Rack mount 303

The clone has been repackaged in order to fit a 1U 19" rack.

There are now 4 boards.


Outline Specification:

Frontend Filter backend
Midi interface    including in, out and thru Cutoff Adjustable distortion
Selectable midi channel via front panel resonance Volume control
4 patches (combinations of saw and square) Env mod headphone out
transpose +/- 12 Decay 2x Line out
Fine tune +/- 40 cents Accent  
Adjustable glide Env depth  
Sub oscillator Accent decay  
  Mod Depth  

Front panel


There are two prototypes, the second has a few mods. incorporated onto the PCB's.


Midi section and oscillator

Midi interface and VCO controls, including adjustable slide and sub oscillator. Transpose and Midi Channel select are via the data entry knob.


Filter Section

Standard TB303 controls plus, Filter FM, accent and envelope decay knobs.

On right is the amp board with original TB303 mix circuit plus a constant level distortion control.


New display PCB

Front panel display is via a 7 + 1  LED  display. To save pin count and software overhead data is clocked through two 8-bit shift registers which hold a steady state and drive the LED display.


top view

Top view highlighting the 50mm front to back.


bottom view

Bottom showing 3 PCB's with bottom cover slid backwards for maintenance.