Rack mount 303
The clone has been repackaged in order to fit a 1U 19" rack.
There are now 4 boards.
Midi Interface and Oscillator
Front panel
Filter board
Amplifier and distortion
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.