Intellijel Pedal I/O 1U User manual

Pedal I/O 1U System
Effects Pedal Send/Return & High Impedance
Instrument Input for Eurorack
Manual (English)
Covers both v1 and v2 of the Pedal I/O 1U module
Revision: 2021.11.15

TABLE OF CONTENTS
COMPLIANCE 2
OVERVIEW 3
System 4
Features 5
INSTALLATION 6
Before You Start 6
Installing Your Module 7
Connecting the Pedal I/O to a Pedal I/O Jacks 1U Module 8
Connecting the Pedal I/O to a 7U Case 9
Connecting to a 2nd Generation Audio Jacks Board 9
Connecting to a 1st Generation Audio Jacks Board 10
Connecting the Pedal I/O to a Palette Case 11
FRONT PANEL (Pedal I/O 1U) 12
Controls 12
Inputs & Outputs 13
FRONT PANEL (Pedal I/O Jacks 1U) 14
Inputs & Outputs 14
TECHNICAL SPECIFICATIONS 15
Pedal IO 1U System Manual

COMPLIANCE
This device complies with Part 15 of the FCC Rules. Operation is subject
to the following two conditions: (1) this device may not cause harmful
interference, and (2) this device must accept any interference received,
including interference that may cause undesired operation.
Changes or modifications not expressly approved by Intellijel Designs,
Inc. could void the user’s authority to operate the equipment.
Any digital equipment has been tested and found to comply with the
limits for a Class A digital device, pursuant to part 15 of the FCC Rules.
These limits are designed to provide reasonable protection against
harmful interference when the equipment is operated in a commercial
environment. This equipment generates, uses, and can radiate radio
frequency energy and, if not installed and used in accordance with the
instruction manual, may cause harmful interference to radio
communications.
This device meets the requirements of the following standards and
directives:
EMC: 2014/30/EU
EN55032:2015 ; EN55103-2:2009 (EN55024) ; EN61000-3-2 ;
EN61000-3-3
Low Voltage: 2014/35/EU
EN 60065:2002+A1:2006+A11:2008+A2:2010+A12:2011
RoHS2: 2011/65/EU
WEEE: 2012/19/EU
Pedal IO 1U System Manual

OVERVIEW
Eurorack is a synthesist’s toy chest. Stompboxes are a guitarist’s toy chest. Each industry offers a
seemingly infinite variety of products that enable musicians to build systems unique to their needs,
and to create a signature sound. Each is also somewhat addictive. Rare is the musician who
doesn’t eventually need a larger toy chest to house the accumulated toys.
Fortunately for the budget conscious musician, Eurorack modules and stompboxes have always
existed in separate worlds — someone whose eurorack system consumes an entire wall in their
home is usually not the same person whose pedalboard now requires a dedicated roadie just to
transport it to the gig.
But those worlds have now collided. Thanks to the release of the Pedal I/O 1U system, Intellijel has
knocked down the barrier between eurorack and stompbox. This seemingly innocuous little product
is both a modular synthesist’s portal to stompbox nirvana, and a guitarist’s wormhole to the sonic
manipulations of eurorack modules.
The Pedal I/O 1U system enables the modular synthesist to interact with the impressive assortment
of delays, choruses, flangers, phasers, fuzz boxes, tremolos, wah-wahs, amp simulators,
compressors and pitch shifter pedals available to guitarists. Conversely, it also grants guitarists
access to the myriad filters, ring mods, wavefolders and — most importantly — the near infinite CV
modulation delights inherent in eurorack.
Pedal IO 1U System Manual

System
A complete Pedal I/O solution requires two components:
1. APedal I/O 1U Module:
The Pedal I/O 1U module houses all the necessary gain and
impedance-matching circuitry, and version 2 includes switches
for inverting phase and selecting between pedal level or
instrument level signals. It features a pair of ⅛” jacks for
interfacing with eurorack modules, and ships with a 3-pin link
cable for connecting to one of several available ¼” jack options,
as detailed below.
2. A pair of ¼” jacks (one send, and one return) for connecting your pedal. There are several ways
to acquire these jacks, including:
Pedal I/O Jacks 1U Module
If you don’t own an Intellijel case with built-in ¼” jacks (or if you
prefer to use those jacks or other purposes), you’ll need to purchase
aPedal I/O Jacks 1U, which connects directly to the Pedal I/O 1U,
and provides a pair of ¼” in/out jacks for connecting stompboxes,
guitars, or instruments.
Palette Case
If you own an Intellijel Palette case, you can connect the Pedal
I/O 1U module directly to a pair of its built-in ¼” jacks, rather than
purchasing a Pedal I/O Jacks 1U module.
7U Case w/ 2nd Generation Audio Jacks Board
If you own an Intellijel 7U case with a 2nd generation
Audio Jacks Board (distinguished by the row of shrouded headers
along its bottom edge), you can use its jacks rather than purchasing
aPedal I/O Jacks 1U module.
7U Case w/ 1st Generation Audio Jacks Board
If your Intellijel 7U case has a 1st generation Audio Jacks Board,
you have two options:
1. Purchase a 2nd gen Audio Jacks Board to replace the 1st.
2. Purchase the Pedal I/O 7U 1st Gen Case
Adapter, which allows you to connect a pair of
Pedal I/O 1U modules to a 1st generation
Audio Jacks Board.
Pedal IO 1U System Manual

Features
● Signals arriving at the Pedal I/O System through the RETURN jack (or from your case’s IN jack
if using a 7U or Palette case) pass through a Class A triode emulator, allowing for some
tube-like overdrive at high gain setting.
● The Pedal I/O is more than just a simple level shifter — it’s also an impedance converter, which
provides proper drive and loading for any FX pedals or instruments you connect.
● Separate gain controls on both the SEND and RETURN. This enables you to adjust the level of
any audio being sent to the FX pedals as well as any audio coming back into the modular. Not
only does this allow you to optimize the signal-to-noise ratio, but by significantly boosting the
RETURN level, you can achieve some pleasingly overdriven tones.
● Supports both Pedal Level and Line Level signals via a front panel switch (version 2 only).
● Use the Pedal I/O’s RETURN circuit as a “direct box” for connecting any instrument.
● The high input impedance of the RETURN circuit allows it to be used as a piezo pickup preamp
for acoustic instruments.
● Use Pedal I/O in the studio as an active “re-amping” device to play pre-recorded tracks back
through guitar amplifiers or pedals.
● All inputs are protected for minimum RF interference.
● Return signal can be phase inverted for use with those pedals or effects types that invert phase
(version 2 only).
● Low MIX output impedance for driving long cables, lower noise, and minimum interference from
outside sources.
Pedal IO 1U System Manual

INSTALLATION
This module is designed for use within an
Intellijel-standard 1U row, like that contained
within the Intellijel 4U, 7U, and Palette cases.
Intellijel’s 1U specification is derived from the
Eurorack mechanical specification set by
Doepfer, which is designed to support the use of
lipped rails within industry standard rack heights.
Before You Start
Intellijel Eurorack modules are designed to be used with a Eurorack-compatible case and power
supply. We recommend you use Intellijel cases and power supplies.
Before installing a new module in your case, you must ensure your power supply has a free power
header and sufficient available capacity to power the module:
● Sum up the specified +12V current draw for all modules, including the new one. Do the same for
the -12 V and +5V current draw. The current draw will be specified in the manufacturer's
technical specifications for each module.
● Compare each of the sums to specifications for your case’s power supply.
● Only proceed with installation if none of the values exceeds the power supply’s specifications.
Otherwise you must remove modules to free up capacity or upgrade your power supply.
You will also need to ensure your case has enough free space (hp) to fit the new module. To
prevent screws or other debris from falling into the case and shorting any electrical contacts, do not
leave gaps between adjacent modules, and cover all unused areas with blank panels. Similarly, do
not use open frames or any other enclosure that exposes the backside of any module or the power
distribution board.
You can use a tool like ModularGrid to assist in your planning. Failure to adequately power your
modules may result in damage to your modules or power supply. If you are unsure, please contact
us before proceeding.
Pedal IO 1U System Manual

Installing Your Module
When installing or removing a module, always turn off the
power to the case and disconnect the power cable. Failure
to do so may result in serious injury or equipment damage.
Ensure the 10-pin connector on the power cable is
connected correctly to the module before proceeding. The
red stripe on the cable must line up with the -12V pins on
the module’s power connector. The pins are indicated with
the label -12V, a white stripe next to the connector, the
words “red stripe”, or some combination of those indicators.
Some modules have shrouded headers to prevent
accidental reversal.
Most modules will come with the cable already connected,
but it is good to double check the orientation. Be aware that
some modules may have headers that serve other purposes
so ensure the cable is connected to the right one.
The other end of the cable, with a 16-pin connector,
connects to the power bus board of your Eurorack case.
Ensure the red stripe on the cable lines up with the -12V
pins on the bus board. On Intellijel power supplies the pins
are labelled with the label “-12V” and a thick white stripe,
while others have shrouded headers to prevent accidental
reversal:
If you’re using another manufacturer’s power
supply, check their documentation for instructions.
Before reconnecting power and turning on your
modular system, double check that the ribbon cable
is fully seated on both ends and that all the pins are
correctly aligned. If the pins are misaligned in any
direction or the ribbon is backwards you can cause
damage to your module, power supply, or other
modules.
After you have confirmed all the connections, you
can reconnect the power cable and turn on your modular system. You should immediately check
that all your modules have powered on and are functioning correctly. If you notice any anomalies,
turn your system off right away and check your cabling again for mistakes.
Pedal IO 1U System Manual

Connecting the Pedal I/O to a Pedal I/O Jacks 1U Module
The Pedal I/O 1U module ships
with a 3-wire link cable. Use this
to connect the Pedal I/O to either
aPedal I/O Jacks module or to a
compatible case with built in ¼”
jacks.
If you purchased the
Pedal I/O Jacks module, simply
connect it to the Pedal I/O
module with the link cable as
shown to the right.
The connectors are keyed, so
you can orient them only one way — ensuring that you can’t connect the cable backwards. The
Pedal I/O Jacks does not require power, and the link cable is long enough that the two modules
don’t have to be installed side-by-side if you don’t wish.
NOTE: Never use the 3-wire link cable to connect a Pedal I/O module to an Intellijel Mixup module.
Although both modules use this same cable/connector — they serve different purposes and carry
different signals.
Pedal IO 1U System Manual

Connecting the Pedal I/O to a 7U Case
The Pedal I/O 1U module ships with a 3-wire link cable. Use this to connect the Pedal I/O to either a
Pedal I/O Jacks module or to a compatible case with built in ¼” jacks.
If you’re connecting to a 7U case, first determine whether it has a 1st or 2nd generation Audio Jacks
board. 1st gen boards (included with cases built before early 2019) have a single connector (other
than the power connector). 2nd gen boards have a large shrouded header flanked by two smaller
shrouded headers, flanked by two link connectors at either end.
Connecting to a 2nd Generation Audio Jacks Board
If your case has a 2nd generation board, you can
connect the link cable directly between the
Pedal I/O 1U module and one of the two link
connectors on your Audio Jacks Board.
The connectors are keyed, so you can orient them
only one way.
The left connector sends/returns from the left pair of
jacks and the right connector sends/returns from the
right pair of jacks. You can connect two Pedal I/O’s to a
single Audio Jack board if you wish.
Pedal IO 1U System Manual

Connecting to a 1st Generation Audio Jacks Board
If your case has the 1st generation board, you have two choices:
A) Purchase and install a 2nd generation Audio Jacks Board. This has the advantage of providing
you with greater flexibility, allowing you to mix and match which modules you wish to connect to
the jacks.
B) Purchase a Pedal I/O 7U Case Adapter, which connects to the single connector on a 1st
generation audio jacks board, enabling you to use it with a pair of Pedal I/O 1U modules.
If you chose to purchase the
Pedal I/O 7U Case Adapter,
simply connect it to the
Pedal I/O module with the link
cable as shown to the right.
Note that you can connect two
Pedal I/O modules to a single
Pedal I/O 7U Case Adapter.
Next, plug the Pedal I/O 7U Case
Adapter into the your case’s first
generation Audio Jacks Board, making
sure to align the white lines on the two
boards, as shown to the right.
Pedal IO 1U System Manual

Connecting the Pedal I/O to a Palette Case
The Pedal I/O 1U module ships with a 3-wire link cable. Use this to connect the Pedal I/O to either a
Pedal I/O Jacks module or to a compatible case with built in ¼” jacks.
If you’re installing the Pedal I/O 1U in a
62 HP Palette case, simply connect the
link cable directly between the Pedal I/O
1U module and the single 3-pin link
connector on your Palette case’s circuit
board. The connectors are keyed, so you
can orient them only one way — ensuring
that you can’t connect the cable
backwards.
If you’re installing the
Pedal I/O 1U in a
104 HP Palette case, you
can choose which pair of ¼”
jacks you want associated
with the Pedal I/O, and each
pair has its own 3-pin link
connector on the Palette’s
circuit board.
Pedal IO 1U System Manual

FRONT PANEL (Pedal I/O 1U)
Controls
[A] SEND LEVEL knob - Adjusts the level
of the signal arriving at the Pedal I/O’s
IN jack before it’s sent out of your
modular and into your FX pedals (by
way of either the ¼” SEND jack on the
Pedal I/O Jacks, or a ¼” OUT on a
compatible case).
[B] RETURN LEVEL knob - Adjusts the
signal level coming back into the
modular from your external effects
pedals, or from an instrument plugged
directly into either the ¼” RETURN jack
on the Pedal I/O Jacks, or a ¼” IN on a
compatible case.
[C] PHASE INVERT switch - In the DOWN
position, the return signal is in phase. In
the UP position, the return signal is 180
degrees out of phase. Some pedals
invert phase, so this switch is useful
when balancing the dry (send) and wet
(return) signals with the MIX knob.
NOTE: This switch was added on Version 2, and is not on Version 1 of the Pedal I/O 1U.
[D] CLIP Indicator LED - This LED monitors the signal level coming back into the modular from
either your external effects pedals, or from a connected instrument input. It lights slightly before
clipping, giving you a bit of headroom before actual clipping occurs. This lets you maximize
levels by allowing the CLIP LED to light occasionally on the highest peaks. But as with all things
musical — use your ears as the deciding factor!
[E] MIX (DRY/WET) knob - Determines the wet/dry balance of the signal sent to the module’s MIX
output. Fully counterclockwise, only the DRY (unprocessed) signal is heard in the MIX. Fully
clockwise, only the WET (processed) signal is heard in the MIX. At the noon position, equal
amounts of WET and DRY appear in the MIX.
NOTE: Not every pedal is designed to have its input signal mixed in with its output. Some (for
example, phase shifters) may return a signal that is out of phase with the original audio, so
balancing the Wet & Dry levels could result in phase cancellation. In such cases, you’ll probably
want to set the MIX knob to maximum wetness.
Pedal IO 1U System Manual

[F] PEDAL/LINE level switch - Sets whether
the signal levels sent to the external
device are driving a guitar PEDAL, or
LINE level, pro audio gear.
NOTE: This switch was added on
Version 2, and is not on Version 1 of the
Pedal I/O 1U.
Inputs & Outputs
[1] IN - Connect the audio signal you want
processed by your external pedals to the
IN jack. Modular-level audio arriving at
this jack is converted to the appropriate
signal level (switchable between
“line-level” or “pedal-level”, if using a v2
Pedal I/O) and impedance-matched
before it’s sent to either the
Pedal I/O Jacks’ SEND jack or to the ¼”
OUT jack on a compatible case.
[2] MIX - Any audio that’s returned from your
FX pedals is converted back to modular-level and impedance-matched prior to appearing here
at the MIX jack. If you plug a guitar or other instrument into the Pedal I/O Jacks’ RETURN jack
(or into a ¼” IN jack on a compatible case), then the modular-level and impedance-matched
signal from that instrument appears at the MIX jack.
Pedal IO 1U System Manual

FRONT PANEL (Pedal I/O Jacks 1U)
Inputs & Outputs
[1] SEND - Connect a ¼” instrument cable from the SEND jack
to the input of your external FX pedal. If using the first
version Pedal I/O, then audio coming out the SEND jack is
an instrument-level & impedance-matched version of the
modular-level audio signal you connected to the Pedal I/O
module’s IN jack. If using v2 of the Pedal I/O, then the
audio is switchable between line and pedal levels.
NOTE: This is an unbalanced TS cable (standard for
guitars and FX pedals), though you can use TRS cables —
you just won’t get any benefit from doing so.
[2] RETURN - Connect a ¼” instrument cable from the output
of your external FX pedal to the RETURN jack on this module. The audio arriving at this jack is
impedance-matched and converted to modular-level by the Pedal I/O module, where it’s then
made available at that module’s MIX jack.
You can also plug a guitar or other instrument directly into the RETURN jack and process it with
your modular synth. This is a high impedance input, allowing the Pedal I/O system to act as a
piezo pickup preamp for acoustic instruments. Audio arriving at the RETURN jack passes
through a Class A triode emulator (enabling anything from clean to tube-like distortion) and an
impedance converter and level shifter to insure full integration in a modular synth environment.
NOTE: This is an unbalanced TS cable (standard for guitars and FX pedals), though you can
use TRS cables — you just won’t get any benefit from doing so.
Pedal IO 1U System Manual

TECHNICAL SPECIFICATIONS
Pedal I/O IN jack:
● Input level = 0 dBV nominal, +17 dBV max
● Input impedance = 60 KΩ
● Gain = -30 dB to -20 dB
● RF filter protected
Pedal I/O Jack SEND (or 7U Case Adapter OUT):
● PEDAL MODE: Output level = -20 dBV to -30 dBv nominal based on Send Level
● LINE MODE: Output level = +5 dBV to -5dBv nominal based on Send Level
● Output impedance = 12 KΩ to simulate the impedance of magnetic guitar pickup
Pedal I/O Jack RETURN (or 7U Case Adapter IN):
● Input level = -20 dBV to -30 dBV nominal based on Return Level
● Input impedance = 1 MegΩ
● Return Gain = fully off to +30 dB
● RF filter protected
Pedal I/O MIX jack:
● Output level = 0 dBV nominal, +17dB max
● Output impedance = 100Ω
● Frequency response is 20Hz to 22KHz
● THD = 0.002% to 0.085% at Vin = 0dBV to +17dBV
(Pedal In to Pedal Out, Mix = effect, Return Level = min, Send Level = max)
THD = 0.04% to 4.0% at Vin = 0dBV to +17dBV
(Pedal In to Pedal Out, Mix = effect, Return Level = max, Send Level = max)
Dimensions & Current Draw:
Pedal I/O Width
Pedal I/O Jacks Width
16 hp
8 hp
Pedal I/O Maximum Depth
Pedal I/O Jacks Depth
29 mm
44 mm
Current Draw
10 mA @ +12V
10 mA @ -12V
Pedal IO 1U System Manual