After growing up with the sound of Trax, Djax-Up and German Acid+Rave (Harthouse, Junkfood etc) i owned a RE-303 25 years later that I sold since I thought something is missing after working with a couple of TB-303. But now Iam pretty satisfied with the sound of this little beast after a fistful essential modifications outlined in this gearslutz thread.

Those were done first (thx Carl) and after that I needed some more (as usual). After some debugging (thanks again to maffez and nordcore!) the „stachelfish“ was born.

Here is the 9 min complete walkthrough:

And here is an A/B comparison:

Download the wave here:
td3-shootout-biased-L-STACHELFISH R-STOCK.aif

And here is the complete list:

essentials to get the 303 sound right:
-lower Cutoff R44 (4k7)
-PW adjust trimmer R189
-declick mod C51 (200nF)
-d22 rubber mod (1uF)
-C52 100nF parallel
-PSU starve mod Reso R92 (100Ohm)

performance mods/devilfish stuff at the front:
-PW pot + 50kPot/switch
-Accent decay mod D15, 500k+1Mlog
-Env times switch (0,47 or 1uF parallel)
-VCA Decay R52 1M+1M Pot
-Lowest Decay aka var. Accent Decay R68 (100k Pot)
-Accent Reso Sweep R39 (1uF)
-Filter FM via VCA vs VCO switch plus Pot (100nF, 100k log)
-portamento switch (220nF) IC10Pin 5
-rubberduck attack mod switch R45 (1uF, 2uF)
-pre filter overdrive R24 parallel (200k lin)
-R123 BP Filter reverted=>sweet but too noisy

others:
-CV Output for Envelope
-Distortion smoother mod (D20 and D28 removed)
-more Resonance R160 (4k7 parallel)

TODO:
-Accent to Pitch
-VCO offset correct

resources:

https://www.gearslutz.com/board/modular-mania-all-things-eurorack-and-modular-synths-effects/1289500-behringer-td3-diy-mods.html

https://www.gearslutz.com/board/atta…2&d=1579634540