DAFM synth GENESIS - DIY kit new (black PCB)

Description

Now the DAFM Synth Genesis YM2612/YM3438 has been redesigned as a DIY friendly kit. This is a nice project that comprises soldering of through-hole components.This kit can be found on Tindie:
https://www.tindie.com/products/17166/
Assembled version with case and knobs can be found here:
https://www.tindie.com/products/13274/

Details

What is it?

Sound synthesis through Frequency Modulation (FM) allows to obtain unique sounds that defined a whole musical generation during the 80's and 90's The model Genesis uses the YM2612 (or YM3438) yamaha chip that was used in the SEGA Genesis / Megadrive home console.

Why did you make it?

This synthesizer is the perfect mix for lovers of retro video games, and makers who want to introduce themselves in the musical experimentation.

What makes it special?

The YM2612 has six channels with four operators per channel. The operators can interact according to eight different algorithms. Attack-Decay-Sustain-Release (ADSR) envelopes, frequencies and low frequency oscillators (LFOs) can be modified to obtain the whole range of FM sounds.

The YM2612 chip has a peculiar form of crossover distortion in the output, which has become known as the "ladder effect" among fans. The YM3438 is a modified CMOS version of the YM2612 with a louder sound output and no "ladder effect". The DAFM Synth can be purchased with the YM2612 or the YM3438 chip. Nostalgic retrogamers would choose the YM2612 chip. The YM3438 would be the first choice for the FM-synthesis lovers.

The synthesizer is operated through 2 rotary encoders and has a complete menu that is shown in 4 blue OLED displays. Thanks to the beautiful tactile keyboard of 12 notes you can try the different patches as they are created. There is also the possibility of changing the octave and thus test the full sound spectrum of the Yamaha chip. Once created, the presets can be saved in the RAM memory or in a SD card as DMP files that can be opened with VGM trackers like Deflemask.

The stereo sound output is 3.5 mm audio jack, has a MIDI input to connect a keyboard, sequencer or any MIDI instrument and can be powered with a USB type B cable (5V).

Files

DAFM GENESIS_user quick guide.pdf

Adobe Portable Document Format - 171.13 kB - 03/18/2023 at 19:45

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DAFM GENESIS_user manual.pdf

Adobe Portable Document Format - 364.01 kB - 03/18/2023 at 19:30

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Components

1 × PCB DAFM Synth Genesis YM2612 / YM3438 PCB

1 × 220Ω Resistor Resistor for MIDI Input Circuit

1 × 1N4148 diode Diode for MIDI Input Circuit

1 × 6N137 Optocoupler Optocoupler for MIDI Input Circuit

1 × 8 pin IC socket IC socket for 6N137

Build Instructions

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1

Warm-up: Be ready for soldering!

Please be careful with soldering. Too cold and you will get cold joints with false contacts. Too hot and you could destroy the soldering pad and break connections. Try to use flux to help you. Use the right solder tip, the right iron and the right temperature for your soldering wire.

Here you can find a tutorial for through hole components soldering:

Through hole components soldering tutorial

If you have any performing issue after finishing soldering, check the TROUBLESHOOTING part at the end of the list.
2

PCB Top

We’ll populate only the top of the board – it’s the side with the DAFM Synth and Genesis YM2612 / YM3438 logos. Here’s a shot of the completed board for reference.
3

MIDI In

220Ω x 1 (red, red, black, black, brown)

Resistors are not polarized, so it doesn’t matter which way around they go in. Bend the legs into a staple shape,and fold the legs over once you’ve inserted them into the board.

You don’t need to fold them over too much, it’s just so they don’t fall out when you flip the board over. It’ll make it easier to solder and snip off the legs if you don’t.

10kΩ x 1 (brown, black, orange, gold)

Solder and snip.

Diode 1N4148

The 1N4148 has a see-through glass body. It is part of the MIDI input circuit. Solder and snip. Watch out, the diodes are polarized, so pay close attention to which side the line marking on the diode body goes – it’s marked with a thicker white line on the PCB.

5 Pin DIN Connector

8 Pin Socket

It’s for the 6N137 optocoupler. The side the notch goes is marked on the board by a broken line on the ICs outline.