Dual Granular Sampler


People have asked us to bring microGranny into the modular, and we decided to rethink the whole granular sampler idea to fit it best into a small size Eurorack module. GrandPA is the result!

GrandPA uses the same sound core as microGranny 2

It has 2 trigger inputs to trigger 2 different samples, CV input assignable to any sound parameter, and signal OUTPUT. The CV input can also be used to trigger the grain shift. GrandPA reads microSD card accessible from the front panel and runs on the same sound core as microGranny 2. For each sample, you can adjust: sample rate, crush, grain size, shift speed, attack, release (full release is hold), start, and end position.


  • granular sampler with microGranny 2.0 soundcore
  • plays wav files from the microSD card, 22050 Hz, 16 bit, mono
  • 12bit output
  • adjustable sample rate (can go up to 44.1 kHz)
  • trigger inputs for playing 2 different samples with different settings
  • each trigger input has a button to do the trigger manually
  • RGB led to indicate page (on each page, the two knobs adjust different parameters)
  • crush distortion
  • adjustable grain size and grain shift (positive or negative)
  • digital attack decay envelope
  • start and end point
  • no interpolation between grain jumps
  • each sample has an adjustable destination of CV input – it can go to any of the parameters
  • grain sync – CV input can act as trigger input for triggering the grain shift
  • can recognize 35 different samples on the microSD card (they need to be the specific name)
  • 35 presets (all settings of the 2 samples is one preset)
  • CV input reacts in 0-10V range
  • front panel from aluminium or oak wood with custom knobs
  • handmade locally by Bastl Instruments in Brno, Czech Republic

    Technical details

  • 5 HP
  • 35mm deep (skiff friendly)
  • current +12 <50mA
  • PTC fuse and diode protected 10 pin power connector
  • pdf user manual (English) download
  • pdf user manual (Chinese 繁體中文) download / translated by Wei Chin

DIY kit

You can build your own grandPA with our DIY kit. Go through the complete assembly guide below and make sure that you understand all the steps.

Want more CV inputs?

Check out the grandPa expander! Treat your grandPa to SPA!

Firmware update to v1.1

Did you know that all grandPAs from 2015 and earlier can be easily upgraded to current firmware v1.1 offering more features? You can find all the information here. You can get the update pack either from our shop or from your local dealer and watch this video