The Drum Module 66 is a Eurorack 5-voice vintage analog drum generator, inspired by DIY and pro machines from the 60’s.
Description
The DM66 recreates the cheesy sounds of the early drum machines. The sounds are quite simple but have a lot of character.
Each voice is activated by individual Gate signals, and each voice has individual output.
The Mix output combines the 5 voices.
Gate signal should be 0..5V. However, other values are tolerated and can give slight variations of the sound.
The voices have an amplitude of about 4Vpp.
In details
The 5 voices of the DM66 are based on 5 damped Twin-T oscillators. This technique was very common in analog drum machines.
The frequency and duration of each voice is set by a combination of resistors and capacitors.
Simulations
Component selection
Component value changes
Version 0.2
The BOM and PCB contain several important value errors, all located in the Mix section (Schematics page 8):
- R61, R65, R75 and R79 should be 100k
Assembly guide
Start by soldering smaller parts first. Then proceed with gradually bigger/taller components.
Bottom Board
Bottom board is particularly crowded.
Resistors are all mounted vertically (one leg is straight while the other is bent at 180°). Be gentle while bending the lead and do not pinch it.
B1 and B2 are useless and can be ignored.
Hi, David!
Do you have any of these DM66 boards and panels available for sale?
I would love to get my hands on a set of one, if possible please.
Tanks for your interesting project
Hi David
I try to built your DM66 and need to know what is the value of C35. You just say its „CP“
But whats CP ? I dont know and dont understand ist. Maybe you can help me
Best regards
Thomas
Hello Thomas,
Oops, “CP” isn’t very useful indeed 🙂
(“CP” stands for Capacitor-Polarized.)
That part of the circuit is a copy of the noise source from the TR606. The same circuit is also used in my 606 Toms clone, and there, I use 47µF.
The value isn’t critical though. Anything between 10~100µF should be fine.