bull frog BULLFROG_XL Volt Music Store User Manual
- June 25, 2024
- bull frog
Table of Contents
bull frog BULLFROG_XL Volt Music Store
Specifications
- Resonant lowpass voltage controlled filter (VCF)
- Voltage controlled amplifier (VCA) with adjustable offset
- Delay effect with adjustable delay time and feedback amount
- Two looping attack-sustain-release envelope generators (EG)
- Sample & Hold circuit with an individual clock
- Attenuverter Slew processor with adjustable slew time
- Two buffered splitter circuits
- Two channel oscilloscope
- 6.3 mm jack sockets
- Manual gate button
- Gate and Trigger out
- Voice card slot
- Built-in speakers
- DIN5 MIDI input
- USB connector for firmware updates and extended functionality
- Keyhole slots on the rear panel
- Dimensions (mm): 820x505x65 (250 with the side panels)
- Mass: 5.3 kg
Product Usage Instructions
Powering On the Synthesizer
To power on the Bullfrog XL synthesizer, connect the universal 12VDC wall
wart adapter to the power input and plug it into a power source.
Connecting External Devices
Use the provided patch cables to connect external devices to the various
input and output jacks on the synthesizer for signal processing and
modulation.
Adjusting Parameters
Use the knobs and controls on the synthesizer to adjust parameters such as
cutoff frequency, delay time, feedback amount, envelope settings, and more to
shape your sound.
Using the Oscilloscope
The built-in oscilloscope can be used to visualize waveforms and understand
the signal processing happening within the synthesizer.
Refer to the user manual for detailed instructions on interpreting
oscilloscope readings.
Updating Firmware
If necessary, connect the Bullfrog XL synthesizer to a computer using the
USB-C connector to perform firmware updates and access extended functionality.
Frequently Asked Questions (FAQ)
-
Q: What is the purpose of the Attenuverter on the synthesizer?
A: The Attenuverter is used for processing control voltages and audio signals by adjusting signal amplitudes and inverting signals as needed. -
Q: How can I perform firmware updates on the Bullfrog XL?
A: Connect the synthesizer to a computer using the USB-C connector to access firmware updates and extended functionality.
The Bullfrog XL does not have BOOT and CONFIG pushbuttons like the regular Bullfrog; these functions are performed on the oscilloscope screen.
Thank you for purchasing erica synths x richie hawtin bullfrog XL
synthesizer!
Created by Erica Synths & Richie Hawtin, Bullfrog is an educational electronic
music instrument designed to captivate and inspire both youth and
professionals alike.
Bullfrog invites you to unlock your musicality while combining the thrill of
electronic music production with a comprehensive learning experience. Bullfrog
XL is designed specifically for teachers to use in front of the classroom and
it expands the concept of the regular Bullfrog by inflating its size by factor
of 3 (literally!).
It features several additions, like a built-in oscilloscope, that helps to
explain the basics of music technology and subtractive synthesis. In order to
improve the visibility of patches, on the Bullfrog XL, we use 6.3 mm patch
sockets.
We believe that Bullfrog XL will find its place not only in science and music
classes, but also in studios, because not only does it sounds great, but also
looks damn good.
For the most part, the Bullfrog XL is identical to the regular Bullfrog and
all patch examples of the Bullfrog are applicable to the Bullfrog XL – please
refer to the Bullfrog manual (enclosed). There are, however, some additional
features that help to explain music technology even deeper.
features
- Fully analog design
- Highly accurate voltage controlled oscillator (VCO) that tracks great over 8 octaves M
- anually adjustable and voltage controlled waveshapes – sine-shark fin and pulse wave with pulse width modulation (PWM)
- Zener diode-based noise generator
- Resonant lowpass voltage controlled filter (VCF) Voltage controlled amplifier (VCA) with adjustable offset
- Delay effect with adjustable delay time and feedback amount
- Two looping attack-sustain-release envelope generators (EG)
- Sample & Hold circuit with an individual clock
- Attenuverter
- Slew processor with adjustable slew time
- Two buffered splitter circuits
- Two channel oscilloscope
- 6.3 mm jack sockets
- Manual gate button
- Gate and Trigger out
- Voice card slot
- Built in speakers
- DIN5 MIDI input
- USB connector
- Keyhole slots on the rear panel
- Dimensions (mm): 820x505x65 (250 with the side panels)
- Mass: 5.3 kg
what’s included
- BULLFROG XL synthesizer with sidepanels
- Universal 12VDC wall wart adapter with the power cable
- User manual
- 12 1/4” patch cables
- Sequencer, Sampler/Looper, Acid Bassline, Hipass filter, LFO and Electric Organ Voice cards
- 3 DIY voice cards
The oscilloscope
The “brain” of the Bullfrog XL is the oscilloscope module. Besides waveform visualization, it is also used for firmware updates, MIDI and voice card configuration.
As you power on the Bullfrog XL, the oscilloscope advances to a default
setting – a two channel scope, where the first channel (INPUT 1) is represented
by the green colour and the second channel (INPUT 2) – by the orange colour.
In the example on the left, the relation between the input (green) and the
output (orange) of the SLEW limiter module is shown.
It essentially lugs sharp rising and falling edges of the pulse wave and turns
it into a triangle wave, where the slope of the triangle is defined by position
of the slew potentiometer.
On the top part of the screen, the oscilloscope resolution settings are
displayed. In the example on the left, a single amplitude unit (vertical side
of the unit rectangle) is 600 millivolts (mV) for both channels and a time
unit (horizontal side of the unit rectangle) is 40 milliseconds (ms).
Laboratory oscilloscopes typically display the period of oscillations as T –
the time it takes to complete one oscillation. Knowing the period, it’s easy
to calculate the frequency, a value more often used in music. As we found out
in the Bullfrog manual, the frequency represents the number of full
oscillations (or periods) per second, so if one oscillation takes 40 ms or
0.04 seconds, the frequency is 1/T, or 1/0.04 = 25 Hz.
Because the amplitude of the pulse wave in the example on the left is roughly
3 units, it’s easy to calculate the peak-to-peak amplitude of the pulse wave.
600 mV x 3 = 1800 mV or 1.8 V. Similar calculations can be performed to
identify the frequency.
You can alter the X and Y resolution by adjusting the X and Y encoders. By
default, Y encoder affect both channels simultaneously, but you can configure
its behaviour in the menu. The timescale, controlled by encoder X, always
adjusts both channels.
As you flip the MENU switch, the configuration menu appears. In the first
submenu, you can set the basic functions of the unit. The options (from bottom
to top) are: OSCILLOSCOPE, LISSAJOUS FIGURES, MASTER SETTINGS AND
CONFIGURATION, VOICE CARD CONFIGURATION. Rotate the Y encoder to select the
relevant feature and push the Y encoder to confirm.
SCOPE, known as the two-channel oscilloscope, is the default setting.
In the LISSAJOUS FIGURES screen, the oscilloscope turns into a Lissajous figure
generator – a visualizer of the superposition of two perpendicular
oscillations in X and Y directions of different angular frequency. The
resulting family of curves was first investigated by Nathaniel Bowditch in 1815
and later in more detail in 1857 by Jules Antoine Lissajous. Lissajous curves
have been used in the past to graphically represent musical intervals via the
use of a Harmonograph -a device that consists of pendulums oscillating at
different frequency ratios. Because different tuning systems employ different
frequency ratios to define intervals, these can be compared using Lissajous
curves to observe their differences. Therefore, Lissajous curves have
applications in music education by graphically representing differences
between intervals and among tuning systems. Also, Lissajous curves are often
used in art and as visual accompaniment in audiovisual performances. In
LISSAJOUS, two signals are fed into INPUT 1 (representing X) and INPUT 2
(representing Y), and both signals trace out voltages – one on the X-axis and,
as if the waveform was turned sideways, the other on the Y-axis. The resultant
image is known as a Lissajous pattern. By examining the Lissajous pattern,
certain information about the relationship between the two signals becomes
clear. The metrics of interest are frequency, ratio, relative amplitude and
phase shift.
Since the Bullfrog XL only has one VCO that can be used as an input signal for
channel X, for the signal source of channel Y, we recommend using a regular
Bullfrog or the VCF set in self-oscillation and patched into INPUT2 through
the ATTENUVERTER module.
In the SETTINGS screen, the Bullfrog XL calibration and configuration options
are available.
Use the X encoder to navigate through the options and the Y encoder to adjust
the setting.
Available settings are:
- Screen brightness
- MIDI channel
- MIDI note offset (up to 60 semitones)
- MIDI pitch bend range (up to extreme 36 semitones)
- Tray timeout ON/OFF. If the tray timeout is ON, the top tray of the oscilloscope, indicating X and Y units, will fade out in approximately 10 seconds.
- Factory Reset
- Oscilloscope channel midpoint calibration
- VCO tuning calibration when controlled by MIDI
In order to perform the last three features, follow the instructions on the screen.
The CARD screen is available only if a digital voice card (Sampler/Looper,
Gesture controller) is inserted in the voice card slot.
The example to the left shows the Sampler/Looper voice card configuration menu.
Here you can set:
- The MIDI channel to play samples from the MIDI controller
- Voice count in sample playback via MIDI controller (poly_count)
- Microphone gain
- Recording threshold
You can also perform voice card firmware updates. In order to do so, follow the
instructions on the screen.
Every digital voice card has different features, therefore the configurable
parameters will vary card by card.
In the MATH menu you can ADD or MULTIPLY signals applied to channels 1 and 2 of the oscillo-scope. The resulting waveform is represented by a yellow color. This feature is very useful to illustrate and visualize different new waveform synthesis techniques.
In the CHANNEL menu, you can activate and deactivate the oscilloscope
channels. There are two channels available, represented by INPUT 1 and INPUT 2
and one virtual channel – MATH, that visualizes the sum or multiplication of
the incoming signals. Each channel has two settings – SEL (select) and ON/OFF.
Rotate the Y encoder to select the channel you want to configure and the X
encoder to navigate between the SEL and ON/OFF options. Push the Y encoder to
select or deselect the feature.
If SELECT on the relevant channel is active (in bold), you can use the Y
encoder to alter the amplitude unit of the channel. If it’s not active, the
amplitude unit of the relevant channel remains fixed and rotation of the
encoders has effect on the selected channels only. This is a handy feature if
input signals are of radically different amplitudes and frequencies, but you
wish to fit them on the same screen. Likewise, when performing MATH – adding or
multiplying incoming signals, the amplitude of the yellow signal can be much
greater than one of the signals connected to INPUT 1 and INPUT 2 and it may
need to be adjusted individually. By default, all three channels are SELECTED.
If the channel is OFF, it is not represented on the oscilloscope screen. By
default, both CH1 (green) and CH2 (orange) are ON.
In the TRIG menu you can configure the oscillo-scope trigger settings – a
moment of time (or you can imagine it as a point on the X axis on the
oscilloscope screen) at which the waveform drawing is refreshed. This allows
for a nice, static representation of the waveforms on the oscilloscope screen.
There are several configuration options: MODE, SOURCE and EDGE in the TRIG
menu. Rotate the Y encoder to navigate between the modes and push it to change
the setting.
The MODE allows to select the trigger mode:
- AUTO (default) mode – the oscilloscope automatically scans for a trigger instance based on the level set by the Y encoder and draws the waveform in a nice and static fashion. If no trigger instance is found, the incoming waveform is drawn out regardless.
- NORMAL mode – functions the same as auto mode, however, if a trigger instance is not found, the incoming data is not drawn on the screen.
- SINGLE mode – the oscilloscope scans all incoming data until a trigger instance is found and only then draws the data on the screen. Then the wave is frozen for the user to observe. Basically, it’s like making a photo of the oscilloscope screen. This is handy for signals that do not periodically oscillate, like an envelope or a specific single oscillation. In the SINGLE mode you can arm the oscilloscope again (make it ready to take another photo) by pushing the X encoder.
- EXT mode – similar to SINGLE mode, but instead of one of the channels triggering the oscilloscope, it requires an external trigger signal patched into the TRIGGER input.
- FREE mode – triggers are ignored and the oscillo-scope is refreshed continuously, therefore the picture on the screen will, most probably, not be static at any time. It differs from AUTO mode by having a smoother and higher-refresh look.
- The SOURCE allows for selecting the trigger reference source – it can be CHANNEL 1 or CHANNEL 2, represented by signals applied to INPUT 1 or INPUT 2 correspondingly. In EXT mode, this setting is disregarded.
The EDGE determines, if the trigger starts on the RISING (default), the FALLING edge or on BOTH edges of the incoming signal. For audio applications, RISING edge triggers are most useful.
Safety instructions
Please follow the instructions for the use of the Erica Synths Bullfrog XL
below, because only this will guarantee the proper operation of the module and
ensure the warranty from Erica Synths.
Use the the Bullfrog XL exclusively with the power supply unit (PSU) supplied
with the system. Powering it with other PSU units may cause permanent damage
to the device.
Water is lethal for most electric devices unless they have been rendered
waterproof. The the Bullfrog XL is NOT intended for use in a humid or wet
environment. No liquids or other conducting substances should be allowed into
the module. Should this happen, the module should be disconnected from mains
power immediately, dried, examined and cleaned by a qualified technician.
Do not expose the instrument to temperatures above +50° C or below -20° C. If
you have transported the instrument in extremely low temperatures, leave it at
room temperature for an hour before plugging it in.
Transport the instrument carefully. Never let it drop or fall over. The
Warranty does not apply to instruments with visual damage.
The Bullfrog XL must be shipped in the original packaging only. Any instrument
shipped to us for return, exchange and/or warranty repair must be in its
original packaging. All other deliveries will be rejected and returned to you.
Ensure that you keep the original packaging and technical documentation.
Disposal
This device complies with EU guidelines and is manufactured and confront RoHS
without the use of lead, mercury, cadmium or chrome. Nevertheless, this device
is special waste and disposal in household waste is not recommended.
User manual by Girts Ozolins@Erica Synths.
Design by Ineta Briede@Black8 & Maija Vitola@Black8.
Copying, distribution or any commercial use in any way is prohibited and needs
the written permission of Erica Synths.
The specifications are subject to change without notice.
If you have any questions, feel free to contact us on SUPPORT section on
www.ericasynths.lv
warranty
You will find the Erica Synths terms of warranty at
www.ericasynths.lv
Items for return, exchange and/or warranty repair should be sent us according
to the guidelines on SUPPORT section on
www.ericasynths.lv
References
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