Two versions:

• 1.0 SMD: The brand new design, with pre-assembled SMD stuff! The easy way!
• 1.0b THT: The classic version with the vintage look-and-feel!

What is it?

The DM77 is a Eurorack-compatible drum synthesizer inspired by the classic Coron DS8, featuring improved characteristics.

This isn't a clone—it's a completely redesigned circuit.

The main advantage over the DS8 is that the primary oscillator now tracks 1V/Oct across several octaves. Other improvements include:

• a better noise generator,
• an external audio input (VCA),
• a Eurorack compatible output level
• and the use of the LM13700 chip instead of the CA3080.

The DM77 features a 1V/Octave saw-core oscillator and a waveform converter that shapes the signal into a triangle wave. A second oscillator enables interesting frequency modulation (FM), ideal for creating metallic sounds.

The release/decay potentiometer lets you adjust the sound from very short to very long. Use the jumper setting to choose between Trigger or Gate response. In Gate mode, the DM77 can function as a versatile VCO/Synth voice. The Sweep setting delivers that classic disco drum sound.

Listen to the demo sounds: https://soundcloud.com/dhaillant/dm77-various-sounds

About the SMD version

The SMD version saves you a lot of work as all the SMD stuff comes pre assembled! You just have to solder the few remaining THT components (the potentiometers, the connectors etc.) You can assemble your DM77 in less than an hour! The circuits are identical to the classic THT version.

About the THT version

The current PCB revision is version 1.0b in THT. Stay in tune for potential updates and mods.

About the Front panel

The module is 10HP wide. The front panel is made of PCB material with black textured finish, 1.6mm thick.

I can offer a matte black finish with white or silver silkscreen. Feel free to contact me for more details.