Source Audio True Spring Reverb User manual

SA247 True Spring Reverb User Guide 1
True Spring Reverb
User Guide
Welcome
Thank you for purchasing the True Spring Reverb. This powerful stereo effects pedal revisits and
reimagines the timeless combination of spring reverb and tremolo. The Source Audio engineering
team put years of collective man-hours into capturing every nuance and idiosyncrasy of the spring
reverb and tremolo effects from some of the music gear industry’s most iconic guitar amps and
outboard gear. We hope you love where this pedal takes you.
The pedal comes in a compact and durable brushed aluminum housing with stereo inputs and
outputs, a three-position toggle switch, and a simple four-knob control surface. When combined with
the Neuro Hub, the True Spring also features full MIDI functionality.
Dialing in a wide selection of gorgeous reverb and tremolo tones is simple right out of the box, but
the True Spring also offers a far deeper set of editing abilities and unique routing options when

SA247 True Spring Reverb User Guide 2
connected to the Neuro Desktop Editor or Neuro Mobile App. Use the Neuro Editor to create highly
customized presets, then save, store, and share them with the rest of the growing Neuro Community.
The Quick Start guide will help you with the basics. For more in-depth information about the True
Spring Reverb, move on to the following sections, starting with Connections.
Enjoy!
-The Source Audio Team
Overview
Three Flavors of Spring Reverb –Select either the Short or Long engines for sounds inspired by the
spring reverb tones of vintage combo amps, or choose the Tank engine for a “drippy” sound inspired
by tube driven outboard spring tanks.
Three Styles of Tremolo –Combine any of the spring reverb effects with any of the True Spring’s
three styles of tremolo. Tremolo effects include Opto, Bias, and Harmonic.
Two Modes of Operation –Use the pedal in Standard Mode for a classic (non-preset) stompbox
experience or turn on Preset Mode and save a user preset (including reverb/tremolo effects and
knob positions) to each of the three toggle switch positions.
Flexible Stereo Routing –The True Spring is equally at home in a mono or stereo rig. A variety of
routing modes such as Stereo to Stereo, Mono to Mono, Mono-to-Stereo, Stereo Sum-to-Mono and
External Loop allow the pedal to adapt quickly to the needs of your rig and harness the full power of
stereo signal chains.
Compact Design –The durable, anodized aluminum housing has a slim profile, a small footprint, and
a sturdy hardware that will withstand the rigors of the road.
Universal BypassTM –True bypass or buffered bypass? The choice is yours. The True Spring features
high-quality signal relays for true bypass and transparent buffers for analog bypass.
Neuro Technology –The Neuro Mobile App and Neuro Desktop Editor open up new possibilities for
the True Spring, including alternate virtual spring lengths, additional control parameters, routing
options, and access to the Neuro Community. Create customized presets then name them, save
them to the cloud, and share them publically with other members of the Neuro Community. It is also
possible to upload presets created by other Neuro Community members.
MIDI Control –Connect the True Spring to the Neuro Hub and access up to 128 presets with MIDI
Program Change (PC) messages as well as control any of the pedal’s parameters with MIDI
Continuous Controller (CC) messages. It is also possible to send MIDI CC messages to the True Spring
through the pedal’s mini USB port. Class compliant USB-MIDI allows the True Spring to work as a
plug-and-play device with recording software running on Mac and Windows.

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Quick Start
Power
To power the unit, connect the included 9V DC power supply to the jack labeled DC 9V on the back
panel. When running a 3rd party power supply, the True Spring requires an isolated 9V DC power
source with a minimum of 165mA and a center-negative plug.
Warning: Using a non-Source Audio supply, especially an unregulated supply, could damage the unit.
Please be very cautious when using 3rd-party power supplies.
Guitar/Audio Connections
Using standard ¼” mono cables, connect your guitar, bass, or other instrument to the INPUT 1 jack
and your amp (or the next audio device in the signal chain) to the OUTPUT 1 jack. When running a
stereo rig, also use Input and Output 2.
Once the power and audio connections have been made, the True Spring is ready to play.
Brief Knob, Footswitch, and Button Descriptions
Please note that the DWELL and TONE knobs, and the center toggle switch have alternate functions
while holding down the CONTROL INPUT button on top of the pedal. These alternate functions
control the key parameters of the tremolo effects. The reverb settings remain unchanged while
making adjustments to the tremolo.
Mix Knob: Controls the ratio between the dry and reverb signals.

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Level Knob: Controls the overall output level. Unity gain between the bypassed and engaged signals
resides at 12 o’clock on the knob. Turning the LEVEL knob fully clockwise boosts the dry signal
roughly 6dB.
Dwell Knob: Controls the level of the dry signal hitting the spring tank. Turning the up the DWELL
control adds a more overdriven and animated quality to the wet signal. Alternate Function:While
holding down the CONTROL INPUT button on the top of the pedal, the DWELL knob temporarily
controls the DEPTH of the tremolo effect without changing the DWELL amount.
Tone Knob: Controls the equalization of the reverb signal. Turn the knob to the left for a darker
sound and to the right for a brighter reverb signal. Alternate Function:While holding down the
CONTROL INPUT button the TONE knob adjusts the RATE of the tremolo effect.
Effect Switch: Selects between the three spring reverb engines –SHORT, LONG, and TANK. Alternate
Function: While holding down the CONTROL INPUT button the center toggle switch selects between
the three types of tremolo - OPTO, HARMONIC, and BIAS. By default, all three of the spring reverbs
are paired with OPTO Tremolo.
Footswitch: Enables or bypasses the effect. Pressing and holding the footswitch from the bypassed
state also toggles between Standard and Preset Modes. The pedal mode is indicated by the
illuminated green (Standard) or red (Preset) center LED color.

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Contents
Welcome..................................................................................................................................................1
Overview..................................................................................................................................................2
Quick Start ...............................................................................................................................................3
Connections.............................................................................................................................................6
Basic Spring Reverb and Tremolo Operation...........................................................................................9
Reverb Effect Engines..............................................................................................................................9
Tremolo Effect Engines............................................................................................................................9
Additional Spring Reverb Engines..........................................................................................................10
Controls..................................................................................................................................................12
Standard and Preset Modes ..................................................................................................................14
Universal Bypass TM................................................................................................................................16
I/O Routing Options (Stereo Routing) ...................................................................................................16
External Control.....................................................................................................................................19
Neuro Mobile App & Neuro Desktop Editor..........................................................................................24
The Neuro Desktop Editor .....................................................................................................................24
The Neuro Mobile App ..........................................................................................................................33
Daisy-Chaining Neuro Communication..................................................................................................40
Neuro Hub (Formerly the Soundblox Hub)............................................................................................42
MIDI .......................................................................................................................................................42
USB.........................................................................................................................................................44
True Spring Reverb Specifications .........................................................................................................44
Troubleshooting.....................................................................................................................................45
Frequently Asked Questions..................................................................................................................46
Rubber Feet ...........................................................................................................................................47
Waste Disposal Notes............................................................................................................................47
Warranty................................................................................................................................................48
Version History ......................................................................................................................................49

SA247 True Spring Reverb User Guide 6
Connections
Input Side Connections
Input 1
This is the primary input for guitar, bass, or other instruments. It can also accept line-level inputs of
up to +6.54 dBV / 8.76 dBu. Connect it to your instrument or other audio source using a mono (TS) ¼”
cable.
Input 2
Input 2 acts as either a second audio input, the data connection for the Neuro Mobile App, or an
input for both audio and Neuro Data simultaneously.
Input 2 as an Audio Input
The tip contact on Input 2 acts as a secondary input for guitar, bass, or other instruments. It is only
active when the True Spring is configured with a signal routing option that uses stereo inputs.
Connect it to your instrument (or the previous effect in the signal chain) using a mono (TS) ¼” cable.
By default, the True Spring will auto-detect the routing mode. Other routing options are available
using the Neuro Mobile App or Desktop Editor. For more information about stereo routing, refer to
the I/O Routing Options section.
Input 2 as a Neuro App Data Input
The ring contact on Input 2 acts as a data connection for the Neuro App. Connect it to your mobile
device using a stereo (TRS) ¼” cable. It can also accept simultaneous audio and daisy-chained Neuro
data from another Neuro-compatible pedal in the chain, provided that a TRS cable is used. The audio
signal (if applicable) will be on the tip contact of the plug, and the Neuro App data will be on the ring
contact.
Input 2 accepts data from the Neuro Mobile App. Data from the Neuro Hub comes through the
CONTROL INPUT port.

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Output Side Connections
Output 1
This is the primary mono Output. Connect this Output to your amplifier, recording interface, or the
next device in your effects signal chain using a mono (TS) ¼” cable.
Output 2
Acts as either an audio output, the daisy-chain data connection for the Neuro App, or both audio and
Neuro Data simultaneously.
Output 2 as an Audio Output
The tip contact on Output 2 acts as the secondary audio output. It carries an audio signal when the
True Spring is configured with a signal routing that uses stereo outputs. Connect it to your amplifier,
recording interface, or the next device in your effects signal chain using a mono (TS) ¼” cable.
Output 2 as a Neuro App Data Daisy-Chain Output
The ring contact on Output 2 acts as a data connection for the Neuro App, passing data from the True
Spring to the next Source Audio effect in your signal chain. You can daisy-chain the Neuro App data
regardless of whether Output 2 is configured to output audio or not. Connect Output 2 to the next
pedal’s Neuro App Data input (Input 2) using a stereo (TRS) ¼” cable. The audio signal (if applicable)
will be on the tip contact of the plug, and the Neuro App data will be on the ring contact. See the
Daisy-Chaining Neuro Communication section for more info.

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Power and Control Connections
DC 9V (Power)
Connect to the included 9 Volt DC power supply. The power supply must be regulated at 9 Volts
(direct current), able to source at least 165 mA (milliamps) of current, and the plug should have a tip-
negative, sleeve-positive polarity (the center tip is ground and the sleeve is power).
USB
Connect your computer (Mac or Windows) to the True Spring’s USB port (denoted by the icon)
using a standard mini USB cable. The USB port handles communication between the pedal and the
Neuro Desktop Editor or a digital audio workstation (DAW). The True Spring is a class compliant USB
device, meaning that Mac and Windows computers will recognize it automatically. For more
information about the True Spring’s USB capabilities, refer to the USB section of the User’s Guide.
Control Input Port
The 3.5 mm CONTROL INPUT Port connects to external control devices such as the Source Audio Tap
Tempo Switch, Dual Expression Pedal, Reflex Universal Expression Pedal, Neuro Hub, and Hot Hand
Motion Controller. For more information, refer to the External Control and Neuro Hub sections of the
User’s Guide.
Control Input Button
Serves a variety of functions including accessing Secondary Functions and assigning external
expression control. Read the Secondary Knob and Switch Functions in the Knobs section for more
info on using the CONTROL INPUT button to access tremolo parameters. See the External Control
section for info on using the CONTROL INPUT button to calibrate and assign parameters to external
expression controllers.

SA247 True Spring Reverb User Guide 9
Basic Spring Reverb and Tremolo Operation
The True Spring’s reverb effects are based on a mechanical design originated by the Hammond Organ
Company™in the late 1930s. This stark design uses a pair of input and output transducers to inject
an instrument’s dry signal into an actual set of spring coils and capture the very distinct
reverberations as the sound bounces back and forth within the springs. Of course, Leo Fender
adopted this design in the 1960s with the Fender Twin Reverb™and Deluxe Reverb™amplifiers and a
revolution was born.
The True Spring Reverb also has the capability to combine its spring reverbs with any of the pedal’s
three classic tremolo effects - Opto, Harmonic, and Bias. There are a number of different designs for
creating the amplitude modulation known as Tremolo (see the descriptions below). The iconic effects
pairing of tremolo and spring reverb create a timeless sound as relevant and exciting today as it was
over 50 years ago.
Reverb Effect Engines
The True Spring includes three basic reverb types.
Short Spring
Modeled after the unmistakable twang of the Fender Twin Reverb™and Deluxe Reverb™amplifiers
of the 1960s. After extensive research we found tremendous diversity in the spring reverb sounds of
a variety of amps. Some offered a tighter, less animated tone while others sounded “drippier,” with
longer sustain and livelier reverb trails. The SHORT Spring reverb engine offers a taut sound with a
quick decay and smooth trails.
Long Spring
Produces long and deep reverb decays with noticeable “drip” and highly animated trails. The LONG
Spring engine is not as dramatic as the TANK Reverb engine, but does offer an extremely authentic
representation of some of the livelier reverb tanks found in vintage combo amps.
Tank Reverb
Captures the unmistakable effect of the tube driven outboard spring tanks of the 60s. The sound of
reverb tanks like the classic Fender 6G15™are characterized by their “drippy” attack and animated
trail. This original two-spring design produces a bouncing, delay like sound inseparable from the early
days of surf rock and spaghetti western soundtracks.
Tremolo Effect Engines
The True Spring also includes three different flavors of tremolo. Any of the True Spring’s tremolos
can be mixed and matched with any of the spring reverb engines.
Opto Tremolo
Optical tremolo (a.k.a. “Photocell Tremolo”) is the effect found in many combo amps of the 1960s.
This version of tremolo relies upon a neon light bulb and a light dependent resistor called an
"optocoupler." An LFO controls the brightness of the neon light, which is picked up by the resistor,
and translated to output gain. The non-symmetrical aspects of the light and the optocoupler give the
tremolo a distinct choppy character, due to its quick ramp up in volume and more gradual decline.

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Harmonic Tremolo
Harmonic tremolo recreates the unique circuit included in some Fender™“brownface” amps made
between 1959 and 1963, which alternately modulated the levels of bass and treble frequencies in the
audio signal. The result is a very pleasing and complex tremolo that has characteristics reminiscent of
a phaser.
Bias Tremolo
Bias tremolo is an approach to tremolo that involves using an LFO to modulate the bias voltage of the
tubes in an amplifier. This essentially pushes the tubes in and out of saturation. The result is a
smooth amplitude modulation with a mild overdrive created by the tube saturation.
Additional Spring Reverb Engines
In addition to the True Spring’s primary reverb engines, the Neuro Mobile App and Neuro Desktop
Editor offer an extra collection of diverse reverb effects. These reverb effects provide a refreshing
variety of tonal options. Visit the Neuro Sound Editor section for details on accessing the True Springs
bonus reverb engines.
Drip Machine
This vibrant effect offers a cascading trail of tremendously drippy reverb reflections.
Tiny Tank
The super-tight Tiny Tank imagines the sound of a reverb tank half the size of traditional tank
dimensions. It produces a strong initial splash with a quick, metallic decay.
Space Spring
This especially prominent effect combines a quick Harmonic tremolo with an accompanying pitch
modulation in the reverb trail. It is quite dramatic, yet very musical.
Three Spring Tank
Unlike the classic two spring reverb tanks, which produce a highly animated sound with distinct
reverb reflections, three spring designs offer a rich reverb effect with a smooth decay. It is a perfect
sound for those looking for subtle spring characteristics with a beautiful, lush trail.
Hall S
This beautiful effect imagines the unlikely cross-pollination of down-and-dirty 60s spring reverb with
lush-and-lofty 80s Lexicon™ Hall reverb. It is a massive, lingering reverb with a smooth and subtle
modulation.
Trash Can Spring
This nasty reverb is exactly what you might expect. Imagine the sound of a spring tank reverberating
through an old metal trash can –it’s trashy!

SA247 True Spring Reverb User Guide 11
Ventris Outboard Spring
This is the original Outboard Spring engine that first appeared in the Ventris Dual Reverb. The Ventris
Outboard Spring offers a different take on the classic Fender 6G15 Reverb. This effect creates an
especially drippy attack with a very lively trail.
Ventris True Spring
This highly realistic spring reverb effect originally appeared in the Ventris Dual Reverb. Its splashy
attack and vibrant trails instantly grabbed the attention of spring reverb enthusiasts worldwide.

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Controls
Knobs
Mix
Sets the relative levels of dry signal and wet reverb signal. Fully counter-clockwise is 100% dry, fully
clockwise is 100% wet. Roughly 3 o’clock on the MIX knob is where a 50/50 split between wet and
dry occurs. Kill Dry Mode is also available as a global option (see Kill Dry Mode in the Neuro
Hardware Options section of this manual).
100% Dry
Dry
Dry
Wet
Wet
100% Wet
50% Wet
50% Dry

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Level
Controls the overall output level of the pedal. Note that unity gain between the engaged and
bypassed signal resides at the 12 o’clock knob position. Turning the knob all the way to the left kills
the signal entirely, while turning the knob all the way to the right boosts the output signal roughly
6dB.
Dwell
Boosts or cuts the level of dry signal that drives the spring tank. As the Dwell knob is increased the
reverb response becomes thicker, more animated, and more overdriven.
Secondary Knob Function: Tremolo Depth
While holding down the CONTROL INPUT button on the top of the pedal, the DWELL knob
temporarily adjusts the DEPTH of the tremolo. With the CONTROL INPUT button held down the
Reverb DWELL parameter will not change from its previous position. If the knob is moved again
after releasing the CONTROL INPUT button, the Reverb DWELL parameter will jump to the
physical knob position.
Tone
Controls the amount of high frequency damping applied to the wet signal. Turn the knob clockwise
for a brighter reverb trail and counter-clockwise for a darker reverb.
Secondary Knob Function: Tremolo Rate
While holding down the CONTROL INPUT button on the top of the pedal, the TONE knob
temporarily adjusts the RATE (or SPEED) of the tremolo. Note that while holding down the
CONTROL INPUT button, the Reverb TONE parameter will not change from its previous position.
If the knob is moved again after releasing the CONTROL INPUT button, the TONE parameter will
jump to the physical knob position.
Effect Toggle Switch
Selects between the three spring reverb engines –SHORT, LONG, or TANK. These effects are
described in further detail in the Reverb Effect Engines section.
Secondary Effect Switch Function: Tremolo Type
While holding down the CONTROL INPUT button on the top of the pedal, the Effect Switch
temporarily selects the style of tremolo –OPTO (in the SHORT position), HARMONIC (in the LONG
position), and BIAS (in the TANK position). With the CONTROL INPUT button held down the reverb
engine will not change. If the Effect Switch is moved again after releasing the CONTROL INPUT
button, the reverb engine will change to reflect the newly selected position and the tremolo type
will revert back to OPTO (or to the tremolo type assigned to that reverb engine with the Neuro
Mobile App or Desktop Editor –see the Tremolo Controls section in the Neuro Desktop Editor for
details on changing the default tremolo types).

SA247 True Spring Reverb User Guide 14
LEDs
Engage / Bypass LED
The Engage / Bypass LED above the footswitch indicates if the effect is active (lit) or bypassed (not lit).
The color of this LED indicates whether the pedal is in Standard or Preset Mode. See the Standard
and Preset Modes section for info on the pedal’s two modes.
External Control LED
The small LED located between the MIX and LEVEL knobs is the External Control LED. When lit, it
indicates that external control mode (expression, hot hand, or MIDI) is active. This LED also blinks in
time with the tremolo effects when External Tap Tempo Control is activated. For more information
on enabling external control, see the External Control section. This LED also blinks whenever the
pedal receives Neuro data.
Footswitch
Enables or bypasses the effect. The Footswitch also toggles the pedal between Standard Mode
(green LED) and Preset Mode (red LED). To change modes press and hold the footswitch from the
bypassed state until the center LED changes color. Also, while in Preset Mode, pressing and holding
the footswitch (from the engaged state) will save a preset to the current position of the Effect Toggle
Switch. See the Standard and Preset Modes section for info on the pedal’s modes.
Control Input Button
This small button at the top side of the pedal is used to access the pedal’s secondary tremolo
controls (see the Secondary Functions listed in the Knobs and Effect Toggle Switch sections). The
CONTROL INPUT button is also used when configuring external control. See the External Control
section for more details.
Standard and Preset Modes
The True Spring Reverb features two user modes - Standard Mode and Preset Mode. To alternate
between the two modes press and hold the footswitch from the disengaged state until the center
LED changes color.
Standard Mode (Green LED)
If the center LED is green, the True Spring is in Standard Mode. In Standard Mode the pedal functions
like a traditional effects pedal. We call it the “what you see is what you get mode,” meaning that the
current physical positions of the knobs are reflected in the output. Note: If you move the toggle
switch to a new position all the primary knob parameters will maintain the settings of the physical
knob positions, but the secondary knob functions (tremolo DEPTH and RATE) will reset to zero.
Preset Mode (Red LED)
If the center LED is red the True Spring is in Preset Mode. This mode allows you to save three user
presets, one for each of the Effect Toggle Switch positions. When a preset is recalled, all of the
parameters instantly jump to their saved values, regardless of the physical position of the knobs. This
allows you to quickly engage your favorite settings without having to adjust the knob positions.

SA247 True Spring Reverb User Guide 15
Creating a Preset (Without the Neuro Desktop Editor)
•Bypass the True Spring Reverb by clicking the footswitch once. The engage/bypass LED should
be dark at this time.
•Press and hold the footswitch for 5 seconds and wait for the engage/bypass LED to turn red.
You are now in Preset Mode.
•Set up the effect how you want it to sound, including the effect switch, MIX, LEVEL, DWELL, and
TONE knobs. You can also adjust the Tremolo type and the DEPTH and RATE parameters. Once
you have made a change, the engage/bypass LED will begin to blink.
•To save your preset, hold down the footswitch until the LED blinks rapidly 3 times.
•Now, each time the effect is engaged and in that Effect Switch position, the saved preset will be
recalled.
•You may save one preset in each of the three switch positions for a total of three.
•One preset can be saved in each of the three Effect Switch positions.
•Additional parameters can be accessed when creating True Spring presets, using the Neuro
Desktop Editor and Neuro Mobile App. Go to the Neuro Desktop Editor section for info a
creating and saving presets.
Editing a Preset
•Activate preset mode. The engage/bypass LED will be solid red.
•Select a preset with the Effect Toggle Switch and change any parameter you wish. Once you
have made a change, the engage/bypass LED will begin to blink.
•When you are ready to save, press and hold the footswitch for a few seconds. The LED will blink
three times to show that the preset was saved.
Quick Preset Switching
Using the Neuro Mobile App or Desktop Editor, it is possible to configure an option that speeds up
the process of switching between Standard and Preset Mode. To make this change go to the Neuro
Hardware Options page and select “On” from the “Quick Change to Preset Mode” dropdown menu.
In this mode, Preset Mode activates in 800 ms instead of 5 seconds.

SA247 True Spring Reverb User Guide 16
Universal Bypass TM
Most effect pedals offer either true bypass or buffered bypass. The True Spring Reverb contains two
separate circuits for bypass mode, allowing you to choose the method you prefer. The true bypass
path uses signal relays, which are electromechanical switches. This provides an ultra-low resistance
path from the input jacks to the output jacks, which is effectively the same as a single wire. The
buffered bypass path uses extremely low noise buffers, which provide very low output impedance
and are effective for driving long cables or long chains of effects following the True Spring’s audio
output.
Out of the box, the True Spring operates in true bypass mode. To select a different bypass mode,
open the True Spring’s Hardware Options menu in the Neuro Mobile App or Desktop Editor, then
select an option from the “Hardware Bypass Mode” pull down menu.
We recommend using the bypass method best suited for your signal chain. Ideally, the first pedal in a
signal chain is a buffered input followed by true bypass in the rest of the signal chain.
Both bypass methods have pros and cons associated with them. Buffered bypass provides consistent
input impedance so that if the source is susceptible to variations in input impedance (similar to a
guitar pickup), there won’t be a noticeable change in tone. True bypass has the benefit of providing a
dedicated hardwired bypass signal path. The True Spring features small-signal relays for true bypass
switching that offer reduced pops and clicks compared to the traditional true bypass switching
method using a mechanical switch.
I/O Routing Options (Stereo Routing)
The True Spring’s stereo inputs and outputs offer dramatic stereo effects and complex signal routing
options.
Auto Detect (Default)
By default, the True Spring automatically detects any cable connected to the stereo inputs and
outputs and sets the routing accordingly. The routing options are listed in the table below:
Input(s)
Output(s)
Routing Mode
1 only
1 only
Mono Input, Mono Output
1 and 2
1 only
Sum to Mono
1 only
1 and 2
Mono to Stereo
1 and 2
1 and 2
Stereo In/Stereo Out
Manually Selecting I/O Routing Options
The I/O Routing Mode can also be selected manually with the Neuro Mobile App or Desktop Editor.
The available routing options are listed below. The right side of each diagram shows Inputs 1 and 2,
the left side shows Outputs 1 and 2, and reverb effect processor (blue box labeled “R”) and dry signal
paths are in the center. Check the Neuro Desktop Editor for details on setting up the I/O Routing
Options.

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Stereo In / Stereo Out
Stereo tremolo/reverb is applied to Inputs 1 and 2 while maintaining dry signal separation. This mode
is also active when running a mono in / mono out rig –the processor simply ignores Input and
Output 2.
Mono To Stereo
Receives a mono signal through Input 1 and processes the dry signal and a stereo effect through
Outputs 1 & 2.

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Mono w/ Dry Through
Takes a mono signal through Input 1 and processes a wet/dry signal through Output 1 and a
completely dry signal through Output 2.
Sum To Mono
Receives a stereo input signal through Inputs 1 & 2 and sums an affected mono signal through
Output 1.

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External Loop Pre-Effect
Place an additional pedal or pedals within the True Spring’s effects loop. Connect as follows: plug
your guitar into Input 1 of the True Spring, run the signal from Output 2 of the True Spring to the
input of the external pedal, from the output of the external pedal to Input 2 of the True Spring, and
from Output 1 of the True Spring to your amp or the next pedal in the effects chain. Now when the
True Spring is engaged, both pedals will be active. When the True Spring is bypassed, so is the
external pedal.
Check the Neuro Desktop Editor for details on setting up the I/O Routing Options.
External Control
The CONTROL INPUT port opens a variety of external control options, allowing for direct control over
many of the True Spring’s parameters. It is an input for the Source Audio Dual Expression Pedal,
Reflex Universal Expression Pedal, Source Audio Tap Switch, or a data port for the Neuro Hub.

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Expression Control
The True Spring’s effects parameters can be controlled directly by an expression pedal or Hot Hand
connected to the CONTROL INPUT port.
Expression Pedal Input
Many parameters of the True Spring Reverb can be controlled with the Source Audio Dual Expression
Pedal or Reflex Universal Expression Pedal. Connect either of these expression pedals to the Control
Input port using a 1/8” (3.5 mm) TRRS cable. By default external expression pedals control the reverb
send.
Source Audio’s expression pedals are configured as follows: the tip connection is power, the first ring
is the X axis expression signal, the second ring is the Y axis expression signal, and the sleeve
connection is ground.
Third party expression pedals can be used as well, as long as they have a 1/8” (3.5 mm) TRS (Tip Ring
Sleeve) plug with power on the tip, expression (the wiper of the potentiometer) on the ring, and
ground on the sleeve, as seen in the diagram below.
Expression pedals with TS (Tip Sleeve) plugs will not work correctly with the True Spring.
The resistance of the expression pedal does not matter. The True Spring will automatically adjust
itself to the range of the expression pedal when it is configured.
Although the CONTROL INPUT port expects a 4-contact TRRS plug, it is still possible to use a 3rd party
expression pedal with a 3-contact TRS plug (Note: you should make sure the expression pedal’s TRS
configuration is the same as the graphic above). Use a 3-contact 1/4” to 1/8” (3.5mm) TRS plug
converter, the expression pedal’s output will be connected to the True Spring’s X expression input.
Ground Power
Y Exp X Exp
Ground Power
Expression