This is a bare PCB for the open-source preenFM2 polyphonic FM synthesizer. Capable of importing DX7 sysex banks, this is the ultimate DIY FM polysynth!

A mostly through-hole design makes this an easy assembly for all levels of DIY experience.

NOTE: While the preenFM2 PCB board is completely through-hole, the preenF405 MCU Board (a separate PCB for the microcontroller) requires some surface mount components. Alternatively, you can use a CERB40 MCU board with an additional USB cable.

Assembly guide is available here. Case and OLED mounting instructions are available here.

Features:

• 4 independent instruments

• up to 14 voices of polyphony (8 if you use 6 op algorithms)

• can import DX7 sysex banks

• Midi over USB

• USB drive: huge preset banks: 64128 presets, 8128 combos, 256*32 DX7 presets (The USB drive holds your preset banks, you scala scale files, your user waveform files)

• Easy firmware upload and flash.

• USB powered

• Comprehensive user interface and associated to a 4×20 characters display for easy preset edition

Each instrument contains:

• arpeggiator (Mutable-Instruments opensource algorithm).

• 1 effect Slot (LP, HP, Bass boost, Band Pass, crusher)

• 1 gate effect

• 4 rapid access performance parameters

• its own modifiable midi channel. They can share the same for FAT quadruple timbres notes.

• Modifiable number of allocated voices… Between 1 and 14.

• 28 FM algorithms from 3 to 6 operators

Each voice has:

• 7 low frequency modulators (3 LFOs, 2 envelopes, 2 step sequencers).

• 12 rows matrix : 16 sources, 32 destination (LP, HP, gate, stereo, MI, attack…)

• Arpeggiator, LFOs and step sequencers synchronizable on external midi clock or internal clock.

Operator features:

• 7 builtin waveforms + 6 user waveforms read from the usb drive.

• Stereo panning (at the carrier operator level)

• 8 envelope parameters per operator (DX7 like)

• Direct Scala scale file loading for microtonality. Up to 128 Scala scales selectable from the preenfm2.

• Modular Randomizer