Tubbutec KAC TM62100 User manual

Tubbutec
KAC TM62100
Midi and more for Yamaha SK synthesizers
User Manual
re ision 1

Introduction
TM62100 adds MIDI and additional features to SK-15, SK-20, SK-30 and SK-50
synthesizers. It is a direct replacement for the Yamaha YM62100 / YM621 key assigner
and can also be used to replace defecti e original ICs – e en when midi is not required.
The original beha iour is fully maintained.
MIDI input and output on se eral channels with optional soft-through
•Independent midi control of upper keyboard, lower keyboard and pedal sections
•Full tonal range in split mode
•Midi filter cutoff and resonance control
•Additional filter LFO
•Midi sustain control
•Midi portamento control
•Midi aftertouch
•Note priority for the pedal/BASS section: Lowest/Last/Highest note
•Built in configuration menu can set midi channels and other parameters.
•Non-destructi e installation can be re erted to original. Installation guides for
arious synthesizers are a ailable
Comparison of the original YM62100 key assigner and the Tubbutec TM62100

MIDI input
Midi note control
Synthesizers with a YM62100 key assigner chip feature se eral instruments, such as
Organ, Poly-Synth, Strings, Mono-Synth, …
Some of these instruments are connected in “synth-groups” in a fixed manner, others can
be played independently in split keyboard modes, or with multiple keyboards. An example
for a fixed grouping is the Poly-Synth and String sections. These are always connected
and will play the same notes.
TM62100 allows independent control of the se eral synths groups ia midi. Each group
has its own midi channel configurable using the built in config menu. Groups 1 and 2 -
corresponding to the lower and upper keyboards - ha e a range of 61 notes and are 7-
oice polyphonic (or paraphonic, depending on the instrument). Group 3, the “pedal” group
is monophonic with a range of 3 octa es, an extended range of 4 octa es is a ailable for
the BASS sound.
Here is how the instruments are connected to the arious groups in se eral synthesizers:
•SK15: All sounds on Group 2 1
•SK20: No split mode: Group 1 plays organ, poly-synth and strings. In split mode:
Group 1 plays Organ (all 61 notes), Group 2 plays String and Polysynth (All 61
notes)
•SK30: Same as SK20, but SOLO-Synth plays on channel 2 in NORMAL mode and
channel 3 in BASS mode.
•SK50D: Group 1 plays the lower keyboard, Group 2 plays the upper keyboard.
BASS Plays on Group 3. Depending on settings, SOLO SYNTH plays on Group 2
(NORMAL) or Group 3 (BASS)
The midi note range of group 1 and 2 is C1 (note 24) – C6 (note 84). The range group 3 is
C#1 (note 25) – C5 (note 72). The range C#1 – B1 is an extension to the original range
and only a ailable for the BASS sound.
1 In case of the SK15, it might be possible to re-route the organ section to Group 1 by modifying the circuit.
This has not been tested yet.

dditional midi control
If applicable, the following parameters can be controlled additionally:
•Poly-synth filter cutoff. A bipolar control. (All SK-Synths)
•Poly-synth filter resonance (All SK-Synths) 2
•Sustain ON/OFF (SK20, SK30, SK50)
•Solo synth filter cutoff (SK30, SK50) 2
•Solo-synth Portamento ON/OFF (SK30, SK50)
•Solo synth Aftertouch (SK30, SK50)
The midi controller numbers for these parameters can be found in the MIDI CC chart
below.
The sustain control acts analogous to the external sustain input. In order to use it, acti ate
the SUSTAIN function of the organ or Poly-synth instrument. You can then turn off the
sustain ia midi.
Similarly, the portamento can only be turned off ia midi. Set a non-zero portamento time
in the SOLO section, then use midi to turn portamento on or off.
Parameter Midi CC Range
Poly-synth filter cutoff 74 Bipolar 64 = middle, no change
Poly-synth resonance 271 0 - 127
Sustain 64 0-63: no change, 64 – 127: OFF
Solo synth filter cutoff 271 0 - 127
Solo-synth Portamento 65 0-63: no change, 64 – 127: OFF
Solo-synth Aftertouch 0 - 127 aftertouch amount
2 For the synths with built in SOLO section, it is possible to control Poly-Synth resonance OR Solo-Synth
cutoff, but not both. This is a choice you need to make during installation.

dditional Filter LFO
An additional filter LFO is accessible ia midi CC controls.
•Frequency range: 0.1 Hz – 1000 Hz
•Free running or midi sync with adjustable di ider
•Triangle, Saw, In erted Saw, Square and Random wa eforms
Audio frequency modulation is possible and can create no el sounds usually not possible
with the SK-series synths.
Warning: Due to the filter IC suffering from some amount of CV bleed-through, the LFO
signal may be audible directly. This is especially the case with high LFO frequencies
and/or wa eforms with discontinuities (all except triangle).
Parameter Midi CC Range
LFO amount 20 0 - 127
LFO frequency 21 0 - 127
LFO shape 22 0 - 127
LFO free / synced 24 0 – 63: FREE, 64 – 127: Synced
LFO clock di ider 23 0 - 127
0 - 25 26 - 51 52 – 77 78 - 103 104 - 127
Triangular Saw In erted Saw Square Random
Midi CC alues for the arious LFO shapes
0 – 6 7 – 13 14 – 20 21 – 27 28 – 34 35 - 41 42 - 48 49 - 55 56 - 62
4 Bars 3 Bars 2.5 Bars 2 Bars 1.5 Bars 1 Bar 3 / 4 1 T 1 / 2
63 – 69 70 – 76 77 – 83 84 – 90 91 – 97 98 – 104 105 – 111 112 – 118 119 - 125
3 / 8 1 / 2 T 1 / 4 3 / 16 1 / 4 T 1 / 8 3 / 32 1 / 8 T 1 / 16
Midi CC alues for the LFO clock di ider in synced mode
VAL Period VAL f[Hz] VAL f[Hz] VAL f[Hz] VAL f[Hz] VAL f[Hz] VAL f[Hz] VAL f[Hz]
0 20 s 16 0.25 32 4.25 48 8.25 64 32.5 80 72.5 96 225 112 625
1 19 s 17 0.33 33 4.5 49 8.5 65 35 81 75 97 250 113 650
2 18 s 18 0.5 34 4.75 50 8.75 66 37.5 82 77.5 98 275 114 675
3 17 s 19 1 35 5 51 9 67 40 83 80 99 300 115 700
4 16 s 20 1.25 36 5.25 52 9.25 68 42.5 84 82.5 100 325 116 725
5 15 s 21 1.5 37 5.5 53 9.5 69 45 85 85 101 350 117 750
6 14 s 22 1.75 38 5.75 54 9.75 70 47.5 86 87.5 102 375 118 775
7 13 s 23 2 39 6 55 10 71 50 87 90 103 400 119 800
8 12 s 24 2.25 40 6.25 56 12.5 72 52.5 88 92.5 104 425 120 825
9 11 s 25 2.5 41 6.5 57 15 73 55 89 95 105 450 121 850
10 10 s 26 2.75 42 6.75 58 17.5 74 57.5 90 97.5 106 475 122 875
11 9 s 27 3 43 7 59 20 75 60 91 100 107 500 123 900
12 8 s 28 3.25 44 7.25 60 22.5 76 62.5 92 125 108 525 124 925
13 7 s 29 3.5 45 7.5 61 25 77 65 93 150 109 550 125 950
14 6 s 30 3.75 46 7.75 62 27.5 78 67.5 94 175 110 575 126 975
15 5 s 31 4 47 8 63 30 79 70 95 200 111 600 127 1000

Midi output
TM62100 features midi output on se eral midi channels. The arious synth-groups (see
MIDI input) also apply here. This means the upper, lower and pedal keyboards can send
on different midi channels. In split mode the two parts send on different midi channels as
well. The midi channel numbers can be set in the config menu, as well as indi idual output
channels turned off.
The range and notes sent are identical to the ones recei ed:
The midi note range of group 1 and 2 is C1 (note 24) – C6 (note 84).
The range group 3 is C2 (note 36) – C5 (note 72).
Only note output is supported. Filter cutoff or other parameters can not be sent.
Pedal note priority
The padal synth group, usually associated with the BASS and SOLO sections, is
monophonic. Usually (and in the original) the note priority is ‘highest note’, meaning when
se eral keys are pressed, the highest note will play.
With TM62100 you can change the note priority to one of the following modes:
•Highest: The highest note plays
•Lowest: The lowest note plays
•Last: When pressing a new key, it plays in e ery case. When releasing a key while
one or more other keys are still pressed, the most recently played note will play.
This continues until all keys are released.
The note priority can be set in the config menu.
Gate dead time
When playing on the keyboard or ia midi, there need to be a short pause between two
notes. This pause is needed for the en elope (for example of the poly-synth) to retrigger.
Without the pause, the en elope will not start the attack phase from the beginning.
While it is almost humanly impossible to not include a short pause between notes when
playing on a keyboard, it is ery common to send a midi note-on command right after a
note-off. The result in this case is that the en elope does not retrigger. This is most likely
not the intended beha iour.
One way to rectify this is to include a short pause when programming the midi notes.
Instead of one full bar, your note might just be a little bit shorter.
Alternati ely, TM62100 can automatically insert a pause before the next note is played.
This is the “gate dead time” and it can be set in the config menu. The best alue needs to

be found experimentally for your synth, as this ery much depends on the analogue
baha iour of your synths. The default is 0, the original beha iour.
Note that the gate dead time, will ine itably delay the next note slightly, so a alues as low
as possible should be chosen.
MIDI soft-through
Optionally MIDI soft through can be acti ated using the config menu. Incoming midi
messages will be merged with the internal midi data and forwarded to the MIDI output.
Note: depending on the configuration, this can lead to midi loops. Use with caution !

Configuration Menu
The built in configuration menu can be used to set parameters such
as midi channels or the pedal note priority.
ccessing the config menu
1. Turn off your synthesizers
2. Press and hold an D-minor chord (D-F-A) anywhere on any
keyboard. Note: Playing an E-minor chord starts the bootloader for
firmware updates instead.
3. Turn on the synthesizers
The following descriptions refer to the config menu graphic --->
Selecting the MIDI input channels
1. Press the key to select the channel group (PEDAL in,
LOWER in or UPPER in).
2. Press the lowest C to turn this channel off, or keys 1 – 16
(C#0 - E1) to select midi channel 1-16
Selecting the MIDI output channels
1. Press the key to select the channel group (PEDAL out,
LOWER out or UPPER out).
2. Press the lowest C to turn this channel off, or keys 1 – 16
(C#0 - E1) to select midi channel 1-16
Midi soft through
Press the THROUGH ON or OFF keys to turn midi soft through orn
or off.
Pedal note priority
Press keys LOWEST, LAST or HIGHEST to set the pedal note
priority accordingly
Gate dead time
Press the “Gate dead time” key (B1) and then use the lowest 17
keys to turn the feature OFF (C0) or adjust the dead time between 2
and 24ms.
factory
reset
SAVE &
EXIT
OFF
1
2
3
4 5
6
7
8
9
10
11 12
13
14
15
16
OUT
OUT
OUT
LAST
LOWEST
HIGHEST
Gate dead time
IN
OFF
ON
IN
IN
UPPER
through LOWER
MIDI
PEDAL PEDAL
note priority