Our hearts are filled with acid!
The x0x-heart is the heart of the infamous TB-303, surgically extracted to be transplanted into your designs. The x0x-heart is just the analog section of the TB-303, replicated with SMT components, and made small enough to fit into a Eurorack modular format. It even has a Eurorack power header on it.
To make the transition to eurorack easier, the pacemaker PCB is also available, which pins out all the useful controls in a small format. Both the pacemaker PCB and front panel are available from Grayscale (PCB, panel).
Temporary video until a better one is produced (audio has aliasing issues at high resonance): x0x-heart slaved to a 303.
The x0x-heart is designed to be small, inexpensive, and a close replica of the TB-303. It is not a perfect replica – some sacrifices were made to keep costs down – but it’s pretty darn close. It also has no pots or controls, making it great for DIY synth building. All of the useful I/O points are pinned out, and as a special bonus feature, digital control is given for Accent, Slide, Decay, Waveform select, Cutoff, and Env Mod. For all the nitty-gritty details, and a user manual, check out the x0x-heart wiki. Or, wander over to the x0x-heart store to pick up your very own.