TB-303 Mod

Today I came across an old mod, 'Devil Fish' for the TB-303 synthesizer, which I doubted at first; what could be done to improve this beast of a machine?

The Devil Fish modification for the TB-303

Well, lots, it turns out:

• CV and Gate inputs.
    
  
• CV input to turn on Slide.  (2.3 volts turns on the Slide circuit and > 4 volts turns on Gate to tie notes together.)
    
  
• CV input for Accent.
    
  
• CV input for Filter Frequency.
    
  
• Output for Accent.
    
  
• Audio In to filter.
    
  
• Audio In to frequency modulate the filter.
    
  
• Audio Out from filter (pre-VCA).
    
  
• Overdrive pot to control the level of oscillator going to the filter: zero to 66.6 times normal level.
    
  
• Separate control of Main Envelope Generator times in accented and non-accented notes.
    
  
• Volume envelope is no longer fixed, and can be varied from 16 msec through 3 seconds – and to no decay at all, i.e. for notes which last indefinitely.
    
  
• Soft Attack control gives attack times between 0.3 and 30 msec. (TB-303 attack was ~3 msec.)
    
  
• Slide time is variable to five times longer than normal.
    
  
• Variable Filter Tracking causes the oscillator CV to control the filter frequency.
    
  
• Internal Filter FM: a unique approach of AC coupled Filter FM from the audio output of the VCA.
    
  
• The Muffler is a unique post-VCA soft-clip distortion circuit which retains bass response.
    
  
• Push-button to manually activate Accent.
    
  
• Filter can be switched to self resonance.
    
  
• Accent Sweep has three modes and can be disabled.
    
  
• Filter Cut Off pot range doubled to 5 kHz max, and widened to include much lower frequencies.
    
  
• Env Mod pot range extended to include zero and go as high as three times the normal maximum.
    
  
• Bass response is improved.
    
  
• Lithium battery for at least ten years battery backup, so there is no need to install C-cell batteries.
    
  
• The six TB-303 knobs Tuning to Accent are mounted 1.5mm higher, making them easier to turn.   
  
• The Devil Fish can still sound like a TB-303.

 So that's what the mod does on paper, but how does it sound?
Check it out below






My verdict?
The finest mod for one of the finest synths in existence.

The modder himself, Robin Whittle is situated in Melbourne, Australia, and you can find all details on Devil Fish, contact details and questions regarding finding a TB-303 at his website, at the official Devil Fish website.