ComboSister is a great single transistor combo organ emulation.

Features:

• 2 oscillators banks:
  Transistor "enriched sine wave" sound (for "Hammond imitator" electric organs).
  Transistor square wave (for buzzer combo!).
  Extra Bass oscillators bank for 16' and 8' ranks.
• 6 drawstops - 16', 5 1/3', 8', 4', 2 2/3', 2'.
• 4 timbre stops - Add (no filter), String, Reed, Flute.
• Effects:
  Percussion: switch (special amplitude envelope).
  Sustain: switch (long release).
  Tremolo: with Rate and Depth knobs.
  Vibrato: with Rate and Depth knobs.
  Booster: smooth analogue saturator with switch and distortion amount knob.
  Transistor: knob for electric click and analogue noisiness amount.
  Soft: tone smoother knob.
• Extra controls :
  Master Fine Tune: -+ 50 cents.
  Max Voices Polyphony selection : 2 to 16 voices.
  MIDI Velocity sensitivity switch.
  Render Quality switch.
• Help on-line with MIDI CC# map by the option menu.
• The coolest presets ready to play.
• 3D retro graphic interface.