Tomcat
EFM
electronics for music
(c) EFM ele4music.com
TomCat Midi Synthesizer
The TomCat is specifically designed to be built by anyone with a little kit building experience. It features simple single
board construction with no wire flying to the board. Minimum parts make it a breeze to assemble. All connections to the
board are made through three headers, a 1/4" output jack and a AC power jack.
The control package is much like the TB except I swapped a keyed AD envelope generator for the TB's decay generator
and accent functions. This particular change in design allows the TomCat to be much more playable using a keyboard
controller.
If I had to declare lineage, I would say it's based on the ARP Axxe however I didn't use any of the original circuitry. It all
starts out about the same place but ends up somewhere completely different.
The Controls
y
Glide - Is keyboard controlled and activated by holding
down any two keys.
y
Tune - Raises or lowers the pitch.
y
Mix - Mixes Sub-generator and VCO output to the VCF.
y
Cutoff - Sets the initial VCF cutoff frequency.
y
Res - Adjusts the amount of ringing - it will self oscillate.
y
Env - Sets the AD envelope generators level to the
VCF.
y
Attack - Adjust the time it takes for the envelope
generator to charge.
y
Decay - Adjust the time it takes for the envelope
generator to discharge.
y
Volume - Overall level.
Header 1
is power switch/LED LED1
y
LED1
y
SW1
y
SW1
Header 2
is control-out/DAC scalePitch
y
Gate
y
Glide
y
Accent
y
V-Ref
y
P.Bend
Header 3
is DC power -12V
y
GND
y
+5V
y
+12V
Header 4
is audio out
y
GND
y
Output
y
Midi Select - switch settings
0000 = 1 1000 = 9
0001 = 2 1001 = 10
0010 = 3 1010 = 11
0011 = 4 1011 = 12
0100 = 5 1100 = 13
0101 = 6 1101 = 14
0110 = 7 1110 = 15
0111 = 8 1111 = 16
