Bastl Instruments SoftPop, User Manual, Page: 8 / 27

LP (output) -
Low Pass – filter output.
BP (output) -
Band Pass – filter output.
HP (output) -
High Pass – filter output.
VCO1 – Voltage Controlled
Oscillator 1
MOD (input) -
Modulation – pitch
control input. Attenuate
input signal with the
modulation slider.
Normalized to the VCO0
+ VCO1 + external signal
mix. Connect another
signal to the socket to
partially override the
normalization.
CV (input) -
Control Voltage – direct
pitch control input (no attenuator).
SYNC (input) -
Connect an external
signal wave to reset the oscillator waveform.
(output) -
Square wave output.
(output) -
Triangle wave output.
OUT -
Outputs looping sequences of
stepped voltages.
See pages “Let’s record a pattern” for more info
on recording and using patterns.
EXT (output) -
External signal. Mix
of the external audio input jack and EXT
(input) socket.
EF (output) -
Envelope Follower.
Envelope signal derived from the EXT
(output) signal – a control voltage
that represents the loudness of the
incoming signal.
Can be used as a modulation source.
Use the EXT (input) in the filter section
of the EXT (input) jack as input for
the EF.
+ EXT (output) -
A mix of VCO0
, VCO1 and the EXT input signals.
(output) -
A mix of VCO0 +
VCO1 waves. Especially useful for
filter modulation.
AUX (input) -
Patch signals
directly to the final output mix
(post filter).
T&H Track and Hold
Track&Hold is a circuit that watches
a modulating voltage (CV or audio),
then either passes that signal directly
to the output (tracks – GATE HIGH)
or holds the voltage at a steady level
(holds – GATE LOW). It is primarily used
as a pseudo-random stepped voltage
source.
IN -
Normalized from the band pass
filter output. Connect signal to override
normalization
GATE (input) -
Normalized to VCO1
square wave output. Connect signal
to override normalization.
OUT -
Modulating voltage output.
See diagram below.
*Tech notes*
• By default, the T&H is gated by VCO1.
Adjusting the VCO1 modulation slider
will change the shape (pulse width) of
VCO1 and dramatically impact the T&H
behavior.
• Slide the VCO1 modulation fader
all the way up to achieve a classic
Sample&Hold effect.
• Slide the fader down to introduce
unstable states, and feedback.
• Try patching T&H OUT to VCF
MOD.
THE SECRET CHAMBER
This section is located on the back of the
housing and is for advanced users who
want to reconfigure the functionality
of their softPop. If you are new here,
then leave this section alone and
enjoy the deep weirdness of softPop
as it is. With the help of the secret
chamber, softPop can be turned from
a semi-modular into a fully modular
synth – where patch cables are required
to produce sound.
NORMALISATION
SWITCHES
At its core, softPop is a fully modular
synthesizer. Several connections have
been made throughout the system to
give it a specific personality, but if these
connections are broken, then the system
can be reconfigured any way the user
likes. I happen to like the way the system
is configured;) but for those who know
what’s up, here are some switches that
you can use to make or break the pre-set
normalizations.
VCO0 <- TRACK&HOLD.
VCO1 <- VCO0 + VCO1 inverted +
EXT jack and socket.
VCF <- VCO0 + VCO1 .
T&H SIG <- VCF BP.
T&H GATE <- VCO1.
PATTERN -> VCO0 CV (input).
ATTINY85 (pattern
generator and quantizer)
The ATTINY85 is a little microcontroller
that analyzes VCO0 and VCO1 and
outputs two variable voltages. One goes
directly to the pitch CV input of VCO0
and the other is available in the patchbay.
The connectivity is relatively simple
and the code is open-source. If you are
interested in writing your own, you can
find diagrams and code online at bastl-
instruments. “github”
Patchbay Patchbay
GATE
IN
HIGH =
TRACK
OUT
LOW =
HOLD