GrandPa + Spa Expander BUNDLE (aluminium)

£249.00 (£207.50 ex VAT)

Experimental Granular Sampler

Stock immediately available from our UK supplier.
Ships from us within 1-2 working days.

Out of stock

Join the waitlist to be emailed when this product becomes available

SKU: grandpa-spa-expander-bundle-aluminium Categories: , ,



Bastl Instruments had been asked by people to bring their standalone microGranny product into the modular and decided to rethink the whole granular sampler idea in order to fit it best into small size eurorack module. Grandpa is the result!

It has 2 trigger inputs to trigger 2 different samples. CV input which is assignable to any sound parameter and signal OUTPUT. The CV input can be also used to trigger grain shift. Grandpa reads microSD card accessible from the front panel and runs 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 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 specific name)
  • 35 presets (all settings of the 2 samples is one preset)
  • CV input reacts in 0-10V range
  • breakout for FTDi USB adaptor for hacking, opensource firmware (see github)


Spa is an expander for the granular sampler module grandPa. It adds CV inputs for nearly all parameters and a clock input to trigger grain shift. It doesn’t work without the grandPa Eurorack module.

The voltage on the CV inputs is relatively added to the grandPa settings on both channels A and B. All CV inputs react only to positive voltages. The update rate of these CV inputs is 20 Hz. Communication between SPA and Grandpa can introduce audible artifacts to some samples while tweaking the SPA knobs.

Four CV inputs have attenuator knobs. These CV inputs are normalised to 5V so the knobs act as a signal source when nothing is connected to the CV input.


  • independent CV inputs for most parameters of the grandPa module
  • CV inputs with attenuators are normalised to 5V so the attenuators work as direct controls of the parameters for both channels A and B of the grandPa
  • CV inputs react only to positive voltages from 0-12V
  • grain size and shift speed CV inputs with attenuators
  • switch to select whether the other two CV inputs with attenuators control Start/End or Attack/Release parameters
  • crush cv input
  • grain sync input to trigger grain shift
  • connects to grandPa with a ribbon cable on the back side

Width: 5hp
Depth: 35mm (Grandpa) 50mm (Spa Expander)
Power: 50mA @ +12V (75mA @ +12V with Spa Expander connected)