Boostron 3 Musician`s Manual - Mu-FX

Boostron 3 Musician`s Manual - Mu-FX
Musician’s Manual:
Mu-FX Boostron 3
FET Boost – Compressor – Distortion
W/ FX Loop
Mu-FX is proud to introduce our first “new” product: the Boostron 3. The Boostron 3 is based on
three classic vintage effects creatively improved and combined into a versatile and synergistic package.
Mike Beigel, inventor of Mu-Tron III and founder of the original Musitonics Corp (1972), has teamed
up with Rand Anderson, a brilliant working guitarist and computer science pro to produce a “Swiss
army knife” signal processor focused on CONVENIENCE and TONE, TONE, TONE.
**We also credit Benjamin Harrison of Synaptic Groove for the SLACKJAW architecture on which
the SLACKER distortion module is based**
We are confident that working musicians “with the ears to hear” will find the Boostron 3 to be the
“One pedal to rule them all.”
The Boostron 3 combines 3 separate signal processes in one compact housing:
BLASTER (FET gain boost): based on the Alembic Stratoblaster ®*
SQUEEZER (compressor): based on the Musitronics/Dan Armstrong Orange Squeezer®*
SLACKER (versatile LM308 distortion): based on the Slackjaw™ version of the ProCo RAT®
In addition, an FX LOOP is placed between the BLASTER output and the SQUEEZER input. Any
effects in the FX LOOP can be bypassed with their own foot switches, and the SQUEEZER and
SLACKER can be bypassed with their two separate foot switches on the Boostron 3 main unit
footswitch platform.
Each process is based on a “classic” product (each one vintage analog) but “as good and better” than
the vintage products that preceded them, reflecting the Mu-FX philosophy of un-compromised
“Modern Vintage Analog” design.
---------------------------------------------------------------------------------------------------------------------------------------Power Supply: The Boostron 3 works with a 9.0 or 9.6 volt DC supply voltage. Either a single wallwart supply or an ISOLATED 9V DC supply from a power block will work. While some FX box
configurations work with “daisy-chained” 9V supplies, this can cause ground loop hum problems,
noise, and even short circuit of an FX box which uses a different barrel jack configuration than the
“de-facto standard” 2.1 mm x 5.5mm supply connection of the Boostron 3.
*See addendum: “Power Supply Best Practices”
Boostron 3 – Back Panel Diagram
Boostron 3 – Top Panel Diagram
Accepts Standard ¼ inch plug, single conductor shielded cable from electric guitar signal level.
The input impedance is a constant 1 meg-ohm, with ESD (surge) protection.
The input jack connects to the BLASTER circuit, which is controlled by a true bypass toggle
switch on the Boostron 3 top panel, and/or subsequently the SQUEEZER circuit and/or the
SLACKER circuit, which are controlled by true bypass footswitches. Each effect can be engaged
separately or in combination with one another (routing moves right to left).
Based on the Alembic Stratoblaster ®* design. The Boostron BLASTER has added function
while preserving low noise level: FET clean gain at low gain settings all the way up to FET
distortion at high gain settings.
Inside the FET Preamp: A buffer amp (unity gain) provides a constant 1 Meg-Ohm input
impedance (won’t load guitar pickups) with gain and treble boost panel controls. FET’s, while
providing low noise amplification and “round” distortion at high gain, have varying characteristics
unit to unit. The circuitry in the (Op-amp) buffer stage provides high input impedance at the input
and low-impedance drive to the FET (the variable FET parameters are the main reason why
individual “Blaster” products have inconsistent product-to-product sound quality).
The BOOST (preamp gain) control boosts the guitar signal from unity gain (at 1 on the dial) to
FET distortion at higher gain settings. Due to the difference in the guitar pickup output levels and
guitar volume control on the instrument, different instruments may require different gain settings
to achieve the output signal level you want.
This true bypass toggle switch determines whether the BLASTER effect is engaged or bypassed.
The BLASTER signal level LED responds to the output level of the preamp, showing a
brightening yellow indication of signal strength, which turns to red when the output signal reaches
distortion. It’s like a little “VU” meter. (With no signal input, it doesn’t light up, either in the
BLASTER or the TRUE BYPASS switch settings).
While a FET preamp seems to intrinsically provide a clean, “open” sound quality at un-distorted
gain settings, the BRIGHT control (treble boost) can compensate for high-impedance guitar
pickups losing treble response when run through long signal cables, or “high capacitance” small
diameter cable. The BRIGHT control provides compensation for this loss of signal quality and in
addition, can “brighten up” an otherwise dull guitar signal.
The FX SEND (by itself) provides a low-impedance signal output set by the BOOST and the
BRIGHT controls of the BLASTER section. This output can be routed to parallel signal
processors or direct to an amplifier, without interrupting the functionality of the Boostron. As the
BOOST control is turned up, the output signal level can increase to the point where it might overdrive the inputs of subsequent signal processors or the amplifier. The FX SEND jack has another
important function, which is to drive other effects inserted into the FX LOOP, which then returns
to the next sections of the Boostron 3 for signal processing by the SQUEEZER and/or SLACKER
The FX RETURN (by itself) provides a direct input into the SQUEEZER and/or BLASTER
circuits, bypassing the BLASTER circuit entirely. The primary purpose of the FX RETURN jack
is to provide a FX LOOP between the SLACKER (preamp) and the subsequent SQUEEZER
(compression) and SLACKER (distortion) processes. You can put any kind of signal processors
you want into the FX LOOP:
Our favorite example is to have the Mu-FX Octave Divider and Tru-Tron 3X (in that order) in
the Boostron 3’s FX LOOP. In this way, the BLASTER preamp drives the OD to track notes
more smoothly and the TT3X to become more touch sensitive and dynamic. Upon return to
the Boostron 3, the SQUEEZER’s compression evens out the volume spikes that envelope
filters are prone to and allows the user to add varied distortion options on top of it all.
Based on the Musitronics/Dan Armstrong Orange Squeezer®* compressor. The Boostron 3
SQUEEZER provides the same great “squash” that the original unit was known for but has added
input and output signal level controls for improved functionality.
JUICE controls the incoming signal level to the compressor’s input (from the BLASTER or FX
LOOP) from a gain of 1-11.
OUTPUT controls the signal level of the SQUEEZER output to either the MAIN OUTPUT
JACK (if only SQUEEZER effect is engaged) or to the SLACKER circuit (if SLACKER effect is
The SQUEEZER footswitch determines whether the effect is engaged or true-bypassed (doesn’t
effect the incoming signal from BLASTER or FX LOOP). When the effect is bypassed the LED
is RED and when the effect is engaged the LED is BLUE.
Based on the Slackjaw™ version of the ProCo RAT®* - a versatile high-gain LM308 based boostdistortion with our modifications and added controls.
(11) GAIN
From unity gain (at 1) to VERY VERY high gain (at 11). The low gain settings give “sizzle” to your
sound, the higher gain settings FUZZ at almost every level of dynamics.
(12) BASS SWITCH (Low Frequency Response)
Controls the low-frequency cut-off of (guitar) signals into the distortion section. By varying the
switch positions and distortion GAIN control, very different distortion response from the
instrument can be obtained.
FLAT: Rolls off low-end response about Low E on electric guitar - a balanced response
( - ): Rolls off low-end response about 200 Hz - gives a “nasal” response distorting the high
fundamentals and overtones
( + ): Rolls off about 5 Hz - even the picking of the string comes through the gain section
(13) MODE SWITCH (Distortion Characteristic)
Allows for 3 different kinds of distortion and properly used, can preserve the guitar’s dynamic
range AND distortion characteristics.
COMP: Asymmetrical distortion and “soft clipping” limiting of dynamic range. Allows
dynamic expression along with lower “high end clipping” of the instrument. Useful for both
solo and 2-note distortion more than the other settings. Odd and Even harmonics.
EXP: Asymmetric distortion, but allows full-dynamic range up to “hard clipping” at the
LM308 rails. Useful for power chords, “thin” chords and solos. Odd and Even harmonics.
DIST: Symmetrical silicon diode (opposite polarity) distortion for “squashed” distortion signal,
varying from “sizzle” to “solo”. Mostly EVEN harmonics.
(14) LEVEL
The LM308 is very high-gain and can put out signals around 8 volts peak-to-peak into “whatever
FX (or amp) comes next.” Advise using low to medium output level unless you want your speakers
to pop out of the cabinet.
The SLACKER footswitch determines whether the effect is engaged or true-bypassed (doesn’t
effect the incoming signal from BLASTER, FX LOOP and/or SQUEEZER). When the effect is
bypassed the LED is RED and when the effect is engaged the LED will display one of 3 colors:
TEAL = EXP mode
BLUE = DIST mode
The “end of the line” for the Boostron 3 processes. The output can go directly to your amplifier or
DI box, or you can add other effects (particularly delay and echo) between Boostron and amp or
final audio destination.
[All the processes can be true-bypassed, though we doubt you will want the BLASTER bypassed!
That’s why it has a toggle switch and not a footswitch. Any effects units going through the FX
LOOP are controlled by their own footswitches.]
This Mu-FX unit runs on 9 – 9.6 Volts DC. The Boostron 3 does not have a battery compartment,
since it draws enough current to exhaust a battery in a relatively short time.
*** BEWARE CHEAP POWER SUPPLIES! Especially “switching mode” wall-warts. The high
gain and frequency response of the Boostron 3 can pass noise pulses from these supplies,
producing a whistling and un-intentionally distorted output signal. ***
--------------------Power Supply Best Practices------------------Take care how you interconnect FX units that have different power supply voltages (AC or DC)
and ground-to-case connections!!!
The Boostron 3 uses an external 9V DC power input ( +/- to 5.5mm Barrel and GND to 2.1mm
Pin). Other 9V effects might have a +9 to Pin and GND to Barrel.
The Mu-FX® TruTron 3X™ and Mu-FX® Octave Divider™ run on 12V AC external power
supplies (12V AC to 2.1mm Pin and GND to 5.5mm Barrel).
We strongly recommend using ISOLATED power supplies to all the effects in your entire signal
The best “brick” power supplies will provide enough isolated DC and AC voltage supplies for all
of the signal processing devices in your chain or pedal-board. If you have MANY effects units
strung together, you might need more than one power supply block.
The many available power supplies, wall-warts, brick supplies and AC-line powered FX devices
vary greatly in the quality and stability of their power outputs, as well as AC HUM FIELDS from
their transformers or RADIATED RF FIELDS from switching power supplies. Even the PHASE
of connection between AC line inputs and power outputs can cause hum and noise in the signal
cables or in the effects devices themselves.
With today’s complex signal processing chains, the possibility of power supply hum, noise or
incompatibility increases with the number of audio processors.
So-called “Daisy Chaining” some of the 9V products MIGHT work, but it could also result in
power supply cables and the audio cables connecting the effects together…
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