GrandPA

Q: What sample format does the Bastl GrandPA use?

Mono WAV at 22,050 Hz (up to 44.1 kHz), named P0 to PZ in the card root, with a maximum of 35 samples.

Q: How does SampleStack help with the GrandPA?

SampleStack converts samples to the GrandPA's lo-fi mono format and applies the strict P0 to PZ naming so the module reads them.

SampleStack supported

Bastl Instruments

A compact granular sampler based on the microGranny engine with lo-fi character.

Format

Eurorack, 5 HP

Sample Rate

22,050 Hz (adjustable up to 44.1 kHz)

Bit Depth

16-bit input, 12-bit output

Channels

Mono

File Formats

WAV

Storage

MicroSD card (35 samples max)

Specifications

Depth	35 mm
Power	< 50 mA (+12V)

Features

Granular sampler (microGranny 2.0 core)
Adjustable grain size/shift speed
Crush distortion
Digital attack/decay envelope
2 trigger inputs, 1 assignable CV input (0-10V)
1 DC-coupled output (0-5V)

Folder Structure

microSD Root/
├── P0.wav
├── P1.wav
├── ...
├── P9.wav
├── PA.wav
├── PB.wav
├── ...
└── PZ.wav

Notes

Files must be in the root directory with strict naming: P0.wav-P9.wav, PA.wav-PZ.wav
Format: 22,050 Hz, 16-bit, mono WAV (44.1 kHz works but disables pitch-up)
Maximum 35 samples on the card
Card can be hot-swapped; hold UP + DOWN for 2 seconds to reboot/reload

Preparing samples for the GrandPA

The Bastl GrandPA is built on the microGranny engine, and it is picky in a charming way. It plays mono WAV at 22,050 Hz for the full lo-fi, pitch-up range (44.1 kHz works but disables pitching up), and the files have to be named exactly P0.wav through P9.wav, then PA.wav through PZ.wav, in the card root.

There is a hard ceiling of 35 samples, and the card can be hot-swapped by holding UP and DOWN to reload. SampleStack converts to the GrandPA's rate and bit depth and applies the strict P-naming, so the module sees your files instead of ignoring a misnamed one.