Roland TR-909 modifications
kick:- -extended decay range
- -extended tune range
- -extended attack range
- -trigger on/off switch (allows the trigger line to be toggled for easy muting of sound without cutting off decay)
- -pitch, tune depth, overdrive (thanks to colin fraser)
snare:
- -extended tune range
- -extended tone range
- -trigger on/off switch
- -noise low pass filter frequency
- -vco 1 tune offset knob
- -pitch envelope switch - normal, off, extra (changes the impact sound)
toms:
- -extended tune range
- -extended decay range
- -trigger on/off switch
- -pitch envelope switch - normal/off
- -vco 2 tune offset knob
- -noise level
rim shot:
- -tune (pitch knob for 2 of the 3 tones)
- -trigger on/off switch
clap:
- -reverb amount
- -filter frequency
- -width (controls spacing of the individual claps)
- -length (controls how long the claps last; along with the width control it determines the number of individual claps)
- -trigger on/off switch
hi hats:
- -sample swap switch (triggers closed sample with open decay on open hits, and open sample with closed decay on closed hits)
- -trigger on/off switch
- -tune (thanks to colin fraser)
crash and ride:
- -lower pitch range switch
- -trigger on/off switch
global:
- -noise frequency - detunes the shift register clock to make low frequency noise with audible clicks. affects the snare snappy, toms, and clap.
schematics and circuit analysis