CH L1 User manual

L1 Dual Monaural Line Preamplier
User Manual

Dear Valued Customer,
We are honored that you chose the L1 Dual Monaural Line Preamplier.
Our team made every effort to design and manufacture this top quality
versatile and future-proof product and is proud to present it to you. We
hope your L1 preamplier will bring 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 following pages, is a Swiss precision product designed for
ultimate performance and exibility. However, reaching 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 preamplier for many years.
The Concert has just begun...
Cossy F.
Heeb T.
L1 User Manual 2

Table of contents
1 Introduction
1.1 Global audio options 4
1.2 Input-specic options 4
1.3 More user congurable options 4
1.4 Chassis congurations/extension 5
1.5 The purpose of this manual 5
2 Setting up your L1
2.1 Safety notice 6
2.2 Changing fuses and operating voltage 6
2.3 Unpacking 7
2.4 Package contents 7
2.5 Placing your L1 and installing the spikes 8
2.6 Stacking the L1 (or not) 9
2.7 Connections 10
2.8.1 USB port 11
2.8.2 Ethernet port 11
2.8.3 Local area network considerations 11
2.8.4 Ground lift jumper 11
2.8.5 Inputs 11
2.8.6 Outputs 11
2.8.7 AC Power 12
3 External power supply connector 12
4 How to congure and operate your L1 13
4.1 Control actions in normal mode 14
4.1.2 To turn the L1 on 14
4.1.3 To select an input 15
4.1.4 To alter volume 15
4.1.5 To engage shortcuts (mute, balance, phase, etc.) 15
4.1.6 To enter menu 15
4.2 Navigating the setup menus 15
4.3 Menu options 16
4.3.1 Audio settings menu 18
4.3.2 Input-specic settings menu 18
4.3.3 Display settings menu 19
4.3.4 Shortcut menu 19
4.3.5 Network menu 19
4.3.6 Factory settings menu 21
4.4 Handheld remote control 22
4.4.1 Batteries 22
5 Firmware update
5.1 Preparing the USB stick 23
5.2 Updating the unit’s rmware 23
5.3 Emergency rmware update procedure 24
6 Troubleshooting 25
7 Specications 26
L1 User Manual 3

1 Introduction
CH products are designed and manufactured in Switzerland by CH Precision Sàrl. We use fully discrete, fully
balanced, fully complementary, ultra-short signal path circuits – but we combine them with sophisticated
software control, monitoring and protection to ensure the highest possible levels of performance, operational
consistency and versatility.
As a result, your L1 offers a number of operational features that are unique and probably unfamiliar. For that
reason it is essential that you fully understand every aspect of the L1’s operation if you are to enjoy its maximum
possible performance.
Please also note that the L1 can be used as a single chassis, a true monaural twin-chassis and with or without
additional X1 power supplies, allowing one, two, three or four-box congurations. The basic instruction
for handling and placing units is identical in all cases. Conguring multi-box systems will be covered in the
appropriate section of this manual.
1.1 Global audio options
Mute
Absolute phase polarity
Mono mode
Balance / channel gain (up to 6dB of gain on either channel in 0.5dB steps)
Maximum starting volume / global volume limit
L1 internal stages calibration
1.2 Input-specic options
Input conguration: active, hidden or bypass
Input coupling: direct coupled or blocking capacitor
Input impedance: high (94kΩ/47kΩ) or low (600Ω/300Ω)
Input gain: ±6dB in 0.5dB steps
Input calibration
Input renaming
1.3 More user congurable options
Display: color, content and brightness
Dene shortcut functions
Network conguration
Firmware version and update
L1 User Manual 4

L1 User Manual 5
1.4 Chassis congurations/extension
As well as being highly congurable in terms of inputs and operation, a single L1 chassis can also be expanded into
a multi-box True Monaural preamplier. This topology offers increased performance but also increased versatility.
Dual monaural: In this conguration, a single L1 is used to hold the two channels (Left and Right, Center and
Sub or Left and Right surround). Two boards are tted inside its chassis, each one independently processing
a single channel. The mains power supply section is common to both the board, however separate dedicated
DC regulation circuits are provided to each board.
True monaural: In this conguration, two L1s are used to hold a single channel each (Left resp. Right, Center
resp. Sub or Left resp. Right surround). One board is tted inside each chassis, each L1 processing a single
audio channel. In this conguration, the entire power supply of the L1 is dedicated to one channel, further
enhancing the system performances.
True monaural extended: The conguration is identical to the True Monaural conguration, with the addition
of a second board in each chassis. The two boards in a chassis work together, as if it was only one board with
twice as many inputs (and outputs). This conguration will be used when more inputs are required than the
amount a single 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
congurations, adding a second stage of power supply regulation to the preampliers, further improving the
system performances.
1.5 The purpose of this manual
This manual will lead you through each step of the installation and set up procedure, in a clear and logical
sequence. Although the operation and options might seem complex, they will quickly become second nature.
But because of the sheer range of options available it is easy to overlook something unless you approach set up
and conguration in a systematic way. If you take the time to follow the manual, it will ensure that you become
completely familiar with the L1’s many options and that your preamplier delivers the best possible performance.

2 Setting up your L1
2.1 Safety notice
Make sure to observe the following rules:
Always handle with care. The L1 unit is very heavy, so have someone help you when moving it around.
Improper handling of the load could lead to risk of injury.
Install your L1 player on a stable base.
Do not install your L1 unit near water.
Do not expose the unit to any kind of liquid.
Do not install in direct sun light or near any heat source such as radiators or other sources of signicant heat.
Do not install in a conned space and make sure sufcient air can ow around the unit.
Do not operate under high ambient temperatures (>35°C) or with extremely high humidity (>85%) such as in
humid cellars.
Only use options and accessories specied or recommended by the manufacturer.
Do not open the unit nor try to service it by yourself. Do not try to install any option board by yourself.
Always refer to a qualied technician for service, maintenance or upgrades. Failure to do so will void the
unit’s warranty.
In Denmark: Apparatets stikprop skal tilsluttes en stikkontakt med jord som giver forbindelse til stikproppens jord.
In Finland: Laite on liitettävä suojakoskettimilla varustettuun pistorasiaan.
In Norway: Apparatet må tilkoples jordet stikkontakt.
In Sweden: Apparaten skall anslutas till jordat uttag.
2.2 Changing fuses and operating voltage
To change the fuses, switch off the L1 and remove the power cable.
The fuse holder is located to the right of the IEC power input. See diagram on page 10 (Arrow 18)
Fuse values vary with operating voltage:
230VAC – Fuse A : T50mA/250Vac. Fuse B : T1.6A/250Vac
100/115VAC – Fuse A : T100mA/250Vac. Fuse B : T3.15A/250Vac
Never change the selectable voltage during operation.
To change operating voltage, switch off the L1 and remove
the power cable.
Before changing the operating voltage rst check the local voltage.
L1 User Manual 6
BA

L1 User Manual 7
To change the operating voltage, remove
the fuse holder from the L1 chassis.
Fuse B (see picture above) is located in a sleeve
that can be slid out of the body of the fuse
holder: by turning the sleeve and reinserting it,
the orientation of the contact pins is altered,
switching the operating voltage. The selected
voltage will appear in the small window in the
base of the fuse holder.
Make sure that if required, you change the fuse
values to match the new voltage (as above).
You can now reinsert the fuse holder.
2.3 Unpacking
The L1’s carton is large and contains both the component and all of its accessories. You will need an open,
preferably carpeted area in which to unpack it. Please also ensure that the rack or support space on which
the L1 will be placed has been cleared and cleaned before you start. At this point it is also worth ensuring that
the connectors on any interconnect cables are cleaned and that the power to your system is turned off. The
carton consists of an inner box and outer sleeve.
Once you open the inner box, remove the top layer of white foam packaging. Inside you will see the
component chassis and various accessories.
With a helper, carefully lift the L1 out of the box and place it to one side. Then carefully remove the plastic bag
in which it is sealed.
Remove the small, brown Accessory Pack and place it with its unit. Also remove the power cord and suction
cup and the four leveling/grounding spikes (inserted into the lower foam block).
We recommend storing the Accessory Pack in a readily accessible place, so don’t put it back in the cartons
with the plastic bag when resealing it.
2.4 Package contents
Your L1 should arrive in a substantial carton. Once unpacked this carton and packaging materials should be
stored safely in case you ever need to transport your unit. When moving or transporting the L1 unit, this should
always be done in the original packaging.
The carton should contain:
The L1 preamplier
Four two-part a hardened aluminum/polymer spikes
A suction cup (used to remove the four top covers)
An accessory box containing:
–an infrared remote control
– a spike adjustment screwdriver
– a Torx T-10 screwdriver
–four support discs
–four stacking caps
–a USB stick containing the latest CH Precision rmware

L1 User Manual 8
In case of damage to the L1 chassis or missing components, please contact your authorized dealer immediately.
If your L1 unit is still very cold from transport, please let it warm up to room temperature in order to avoid
condensation developing inside it.
2.5 Placing your L1 and installing the spikes
Before positioning your L1, it is worth taking the time to make a few preliminary decisions.
Decide how many (and which) inputs you will use. Familiarizing yourself with (and making a note of) their
position on the rear panel will be extremely useful when you come to actually make connections and allocate
/ congure those inputs.
Decide whether you will use the CH Precision supplied leveling / grounding spikes.
If you do plan to use the CH spikes, use the blue suction cup to remove the four circular covers in the top plate
of each unit. Gently insert the hardened aluminum composite spikes into each exposed shaft and use the
short red screwdriver to turn them enough to engage the threads at the bottom of each spike. Each internal
thread is coated with a thin layer of grease during assembly to prevent galling between it and the aluminum
spike, but adding a thin coating of grease to each thread before insertion is still a good idea, making
adjustment easier and more precise.
Do not screw the spikes in too far at this point or they will protrude from the feet and potentially damage the
supporting surface. Do not replace the top-caps yet.
Check that the voltage selector switch on the unit is set to the correct local voltage and that the power switch
is off (the 0 side depressed).
Now you are ready to place your L1. The chassis is heavy and the feet are tted with rubber rings to protect the
supporting surface, which makes it hard to slide the unit. Having a partner to lift and help place the chassis will
make things considerably easier.
The L1 is supplied with a set of four support discs. These have a groove machined in the upper face that ts
over the rubber ring in the underside of each foot. Lift each corner of the chassis in turn and position the
disc beneath each foot. (Using an AirWedge or similar lifting bladder will make this considerably easier.) The
groove that interfaces with the rubber ring will ensure that the footer disc stays in place if you slide the unit.
As well as making the units easier to position, the support discs can also offer a superior interface between
the grounding spikes and the supporting surface. The spikes are designed to drain internally generated
energy away from sensitive circuitry and into a dispersive support structure, but if the supporting surface
is extremely hard or forms an impedance mismatch with the spike tips, the material and footprint of the
support discs can function as a lossy mechanical buffer, easing the passage of mechanical energy out of the
unit. As a rule, the support discs work well with very hard surfaces, but results will vary with system and
supporting surface. Once set up and warmed up, compare the sound of the unit(s) with and without the discs
in place.
Use the red screwdriver to wind down each four spikes until you feel that they touch the surface underneath.
You will feel a slight resistance due to the chassis’ weight. Then turn each spike by the same amount, for
instance one more full turn. This should ensure that the load is evenly applied on all four spikes.
It is worth using a spirit level to ensure that the L1 is perfectly level. If it is not, adjust the spikes with the
screwdriver. Once this is done, simply check that all four spikes show the same resistance to turning. This
means that the spikes are rigidly coupled to the supporting discs and equally loaded.
Replace the top caps, using the suction cup to ensure that they are screwed tightly into place.

L1 User Manual 9
L1
preamplier
X1 external
power supply
unit or other
CH unit
cosmetic
caps
stacking
caps
support
discs
Stacking the L1 (or not)
2.6 Stacking the L1 (or not)
Also included in the accessory packs is a set of stacking caps. These polymer inserts allow owners to stack
the L1 chassis on top of other CH 1 Series components. The spikes and interface caps will ensure mechanical
grounding of the stacked chassis. However, this will inevitably compromise performance to some extent and
should only be done when space is at an absolute premium.
The optimum support for any CH unit is to mechanically ground it to a stable, dispersive structure, either
using the supplied spikes or an after-market solution. But if lack of space absolutely mandates the stacking of
CH components, then using the supplied spikes and stacking caps will provide the best possible solution.
The stacking caps simply screw into the top of the spike wells in the lower unit(s), taking the place of the
cosmetic caps. When a second unit is stood on top of them, its spikes can be wound down into the wells in
the caps, providing a stable, safe and easily managed stacking option that improves mechanical termination
and satises aesthetic and practical considerations.
Make sure that you retain the cosmetic top caps and store them safely as you may well require them in the
future if (or rather, when) your system or circumstances change.

2.7 Connections
With the L1 unit(s) placed and levelled, you are now ready to connect your signal cables.
The rear panel layout is shown below:
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(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) Signal ground (analog GND) socket
(15) Multi pin socket for X1 power supply only
(16) Power on/off switch
(17) Power cord socket
(18) Fuses and voltage selector
(19) Signal ground (analog GND) socket. Place the
ground lift jumper in the lower position, between (19)
and (20), to connect signal ground (analog GND) to earth
(digital GND). Keep it in the upper position, between (14)
and (19), to store it
(20) Chassis earth (digital GND) socket.
(21) USB socket for software upgrades only
(22) RCA right output
(23) BNC right output
(24) XLR 2 right output
(25) XLR 1 right output
(26) XLR 4 right input
(27) XLR 3 right input
(28) XLR 2 right input
(29) XLR 1 right input
(30) RCA 2 right input
(31) BNC 2 right input
(32) RCA 1 right input
(33) BNC 1 right input
L1 audio unit rear panel connections
16
151413124
30 22 19
2
32
111098765
29 28 27 26 25 24 21 20 18 1723
3
31
1
33
You will note that as well as the array of conventional inputs and outputs, there are a number of other sockets
available which are used for control and update functions.