Projecttitel: DINSYNC RE-303

Status:  DONE

Startdate: 2016

Duedate: 09/2018

last update : 02/2023

Manufacture link:

Forum :

Page Content:

its not a clone, its a replica of the famous Roland TB-303

The Founder Paul Barker developed in 2016 the RE-303.

the "internal Name" is Space Cadet.

few different case types are avaiable/fits with the pcbs: TT-303 (old version),

you find a german article from me, about the RE-303 here:


The PCB set contains:  (available on

RE-303 v1.2 main-board and switch-board PCB.

Sumida coil and adapter.

3pc set of power transistors.

8pc set of potentiometers (tune, cutoff, resonance, env, decay, accent, tempo and volume with switch)

2pc set of rotary switches (pattern/mode)

3pc set of 6.3mm jacks (mix in, headphone, main out)

2pc set of 3.5mm jacks (cv/gate)

1pc DC jack

1pc waveform switch

Parts what you have to source:

the following files are based on the same version but with different office formats:

RE-303 BOM_1.2_official.pdf

RE-303 BOM_1.2_official.xlsx

RE-303 BOM_1.2_official.ods

MOUSER BOM project card:

plus tactiles: 688-SKQEAA 

when you use the PIXIE or Sonic Potions CPU you dont need following parts

ift(y): yellow coil for the original cpu clock
ic2: cd4556B decoder/multiplexer
ic3, ic4, ic5: cmos ram
D4: 1n4148
R6: 33k
R7: 100k 
R23: 22k 
R39, R40, R41, R44: 3.3k
C12: 0.01uf film 

C57: 100uf / 25v electrolytic
Q4: 2sc536f/2sc945p 

Buildguide v1.2



IDIssueIssue/Mod  Description and fix
1Gate in case you hear the gate signal  - attack clicks  - you can try to connect a 100nF polar cap**  between GND and Trigger.  Measure with an scope to find the best value - maybe you need a bigger value 220-470nf 

Pixie CPU (the better Version) 


"The Pixiepowered RE-CPU is a D650C emulator, which will allow you to run original maskrom firmware from original Roland(tm) machines."

Firmware and more:

FW manual 1.4.3


Firmware Installation (on your own risk)

  1. turn on and send 303.sysx with sysex librian tool
  2. turn off and on again
  3. send the boot loader sysex (1.30 version)
  4. turn off
  5. turn on while hold Step1 (all lets flashes like night rider mode)(some older boot loaders don't have the night rider mode)
  6. now send the REEMU 1.3.0 sysex
  7. machine restarts byself in 1.3.0 mode
  8. turn off and on the 303
  9. send the 303 sysx (optional)
  10. reload the boot loader 1.4.3 in boot loader mode (hold step1) and upload the REEMU 1.4.3 sysex

Sonicpotions CPU:  (deprecated ) pls. use the Pixie CPU

Julian from Sonic Potions developed a CPU for the RE303, this CPU is also an replacement for TB-303

(more here: )

User guide: SonicPotions_Re-303_User_Guide.pdf

Installation guide:SonicPotions_Re-303_Installation_Guide.pdf

Forum about the CPU:


different cases are on the market:

Alu case in black, silver, white, gold..

Buildguide for the case:



you can also use a Bassbot TT-303 case (the first 303 style case)


Potentiometer Modification:

Available in my shop: (shipping starts end of June 2020)


no wobbling potentiometers anymore !!! 

you also need for the Midi Jacks an adapter.


you need one of this Stereo Pot: (VR4 in the 303)

VR4 B50K Stereo !! (linear stereo)

VR2, VR7 = 50KB (lin)

VR3, VR5 =50KA (log)

VR6 = 1MA (log)

in total 6 potentiometers

and you need:

pinstripes as shown above in my pictures.

2x 3.5mm (1/8inch) stereo jacks    Lumberg KLB-4 which is available worldwide in hundreds of shops - its a quality part.

2x Adapter for the Midi holes to use the 3.5mm jacks - ONLY if you use the RE-303 Aluminum case - this are included with the PCB order in my shop !

2x 3.5mm (1/8 inch) plug to MIDI Cable - thonk or make your own.. or DIY: NYS322 + 172-7435-E (mouser) 

update 01/2020: ground the MIDI IN port too, that's needed because the acrylic's adapter to the stereo 3.5mm jacks are isolated

in case you use silver knobs: they are metalized and make grounding issues, you have to remove from the bottom the paint with a cutter knife.(easy)

the blue cable connects ground from MIDI out to the MIDI IN jack.


Battery Tray - optional

You will need 5x 1.2V AA batteries, get the ones from IKEA, they're from the same factory as the Eneloop ones but for a fraction of the cost.

Unless you can find a 5x AA battery tray best bet is to 3d print your own.

Then follow the official guide for installing the battery tray.

It is important to fit a 10 Ohm resistor as in this photo.



DIN JACK Connector with integrated switch

assembled versions are here:


or create your own by 3D print it (SLA)

Switching DIN Sync Jack - housing.stl

Switching DIN Sync Jack - actuator.stl

  • -  Switch: Alps Alpine SPVQ910205

  • -  DIN 5 Jack: Multicomp PSG03463

my own VCF Resonance modification:

the underlined lines are the value which I installed, you should use milled ic pins to make testing and replacement to your favorite sound easier

Random pics:


  1. Do you have any potentiometer mod pcb's left?

      1. Great! I need at least 1, 2 would be great.

  2. Finishing my re303, interesting pots pcb's, do you have some spare?

    I've also updated the BOM on Mouser still some parts are missing.



      1. Yo man! (big grin) thankyou

  3. Hi Led-man 

    I started to build my RE-303 and I see your potentiometer modification (PCB) . So, If you have any I would like to buy 2 PCBs




  4. Hi Led-man,

    are the Potentiometer Modification boards still available? I'm interested in 2 and maybe with Potentiometer included or please let me know which Potentiometer I exactly wave to buy. Should be some top quality Potentiometer like ALPS then.

    You should present the Potentiometer PCB to DinSync maybe they can offer it in the shop as complete kit then.

    Thanks a lot, great work!!!

  5. hi all,

    I left not enough pcbs for all.

    i have to reorder the pcbs.

    please send me a email with the amount. Patrick at DSL-man dot de

    the alpha Potis are available from THONK, MUSIKDING, UK-ELEKTRONIK and others.

    the Filter Pot is stereo and available on ebay

  6. I´ll bundled the 2 Adapter for the MIDI Connectors with the Potentiometer Adapter PCB !!

  7. Jay

    Hi LED-man,

    Any update on if you will be selling the pot mod PCBs in 2022? I can shoot you an email, just thought it useful for other readers (smile)

    1. Potentiometer adapters are back in stock in 2week.

      1. Jay

        Awesome thanks for the update

  8. mv

    Hi, can you recommend a battery contact that will fit your RE-303 3D printed AA battery tray?

    1. I have a 3D printed battery holder for the RE-303 available

    2. I just used a female snap on terminal.

      They are sometimes called female crimp on spade.