Bastl Instruments SPA Grandpa Expander


Expander for the granular sampler module grandPa

Out of stock

SKU: BASTLSPA1 Categories: , Brand:


Spa is an expander for the granular sampler module grandPa. It adds CV inputs for nearly all parameters and a clock input to trigger the 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.

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


  • 5HP
  • PTC fuse and diode protected 10pin power connector
  • 50mm deep
  • Connects to grandPa with a ribbon cable on the back side
  • Module does not draw current

Additional information

Weight 0.125 kg
Dimensions 15 × 10 × 4 cm