Luma-mu is a 10HP Eurorack module, essentially a single drum channel of Luma-1 which holds multiple sounds in its ROM. It plays samples digitally without microcontroller or software used, which guarantees the lowest latency and highest response of its 8-bit mu-Law DAC. It’s perfect for Luma-1 expansion or standalone operation.

How different Luma-mu to Luma-1? Luma-mu schematics is an exact copy of a playback circuit of the Luma-1 / LM-1 drum machine. Similarly to those, Luma-mu uses an 8-bit mu-law DAC (AM6072DC) and 555 timer circuit to drive the clock and determine a pitch of the sound stored in the ROM. The sound data is stored in 1MBit EPROM, which holds 8 separate sounds. Luma-mu is a monophonic channel, however sounds can be switched in realtime. Sounds can be changed by replacing EPROMs located in a ZIF socket. Installation requires no extra tools or soldering. Users can create their own ROMs with Luma toools web-based editor. Deftaudio can ship it with extra sounds of your choice.

Guaranteed response time Luma-mu playback is fully driven in hardware implementation without microcontroller involved. It’s achieved by a number of simple logic chips which scan ROM data to play its content. This provides a determined response which is consistent and free of any jitter. In practice this means a very low latency (order of nanoseconds propagation delay), and guaranteed response time to the first sample after sending Gate to the Trigger input.

Expanded control by CV/Gate inputs Luma-mu brings an extra control and sound manipulation which are not possible by Luma-1. With Gate and CV patchpoints it’s possible to externally control the sound slot playing, Pitch, DAC amplitude as well as pause and playback rest. CV range is -5V to +5V nominal range, each input has an offset control for up to 0 to 10V range. Gate inputs are anywhere from 3V-12V.

Luma-mu feature set

• 8-bit µ-law EPROM playback, exact copy of LM-1/Luma-1 channel with authentic AM6072DAC (ceramic package, 40 years old)
• Removable EPROMs with 8 sounds on each, 16KB each (~1.5sec/ea)
• True hardware-only playback provides lowest (and constant) Trigger latency
• CV control for Sample Select allows changing sounds any time (even during playback)
• CV control for Pitch and Dynamics
• Gate control for Reset, Pause and sample Trigger
• Can be Clocked (sample rate) externally
• Plays one shot or loop sounds (perfectly looped sounds enable use as a wave oscillator)
• Comes with web-based tool to make your own sound EPROMs (see luma.tools)
• Designed and Assembled in California
• EPROM accessible from front with optional Luma-mu Reacharound extender module
• Eurorack 10HP, 50mm depth, requires 5V/+12V/-12V, total current is less than 0.43A

Package includes:

• Luma-mu Eurorack module
• LM-1 Factory sounds ROM
• Eurorack power cable
• Quick Start Guide