Triangle core VCO
exponential FM input with Attenuator Knob
tracks 1 volt per octave over about 5 octaves when
attenuator is fully open
switch to change range of the VCO Range – high=
= 2Hz-45kHz, low=50s – 50Hz
VCO output is normalised to the Comparator Input, thus
the Comparator Output creates pulse waveform for the
VCO (Threshold = PWM)
comparator has a Threshold Knob, CV Input for
Threshold and an Input and Output with an indication LED
S&H section has a gate INput, signal INput and OUTput
switch to select mode: Sample & Hold (samples at rising
gate and then holds) or Track & Hold (at high gate tracks,
at low gate holds)
Sampling time S&H mode <25uS, in T&H mode up to 5uS
S&H hold drift rate <0.4mV/s
Hold capacitor charging slew rate 0.5 V/uS
Alications of Tromsø
VC downsampler with VC Intensity is achieved simply
by plugging the processed signal into the S&H input and
listening to the S&H output. Both switches should be in
the upper position (VCO, T&H). In this setup the audio
rate VCO sets the sample rate at which the S&H circuit
is being triggered. Because the T&H mode is used, the
Comparator threshold sets the pulse width at which the
downsampling is processed and therefore acts as an
intensity control. Soundwise it is similar to a DRY/WET
mix, but technically different. Both the VCO Rate = Sample
Rate and the Threshold=intensity are voltage controllable
in this setup. Please note that the VCO tracks 1V/Oct with
the Attenuator fully CW, so the downsampling effect can
track your main VCO.
Experimental FM VCO with T&H on the input is achieved
by plugging the S&H output to the FM input on the
Tromsø and feeding (preferably) audio rate modulation
signals into the S&H input. With the comparator threshold
knob fully CCW, we obtain a classical exponential FM
sound, when listening to the Triangle output of the VCO.
However, adjusting the Threshold CW brings in a lot of
chaotic and rich sound behaviours. When the Comparator
is producing very narrow pulses (almost fully CW), it
samples the FM input on each full waveform cycle of the
Tromsø VCO and outputs the whole waveform and then
samples again at the next waveform cycle. This results in
very deep and unique FM modulation sound even at very
high pitch.
Random stepped voltages & Colorful noise patch is simply
achieved by plugging any type of noise signal into the S&H
input. When the VCO is in LFO range and in S&H mode
it produces stepped random voltages. When the VCO is
in VCO range the result is colorful noise. If used at audio
rate and in T&H mode, the comparator Threshold gives
technical details
features
5HP width
PTC fuse and diode protected 10pin power connector
45mm deep
current consumption: +12V: <35mA, -12V: <35 mA
Before connectin the ribbon cable to this module
disconnect our sstem from ower !
Double check the olarit of the ribbon cable and that
it is not shifted in an direction. The red cable should
be attached to the -12V rail, both on the module and
on the bus board side!
lease make sure of the followin
you have a standard pinout eurorack bus board
you have +12 and -12 power rails on that bus board
the power rails are not overloaded
Although we put protection circuits in the device,
we do not take any responsibility for damages
caused by wrong power supply connection.
After you connected everything, double checked
it and closed your system so no power lines can be
touched by your hand, turn on your system and
test the module.
!
Connectin module to our sstem
Take it Carefull
P C B
amuch greater timbral control over the sound. In both of
these setups it is more interesting to use different types
of noises than white or pink. The Noise Square module of
Bastl offers plenty of choices. Especially for the random
stepped voltages, sources such as Metallic or Digital noise
result in a limited number of voltages at the output, which
is very musical.
Classical S&H Staircase LFO waveforms can be obtained by
plugging in any LFO type of signal and using the Tromsø
VCO to trigger the staircase effect. You should be in LFO
and S&H mode. More complex waveforms can be achieved
by using the T&H mode and adjusting the comparator
Threshold.
power
-12
red
tromso v1.0
+12
GND
designed and produced in czech republic
BASTL-INSTRUMENTS.com
!
www.bastl-instruments.com
