilhelm and Oliver Jaeggi.

On the board are 2 TBridge sounds circuits that can be played separately.


  • IC TL082P op-amp (or similar)


  • R1 100k RESISTOR
  • R2 100k RESISTOR
  • R3 100k RESISTOR
  • R4 10 RESISTOR
  • R5 1.9M RESISTOR
  • R6 3.8M RESISTOR
  • R7 100k RESISTOR
  • R8 100k RESISTOR
  • R9 100k RESISTOR
  • R10 10 RESISTOR
  • R11 1.9M RESISTOR
  • R12 3.8M RESISTOR
  • R13 100k RESISTOR
  • R14 100k RESISTOR
  • R15 1k RESISTOR
  • P1, 2 1k. POTENTIOMETER for frequency of the percussion sound


  • C1 100n NONPOL (C1B for wider cap)
  • C2 100n NONPOL (C2B for wider cap)
  • C3 100n NONPOL (C3B for wider cap)
  • C4 100n NONPOL (C4B for wider cap)
  • C5 10n NONPOL
  • C6 10n NONPOL
  • C7 4.7u POL
  • C8 4.7u POL
  • C9 47u POL
  • 2* switches (on-off-on) select the decay ranges
  • 5* jack connectors (2 * trigger in / 2 * boom out / mix out)


A Dual OpAmp is used for 2 TBridge Oscillators. The Potentiometer controlls the frequency of the oscillator. The decayswitch selects different decay times of the sound (this also affects the frequency).

DualTbridge schema.png


DualTBridge PCB.jpg

Mask (bottom): File:DualTbridge PCB.pdf

Parts (top): File:DualTbridge parts.pdf

EAGLE Files: File:DualTBridge eagle.zip

Built Devices


Dual TBridge Percussion device with piezo triggerpad to play the sounds by hand. The sounds can also be triggered by an external trigger signal. The piezo trigger pads have also trigger outputs to play external gear.