KHE AUDIO ELECTRONICS ACS Series User manual

V1.0 2020-05-08 www.KHE-AudioElectronics.com
KHE AUDIO ELECTRONICS
AMPLIFIER CABINET SELECTOR
ACS – Series
A Switching-System for Guitar Amplifiers, Speaker
Cabinets and Load Boxes.
"... focus on your sound and creativity, instead of wasting your time with
plugging cables and waiting for amps to heat-up!"
IMPORTANT: READ THIS MANUAL BEFORE USING THE SWITCHER !
USER MANUAL

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For reasons of the product liability, we are obligated to make clear certain safety aspects which must not be
ignored under any circumstances:
- Read, retain, and follow all instructions. Heed all warnings.
- To prevent damage, fire or shock hazard, do not expose this unit to rain or moisture. Do not use this
product near water or any other liquids.
- This product should be located away from heat sources such as radiators, heat registers, etc.
- Unplug the power supply before cleaning the unit exterior. Use a dry cloth only. Wait until the unit is
completely dry before reconnecting it to the power supply.
- Maintain unobstructed air space behind and above the unit for proper ventilation and cooling.
- Protect the power supply and all attached cables from being pinched or abraded.
- The power supply of this product should be unplugged from the outlet when left unused for a long
period of time or during storm weather.
- Use only the power supply supplied with the unit.
- Install in accordance with the manufacturer's instructions
- Keep these instructions for future reference.
CAUTION: If the unit becomes physically damaged due to dropping or for other reasons, it should be returned
to the factory for repair to avoid the risk of further damage to the unit or to attached units. No user serviceable
parts inside. Warranty is void if device gets modifyed by unauthorized personal. In case of malfunction or
mechanical damages, please contact KHE Audio Electronics for further assistance.
By purchasing and using this product, you clearly understand that you are taking full responsibility for the use
of this product.
KHE Audio Electronics accepts no responsibility (consequential or inconsequential) for damage or injury caused
by improper connections, improperly grounded amplifiers, user error, or injury caused by failure of the ACS or
any component inside the ACS. Use of the ACS implies that the owner/user clearly understands and agrees to
all of the terms stated within this user manual, has decided to use the ACS under these terms, accepts full
responsibility for any damage or injury, and waives his/her rights to a liability claim against KHE Audio
Electronics (or associated companies or directors) for any damage or injury caused while using the ACS. As it
is impossible for KHE Audio Electronics to ensure the user is following these instructions, the user must take
full responsibility in the suitability of purchasing a KHE product for his or her use.
The device serves for routing guitar and amplifier signals as well as for controlling amplifiers, speaker cabinets
and load boxes, and must be used exclusively for this purpose.
KHE AUDIO ELECTRONICS IS NOT RESPONSIBLE FOR ANY DAMAGE TO YOUR AMPLIFIER THAT MAY OCCUR IN
CONNECTION WITH ANY USE OF THE ACS.
SAFTEY PRECAUTIONS
WARNING & LIABILITY NOTICE

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Congratulations on your purchase of a KHE Amplifier Cabinet Selector !
The KHE ACS is a switching and routing system for guitar amplifiers, speaker cabinets and load boxes.
Connect them to the ACS, power them up, and you are ready to go : Switch and play between all
your amps, speakers and loadboxes by a single push of a button. Use stompboxes like boosts and
overdrives with all amplifiers, and share effect pedals like delays or gates in the fx-loops of all
amplifiers. No need to interrupt or stop playing - switch all amps and cabs on the fly !
The KHE ACS-Series is the ultimate solution for any situation where more than one amp or cab is
available : recording studios, reampers & profilers, gear enthusiasts & collectors, music stores &
showrooms, amp manufacturers, repair shops, gear reviews & comparisons and live musicians.
The KHE ACS-Series features an extensive product line-up with a total of 7 different switchers,
providing the perfect switching configuration for any kind of setup or application. All switchers can
be dasy-chained and linked together to create the most flexible switching system possible. This
manual covers all 7 switchers and their use, functions and features.
To take advantages of all the features that have been implemented into the ACS, please take your
time to read through this manual before you use the switcher. If you have any questions that are not
answered in this manual, please refer to the FAQ section on our website. If you have any questions
or feedback, please contact us at [e-mail] .
RULES OF OPERATION
NEVER change cable wiring while ACS, amps or load boxes are powerd ON.
NEVER unplug any connections of an amplifier that is connected to the ACS while the amplifier is on.
NEVER unplug the amplifier input cable and never plug the guitar cable straight in the amp input.
NEVER exceed the maximum amplifier & load power rating.
NEVER unplug a power attenuator in the power attenuator insert while the ACS is ON.
ALWAYS power-on the ACS before the connected equipment.
BE CAREFUL when using built-in time-based effects in amps like reverb or delay. Always make sure to either
A) turn the effect pedal off before disableing or changing an amp or
B) let the effect completely ring out before disabeling / changing the amp.
 These rules also apply to permanentely connected effect pedals in the fx-loop of a single amplifier.
Ignoring these rules can damage the ACS or the connected equipment.
INTRODUCTION

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Controls & Display 5
Guitar Input 6
Amplifier Switching 6
Cabinet & Load Switching 7
Attenuator Insert 8
FX-Loop Switching 9
Tuner Output 10
Re-Amping 10
Ground Lift 10
Recall Mode 10
Setup Procedure 11
ACS 4x2 12
ACS 4x4 12
ACS 4x4 FX 12
ACS 8x4 12
ASX 8 13
CSX 8 13
AFX 8 14
Feature List 14
MIDI Control 15
Link Mode 16
Link Mode – Setup Examples 18
Setup Menu 19
Things To Know 20
Technical Specifications 22
Warranty 22
Declaraction Of Conformity 23
TABLE OF CONTENT

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AMPLIFIER SWITCHES
Switches to enable, disable or change amplifiers. No need to disable an amplifier before activating a different
one – the ACS manages the complete switching procedure! Amplifiers can not be enabled if no cabinet is
activated. All amplifiers are protected by an internal load resistor. The leds shows the current status:
 RED: Amplifier activated
 OFF: Amplifier deactivated
CABINET SWITCHES
Switches to enable, disable and change cabinets and loads. Up to 2 load devices can be activated in parallel
Cabinet jacks are supervised for a speaker cabinet or load box. Unused cabinet jacks are automatically excluded
and locked from the switching operation, so amps can never be switched to an unused cabinet jack. In case a
cabinet gets deactivated while an amp is still on, the ACS will disable the activated amp automatically before
removing the load. The leds shows the current status of the cabinet output:
 RED: Cabinet activated
 DIM: Cabinet deactivated
 OFF: no load connected
FX SWITCH
Switches to bypass or activate connected fx-loops and effect pedals. The state of the fx-loop gets saved and
recalled automatically when switching amplifiers. The leds shows the current status of the fx-loop:
 RED: FX-Loop activated
 OFF: FX-Loop deactivated
CTRL SWITCH
Switch to control System Functions & Midi Settings. The leds shows the current status of the ACS:
 RED: Standalone Mode
 GREEN: Link Mode
 OFF: Power Off
 RED / GREEN, blinking: Link Mode – Setup Error
 RED, blinking: MIDI PC – Preset Changed
 ORANGE, blinking: System Error
POWER SWITCH
Switch to power on the ACS. Amplifiers are always protected by an internal load resistor, even when the
power-switch is off.
CONTROLS & DISPLAY

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The KHE Amp Switchers features two guitar inputs, one on the
front panel and one on the rear panel. The front input has
higher priority than the rear input.
The KHE ACS guitar input works perfectly with reamping boxes,
stomboxes like overdrives, boosts and distortions and effect
pedals like delays or reverb.
The KHE Amp Switchers let you switch between mono guitar amplifiers. Instantly, by the single push of a
button. No need to stop or interrupt playing. The signal path of the ACS is completely transparent and
extremely low-noise. It does not color the sound of your amplifiers in any way.
WIRING
 Connect the guitar inputs of the amplifier to the black AMP INPUT jacks.
Use high-quality shielded unbalanced instrument cables only.
 Connect the speaker outputs of the amplifier to the blue AMP OUTPUT jacks.
Use high-quality speaker cable only (we recommend 1,5mm2).
NOTES
 The KHE ACS is compatible with any kind of mono amplifier, up to 150 watts per channel :
Tube, solid-state, (bridged) class-d, heads and xombos.
 Amplifiers can not be activated if no cabinet ouput is activated.
 All amplifiers are protected by an internal load resistor and the unused amps are muted at their input,
so no singals can reach the power amp.
 A special mute circuit removes all switching noise like clicks and pops - switching between amps or
loads is more silent than most amps channel switching!
GUITAR INPUT
AMPLIFIER SWITCHING

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The KHE Amp Switchers let you switch between load devices like speaker cabinets and load boxes. Instantly by
the single push of a button. No need to stop or interrupt playing.
WIRING
 Connect the load devices to the red CABINET jacks.
Use high-quality speaker cable only (we recommend 1,5mm2).
 Once a load gets connected, the corresponding LED on the front panel will light up in a dimmed red
state. This indicates a load got detected and the output can now be activated.
NOTES
 The KHE ACS is compatible with any kind of load device up to 150 Watts per channel :
Speaker Cabinets, reactive and resistive Load Boxes, active Load Boxes and Combo Speakers.
 The Dual Cab Mode lets you activate and play two speaker cabinets or load boxes in parallel.
Activate the Dual Cab Mode by entering the SETUP MENU and push AMP-SWITCH 2. See « SETUP
MENU » for more details.
 The load switching is completly passive with no active components. High-quality relays were used for
the switching procedure.
CABINET & LOAD SWITCHING

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The Attenuator Insert is an post-amplifier pre-speaker insert loop. It lets you use an power attenuator across all
amps and attenuate the volume of all amps simuntaneously, and switch the attenuated output signal to all
connected cabinets or loads. The Attenuator Insert feautre is disabled by default (both S-LINE send and S-LINE
jacks are wired in parallel). By activating the Attenuator Insert Loop, the parallel connection of these jacks will
be removed so they can be used as a serial insert loop.
WIRING & SETUP
To activate the Attenuator Insert, follow this setup procedure:
1) Turn off the ACS and all amps and attenuators.
2) Connect the Input of the Attenuator to the white S-LINE SEND jack of the ACS. This connection sends
the speaker-signal from the amplifier to the input of the power attenuator device.
3) Connect the Output of the Attenuator to the white S-LINE RETURN jack of the ACS. This connection
sends the attenuated speaker signal back to the ACS to be switched to a speaker cabinet.
4) Power on the ACS and activate the Attenuator Insert funtion by entering the SETUP MENU and push
AMP-SWITCH 4. In case no attenuator is connected, the insert loop won’t be activated (AMP-LED 4
will blink four times). See « SETUP MENU » for more details. Don’t miss this step!
WARNING
 Connecting an attenuator without having the Attenuator Insert activated may damage your amps
and attenuators!
 Never change the wiring of the S-Line Jacks while the ACS, the attenuator and the amps are powerd
on! Removing the connected attenuator while the ACS is on can lead to no-load scenarios !
 When using active attenuators, such as Boss Waza TAX, make sure to power-on the ACS before the
attenuator or turn the ouput volume down while the ACS is powerd off. Otherwhise oscillations
may happen on the attenuator.
NOTES
 The KHE ACS is compatible with all type of attenuators : Boss Waza Tube Expander, UA OX Top Box,
Palmer Power Pad, SPL Reducer, Harley Benton PA-100, Bugera PS1, TAD Silencer, Jet City Attenuator,
Weber Attenuators, Koch Attenuators, THD Hotplate, Rivera Attenuators and many more.
ATTENUATOR INSERT

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 Like the cabinet jacks, the Attenuator Insert gets supervised for a proper load. If no attenuator is
connected, it wont get activated (error shown by 5x blinking the Amp4-Led).
 The state of the attenuator insert function gets saved and recalled when powering up the ACS.
 When linking multiple ACS together, the Attenuator Insert feature will be limited, as the S-LINE jacks
will used for the linking of the speaker lines. If you want to use the Attenuator Insert in Link Mode,
shoot us a message to discuss setup possibilities.
The FX-LOOP SWITCHING is an optional feature for the KHE ACS:
Route your pedal board and all the amplifiers fx-loops thru the ACS and share effect pedals like delays, gates,
reverb, chorus, eq and multi-fx pedals with all amps. You can even hook up a dedicated pedal-switching system
and create the most flexible setup possible.
CONTROL
The FX-Loops can be true-bypassed on the ACS: Push the FX button on the frontpanel short to toggle the FX
state. The ON/OFF state gets saved and automatically recalled when switching amps. All fx-switching functions
can be controlled via MIDI.
WIRING: FX-Loop
 Connect the fx-send jack of the amplifiers to the black FX-LOOP SEND jacks of the ACS.
 Connect the fx-return jack of the amplifiers to the black FX-LOOP RETURN jacks of the ACS
WIRING: Effect Pedals
 Connect the input jack of the effect pedals to the black FX-INPUT jack of the ACS.
 Connect the output jack of the effects pedals to the black FX-OUTPUT jack of the ACS.
NOTES
 Proper gain-staging of the amps is very important when using delay pedals: make sure all the amps
send a similar signal level out of the fx-loop send. Otherwise, there is a change of nasty sounds while
switching amps, because of the different signal levels saved in the delay. This is highly dependent on
FX-LOOP SWITCHING

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the construction of the amp (channel-volume, master volume, fx-level) and probably needs some trial
and error.
 Clean power sources & wiring is needed to make the fx-loop switching work without noise, hum, or
clicking.
 Gates in the fx-loops can be side-chained from the tuner output of the ACS. Make sure to use a
isolated power-source with only the gate powerd by this power output. Depending on the gate circuit,
this may can cause a slight hum (ground-loop). If this is the case, it’s best to use an isolation
transformer at the key-input to remove any ground-loops.
 When setting everything up, start small with only 1 pedal, test, add another pedal, test, and so on.
This way it’s easy to identify problems with wiring / pedals / power sources.
 The switching path is completly passive with no active components in the signal path. High-quality
relays were used for the switching procedure.
 The FX-Loop switching feature does not add fx-loops to amplifiers without one!
The TUNER OUTPUT lets you feed a guitar tuner in parallel to the input signal. The buffered input signal is
always present at the tuner output jack.
The tuner output can also be used to record a clean di-track of your guitar, simultaneously to the amplified
track. The tuner output can also be used to side-chain a key input of a gate pedal in the fx-loops of the
amplifiers.
The KHE ACS plays very nicely along with re-amping setups. Connect the DI output signal from your DAW to the
GUITAR INPUT on the rear of the ACS by a reamping box to feed your entire amp collection. You can override
and disable the rear input signal by plugging in the guitar directly into the front guitar input of the ACS.
The GROUND LIFT helps to eliminate hum and buzz from sub-optimal grounding schemes.
Activate the GROUND LIFT by entering the SETUP MENU and push AMP-SWITCH 3. See « SETUP
MENU » for more details.
In case ground loops occur, NEVER defeat or remove or an amplifiers safety ground, PROTECTIVE EARTH,
which is provided by the 3-prong AC power-cord plug! Doing so may not only be ILLEGAL, but it may also
pose a SHOCK or ELECTROCUTION HAZARD.
The RECALL MODE automatically loads the last activated configuration on start-up of the ACS.
 Activate the RECALL MODE by entering the SETUP MENU and push AMP-SWITCH 1. See « SETUP MENU » for
more details.
 In case a configuration cannot be loaded (due missing or removed cabinet), the amplifier won’t be
enabled. The Recall Mode gets deactivead automatically once the LINK MODE gets activated.
TUNER OUTPUT
RE-AMPING
GROUND LIFT
RECALL MODE

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For an easy and quick setup of the ACS systems, follow a simple setup procedure:
 Study this manual in detail before using the ACS, making sure you understand functions, features
and wiring correctly and as intended.
 Start with the most simple and basic setup. Hook up one amp and one cab, and verify all functions.
 Add more amps and cabs step by step, always testing and verifying.
 Add more complex elemens such as Load Boxes, Attenuators, Reamping Boxes and Effect Pedals
last, after verifying the basic operation of the system. Add them step by step, and always making
sure the wiring is correct and the system operates correctly.
INITIAL SETUP PROCEDURE
1) Make sure all amplifiers and the ACS are powered OFF and the volume turned down.
2) Power on the ACS.
3) Connect all load devices to the ACS.
4) Connect the amplifiers inputs and outputs one by one to the ACS :
5) Verify the cabeling once again, make 100% sure there is no misrouting or cable mixup.
Misrouting can damage the amplifiers and the ACS!
6) Activate one cabinet output by pressing the switch on the frontpanel
7) Power-on the first amplifier and activate the amp by pressing the switch on the panel.
8) Slowly turn-up the volume control on the selected amp. In case there is no sound, noise or other
irregularities from your amplifier, imediately turn off the amplifier and verify the wiring and the
settings on the amplifier (volume gain etc).
9) repeat step 8) for all amplifiers
10) enjoy!
NORMAL START-UP SEQUENCE
1) Power-ON the ACS
2) Turn on the amplifiers, standby mode.
3) Let the amplifiers heat up.
4) Disable the standby mode of the amplifiers.
5) Enjoy!
RULES OF OPERATION
NEVER change cable wiring while ACS, amps or load boxes are powerd ON.
NEVER unplug any connections of an amplifier that is connected to the ACS while the amplifier is on.
NEVER unplug the amplifier input cable and never plug the guitar cable straight in the amp input.
NEVER exceed the maximum amplifier & load power rating.
NEVER unplug a power attenuator in the power attenuator insert while the ACS is ON.
ALWAYS power-on the ACS before the connected equipment.
BE CAREFUL when using built-in time-based effects in amps like reverb or delay. Always make sure to either
C) turn the effect pedal off before disableing or changing an amp or
D) let the effect completely ring out before disabeling / changing the amp.
 These rules also apply to permanentely connected effect pedals in the fx-loop of a single amplifier.
Ignoring these rules can damage the ACS or the connected equipment.
SETUP PROCEDURE

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The KHE ACS 4x2 is our most basic amp switcher for 4 amplifiers and 2 speaker cabinets or load boxes in
compact desk-style format. Features: MIDI Control, Dual Cab Mode, Tuner Output
 NOT included features: Attenuator Insert, FX-Loop Switching and Link Mode.
The KHE ACS 4x4 is an amp switcher for 4 amplifiers and 4 speaker cabinets or load boxes in compact 19” 1u
format. The KHE ACS 4x4 FX has the same switching capabilities and features like the ACS 4x4, but with added
fx-loop switching. Features: Attenuator Insert, Link Mode, MIDI Control, Dual Cab Mode, Tuner Output
The KHE ACS 8x4 is an amp switcher for 8 amplifiers and 4 speaker cabinets or load boxes in compact 19” 1u
format. FX-Loop switching functionallity can be added by adding a AFX 8 to the setup. Features: Attenuator
Insert, Link Mode, MIDI Control, Dual Cab Mode, Tuner Output
ACS 4x2
ACS 4x4 & ACS 4x4 FX
ACS 8x4

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The KHE ASX8 is an amp switcher for 8 amplifiers and a single speaker cabinet or load boxe in compact 19” 1u
format. The KHE ASX 8 Amp Switcher can be used in standalone mode with a single cabinet, or in link mode to
add 8 additional amp channels to other switching systems. The ASX 8 operates in Standalone Mode as long as
no other units are linked. In case no load is connected to the ASX’s output, the operation will be blocked and no
amps can be activated (all LED’s blink red).
CONNECTIONS
Connect the speaker cabinet or load box to the CABINET OUTPUT jack. The THRU jack is wired parallel to the
CABINET OUTPUT jack and is used to link the ASX to other switchers in link mode.
The KHE CSX 8 is a load switcher for 8 speaker cabinets or load boxes and a single amplifier in compact 19” 1u
format. The KHE CSX 8 Cab Switcher can either be used in standalone mode with 1 single amplifier, or in link
mode to add 8 additional load channels to other switching systems. The CSX 8 operates in Standalone Mode as
long as no other units are linked.
CONNECTIONS
INPUT 1-8: In Standalone Mode, connect your amplifiers speaker output to this jack. In Link Mode,
connect the other switchers S-LINE output to this jack to interconnect the load lines with the
speaker singal.
INPUT 5-8: The blue jack INPUT 5 – 8 is not used at the moment. Do not connect anything to the INPUT
5-8 jack. The use of this jack will may be activated and enabled later this year by a firmware
update.
THRU OUTPUT: This jack is connected in parallel to the INPUT 1-8 jack and is used to interconnect the load
lines in link mode.
CSX STANDALONE MODE
When the CSX 8 is used in Standalone Mode:
 a load MUST always be connected to CABINET 1 output. If no load is connected to the ASX, the
operation will be blocked and no output can be activated.
 Make sure to power on the CSX before the connected amplifier.
ASX 8
CSX 8

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The KHE AFX 8 FX-Loop Switcher can be used to expand both amp switchers ACS 8x4 and ASX 8 with 8 channel
of mono fx-loop switching. See chapter “FX-LOOP SWITCHING” for more details on how to use the fx-loop
switching feature.
CONTROL
The FX-Loops can be true-bypassed on the ACS: Push the FX/CTRL button on the frontpanel short to toggle the
FX state. The ON/OFF state gets saved and automatically recalled when switching amps. All FX-Switching
functions can be controlled via MIDI.
CONNECTIONS
The two jacks LINK FX INPUT and OUTPUT are connected in parallel to the FX INPUT and OUTPUT jack and are
used to interconnect fx-loop switchers in link mode.
SETUP PROCEDURE
The ASX 8 needs a special initial setup procedure to syncronize the ASX to a amp switcher. Before syncing a AFX
to a amp switcher, make sure to connect and activate the Link Mode. See « LINK MODE » for more details.
1) Activate an amplifier on the amp switcher which you want snyc to the AFX.
2) Push and hold the FX/CTRL button on the AFX for more than 3 seconds to enter the setup menu.
3) Release the FX/CTRL button.
4) Push and hold the FX/CTRL button on the AFX for more than 3 seconds to exit the setup menu.
 Now the AFX is syncronized to it’s amp switcher. After the first syncronization, the configuration
will be recalled automatically.
AFX 8
FEATURE LIST

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Control the ACS remotely via MIDI controllers such as footswitches, pedalboards or daw. The MIDI setup and
operation is very simple and intuitive. Load complete presets with amp and cab combinations, or control the
ACS by single commands, similar to the frontpanel switches.
MIDI CHANNEL SETTING
In the SETUP MENU, the MIDI channel of
the ACS can be set between 1 – 15. When
entering the SETUP MENU – PAGE 2, the
first 4 switches and leds from the left
represent the MIDI channel of the ACS. The
midi channel value is binary coded by the
on/off state of the led of the four switches. See “SETUP MENU” for more details.
PRESETS: PROGRAM CHANGE MESSAGES
When sending MIDI PC instructions (0xC0 / 192), you can load presets of combinations of amps, cabs and fx-
loop states. There are 100 presets avaiable, 0 - 99 (or 0x00 – 0x63). To save a preset, activate the blank preset
by sending the PC instructions with your Midi controller. Enable the wanted amp-cab combination. Now the
CTRL led starts to blink, which means that the (blank) preset got changed. To save the preset, simply push and
release the CTLR switch. Now the CTRL led is continously on and the preset is saved.
SINGLE COMMANDS: CONTROL CHANGE MESSAGES
When sending Midi CC instructions (0xB0 / 176), you can enable / disable all amps and cabs individually, similar
to the key operation at the front panel of the ACS. Send the value of 127 / 0xFE to toggle the on/off state of an
amp or cab. Midi CC instructions get filterd by the same advanced switching logic as the amp/cab switches.
 If LINK MODE is active, address each function by multiplying the MIDI CC command by it’s MIDI
Channel.
 You can toggle the FX-Loop state of the currently active amplifier by sending MIDI CC 127 or disable all
active devices by sending MIDI CC 126.
 A maximum of 10 switchers can be addressed with MIDI CC commands.
MIDI CONTROL

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The Link-Mode lets you to dasy-chain up to 15 switchers together: switch between amps and cabs across
multiple switchers, by a single push of a button (or midi-command). No need to disable already activated amps
or cabs before switching to a different one - the switchers completly takes care of that !
 create massive setups like 12x4, 16x8, 24x12, 24x1 and so on
 add the fx-loop switching to the ACS 8x4 or ASX 8
 use different versions of the ACS-Series linked together, to create your dream switcher setup (eg. ACS
4x4FX + ACS8x4 + AFX8)
All switchers constantly exchange their statuses and commands by a special communication protocol, to ensure
only one amp / cab is active at the time and no amps can be activated without a load activated. Lots of safety
measures (hardware and software) has been taken to make sure the Link Mode is 100% safe for your amps,
with no chance of activating invalid states.
The Link-Mode feature is NOT available for the KHE ACS 4x2 !
EXAMPLE : 3x ACS 8x4 in link-mode 24x12 setup.
CABLES
The Link Mode needs 3 different patch-cables types to link one switcher to another :
1x MIDI Patch Cable (for linking Communication Lines)
1x Speaker Patch Cable (for linking Speaker Lines)
1x Instrument Patch Cable (for linking Guitar Input Signal)
WARNING
Follow the setup procedure precisely, step by step. Double and triple-check the wiring of the speaker lines and
instrument lines before using the Link Mode. Mis-wiring can cause serious damage to the amplifiers and the
switchers. Be 100% sure you got this wiring right before using the Link Mode. If in doubt, do not hesitate to
send us a message and ask for assistance, we are happy to help! [e-mail]
SETUP PROCEDURE
1. Power up units
2. Set individual MIDI channels
Each switcher must have a individual MIDI channel. Set MIDI channel for all switchers in increasing order,
starting by MIDI channel #1 for device #1. Do not skip a channel, and do not use a channel twice ! See « MIDI
CONTROL » for more details.
3. Power down all units
4. Setup communication lines
Link all switchers together by a short 5-Pin MIDI cable. Connect CTRL-OUT from device #1 to CTRL-IN from device
#2. Repeat this wiring scheme for any number of switchers. The communication lines are used and needed to let
the switchers talk together (exchanging status and commands).
5. Setup speaker and load lines
Link the speaker lines of the switchers together by a short speaker patch cable (1,5mm2):
LINK MODE

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Connect S-LINE SEND from device #1 to S-LINE RETURN from device #2. Repeat this wiring scheme for any number
of switchers. Do not use instrument-type patch cables, as this line is carrying high power speaker signals.
6. Setup guitar input lines
Link the guitar inputs lines of the switchers together by a short instrument pactch cable (unbalanced, shielded) :
Connect TUNER-OUT from device #1 to GUITAR-INPUT (rear) of device # 2. Repeat this wiring scheme for any
number of switchers.
7. Power up all units
8. Check status of the CTRL-LED:
green: Network setup ok. System ready to use.
red & green: Network setup failed. Check MIDI channels and communicaiton lines.
red: Standalone mode. No switchers in network detected.
Notes
 Always plug your guitar into ACS#1.
 MIDI control by CC or PC messages works perfectly in Link Mode. You can save and recall presets
across multiple switchers.
 When Link Mode is enabled, the Recall Mode will be disabled.
 Use high-quality 5-pin MIDI cable for connecting the devices together. All 5 pins are needed !
 All linked switchers must be powerd on to activate the switching operation.
 When adding new switchers to your setup, perform a system reset prior setting up the Link Mode (to
clear any stored MIDI PC presets, to avoid possible collision of preset configurations.
FAQ Link Mode
 Can i link different versions of the ACS-Series together (eg. ACS 4x4FX + ACS 8x4 + AFX8) ?
Yes, you can link any version together, EXCEPT for the ACS 4x2 (unfortunately no more space on the
ACS 4x2 for the needed additional jacks and circuitry)
 Can i link multiple fx-loop switchers such as ACS 4x4 FX and ASX ?
Yes ! For linking multiple ACS 4x4 FX, use two y-splitter cables to connect the fx-loop lines.
 When using Link Mode, can i still use a MIDI controller to control all the switchers?
Yes, you can use a MIDI controller to control any number of switchers. Simply connect your MIDI
controller in one of the MIDI inputs. The switcher takes care of exchanging the received Midi
commands with all other switchers in the network. Please refere to XXX to learn more on how to use
and address all MIDI functions in network operation.
 Is MIDI the used communication protocol between the switchers?
No. Standard MIDI protocol is uni-directional only. In order to exchange status and commands, the
communication needs to be bi-directional, so the switchers can properly talk together (call &
response). The ACS uses a robust, industry-standard CAN communication protocoll.
 But why the MIDI connectors?
MIDI connectors are used because they already exist in most studios wall connector boxes. This way,
you can easily setup multi-room setups, connecting the switchers by already existing connections
between the rooms (for example, ASX in the control room, CSX in the recording room).
 Can i damage something if i accidentally mix-up MIDI connectors and control connectors?
No, all jacks are protected for this scenario, nothing bad will happen to the switcher or the MIDI
device.
 Can i user the Attenuator Insert in Link Mode?
When linking multiple ACS together, the Attenuator Insert feature will be limited, as the S-LINE jacks
will used for the linking of the speaker lines. If you want to use the Attenuator Insert in Link Mode,
shoot us a message to discuss setup possibilities.

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ACS 8x4 + ASX 8
ASX 8 + CSX 8
ACS 4x4 + ACS 4x4
ACS 8x4 + AFX 8
CABLES
1x MIDI Patch Cable (for linking Communication Lines)
1x Speaker Patch Cable (for linking Speaker Lines)
1x Instrument Patch Cable (for linking Guitar Input Signal)
LINK MODE – SETUP EXAMPLES

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In the setup menu, various system configurations can be set, such as: RECALL MODE, DUAL CAB MODE,
GROUND LIFT or ATTENUATOR INSERT or setting the MIDI channel of the device. All parameters and settings
are saved and get recalled on power up of the unit.
ENTER SETUP MENU
Push and hold the CTRL SWITCH more than 2 seconds. When the CTRL LED starts to blink red, release the
button.
MENU LAYERS
When the setup menu is activated, various functions are assigned to the first four switches of the ACS (usually
Amp 1 -4). These functions are distributed over two layers. The current activated layer is shown by the blink
interval of the red CTRL LED. Functions can be set by pushing the amplifier switches.
To flip between the menu layer, push the CTRL SWITCH short and release.
LAYER 1: System Functions (CTRL LED blinks 1x)
Amp-Switch 1: activates / deactivates Recall Mode
Amp-Switch 2: activates / deactivates Dual Cab Mode
Amp-Switch 3: activates / deactivated the Ground Lift
Amp-Switch 4: activates / deactivates the Attenuator Insert
LAYER 2: MIDI Channel (CTRL LED blinks 2x)
On layer 2, switches 1 – 4 represent the MIDI channel of the unit. The MIDI channel of the ACS can be
set between 1 – 15. The MIDI channel value is binary coded by the on/off state of the led of the first
four switches. Each press of switch A1 increases the MIDI channel by 1.
Examples:
MIDI Channel 1 = LED 1 ON, all others OFF
MIDI Channel 5 = LED 1 ON, LED 3 ON, all others OFF
MIDI Channel 12 = LED 3 ON, LED 4 ON, all others OFF
EXIT SETUP MENU
Push and hold the CTRL SWITCH more than 2 seconds. When the CTRL LED is continously on red, release the
button.
SETUP MENU

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INPUT BUFFER
After the guitar input jacks, a high-end impedance converter («buffer») is built into the ACS. This buffer
converts the high-impedance guitar signal into a low-impedance signal, which makes the signal more stable
and less sensitive to noise or other interference. With this buffer, the length of cables connected to the ACS
outputs doesn’t matter anymore (no signal- or high-end-loss). The buffer circuit is high-end studio-grade
quality, capable to swing output-voltages up to 15Vpp without any distortion or coloration. The input
characteristics of the buffer reproduce a classic tube input stage. This buffer circuit is an essential ingredient of
the ACS and cannot be disabled.
USING AMPS WITHOUT LOAD
The ACS is not replacement for a load box! Always connect at least one load device, such as a speaker cabinet
or load box, to the ACS.
LOAD DETECTION
Each cabinet jack is equipped with a detection circuit which monitors the state of the cabinet jack. If there is no
valid speaker cabinet or load connected, it is not possible to enable the cabinet ouput. The detection circuit
measures the actual cabinet, not just the switch contact on the jack.
LOAD RESISTORS
Each amplifier has its own internal load resistor to protect the unused amps from damage and failure. Unused
amplifiers get muted at their input, so no signals can reach the power amp.
TECHNOLOGY
Inside the ACS, a massive relay matrix switches between amplifiers and load devices up to 150 watts. The
switching procedure is precisely timed and supervised by a microcontroller for fast and precise switching,
making sure no invalid combinations can happen. Advanced shielding techniques are used inside the ACS to
shield the sensitive input lines from the powerful output lines. The KHE ACS is built in Switzerland, using highest
quality parts and construction, such as high-quality toggle switches, AMPHENOL jacks, OMRON relays, in a
robust 19" 1u steel enclosure.
PEDALS IN FRONT OF THE AMP
Using pedals like boosts, overdrive, distortion, fuzz, eq, gates, filters, reamp boxes etc. work perfectly in front
of the ACS. Make sure to use clean power sources and quality cables for your pedals!
AMPS WITH BUILT-IN EFFECTS
It is possible to use amps with build-in effects, or to use effect pedals with single amps in their fx-loops, without
having them connected to the ACS. However, in case you use time-based effects such as Delay or Reverb,
follow some additional operation rules. Always make sure to either: a) turn the effect pedal off before
disableing or changing an amp or b) let the effect completely ring out before disabeling or changing the amp.
Ignoring this rule may damage the ACS or the connected amplifiers!
CABLE TYPES
For all BLACK jacks, use high quality shielded unbalanced instrument cables only. For all BLUE, RED and WHITE
jacks, use high quality unshielded unbalanced speaker cable only (2x 1,5mm2 or higher).
CABLE LABELING
It’s useful to equip all cables with numbered labels on both ends for easy identification of the connected
amplifier to avoid wiring faults. Use masking tape or such.
THINGS TO KNOW