Black Widow Eclipse Series MGP-1A User manual

Eclipse Series MGP-1A Modeling Guitar Preamp Owner’s Manual January 2015
Black Widow
Audio Designs
MGP-1A Modeling Guitar Preamp
Eclipse Series
Standby
Wa rm
Normal
Bass Mid
Bright
Treble Vo lume
Crunch
MidBass Treble Volume
Drive
Crunch
Clean
Drive
MidBass Treble Vo lume
UK
Vintage
US
Vintage
Class
A
InputMod
UK800 Mod
ModEuroRecto Hot
Rod
Deep Deep
Bright Bright
EQ
Shift
Alt
EQ
EQ
Shift
Alt
EQ
EQ
Shift
Alt
EQ
CitrusCali
MIDI
Play
Driv
e
C
runch
Bass B
a
ss
Mid
Mi
d
Tr
eb
l
e
T
r
eb
l
e
Vo
l
u
m
e
Vo
l
u
m
e
|
O
Black Widow
Audio Designs

i
MGP-1A Modeling Guitar Preamplifier Owner’s Manual i
Contents
Contents
Safety Instructions ii
Introduction iii
Getting Acquainted 1
Getting Started 2
Included Items 2
Quick Start 2
Power Section 3
Front Panel Controls 4
Rear Panel 7
The Clean Channel 9
The Models 9
US Vintage 9
UK Vintage 10
Class A 10
Tone Tips 11
The Clean Channel 12
The Models 12
Cali 12
UK800 13
Citrus 14
Tone Tips 15
The Drive Channel 16
The Models 16
Recto 16
Hot Rod 17
Euro 17
Tone Tips 18
Model Summary 19
MIDI 20
MIDI Mode 20
Assigning a Program 21
Changing the MIDI Channel 21
Omni Mode 22
MIDI Notes 22
Tubes 23
Warranty and Repair 24
Certificates of Compliance 25

ii
MGP-1A Modeling Guitar Preamplifier Owner’s Manual ii
Safety Instr
Safety Instructions
This symbol warns the user of dangerous voltages levels localized within the
enclosure.
This symbol advises the user to read all accompanying literature for safe
operation of the unit.
• Read these instructions.
•WARNING: To prevent damage, re or shock hazard, do not expose this unit to rain or moisture.
• Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including ampliers) that produce heat.
• Black Widow Audio Designs products are capable of producing very high sound pressure levels which may cause temporary or
permanent hearing damage. Use care when setting and adjusting volume levels during use.
• Keep these instructions.
• Heed all warnings.
• Follow all instructions.
• Do not use this apparatus near water.
• Clean only with dry cloth.
• Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
• Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with one wider than the other.
A grounding type plug has two blades and a third grounding prong. The wide blade or the third prong are provided for your safety. If the
provided plug does not t into your outlet, consult an electrician for replacement of the obsolete outlet.
• Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and the point where they exit
from the apparatus.
• Only use attachments/accessories specied by the manufacturer.
• Unplug this apparatus during lightning storms or when unused for long periods of time.
• Refer all servicing to qualied service personnel. Servicing is required when the apparatus has been damaged in any way, such as
power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed
to rain or moisture, does not operate normally, or has been dropped.
• To insure proper ventilation always make sure there is at minimum four inches (101.6mm) of space behind the rear of the apparatus. The
ventilation should not be impeded by covering the ventilation openings with items, such as newspapers, tablecloths, curtains, etc. Do not
impede ventilation by placing objects on top of the apparatus which extend past the rear edge of its cabinet.
• No naked ame sources, such as lighted candles, should be placed on the apparatus.
• The apparatus shall not be exposed to dripping or splashing and no objects lled with liquids, such as vases, shall be placed on the
apparatus.
• The AC plug is the mains disconnect. The plug should remain accessible after installation.
• WARNING: EU: permission from the Supply Authority is needed before connection.
• WARNING: Always make sure proper load is connected before operating the amplier. Failure to do so could pose a shock hazard and
may result in damage to the amplier.
• Do not expose amplier to direct sunlight or extremely high temperatures.
• Always insure the amplier is properly grounded. Always unplug AC power cord before changing fuse, tubes or removing chassis. Use
only same type and rating when replacing fuse.
• Avoid direct contact with heated tubes. Keep amplier away from children.
• To avoid damaging your speakers and other playback equipment, turn off the power of all related equipment before making the
connections.
• Do not use excessive force when handling buttons, switches and controls. Do not use solvents such as benzene or paint thinner to clean
the unit.

iii
MGP-1A Modeling Guitar Preamplifier Owner’s Manual iii
Introduction
Introduction
Thank you for purchasing the MGP-1A Modeling Guitar Preamplifier! The MGP-1A is the world’s first
All-Tube Modeling Preamplifier offering an extensive collection of the most sought after preamplifiers
all in one unit.
Unlike digital devices which use digital signal processing to emulate what a given amplifier would
do to your guitar signal, our patent-pending VEnuM™ All-Tube Modeling Technology actually re-
configures the internal vacuum tube circuitry to give you authentic tube tone. There are no solid-state
or digital devices in the signal path to degrade the quality of sound.
VEnuM® All-Tube Modeling Technology changes the breakup characteristics, harmonic generation,
gain and filtering characteristics to ensure the tone is as close to the originals as possible. The only
thing we didn’t model was the noise, hiss, and hum.
The MGP-1A is a 3 channel preamplifier where each channel has 6 selectable Models that have been
chosen as history’s best representatives of those channels. Each model has its own unique circuitry
and its own tone stack assuring authentic tone.
In addition, each model has a number of unique selectable features which provide further control
over the tone of that model. All together, this combines for a total of 264 all-tube, all-analog
preamplifier circuits.
Design Philosophy
The primary goal of the MGP-1A Modeling Guitar Preamplifier to combine the best qualities of digital amp
modeling and tube circuitry. Digital amp modeling gives you tons of tonal options in small packages, where tubes
give you great tone and feel.
We’ve taken a “product first, no-compromise” approach to the design of the MGP-1A resulting in a performance
not typical of traditional tube amplifiers. Every single detail has been well thought out.
Contrary to digital devices, the MGP-1A was designed from the ground up to be extremely effortless to use and
to look and feel like a tube preamp. Each knob and switch has a dedicated function (except some MIDI controls)
so it is easy to find your way around the unit.
Tube circuits often get knocked for excessive noise, hiss and buzz; however, much of this is due to economics
rather than the fault of the tubes themselves. We’ve designed as much noise out of the MGP-1A as possible. The
result is a cleaner, sweeter sound at every setting with far more note articulation than you are probably used to.
Additionally, we’ve taken many measures to extend tube life; you’ll notice the tubes in the MGP-1A will last longer
than in other tube devices. Vacuum tubes can be very reliable and long lasting devices. This doesn’t seem to be
the popular view these days, no doubt thanks (again) to budget tube designs.
We also wanted the MGP-1A to be extremely rugged and reliable, so many design aspects and component
choices were made with dependability in mind. However, should anything happen to your unit, rest assured our
goal is to have the best customer service in the business.
Finally, a device like this is designed to inspire you. Fantastic sound quality, ease of use, low noise, reliability
and a solid feel are all purposely designed to make your guitar playing experience an effortless one. We believe
effortlessly sounding your best makes you to play your best.
Whether it’s the studio or the stage, the MGP-1A Modeling Guitar Preamp will no doubt be a centerpiece of your
rig for years to come.

1
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 1
Getting Acq
Getting Acquainted
Warm LED
The MGP-1A comes equipped with a Warm LED which notifies you when the tubes have had adequate time to
warm up and the unit can be switched out of Standby Mode.
Standby Mode
The Standby Mode of the MGP-1A is not like your average guitar amplifier’s Standby Mode. Like most
amplifiers, the tube’s high voltage is switched off but at the same time the tube heater voltage is reduced. This
not only conserves energy but is great for tube health (prevents cathode poisoning). The auxiliary power supplies
are also switched off so more energy is conserved, only the front panel power supply is running normally.
NOTE: Even though the tubes aren’t seeing high voltage, a portion of the high voltage supply remains active in
Standby Mode. It is not safe to open the unit when the unit is receiving power for ANY reason.
Auto-Save
You’ll notice the MGP-1A automatically saves your last settings per Model. For instance, if you have a tone you
love on US Vintage, but want to check out UK Vintage, next time you return to US Vintage the feature settings
will all be how you left them. This is so you don’t have to remember where that really cool setting was, leaving you
free to explore the unit.
Similarly, the unit powers up to its last known state. This includes all Channel and Model settings. We’ve done
this to assure ease of use; even if the power goes out, you can start up right where you left off.
InPhase™ Phase Correction
Our InPhase™ Phase Correction circuitry eliminates one of the most common problems with tube amplifiers.
Every gain stage in a tube amplifier inverts the phase of the signal it is amplifying. If you have an odd number of
gain stages (usually in the mid-gain channels), the input signal will be out of phase with the output signal. This is
not normally a problem when playing by yourself, but is a huge deal when other instruments are added to the mix.
If two guitars are out of phase with each other, frequencies will cancel out and the result is both guitars will sound
weak. This is especially common with medium gain channels being mixed with either low or high gain channels.
Your MGP-1A always outputs the signal in phase with the input signal assuring phase issues are never a problem.
Output Levels
Each Model will have different output levels, so the output may jump, sometimes quite drastically, as you are
changing settings and Models. This is done for authenticity, as some Models may send higher levels to their
respective power amplifiers as part of their sound. However, the Volume controls of the MGP-1A are designed
to be extremely transparent, so don’t be afraid to use them.
Speaking of levels, its extremely important to set levels correctly in any system. Generally, the first device in the
signal chain should do as much of the amplifying as possible, so set the Volume controls of the MGP-1A as high
as you can while still respecting the receiving device. This maximizes your signal-to-noise ratio which is essential
to getting the most from any audio system.
Before we explain the controls and what they do, there’s a couple of things you should know about
how the MGP-1A operates. Sure, it looks like a standard 3-channel guitar preamplifier, but there’s
much more going on behind the scenes to make All-Tube Preamplifier Modeling a reality.

2
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 2
Getting Sta
Getting Started
• MGP-1A Modeling Guitar Preamplifier
• MGP-1A Owner’s Manual
• Power Cord
• FS-3 Foot Switch
• 5-Pin MIDI Cable
Included Items
1. Carefully unpack your unit. If there is any damage to the shipping packaging or box, please inspect the unit for
damage. Should you find anything, please contact us immediately!
2. Make sure the Voltage Selection Switch is set to the correct mains voltage in your area.
WARNING: Incorrect voltage settings will result in damage to the unit.
3. Carefully fit the unit in your rack and secure with 4 rack mounting screws. For optimum results with all rack mount
systems, invest in some rack isolation tabs. Installed correctly, these can make a huge difference in overall
system noise performance.
4. Hook up the FS-3 Foot Switch using the supplied 5-Pin MIDI cable from the foot switch to the FS-3 jack on the
rear of the unit. If you have a MIDI controller, please use the MIDI IN jack as the FS-3 jack does not receive MIDI
data.
5. Connect a 1/4” TS cable into the output jack, and connect the opposite end of this cable to one of the following:
 •Apoweramplifier(forliveandstudiouse)
 •Aspeakersimulator(fordirectrecording)
 •Asoundcard/interfaceinput(fordirectrecordingwhenusedwithcabinetimpulses)
 •Aneffectsprocessororanythingelsethatacceptsalinelevelsignal
6. Connect a guitar cable to one of the two input jacks. Needless to say, plug your guitar into the other end.
7. Connect the power cord to the AC input on the rear of the unit and to a mains outlet.
8. Turn the Power Switch on. The Black Widow Audio Designs logo will light up indicating the unit is powered on.
One minute after the unit is powered on, the front panel “Warm” LED will come on. This LED indicates the tubes
have warmed up and the unit is ready to play.
9. Flip the Standby Switch in the “off” position and enjoy the ride!
Quick Start
WARNING: With the power cord attached, mains voltage is present inside the unit. To change a tube or
an internal fuse, check TWICE to ensure the power cable is not attached AND the Black Widow Audio
Designs logo is not lit on the front panel. Wait an additional 10 minutes after you’ve verified the power
cord is detached before removing the top cover to allow any capacitors to fully discharge.

3
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 3
Getting Sta
Getting Started
Power Indicator
When the Power Switch (rear) is on, the Black Widow Audio
Designs hourglass logo will illuminate indicating power is applied to
the unit and it is ready for operation.
Standby Switch
The Standby Switch has two purposes. One is to let the tubes heat
up before voltage is applied and the other is to conserve power
when not in use.
Standby disconnects the high voltage fed to the tubes, turns off the
auxiliary switching supply, and reduces the voltage supplied to the
heaters to extend their life.
If the MGP-1A will remain inactive for long periods of time, we
recommend turning the power off instead of using Standby.
Warm LED
The Warm LED alerts you that the MGP-1A’s preamp tubes have
had sufficient time to warm up for optimum use. Please wait until the
Warm LED is lit to take the unit out of standby.
Black Widow
Audio Designs
MGP-1A Modeling Guitar Preamp Eclipse Series
Standby
Wa rm
Normal Bass Mid
Bright Treble Volume
Crunch MidBass Treble Volume
Drive
Crunch
Clean
Drive MidBass Treble Volume
UK
Vintage
US
Vintage
Class
A
InputMod
UK800 Mod
ModEuroRecto Hot
Rod
Deep
Deep
Bright
Bright EQ
Shift
Alt
EQ
EQ
Shift
Alt
EQ
EQ
Shift
Alt
EQ
CitrusCali
MIDI
Learn
|
O
Power Section
MIDI Button and LED
When held for 2 seconds, the MIDI button is used to enter and exit the MGP-1A’s MIDI programming mode.
The MIDI LED will illuminate to provide visual indication that the unit is ready to be programmed. See the MIDI
section for an in-depth explanation.
Black Widow
Audio Designs
MGP-1A Modeling Guitar Preamp Eclipse Series
Standby
Wa rm
Normal Bass Mid
Bright Treble Volume
Crunch MidBass Treble Volume
Drive
Crunch
Clean
Drive MidBass Treble Volume
UK
Vintage
US
Vintage
Class
A
InputMod
UK800 Mod
ModEuroRecto Hot
Rod
Deep
Deep
Bright
Bright EQ
Shift
Alt
EQ
EQ
Shift
Alt
EQ
EQ
Shift
Alt
EQ
CitrusCali
MIDI
Learn
|
O
MGP-1A Front Panel

4
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 4
Getting Sta
Getting Started
Front Panel Controls
The MGP-1A’s channel controls are nearly identical, with the Clean Channel being the
exception. We will cover these controls and their function in this section so you know what
they do. This will come in handy later in the manual when we reference these controls and their
Model-specific functionality.
Front Input
The Front Input allows you to plug your guitar into the front panel. If a cable is inserted here, it will disable the
Rear Input. This is great for studio use as it allows players to easily plug into permanent rack fixtures.
Channel Switches
The Channel Switches are the 3 large push button switches labelled, Clean, Crunch and Drive. Use these
switches to select the channel you would like to activate. The switch will light up indicating which channel is
currently active. Channels can also be changed via the included FS-3 foot switch or with MIDI.
Model Switches
The Model Switches (US Vintage, UK Vintage, Cali, Euro, etc.) select which Model is active for each channel.
An LED above each switch will indicate which Model is currently active. When a new Model is selected, you will
notice that all or some of the other switch LEDs will change. This is because the MGP-1A stores the last state
each Model was in (Mod, EQ Shift, Alt. EQ, etc.) and recalls those settings.
NOTE: Settings on an inactive channel can be changed at any time. This may be useful in a live setting where
different songs use different Models and settings and need to be quickly changed.
Mod Switches
The Mod Switch activates the Mod (Short for “Modification”) feature. This is essentially a second bank of
Models, calling up a Model that is related to the base Model currently selected.
Black Widow
Audio Designs
MGP-1A Modeling Guitar Preamp Eclipse Series
Standby
Wa rm
Normal Bass Mid
Bright Treble Volume
Crunch MidBass Treble Volume
Drive
Crunch
Clean
Drive MidBass Treble Volume
UK
Vintage
US
Vintage
Class
A
InputMod
UK800 Mod
ModEuroRecto Hot
Rod
Deep
Deep
Bright
Bright EQ
Shift
Alt
EQ
EQ
Shift
Alt
EQ
EQ
Shift
Alt
EQ
CitrusCali
MIDI
Learn
|
O
MGP-1A Front Panel

5
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 5
Getting Sta
Getting Started
Front Panel Controls (continued)
Input Switch (Clean Channel Only)
The MGP-1A’s Clean Channel is unique in that it is a Dual-Input Topology like the classic amplifiers of yesteryear.
These amps had two input channels, usually one for guitar and one for bass, each with their own gain control.
The output of these controls was mixed together and they shared a common second stage and tone stack.
The Input Switch routes the guitar signal to the selected input channel, Bright, Normal, or Bridged. To change
channels on the originals, you would have to physically plug your guitar into the desired input jack. The Input
Switch does this for you and an LED will light up telling you which input, Bright or Normal, is active.
When both the Bright and Normal LEDs are lit, the unit is in Bridged mode. In Bridged mode, the inputs are
tied together and the input signal is sent to both the Bright and Normal channels simultaneously. This is the old
“jumpered input trick”, which gives a slight gain boost and allows you to change the character of the tone using
the Bright and Normal gain controls, kind of similar to an active EQ (albeit one with distortion!).
Bright and Normal Gain Controls
Bright and Normal control the gain for their respective Clean channel inputs. Like on the originals however, they
are interactive with each other and both remain “active” regardless of which input you are using. This is normal
and allows for some unique things:
• Use the inactive channel’s control as a tone control. For instance, with the Bright channel active, you can add
a little bottom to the tone by increasing the Normal control.
• This can also be used as a boost. To compensate for the extra bottom end, reduce the bass control slightly.
• Get the tone of single input amplifiers by setting the inactive control to minimum. Use the Bright Input for an
amp with a “Bright” switch engaged, Normal for an amp with the “Bright” switch off.
It goes without saying that in Bridged mode, both controls are fully active. You can use this not just for gain but
for changing the balance and character of the overall tone as well.
Crunch and Drive Gain Controls
Crunch and Drive are the gain controls for the Crunch and Drive channels, respectively. For the Crunch channel,
the Crunch knob will get you anything from clean to heavy distortion tones. The Drive control will take you from
overdrive and crunch tones all the way to white hot metal tones.
Bass Controls
Bass adjusts the low frequency level of the corresponding channel.
Black Widow
Audio Designs
MGP-1A Modeling Guitar Preamp Eclipse Series
Standby
Wa rm
Normal Bass Mid
Bright Treble Volume
Crunch MidBass Treble Volume
Drive
Crunch
Clean
Drive MidBass Treble Volume
UK
Vintage
US
Vintage
Class
A
InputMod
UK800 Mod
ModEuroRecto Hot
Rod
Deep
Deep
Bright
Bright EQ
Shift
Alt
EQ
EQ
Shift
Alt
EQ
EQ
Shift
Alt
EQ
CitrusCali
MIDI
Learn
|
O
MGP-1A Front Panel

6
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 6
Getting Sta
Getting Started
Front Panel Controls (continued)
Mid Controls
Mid adjusts the midrange frequency level of the corresponding channel.
Treble Controls
Treble adjusts the high frequency level of the corresponding channel.
Volume Controls
Volume adjusts the overall output level of the corresponding channel.
EQ Shift Switches
The EQ Shift feature modifies the tone stack circuit so that it affects a new frequency range. Like every tonal
feature of the MGP-1A, it’s function is Model dependant, meaning it will do something different for each Model.
This can be useful helping you find your tone or while double tracking to give a slightly different tone, which when
combined with little differences in how each take is played will create a huge sound.
Alt EQ Switches
Alt EQ feature rewires the tone stack to be a completely different circuit. We included this feature to help
effectively model more amplifiers, and/or to help dial in the exact sound you want to have.
Keep in mind, the EQ Shift works on both the base and Alt EQ tone stacks. This allows for a total of 4 unique
tone stacks to be used for each Model.
Alt EQ MIDI Functions
You’ll notice the Alt EQ labels also have a (+), (-), (esc) next to them. These labels indicate their function when in
MIDI Mode.
The Clean Channel’s Alt EQ(+) will toggle Omni Mode on or off, or will increase the MIDI channel.
The Crunch Channel’s Alt EQ(-) will toggle Omni Mode on or off, or will decrease the MIDI channel.
Holding the Drive Channel’s Alt EQ(esc) for 2 seconds will exit MIDI Mode without saving any changes made in
case a button was pressed accidentally.
Black Widow
Audio Designs
MGP-1A Modeling Guitar Preamp Eclipse Series
Standby
Wa rm
Normal Bass Mid
Bright Treble Volume
Crunch MidBass Treble Volume
Drive
Crunch
Clean
Drive MidBass Treble Volume
UK
Vintage
US
Vintage
Class
A
InputMod
UK800 Mod
ModEuroRecto Hot
Rod
Deep
Deep
Bright
Bright EQ
Shift
Alt
EQ
EQ
Shift
Alt
EQ
EQ
Shift
Alt
EQ
CitrusCali
MIDI
Learn
|
O
MGP-1A Front Panel

7
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 7
Rear Panel
AC Mains Input
Connect AC Power cord to a grounded mains outlet only.
Only use the supplied power cord or a UL approved type.
Power Switch
Applies power to the MGP-1A when in the ‘On’ (I) position. The power switch is on the rear of the unit as a
rackmount system typically has a power conditioner or a power strip attached.
Mains Fuses
These protect your MGP-1A from electrical faults. Replace only with the same type and rating specified on the
rear panel. Failure to do so could result in damage or fire.
WARNING: Replace only with same fuse type and rating!
Voltage Select
Make sure the Voltage selection switch is set to the mains voltage in your region before applying power to the
unit. Failure to do so may result in damage or fire.
Ground Lift Switch
Lifts the signal ground from the chassis ground to potentially eliminate ground loops. If your AC outlet is properly
grounded, this switch will likely not be necessary.
FS-3 Jack
Connector for the FS-3 foot switch. The unit will automatically recognize if the FS-3 is attached or not, even if it
is plugged in or comes unplugged during a set.
NOTE: This jack does not recognize or send MIDI data so if MIDI isn’t working, check here.
Getting Sta
Getting Started
115V
I
O
|
O
MGP0000000
SERIAL
115/230V
50/60Hz 64W
Outputs Input
WARNING: POTENTIALLY LETHAL VOLTAGES
INSIDE
Voltage Select Ground
Lift
St. Louis, Mo
www.hearblackwidow.com
CAUTION
RISK OF ELECTRIC SHOCK
WARNING: TO REDUCE THE RISK OF FIRE OR
ELECTRIC SHOCK DO NOT EXPOSE THIS EQUIPMENT
TO RAIN OR MOISTURE
T 500mA 250V H
each
CAUTION: TO REDUCE THE RISK OF FIRE, REPLACE
FUSES WITH SAME TYPE AND RATING.
ATTENTION: UTILISER UN FUSIBLE DE RECHANGE DE
MEME TYPE.
Patent Pending
Power MIDI
In
MIDI
Thru
FS-3
only
Mains Fuses
Not MIDI
Lift
Normal
MGP-1A Modeling Guitar Preamp
Eclipse Series
Black Widow
Audio Designs
MGP-1A Real Panel

8
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 8
Getting Sta
Getting Started
Rear Panel (Continued)
MIDI IN
Connect a MIDI foot controller here or a cable from another device’s MIDI Thru or Out jack. This jack receives
MIDI data so the MGP-1A can be controlled remotely.
MIDI Thru
If you have other MIDI devices in your rig, this jack can be used to daisy chain to other MIDI capable devices. This
jack forwards a copy of any MIDI messages received through the MIDI IN jack. Please note that this jack does
nothing without a cable connected to MIDI IN.
Outputs
Use these jacks to connect the output signal of the MGP-1A to other devices. The same signal appears on both
jacks allowing for some flexible hookup options. Try one or combinations of the following:
• Black Widow Audio Designs MPA-XX Modeling Power Amplifier input.
• Speaker simulator line input.
• FX unit, mixer, sound card or audio interface unbalanced input.
FX Loop
Don’t see it? It’s there...
The typical FX loop is a patch point inserted between the preamp and power amplifier section of a guitar amp.
Since this is a preamp, returning the FX signal back to the unit and then out again requires another tube and
adds unnecessary noise. To use effects, simply use one of the outputs as an FX Send, and return the FX output
to a power amplifier or the next device in the chain.
If you are using the MGP-1A with a guitar amplifier head or combo unit with an effects loop and “power amplifier
input”, try both to see which sounds best. The reason for this is the FX return will normally provide some gain to
boost the return signal up from line levels. If power amplifier distortion is part of your sound, then the FX unit itself
may not be able to drive the power amplifier hard enough, so it will need some help from the FX return amplifier.
Input (Rear Panel)
This is the MGP-1A’s rear input. This input allows for easy integration into professional studios using patchbays
or for those who don’t like front panel inputs.
NOTE: This input is automatically disconnected when a cable is inserted into the Front Input.
115V
I
O
|
O
MGP0000000
SERIAL
115/230V
50/60Hz 64W
Outputs Input
WARNING: POTENTIALLY LETHAL VOLTAGES
INSIDE
Voltage Select Ground
Lift
St. Louis, Mo
www.hearblackwidow.com
CAUTION
RISK OF ELECTRIC SHOCK
WARNING: TO REDUCE THE RISK OF FIRE OR
ELECTRIC SHOCK DO NOT EXPOSE THIS EQUIPMENT
TO RAIN OR MOISTURE
T 500mA 250V H
each
CAUTION: TO REDUCE THE RISK OF FIRE, REPLACE
FUSES WITH SAME TYPE AND RATING.
ATTENTION: UTILISER UN FUSIBLE DE RECHANGE DE
MEME TYPE.
Patent Pending
Power MIDI
In
MIDI
Thru
FS-3
only
Mains Fuses
Not MIDI
Lift
Normal
MGP-1A Modeling Guitar Preamp
Eclipse Series
Black Widow
Audio Designs
MGP-1A Real Panel

9
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 9
Clean Chann
Normal Bass Mid
Bright Treble Volume
Clean
UK
Vintage
US
Vintage
Class
A
InputMod EQ
Shift
Alt
EQ(+)
The Clean Channel
The MGP-1A’s Clean Channel accurately models many of the most sought after amplifiers of all time. This
channel will take you from glassy cleans to raunchy overdrive just like the originals.
These amplifiers all used a Dual-Input Topology which is essentially a two-channel preamplifier. Each
“channel” has its own gain control, but share a common EQ and volume control. We’ve kept this
arrangement as it allows you to do some really useful things for both tone and modeling purposes.
US Vintage
The US Vintage Model is based on the classic Fender® ‘59 Bassman®. This Model has fat lows and silky
smooth highs and just adores single coils. The default tone stack circuit is the “classic Fender®” tone stack which
allows for a wide range of tonal control and a slightly scooped midrange.
Mod
When Mod is engaged, we are modeling the tone of the later Fender preamplifiers with 12AX7’s in V1. There’s
more gain on tap, the tone controls are a bit sweeter and the overall touch response is improved.
EQ Shift
In our first designs, US Vintage’s EQ Shift was a bass boost like the “Deep” Switch found on the Super
Bassman®. However, this model has enough bass as is, so instead we opted for a more useful treble shift,
which lowers the treble frequency deeper into the midrange.
Alt EQ
The Alt EQ rewires the tone stack to the original “vintage Fender®” design which is a bit weaker as far as
the range of controls are concerned, but it has less insertion loss (higher volume). The frequency ranges are
shifted higher and the mids are a bit stronger.
The Models
* All product names used hereon are trademarks of their respective owners, which are in no way associated or aliated with Black Widow Audio Designs. ese trademarks of other
manufacturers are used solely to identify the products of those manufacturers as a means to compare the sonic performance characteristics and tones of the Black Widow Audio Designs
MGP-1A. e MGP-1A and its features have been created by incredibly detailed analysis of the actual ampliers from which they are inspired.

10
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 10
Clean Chann
The Clean Channel
The Models (continued)
UK Vintage
This model is based on the early Marshall® JTM-45. Marshall’s first amplifiers were part for part copies of the
Fender amps, but the JTM-45 was the first amplifier with the Marshall “voice”.
This model is more aggressive and much brighter than its US counterpart and has a classic, crunchy tone that
is timeless. The default EQ is the “classic Marshall®” tone stack, which is a bit harder sounding than the classic
Fender EQ.
Mod
UK Vintage’s Mod feature evokes the sound of the classic 1987 “Plexi” Super Lead which has more gain,
edge and grind than the JTM-45.
EQ Shift
Marshall® didn’t mess with their EQ too much over the years, so we had to come up with something that would
be useful. Since the UK Vintage tone is bright, the EQ shift is a bass boost to give a little more bottom end.
Alt EQ
The alternate EQ is the “vintage Marshall®” tone stack which has a lower midrange frequency and trades some
gain for extra range in the controls.
Class A
The Class A Model is based on the Vox® AC-30®. This amplifier is known for its chime and sharp overdriven
tone and has been used on too many albums to count. The AC-30® never had a midrange control, but we’ve
added one for extra tone shaping. Set the midrange around 11 o’clock for the authentic Vox® EQ.
Mod
The Class A mod switch is based on the original AC-30® Top Boost. It has a harder, glassier tone and more
gain.
EQ Shift
The Class A EQ Shift is a mid shift lowering the midrange frequencies but boosting them as well. The classic
Vox® EQ scoops the mids quite a bit, so a stronger midrange presence can be welcome for new tones.
Alt EQ
For the Class A Alt EQ, the tone stack rewires itself to the classic Fender® tone stack. This EQ circuit is found
in the AC-120® and has a really sweet tone when used with this model.
* All product names used hereon are trademarks of their respective owners, which are in no way associated or aliated with Black Widow Audio Designs. ese trademarks of other
manufacturers are used solely to identify the products of those manufacturers as a means to compare the sonic performance characteristics and tones of the Black Widow Audio Designs
MGP-1A. e MGP-1A and its features have been created by incredibly detailed analysis of the actual ampliers from which they are inspired.

11
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 11
Clean Chann
The Clean Channel
While these Models were primarily designed for “clean” tones, don’t be afraid to drive them hard. Many of the
best guitar sounds in history came from pushing these amplifiers to their limits. To get the best overdriven tones,
remember that the preamplifier sections of these amplifiers contribute very little towards the overdrive sound,
most of that happens in the phase splitter and power tubes. Clean amps are unique in this regard.
The power amplifier section is also the major contributor to the touch response of these “clean” amplifiers,
caused by the inability of the power supplies to keep the voltage levels constant. This is called ‘sag’. When the
power supply sags, the amp distorts a little easier and the sound is somewhat compressed. If you don’t have a
tube power amplifier, you can emulate the power amp “sag” sound by using a compressor after the MGP-1A.
Clean tones don’t naturally compress as much as overdriven and distorted tones do anyway, so a compressor
can tame the ‘attack’ (sharp beginning of a plucked note). The ‘attack’ of a clean tone is usually very high in
amplitude relative to the sustain portion of a note, which can be good or bad depending on your playing style.
If using the MGP-1A in conjunction with a power amp simulator and/or cabinet simulator, do not be afraid
to experiment with different power tube models, power amplifier topologies, and speaker combinations for
modeling purposes or just pure tonal experimentation.
You can successfully model many Fender® amplifiers this way. The tones of the early Fender® Champs, for
instance, can be found with US Vintage (Mod off) with a single-ended 6V6 or 6L6 model.
If you are trying to get the tone of an amplifier with a single ‘tone’ knob EQ, try setting Bass and Treble to 0, and
Mid control at 10. Then bring the bass or treble up to give the sound of treble ‘cut’ or bass ‘cut’ respectively.
Tone Tips

12
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 12
Cali
The Cali Model is based on the classic Mesa Boogie® Mark IV®’s Rhythm 1 channel. The Mark IV’s Rhythm 1
channel is a direct descendant of Fender’s reverb equipped models, so many of those tones can be found here.
An interesting thing about this preamplifier is the EQ is found after the first stage as opposed to most amplifiers
which place it after the last stage. This allows you to shape some of the breakup character of the amplifier but
can make the EQ weaker at higher gain settings. The default EQ is the classic Fender® EQ circuit.
Mod
When Mod is engaged, the MGP-1A switches to the Mark IV®’s Rhythm 2 channel, which has much more gain
and a slightly different voicing. This tone is great from both rhythm and lead tones, and has excellent high gain
breakup when pushed.
Bright Switch
The Bright Switch engages the same bright sound as the original “Pull Bright” found on the Mark IV®. Adds a
nice sparkle, especially at lower Crunch settings.
Deep Switch
The Deep Switch performs the same low-midrange boost as you get with the “Pull Fat” option on the Mark
IV®. Adds a little fatness without being muddy.
EQ Shift
Cali’s EQ Shift is the “Treble Shift” feature which lowers the treble into the mids which is great for adding a bit
of presence to the tone.
Crunch Cha
The Crunch Channel
The Crunch Channel gives you classic preamplifier models known for their crunch and overdrive
sounds. You can coax anything from clean to distorted tones from this channel; it may be the most
versatile of them all.
You’ll notice the Crunch Channel looks a bit different than the Clean. That’s because this is where we
begin to see a movement towards a single input design and we also begin to see some switchable
tone shaping options added to the feature set. We’ve included these options as our Bright and Deep
switches.
Crunch
UK800 Mod DeepBright EQ
Shift
Alt
EQ(-)
CitrusCali
Crunch MidBass Treble Volume
The Models
* All product names used hereon are trademarks of their respective owners, which are in no way associated or aliated with Black Widow Audio Designs. ese trademarks of other
manufacturers are used solely to identify the products of those manufacturers as a means to compare the sonic performance characteristics and tones of the Black Widow Audio Designs
MGP-1A. e MGP-1A and its features have been created by incredibly detailed analysis of the actual ampliers from which they are inspired.

13
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 13
Crunch Cha
The Crunch Channel
Alt EQ
The Alt EQ rewires the tone stack to be a Fender® /Marshall® hybrid EQ circuit which has a beefier low end but
still has a great range of control.
UK800
The UK800 Model is based on the Marshall® JCM-800 2203/4. It can be thought of as a high gain Plexi, and
when people talk about the Marshall® sound, this is it. Bright and crunchy, when pushed it has a very fluid feel
about it. Most of the classic tones from this amplifier came from driving the EL-34 based power section hard, so
keep this in mind.
The default EQ is the classic Marshall EQ which has higher gain, more midrange presence but less range than a
Fender style tone stack.
Mod
UK800’s Mod feature is based on the JCM-900 which has higher preamp gain but a classic Marshall® voice.
Bright Switch
The JCM-800’s are very bright, too bright for some. Common modifications remove the bright capacitor
across the gain control. We’ve removed it by default, but the Bright Switch puts it back for authentic JCM-
800/900 tone.
Deep Switch
Since Marshall® amplifier’s are bright, the Deep Switch adds some extra punch in the low end. This is based
on common modifications done to this amplifier to fatten it up.
EQ Shift
UK800’s EQ Shift is a ‘Mid Boost’ which again was a commonly performed modification from the era. This
results in a bit more “grind” in the tone which can be very nice for rhythm.
Alt EQ
The alternate EQ is the JCM-800 2205’s tone stack which isolates the mids and makes the bass control
more powerful.
The Models (Cali)
* All product names used hereon are trademarks of their respective owners, which are in no way associated or aliated with Black Widow Audio Designs. ese trademarks of other
manufacturers are used solely to identify the products of those manufacturers as a means to compare the sonic performance characteristics and tones of the Black Widow Audio Designs
MGP-1A. e MGP-1A and its features have been created by incredibly detailed analysis of the actual ampliers from which they are inspired.

14
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 14
Crunch Cha
The Crunch Channel
Citrus
Citrus is based on the original Orange® Graphic Mk. II. This is THE Orange® tone, not to be confused with the
current modern offerings. This is a great, growly tone that can sound raw or refined depending on how you set it.
Like the Cali Model, the EQ comes early but here the Graphic Series amplifiers use the unique James tone stack.
This tone stack has hi-fi origins and can be a bit odd at first to use, so we’ll spend a bit of time covering it.
The first thing you need to know is that this EQ never had a midrange control, but it still allows for potent
midrange shaping. Its response is nearly ‘flat’ with the Bass and Treble controls set to 5. The mids will stay flat,
so turning the Bass and Treble controls up will not only boost bass and treble frequencies, but also ‘scoop’ the
mids, and turning both down will ‘boost’ the mids.
Since we didn’t want a ‘dead’ control, we modified the tone stack so the Mid control cuts and boosts the
midrange frequencies. The Mid control in this tone stack is weaker than you may be used to, so don’t forget to
adjust the bass and treble for stronger/weaker midrange effect.
Mod
The Citrus Mod rewires the circuitry to that of a later version of the Graphic Mk. II. This version is brighter, has
more gain, and has a different character than the former.
Bright Switch
The bright capacitor was hard wired on these amplifiers, so we’ve made it switchable. With Bright on, the
bright capacitor is in the circuit. This really sweetens the top end.
Deep Switch
The Graphic Mk. II has great low end already, so we’ve made its default state a bit brighter. Engaging the
Deep Switch puts the low end back to it’s normal, dominant position.
EQ Shift
The Citrus EQ Shift is a mid shift control, shifting the midrange lower. This also makes the ‘scoop’ a bit less
strong, but the ‘boost’ a bit stronger. If Alt EQ is off, then EQ Shift models the tone stack found in the “Pics
and Text” model.
Alt EQ
The Alt EQ for the Citrus Model is the classic Marshall tone stack.
The Models (Citrus)
* All product names used hereon are trademarks of their respective owners, which are in no way associated or aliated with Black Widow Audio Designs. ese trademarks of other
manufacturers are used solely to identify the products of those manufacturers as a means to compare the sonic performance characteristics and tones of the Black Widow Audio Designs
MGP-1A. e MGP-1A and its features have been created by incredibly detailed analysis of the actual ampliers from which they are inspired.

15
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 15
Just like the Clean Channel, using a tube power amplifier or power amp simulator can be put to good use on this
channel. This is especially true for the UK800 and Citrus Models, as most of the best distorted tones coming
from those amplifiers relied on power amplifier distortion.
This channel is perhaps the most versatile of the three, as you can get anything from clean to overdrive to lead
tones. A distortion pedal in front of this channel can give you another layer of versatility, as these amplifiers saw
fuzz and overdrive pedals really come into their own around the same time period. You can bet many great guitar
tones over the years were from a combination of a dirt pedal and amplifier distortion.
With the higher gains in this channel, speaker choice can have a huge tonal impact since overdrive produces
far more harmonics than clean sounds. Speaker simulators can be put to great use here for both live and studio
purposes.
This is also the point where double tracking a rhythm part and panning one left and the other right can really
make the recorded guitar tone “pop” (sound huge). Make sure you record two separate takes, simply copying a
single take to a new track doesn’t have the same effect.
Tone Tips
Crunch Cha
The Crunch Channel

16
MGP-1A Modeling Guitar Preamplifier Owner’s Manual 16
Drive Chann
The Drive Channel
The Drive Channel conjures up the most coveted hi-gain sounds. Here you’ll find everything from
mild overdrive, chunky riffage and white hot lead tones. This channel is perfect for solos, rock and
metal and anything else you decide to do with massive amounts of all-tube distortion.
Drive
Drive MidBass Treble Volume
ModEuroRecto Hot
Rod
DeepBright EQ
Shift
Alt
EQ
(esc)
The Models
Recto
Recto is based on the Red Channel of the early Mesa Boogie® Dual Rectifier®. For the longest time, this was
THE hi-gain sound. It has a rather chainsaw-ish quality to it’s breakup, with massive low end and a liquid high
end. This tone has been heard on countless records and is very versatile in what it does well.
This circuit originally was developed by Soldano® in the form of the SLO-100, X Series Preamps and others.
Since then, other manufacturers have used this preamp circuit like Peavey®, Framus® and more. Expect those
tones to be available from this Model as well.
Mod
When Mod is engaged, the MGP-1A calls up the tone of the Splawn Nitro. The Nitro has some similarities
with the Dual Rectifier but tonally it is a different beast. You’ll notice this especially in the character of the
distortion.
Bright Switch
The Bright Switch engages a bright cap. The Dual Rectifier’s® bright cap is normally hardwired, but the Nitro
never had one. Now you can have it both ways.
Deep Switch
The Deep Switch never was a feature in the Mesa Boogie® Rectifier® Series but one of the refinements made
to the preamplifier circuitry over the years by Mesa Boogie® was to reduce the low end emphasis. We’ve used
the reduced low end as our default setting, but engage the Deep Switch for authentic early Rectifier® tone.
EQ Shift
We’ve made the default EQ for the Recto the classic Marshall® EQ, which was used in the Orange Channel of
the Dual Rectifier® and the Nitro. The EQ Shift changes this to the Dual Rectifier’s® Red Channel’s EQ, which
lowers the treble and mids slightly.
Alt EQ
The Alt EQ rewires the tone stack to the classic Fender® EQ. We really love this EQ with this model, as it digs
into the mids a bit more, resulting in a smoother tone.
* All product names used hereon are trademarks of their respective owners, which are in no way associated or aliated with Black Widow Audio Designs. ese trademarks of other
manufacturers are used solely to identify the products of those manufacturers as a means to compare the sonic performance characteristics and tones of the Black Widow Audio Designs
MGP-1A. e MGP-1A and its features have been created by incredibly detailed analysis of the actual ampliers from which they are inspired.