CH L1 User manual

L1 Dual Monaural Line Preamplifier
User Manual

Dear Valued Customer,
We are honored that you chose the L1 Dual Monaural Line Preamplifier. Our team made every effort to desi n and manufacture
this top quality versatile and future-proof product and is proud to present it to you. We hope your L1 preamplifier will brin you
uncountable hours of emotion from your music collection.
But before you embark on your musical journey, we kindly request your attention to the information contained in this manual. The
L1, as you will discover in the followin pa es, is a Swiss precision product desi ned for ultimate performance and flexibility.
However, reachin sonic excellence requires your unit to be setup and operated correctly and this what this manual is all about. If
you have any questions or require assistance, please don't hesitate to contact your authorized dealer.
We hope you will enjoy your L1 preamplifier for many years.
The Concert has just be un...
Cossy F.
Heeb T.

FCC-Notice
Note: This equipment has been tested and found to comply with the limits for a Class B di ital device, pursuant to Part 15 of
the FCC Rules. These limits are desi ned to provide reasonable protection a ainst harmful interference in a residential
installation. This equipment enerates, uses and can radiate radio frequency ener y and, if not installed and used in
accordance with the instructions, may cause harmful interference to radio communications. However there is no uarantee that
interference will not occur in a particular installation.
If this equipment does cause harmful interference to radio or television reception, which can be determined by turnin the
equipment off and on, the user is encoura ed to try to correct the interference by one or more of the followin measures:
•adjust or relocate the receivin antenna
•increase the separation between the equipment and the receiver
•connect the equipment into a mains outlet on a circuit different from that to which the receiver is connected
•consult the dealer or an experienced ratio/TV technician for help
Disposal – Environmental care
Directive 2002/96/EG of the European Parliament requires consumer electro-technical appliances to be
disposed separately and have to be indicated with the followin symbol. Should you dispose this
component please do so in conformity with local and lobal le al and environmental re ulations and
accordin to best practices. We stron ly encoura e you to recycle any batteries used with this component.

Table of contents
1 Technical Hi hli hts.............................................................................................................................................................. 8
1.1 Unmatched flexibility.................................................................................................................................................. 9
1.1.1 Confi urations.................................................................................................................................................... 9
1.1.2 Input sta e....................................................................................................................................................... 10
1.1.3 Volume control................................................................................................................................................. 10
1.1.4 Output sta e.................................................................................................................................................... 10
1.2 Advanced DC offset cancellation................................................................................................................................. 10
1.3 Careful Metal Work Construction................................................................................................................................ 10
1.4 Power supply............................................................................................................................................................ 11
2 Read carefully before use................................................................................................................................................... 12
2.1 Packa e content........................................................................................................................................................ 12
2.2 Safety notice............................................................................................................................................................. 12
2.3 User Manual............................................................................................................................................................. 13
2.4 Mains supply............................................................................................................................................................. 13
2.5 Transport and packa in ............................................................................................................................................ 13
2.6 Cleanin ................................................................................................................................................................... 13
2.7 Maintenance and Servicin ........................................................................................................................................ 13
3 Installation........................................................................................................................................................................ 15
3.1 Unpackin ................................................................................................................................................................ 15
3.1.1 Removin the security screw.............................................................................................................................. 15
3.2 Positionin your unit................................................................................................................................................. 15
3.2.1 Unit level adjustment........................................................................................................................................ 15
3.2.2 Shaft covers..................................................................................................................................................... 16
3.3 Connections............................................................................................................................................................... 17
3.3.1 CONTROL Section.............................................................................................................................................. 18
3.3.1.1 USB port.................................................................................................................................................. 18
3.3.1.2 Ethernet port........................................................................................................................................... 18
3.3.2 Sin le-channel preamplification board............................................................................................................... 19
3.3.3 Power cord receptacle and volta e selection....................................................................................................... 20
3.3.4 External DC Power Supply Connector.................................................................................................................. 20
3.4 Preamplifier Confi uration......................................................................................................................................... 20
3.4.1 Dual Monaural confi uration............................................................................................................................. 21
3.4.2 True Monaural Confi uration............................................................................................................................. 21
3.4.3 True Monaural Extended Confi uration.............................................................................................................. 22
4 Operation.......................................................................................................................................................................... 24
4.1 Front panel controls................................................................................................................................................... 24
4.1.1 Front panel...................................................................................................................................................... 24
4.1.2 User control knob............................................................................................................................................. 24
4.2 Operatin modes....................................................................................................................................................... 26
4.2.1 Normal mode................................................................................................................................................... 26
4.2.2 Shortcuts.......................................................................................................................................................... 27
4.2.3 Menu mode...................................................................................................................................................... 29
4.3 Confi uration............................................................................................................................................................ 32
4.3.1 L1 confi uration menu items............................................................................................................................. 33
4.3.1.1 AUDIO SETTING........................................................................................................................................ 33
6 L1 User Manual Rev 1.0

4.3.1.2 DISPLAY SETTING...................................................................................................................................... 35
4.3.1.3 SHORTCUTS.............................................................................................................................................. 36
4.3.1.4 FACTORY SETTING..................................................................................................................................... 37
4.3.1.5 INSTALLED OPTIONS................................................................................................................................. 38
4.3.1.6 NETWORK................................................................................................................................................ 39
4.4 Remote control.......................................................................................................................................................... 40
4.4.1 Remote control operation.................................................................................................................................. 40
4.4.2 Chan in the remote control batteries................................................................................................................ 41
4.5 Returnin to Factory defaults..................................................................................................................................... 41
5 Firmware update............................................................................................................................................................... 42
5.1 Introduction.............................................................................................................................................................. 42
5.2 Firmware Update procedure....................................................................................................................................... 42
5.2.1 Preparin the firmware ima e........................................................................................................................... 42
5.2.2 Updatin the firmware (Firmware Update procedure).........................................................................................43
5.2.3 Emer ency Firmware Update procedure............................................................................................................. 43
6 Troubleshootin ................................................................................................................................................................. 45
7 Specifications..................................................................................................................................................................... 46
7.1 Specifications............................................................................................................................................................ 46
7.2 Dimensions............................................................................................................................................................... 47
7.3 Factory settin s......................................................................................................................................................... 47
Rev 1.0 L1 User Manual 7

1 Technical Highlights
CH products are proudly desi ned and manufactured in Switzerland by CH Precision Sàrl. Our en ineers put to ether all their
know-how, expertise and in eniousness to brin you the L1, a top performance future-proof modular two channel preamplifier
with USB flash-drive firmware update and Ethernet control capabilities. Like all CH Precision products, the L1 is hi hly versatile: 3
confi urations are possible: Dual Monaural (the L1 holds two channels in a sin le chassis), Monaural (two L1s work to ether, each
one processin a sin le channel, one board in each chassis) and finally the Monaural Extended (two L1s work to ether, each one
processin a sin le channel, however with two boards in each L1 chassis, allowin twice the amount of inputs). All these
confi urations can be further enhanced by addin the X1 External power supply.
The L1 is a fully symmetrical desi n, pure Class A discrete transistor based circuitry. This results in ultra low noise, hi h bandwidth
and hi h slew rate performances. The si nal stays in the analo domain all the way throu h. By default, the L1 is confi ured for
no series capacitor throu hout the si nal chain. The volume control is based on a discrete 20 bits R-2R resistor network circuit
topolo y, providin a ran e of 118dB in 0.5 steps. The output sta e is desi ned to be able to deliver ample current to drive heavy
loads and/or multiple pieces of equipment simultaneously. The L1 uses ti ht tolerance, hi h- rade metal film resistors throu hout
the audio si nal path.
Balanced XLR, sin le-ended RCA and BNC connectors are available at both the input and output. All the inputs can be confi ured as
hi h-impedance input, or a 600 Ohm load can be en a ed on balanced inputs (300 Ohm for sin le-ended inputs) to reduce
reflections as well as to improve external noise immunity, therefore improvin the overall si nal transmission.
L1 main components
8 L1 User Manual Rev 1.0

(1) External power supply input. For X1 optional external power supply only
(2) Mains switch and power cord receptacle (on back panel)
(3) Adjustment shafts and screws
(4) Mains filter board
(5) Power supply section
(6) Main power transformer
(7) Standby power transformer (ensures reen mode standby)
(8) Front panel power supply board
(9) Display (on front panel)
(10) Balanced and sin le-ended outputs
(11) Balanced and sin le-ended inputs
(12) Control board (USB plu for firmware update and Ethernet RJ-45 plu for control from Android App)
(13) Sin le-channel preamplification board (one or two per unit)
(14) Backplane board
(15) Power supply re ulation board
(16) Dual concentric control knob with pushbutton
1.1 Unmatched flexibility
The L1 offers unmatched system inte ration flexibility. Not only can it be used in multiple confi urations (Dual Monaural,
Monaural, and Monaural Extended) but it also allows adjustments to match the impedance of the upstream unit, improvin the
overall si nal transmission with the surroundin pieces of equipment.
1.1.1 Configurations
A sin le L1 can be fitted with one or two channel boards, dependin on the desired confi uration. The followin confi urations can
be realized:
•Dual Monaural: In this confi uration, a sin le L1 is used to hold the two channels (Left and Ri ht, Center and Sub or Left
and Ri ht surround). Two boards are fitted inside its chassis, each one independently processin a sin le channel. The
mains power supply section is common to both the board, however separate dedicated DC re ulation circuits are provided
to each board.
•True Monaural: In this confi uration, two L1s are used to hold a sin le channel each (Left resp. Ri ht, Center resp. Sub or
Left resp. Ri ht surround). One board is fitted inside each chassis, each L1 processin a sin le audio channel. In this
confi uration, the entire power supply of the L1 is dedicated to one channel, further enhancin the system performances.
•True Monaural Extended: The confi uration is identical to the True Monaural confi uration, with the addition of a second
board in each chassis. The two boards in a chassis work to ether, as if it was only one board with twice as many inputs
(and outputs). This confi uration will be used when more inputs are required than the amount a sin le board can
provide.
For ultimate results, one/two X1 External Power Supply unit(s) can be connected to the L1(s) in all the above confi urations,
addin a second sta e of power supply re ulation to the preamplifiers, further improvin the system performances.
Rev 1.0 L1 User Manual 9

1.1.2 Input stage
The L1 input sta e is equipped with both balanced and sin le-ended types of connections, 4x XLR, 2x RCA and 2x BNC. A hi h
bandwidth, hi h performances discrete amplifier buffers the si nal prior to applyin the volume. A DC blockin capacitor can be
en a ed to remove unwanted DC offset comin from sources connected to the L1's inputs. For more information about this
feature, please refer to section 1.2 Advanced DC offset cancellation.
1.1.3 olume control
The L1 volume control is based on a discrete 20 bits R-2R resistor network circuit topolo y, providin a ran e of 118dB in 0.5
steps. The volume set by the user from the front panel rotary knob or from the remote control is translated by the main controller
into commands that open or close analo switches, creatin a different combination of resistors for each of the volume steps,
therefore applyin the required attenuation. A ain of up to 18dBs is available for sources providin low output levels. A Mute
function is also available.
1.1.4 Output stage
The L1 output sta e is equipped with both balanced and sin le-ended types of connections, 2x XLR, 1x RCA and 1x BNC. A
powerful, hi h bandwidth, hi h performances discrete amplifier provides with ample current to drive one or more outputs
simultaneously.
1.2 Advanced DC offset cancellation
DC (continuous) volta e in an R-2R resistor network circuit topolo y translates into audible clicks in the audio si nal when a
volume chan e is applied. In order to remove the clicks, DC offsets must be canceled. The L1 features an advanced DC offset
cancellation system allowin to reduce the DC volta es to insi nificant levels, preventin audible clicks from happenin . The DC
offset cancellation system works in parallel with the audio path. It acts on the DC component of the audio si nal only, leavin the
audio content unaltered, but DC free. Ei ht pick up points are measured and corrected in real time throu hout the si nal path,
ensurin all sta es includin the L1 outputs are DC free.
DC offset wise, if there is one thin the L1 cannot control, it is the DC inherited from the pieces of equipment connected to its
inputs. Althou h care has been taken to try and counteract a fair amount of DC offset from upstream pieces of equipment
connected the its inputs, if these pieces of equipment exhibit hi h levels of DC at their outputs, the L1 will reach a state where it
can't counteract the inherited DC any more. If this condition happens, clicks mi ht start to become audible when a volume chan e
is applied. The only way to remove the excessive DC offset is to add a capacitor in series with the si nal path. The L1 front panel
display indicates that it cannot counteract DC any further and recommends to en a e the DC blockin capacitor. By default, there is
no capacitor in series inside the si nal chain, however the lar e value hi h- rade polypropylene capacitor can be en a ed when
excessive DC comin from the upstream piece of equipment has been detected at the input. Please note that en a in the
capacitor is a recommendation only, it is up to the user to en a e the capacitor or not. It is done from the unit's menu, but in no
circumstances will the unit en a e the DC blockin capacitor automatically. The DC blockin capacitor is en a ed on a sin le input
basis, it is not a lobal settin for all the inputs.
1.3 Careful Metal Work Construction
The L1 preamplifier chassis is made of hi h rade aluminum alloy with no visible screws on the front, top and side panels. First
class mechanical and chemical surface treatments provide the luxury finish of the L1. Pin assembly of all chassis elements enables
10 L1 User Manual Rev 1.0

smooth joints between metal parts while screws every 6cm ensure protection a ainst electroma netic interferences.
Four stainless steel feet support the unit. Each foot ends with an elastomer rin to sit on delicate surfaces but is also equipped with
hei ht adjustable hardened steel spikes to fine tune the unit position. Horizontal levelin is accomplished usin the provided
screwdriver throu h the four adjustment shafts accessible from the top of the unit. Moreover, the steel spikes serve as vibration
evacuation channels in a stack of units. Special covers are provided to interface with the spikes of the unit above. Any vibration
from the upper unit is transmitted by the stackin cover to the shaft of the lower unit and from there to the lower unit's feet or
spikes, formin a privile ed path for vibrations evacuation.
1.4 Power supply
The power supply of the L1 is a linear supply with multiple independent local re ulations circuits.
The lar est mains transformer is an oversized toroidal transformer and is used to supply power to the local re ulation circuits,
which in turns, supply both preamplifier boards. The transformer also supplies power to the di ital areas of the amplifier (front
panel display, microcontroller and DSPs that control and monitor the unit).
Discrete (power-transistor and operational amplifier based) ultra low noise re ulators are used throu hout the power supply to
ensure the purest low noise DC feed possible to the different audio sections. Each preamplifier board enjoys dedicated analo
re ulators.
The second, smaller toroidal transformer inside the L1 is used as the Standby transformer to ensure reen Standby mode, meetin
the latest ener y savin re ulations.
Both transformers have static shields between primaries and secondaries. They are mounted on a separate steel plate which is
isolated from the main base steel plate by silent blocks to prevent vibration transmission to the rest of the unit.
Input AC volta e to the power supply can be set to 100V, 115V or 230V AC dependin on your local mains volta e.
Rev 1.0 L1 User Manual 11

2 Read carefully before use
2.1 Package content
Make sure that the packa e content is complete. If not, please contact your authorized dealer. Your packa e should contain:
•L1 preamplifier
•Power cord (located in the Power Cord box)
•Accessory box
•Adjustment screwdriver (located in the Accessory box)
•4x adjustment steel spikes (located in the Accessory box)
•4x adjustment shafts aluminum top covers (located in the Accessory box)
•4x adjustment shafts steel stackin covers (located in the Accessory box)
•User Manual (this manual, located in the Accessory box)
Please store the packa in material for future use. Check your L1 preamplifier for any apparent dama e. In case of a dama e,
please contact your authorized dealer. If your L1 preamplifier is still very cold from transport, please let it warm to room
temperature in order to avoid condensation inside the unit.
2.2 Safety notice
Make sure to observe the followin rules:
•Install your L1 preamplifier on a stable base
•Do not install your L1 preamplifier near water
•Always handle with care. The L1 preamplifier is fairly heavy, so have someone to help you when movin it around
•Do not expose the unit to any kind of liquid
•Do not install it under direct sunli ht or near any heat source such as radiators or other apparatus eneratin heat
•Do not install it in a confined space and make sure there is sufficient airflow around the unit, includin under the unit.
•Do not operate under hi h ambient temperature (>40°C) or in extremely hi h humidity conditions
•Only use options and accessories specified or recommended by the manufacturer
12 L1 User Manual Rev 1.0

•Do not open the unit nor try to service it by yourself. Always refer to a qualified technician for service, maintenance or
up rades. Failure to do so will void the unit's warranty
2.3 User Manual
Please read this manual carefully before makin connections or operatin your L1 preamplifier. After readin this manual, please
store it in an accessible place for future reference. If, after readin this manual, you feel unsure about how to make connections or
how to operate the unit, please contact your authorized dealer for assistance.
2.4 Mains supply
Before connectin the mains power cord, make sure that the mains volta e selection at the back of the unit matches your local
mains volta e.
Make sure your L1 preamplifier is disconnected from the AC wall socket in the followin cases:
•When makin connections (it is also recommended to disconnect the rest of the system from the AC wall socket)
•When cleanin the unit
•Durin thunderstorms
•When unused for a lon period of time
2.5 Transport and packaging
The L1 preamplifier must always be stored in its ori inal packa in for transportation. Doin so will ensure an optimal level of
protection of your unit. Therefore, keep all packa in in a dry and clean place for future use.
In addition, the transformer base plate must be secured for transportation to avoid excessive constraints on the silent blocks
isolatin the chassis from transformer vibrations. This is done with the insertion of the security screw at the bottom of the unit.
Please refer to section 3.1.1 for further details. Do not for et to install this screw for transportation and to remove it durin the
installation of the unit in its new location.
Finally we recommend to remove the adjustment spikes and to put them in the accessory box prior transportation. Vibrations
durin transport may cause the adjustment spikes to move from their fully retracted position. There is risk of scratchin the
installation base if the spikes are not fully retracted when installin the unit.
2.6 Cleaning
Use a soft, dry cloth for cleanin . Never use any solvent or liquids as they may dama e the surface or infiltrate the unit. Please
use an ultra-soft piece of fabric desi ned to clean lasses for the front display area.
2.7 Maintenance and Servicing
The L1 preamplifier contains no user serviceable parts. Do not try to open, modify or repair your L1 by yourself. This will void any
warranty. Your L1 preamplifier must be checked by a qualified technician in any of the followin cases:
Rev 1.0 L1 User Manual 13

•The unit is not functionin properly
•The power cords or mains plu at the back of the unit is dama ed
•The unit was dropped to the floor or presents external dama e
•The L1 preamplifier has been exposed to liquids or unknown substances
14 L1 User Manual Rev 1.0

3 Installation
3.1 Unpacking
Unpack your L1 preamplifier and store the packa in for future use.
3.1.1 Removing the security screw
The transformer base plate must be secured durin transportation to avoid dama e to the isolatin silent blocks. The security screw
is located at the bottom of the unit. To remove the security screw, tilt the unit on its side and unscrew. Do not tilt the unit on the
front or back panels as this may dama e the user control knob or the connectors.
Security screw location
(1) Security screw. Must be mounted for transport and removed at installation
3.2 Positioning your unit
Position the L1 unit on a stable and sturdy base. Make sure air is able to flow freely around the unit.
For best transmission and immunity to external noise, the L1 input should be connected to the upstream unit usin a balanced XLR
cable like the CH Balanced Link cable.
3.2.1 Unit level adjustment
The L1 preamplifier is equipped with adjustable feet. Each foot has an internal spike which, when correctly adjusted, allows the unit
to rest on the spikes and provides a preferred path to evacuate mechanical vibrations. When delivered from factory, the
Rev 1.0 L1 User Manual 15
(1)

adjustment spikes are located in the accessory box and the L1 sits on elastomer rin s to protect the base.
Insert the adjustment spikes into each foot. Please use the provided screwdriver to screw the spikes into the feet and make the
level adjustments. Optional CH support discs have been desi ned to optimally couple the spikes with the rack on which the L1 sits,
simultaneously ensurin vibration channelin outside the system and decouplin from external vibration sources.
Adjustment shafts, feet and spikes
(1) Adjustment shafts. Insert the adjustment spikes and use the provided screwdriver to secure and adjust individual spikes
(2) Feet
(3) Adjustment spike heads (when inserted into the adjustment shafts)
(4) Adjustment spike
3.2.2 Shaft covers
There are two types of shaft covers delivered with your L1 unit. One type of shaft covers (stackin covers, made of steel) is used
when multiple CH units are stacked. This type of cover includes a receptacle to receive the correspondin spike of the unit placed
just above it. By doin so, mechanical vibrations are optimally transmitted to round and minimized inside the units. The second
type of shaft cover (top cover, made of aluminum) can be used when units are not stacked or for the top unit when stacked. It
covers the shaft and provides a smooth finish to the top unit. Shaft covers are located in the accessory box delivered with your L1
unit.
Never stack any component other than CH's on your L1. Never use the aluminum shaft covers (top covers) when another CH
component is to be stacked on top of your L1.
Shaft covers (left: stacking cover, right: top cover)
16 L1 User Manual Rev 1.0

3.3 Connections
This section provides information about how to connect a dual-monaural L1 preamplifier to your system. For details about how to
inte rate your L1 in a specific setup, please refer to the preamplifier confi uration section of this user manual. If you don't feel
confident with the connections to be applied, please contact your authorized dealer for assistance.
L1 rear panel connections
(1) RCA 1 left input
(2) BNC 1 left input
(3) RCA 2 left input
(4) BNC 2 left input
(5) XLR 1 left input
(6) XLR 2 left input
(7) XLR 3 left input
(8) XLR 4 left input
(9) XLR 1 left output
(10) XLR 2 left output
(11) RCA left output
(12) BNC left output
(13) Ethernet port for command interface
(14) Earth connector. Internally connected to di ital round
(15) External power supply connector for X1 power supply option
(16) Power on/off switch
(17) Power cord receptacle
(18) Power fuse and volta e selection
(19) Analo round connector 1.Can be connected to di ital round (Earth) usin provided jumper
(20) Analo round connector 2
(21) USB port for software up rades
(22) RCA ri ht output
Rev 1.0 L1 User Manual 17

(23) BNC ri ht output
(24) XLR 2 ri ht output
(25) XLR 1 ri ht output
(26) XLR 4 ri ht input
(27) XLR 3 ri ht input
(28) XLR 2 ri ht input
(29) XLR 1 ri ht input
(30) RCA 2 ri ht input
(31) BNC 2 ri ht input
(32) RCA 1 ri ht input
(33) BNC 1 ri ht input
3.3.1 CONTROL Section
The CONTROL section provides a USB port for software up rades and an Ethernet port for controllin the unit over an Ethernet
network. The followin drawin shows the layout of the CONTROL section of the back panel:
CONTROL section of the back panel
3.3.1.1 USB port
The USB port on the CONTROL section is dedicated to up radin the firmware of the L1 unit. Do not use it for any other purposes.
For more information on unit firmware update, please refer to the relevant section in this manual.
3.3.1.2 Ethernet port
The Ethernet port has two major purposes:
•It allows the control of the L1 preamplifier settin s throu h a standard Ethernet network. Connect the L1 Ethernet port to
an Ethernet Router usin an Ethernet RJ45 Cate ory 5 or better cable. Usin the CH Android App, the L1 settin s can be
accessed and adjusted on the fly via a tablet or smartphone.
•In both Monaural and Monaural Extended confi urations, two L1 chassis are used. In order to set the volume or to select
a new input, the two units must talk to each other. They are set in a Master and Slave arran ement. One unit becomes
slave of the other unit and receives commands from it. The two units exchan e information usin the Ethernet connectors
located on the back panel. Both L1s should be connected to a router (that has a DHCP server). The two units must be set
18 L1 User Manual Rev 1.0

to Master, respectively Slave, usin the units' set of menus available via the front panel pushbuttons and display. Please
refer to section 4 of this manual for more information on how to set up both units.
3.3.2 Single-channel preamplification board
The sin le-channel preamplifier board holds the audio path creatin the preamplifier itself. It is a monaural path, one channel can
be processed on a sin le board (Left or Ri ht in stereo confi urations, Center, Sub, Left surround or Ri ht surround in multichannel
confi urations). The preamplifier board contains the input sta e, the volume control circuitry and the output buffer. It also holds
the DC offset cancellation circuitry, allowin to reduce clicks to near zero levels.
It features selectable analo inputs on three different types of connectors: balanced XLR, sin le-ended RCA and BNC. The inputs can
be confi ured for hi h-impedance or 600 Ohms load (for balanced inputs) and 300 Ohms (for sin le-ended inputs). It allows an
optimal si nal transmission when connected to upstream pieces of equipment with 50 or 75 Ohm output impedance. The 600/300
Ohms load is en a ed on a sin le input basis, it is not a lobal settin for all the inputs.
Connect your sources to the inputs of the sin le-channel preamplifier board. The name of the inputs displayed on the front panel
screen can be customized for better clarity (please refer to section 4 of this manual for more information on how to chan e the
default input names). If more inputs are needed, the True Monaural Extended confi uration is the way forward. Please refer to
section 1.1.1 of this manual for more information.
The outputs are driven by a discrete buffer, capable of supplyin ample current to drive even the most demandin amplifier's input
sta es or lon molulation cables all the way to distant monoblocs. The multiple outputs are in parallel, allowin to connect multiple
amplifiers in a multi-amplification system.
Left Channel Board Layout
Right Channel Board Layout
Rev 1.0 L1 User Manual 19

Extended Left Channel Board Layout
Extended Right Channel Board Layout
3.3.3 Power cord receptacle and voltage selection
Make sure that the volta e selection is set to the correct value with respect to the AC volta e in your location. Connect the power
cord to the power cord receptacle and plu the power plu to a wall socket only after all other connections have been made.
3.3.4 External DC Power Supply Connector
This connector allows to connect the X1External power supply. A custom made interconnect cable delivered with the X1 plu s into
this connector, allowin to reach the next step in power supply re ulation. At power up, when the L1 detects that the cable has
been plu ed, it leaves its mains section off and connects to the X1 instead. Please note that the L1 AC socket must remain plu ed
to the AC wall socket. It is used only when the unit is in standby mode, supplyin the standby transformer, consequently allowin
the unit to power up.
3.4 Preamplifier Configuration
This section describes most standard setups in which one or more L1s can be inte rated into. Please note than in any of these
confi urations, one or more X1 external power supplies can be added to further improve sonic performances.
20 L1 User Manual Rev 1.0