Audio Note L2 Line Preamplifier User manual

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Manual Version 2.3 - May 2008

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Table of Contents
Section1: Introduction..............................................................................................................................................................4
General Information .............................................................................................................................................................4
reparation ..........................................................................................................................................................................4
Soldering ..............................................................................................................................................................................5
De-soldering.........................................................................................................................................................................6
Section 2: Mechanical Assembly.............................................................................................................................................7
Installing the feet..................................................................................................................................................................7
Mains Transformer, Choke, and Mains Installation .............................................................................................................7
Configuring the rimary Winding for your World Region .................................................................................................9
Installing the IEC Socket (AC Socket) and Rocker Switch ............................................................................................12
Installing the Choke........................................................................................................................................................13
Installing the Mains Transformer....................................................................................................................................13
Wiring up the Mains........................................................................................................................................................14
Shield ositioning...........................................................................................................................................................15
Section 3: M2 ower Supply .................................................................................................................................................17
M2 ower Supply Board arts List ....................................................................................................................................18
M2 ower Supply Board Construction Steps.....................................................................................................................19
Installing the Valve Bases ..............................................................................................................................................19
Installing the Resistors ...................................................................................................................................................21
Installing resistors in the HT ADJUST position ..............................................................................................................23
Zener Diode Installation .................................................................................................................................................24
Electrolytic Capacitor Installation ...................................................................................................................................25
Installing the Bridge Rectifier .........................................................................................................................................27
Installing the Non- olarized Capacitors .........................................................................................................................27
Wiring the M2 ower Supply Board ...............................................................................................................................28
Filament Component Section of the M2 ower Supply Board.......................................................................................31
Regulator Installation......................................................................................................................................................32
Installing the LED Harness.............................................................................................................................................33
Remaining Wire Connections.........................................................................................................................................33
Installing the Heatsink ....................................................................................................................................................34
Installing the Choke Wire ...............................................................................................................................................35
Inter-wiring to the Mains Transformer ............................................................................................................................36
Securing the Regulators to the Heatsink........................................................................................................................39
Section 4: M2 ower Supply Testing ....................................................................................................................................41
reparations.......................................................................................................................................................................41
Fitting the Mains Fuse ....................................................................................................................................................41
Installing the LED Indicator ............................................................................................................................................42
Installing the tubes .........................................................................................................................................................42
Tidying Up ......................................................................................................................................................................42
Ohm Check ........................................................................................................................................................................43
Electrical Testing................................................................................................................................................................43
Voltage Check Summary ...................................................................................................................................................45
DC Voltage Checks ........................................................................................................................................................45
AC Voltage Checks ........................................................................................................................................................45
Section 5: Install the Screen..................................................................................................................................................46
Section 6: Line Board Assembly ...........................................................................................................................................47
Line Stage Schematic ........................................................................................................................................................48
Line Board arts List..........................................................................................................................................................49
Installing the Board Spacers..............................................................................................................................................49
Valve Base Installation.......................................................................................................................................................49
Resistor Installation............................................................................................................................................................50
Capacitor Installation .........................................................................................................................................................51
Section 7: Wiring Up the Line Stage .....................................................................................................................................53
Filament Wiring ..................................................................................................................................................................53

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HT and ower Supply Ground Wiring................................................................................................................................54
Electrical Test ....................................................................................................................................................................55
Section 8: RCA input, Selector and Noble Volume ot.........................................................................................................57
Installing and wiring your first pair of RCA inputs ..............................................................................................................57
ELMA Switch Hook-up .......................................................................................................................................................59
Volume ot Installation ......................................................................................................................................................60
Section 9: Audio Signal Test .................................................................................................................................................65
Section 10: Output Wiring......................................................................................................................................................67
RCA Connections ..............................................................................................................................................................67
Line Board Connections.....................................................................................................................................................67
Section 11: L2 hono Board Build and Installation ...............................................................................................................68
hono Board arts List ......................................................................................................................................................69
Installing the Spacers and Valve Bases ............................................................................................................................70
Installing the Resistors.......................................................................................................................................................72
Installing the Capacitors.....................................................................................................................................................73
Filament Wiring ..................................................................................................................................................................77
Wiring the Output of the HONO Stage into the ELMA selector.......................................................................................78
Connecting the HT and ower Supply Ground..................................................................................................................79
hono Input Connections...................................................................................................................................................79
Controlled hono Input Test ..............................................................................................................................................80
Ground ost Installation.....................................................................................................................................................81
Section 11: Finishing Off .......................................................................................................................................................82
Fitting the Faceplate ..........................................................................................................................................................82
Attaching the LED to the Faceplate ...................................................................................................................................82
Final Thoughts ...................................................................................................................................................................83
Appendix................................................................................................................................................................................84
Resistor Color Code Reference .........................................................................................................................................85
Line Stage Schematic ........................................................................................................................................................86
M2 ower Supply Schematic.............................................................................................................................................87
hono Board Schematic ....................................................................................................................................................88

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Section1: Introduction
Thank you for choosing the L2 re-Amplifier Kit from AudioNote Kits.
We hope that your build experience will be a satisfying and rewarding one.
General Information
Should you encounter any problems with the kit, please call AudioNote Kits on 613 822 7188 or via e-mail to
[e-mail].
Please read t roug t e assembly manual fully to familiarize yourself wit eac stage of assembly before starting
construction. Also read eac individual section t oroug ly before and during construction.
This manual has been presented in a simple step-by-step manner following a logical method of assembly.
Preparation
Before starting assembly, open the packaging and familiarize yourself with the components and compare them with the
parts list(s) provided in the manual. Take sufficient time to become really familiar with the parts, as this will help prevent
any confusion later. Don’t worry if you cannot read the resistor values from their color codes, for we have prepared a chart
toward the end of the manual to help you differentiate the values. Alternatively, a web-based resistance calculator is
available on the AudioNote Kits website.
Upon inspection of the parts, you will notice that in particular the electrolytic capacitors and rectifier diodes are polarized,
that is, have a plus and a minus terminal. These components must be inserted correctly, otherwise serious damage to the
kit could occur.
The electrolytic capacitors have the plus and minus identifiers marked on them. The rectifier diodes have their polarity
indicated by a light colored band on one end of the body of the diode, which is always the cathode end of the diode.
The following tools are required to assemble the kit:
1. A soldering Iron, preferably 15 to 35 Watts power, with a small chisel tip (approximately 1/8” or 2.5 mm). Also, an
accessory stand with damp sponge for cleaning the soldering iron tip is recommended. It is appropriate to note
here that we do not provide solder with the kit. We recommend a rosin core flux solder, NOT acid core, such as
“Kester 44”. An even higher recommendation is AUDIO NOTE corrosive-free silver solder, which you can
purchase from Audio Note.
2. Small and medium size hilips head screwdrivers (No.1 and No.2 size) for the 4-40 and 6-32 machine screws
respectively.

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3. Long nose or “needle” nose electronic pliers. Round nose pliers for bending component leads are recommended,
but not essential.
4. A pair of small diagonal wire cutters and a wire stripper. The US made ‘T-Stripper’® is recommended.
5. 1/4”(7mm), 5/16”(8mm), 11/32”(9mm), 3/8”(10mm) and 1/2”(13mm) open-end wrenches and/or nut drivers.
6. 5/32” (3.5mm) Allen or hex key.
7. Adjustable wrench.
8. A de-soldering tool is also useful. The best type is a ‘solder-sucker’ (Edsyn™ brand) but a de-soldering wick will
suffice.
9. Clear silicone adhesive.
Soldering
The golden rule is that solder is not glue, so that even though it is electrically conductive, the joints to be soldered joints
should be as mechanically solid and electrically sound as possible before the connection is soldered. This will ensure low
oxidization, prevent crystallization and thereby reduce the chances of the joint going “cold”.
Once a good mechanical joint has been made between the two parts, touch both materials with the soldering iron’s tip and
after a few seconds of pre-heating the junction, apply the solder to the joint - not the tip of the soldering iron. It is
important that both the components, or the component and CB pad, are hot enough to melt the solder to ensure even
flow of the melted solder around and between the parts being joined, as you gradually feed in the strand of solder as it
melts. You then remove first the solder and then the soldering iron.
Try not to leave the soldering iron in contact for much longer than two or three seconds. If you fail to complete the joint in
this time, remove the iron and leave the CB to cool for 10 to 15 seconds, then repeat the operation. With experience it
should be possible to take the soldering iron away within one and a half seconds of first touching the iron to the joint.
Wipe the tip of the soldering iron on a damp cloth, or damp (not wet) sponge to clean off the excess solder and leave a
thin film on the tip. This should be done before and after every joint is made to ensure a ‘wet’ tip.
A good solder joint looks bright and clean, with concave surfaces, and with a slight residue of flux around it. If the wire
from the joint is pulled, the wire should not pull out of the joint.
It is worth repeating that unless both the materials are hot enough, the solder will not flow properly, even though there is a
metal-to-metal contact. Very often a film of oxide on the surface of the component leg is enough to insulate the two parts
and the result is a “dry” or “cold” joint that will soon give problems with electrical contact.
If you are unsure as to your abilities, practice by joining some pieces of wire until you are happy that you can achieve the
type of connection described above. You will never lose the feeling that you need three hands but experience allows you
to ignore it more frequently!
Thanks for purchasing this Audio Note kit. Our goal is to provide you with the highest quality Kit that you will build from
scratch with these instructions. If you have any questions or comments during the build feel free to contact us and we
would be happy to help out.

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De-soldering
Should you have to remove a component from the board, you will need to use either a solder ‘sucker’ or de-soldering
braid.
Removal is best achieved from the solder side of the board in either of the following ways:
Solder Sucker - first ensure that the plunger is depressed on the tool; next re-heat the joint to be de-soldered. When the
solder is molten, and with the iron still applied to the joint, place the solder sucker over the joint and activate.
It may take more than one attempt to remove enough solder for the component leg to be freed.
It is important that the component is not over-heated; therefore allow it to cool for several minutes before re-attempting the
above.
Use a pair of fine-nosed pliers to pull the leg from the board once the solder has been removed.
De-Solder Braid - once the offending joint has been re-heated, apply the de-soldering braid with the soldering iron on top
of it to keep the joint hot. The waste solder will be drawn up into the braid by capillary action.
Remove the component lead with fine-nose pliers.

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Section 2: Mec anical Assembly
In this beginning section we will start by installing the 4 feet from the Fittings Bag then we will install the Mains transformer
and Choke as shown in the pictures below.
Installing the feet
Insert 4 feet in the bottom of the chassis.
Fix them each in place using an M4 nut and washer.
Mains Transformer, hoke, and Mains Installation
Above you can see the Mains transformer that is used with the M2 ower Supply. The first step is to take the supplied M4
GND lug from the Hardware Bag and solder it to the end of the green wire.

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Trim the wire to about __ inches.
Strip about ¼” of insulation off the end of the green wire.
Tin the bare wire by adding solder to the end.

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Add solder to secure the GND Lug to the end of the wire.
Configuring t e Primary Winding for your World Region
Next step is to decide what world voltage you require – for example we have some of the most popular regions listed
below:
United States 120v
Canada 120v
UK 230v or 240v
Europe 230v / 240v
Hong Kong 220v
In order to wire up the for 120V operation we will need to connect the primaries as shown below:
The graphic shows above the correct wiring for of the rimaries for 120V operation where the 0 of one winding connects
to the 0 of the second winding & the 120 of one winding connects to the 120 of the second primary winding. Check the
chart on the next page for the correct RIMARY winding for the world Voltage you live in.

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Now we must configure our Mains transformer for the World Voltage that we reside in. For t is example we will s ow
120V Operation.
Start by cutting two short pieces of
wire approx 2” in length each, stripping
the insulation off the ends and tinning
the wire.
Then we will inter-wire the Mains transformer primaries.
Remember, we are wiring here or 120v - i your region is
di erent then you will need to consult the wiring chart on
the previous page to determine how you inter-wire or your
region.
From the IEC bag we want to take the brown and blue
wires with the crimps on one end.
Trim the wires to about _____ inches in length and then
solder on to the correct Mains transformer primary tags for
your region.

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Here, the wires are soldered onto the top-most 0v and the
bottom-most 120v for North American/Canadian 120v.
Remember, we are wiring here or 120v - i your region is
di erent then you will need to consult the regional wiring
chart to determine how you inter-wire or your region.
Installing t e IEC Socket (AC Socket) and Rocker Switc
The rocker switch simply snaps into
pace in the chassis slot.
Use the CSK M3 10mm screw and M3
nut to secure the IEC socket into
position.
Here you can see the correct installation of the IEC socket
and rocker switch from inside the chassis.

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Installing t e C oke
Since the Choke fits into a tight
location we suggest you put the
screws and washers into position
through the holes in the choke covers
– then lower the choke into position
making sure that you align with the
non painted hole - see opposite.
Note the wires at the back of the
choke.
The left-most picture shows the final
position of the choke from inside the
chassis.
The central picture shows its position
under the chassis where you will now
secure the 4 holes of the choke with
serrated M4 washers and M4 nuts.
Installing t e Mains Transformer
The picture opposite shows the correct orientation for the
Mains Transformer.
The following instructions will show how this is achieved.

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When installing the Mains transformer
be sure to line it up with the unpainted
hole in order to ensure a ground
connection.
Secure the transformer at all four
corners.
Wiring up t e Mains
Once the transformer is installed you can connect up the
Blue and Brown Crimped wires from the Mains transformer
directly to the Rocker Switch.
Also connect the green earth wire from the mains
transformer to the GND lug as shown opposite.

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Add the twisted wire (Cable #3) and the ground wire (Cable
#4) as shown in the graphic opposite.
Let’s add one final GROUND wire connection from the M4 screw in the chassis. Strip, tin and solder this wire to the 0 on
the 400-300-0-300-400 side of the transformer SECONDARY – the text on the transformer and the lug will not line up so
you need to count down from the top – the ZERO tap will be the third one from the top. See the following pictures:
S ield Positioning
I would like to explain where the shield fits at this stage – you won’t actually be installing t is until t e end of t e
build but by then there will be a number of things inside the chassis.
Take a look at the shield provided and locate the hole underneath that has no paint on it – this will match up with a hole
on the chassis that is also unpainted in order to ensure a good grounding of the SHIELD when in stalled in the chassis.

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Here you can see the correct
installation of the shield – You will
need to remove it later on when we
wire up to the Mains transformer but
for now you can leave it in and show
off your wonderful work to your wife!
This concludes the IEC Wiring section for the Mains Transformer.
You may want to double-check your work at this point. Also, make sure that the crimped end on the Rocker switch are not
coming into contact with each other - make sure there is plenty of clearance. If you want to add some solder to hold them
into place that is fine but I would wait a little bit. Also remember that you can use the rubber hoods that are supplied to
cover up the rocker and IEC plug and it is a matter of threading the crimped end through the rubber hood.
With this section completed we are going to move onto the building of the M2 ower Supply Board.

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Section 3: M2 Power Supply
In this section we will be assembling the M2 ower Supply Board CB.
Here is a view of the parts that you will find in the M2 ower Supply Kit Bag
Most of the parts for this section can be found in the M2 ower Supply bag (although the filament wires may be located
elsewhere).
For an experienced builder you can look at the parts list on the next page and get started but I would read through the
step by step instructions as we feel that this is the best and most efficient error free method of building the board.

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M2 Power Supply Board Parts List
The Complete arts list for the M2 board is shown below.
For resistor color code chart refer to the A ENDIX. You can also find an 'Interactive Resistor Color Code Calculator' on
our website (available from the Links page).
Category Quantity Part Designator
2 470uf 16V C2, C4
1 2200uF 35V C9
2 22uF 450V C6 ,C7
Capacitors (Electrolytic)
2 68uF 450V C3, C5
1 Disc 4700uF 1000v C10
1 .22uf 600V C8
Capacitors (Non-polarized)
1 .47uF 600V C1
1 100R R8
2 1K0 R5, R6
1 2K7 R12
1 15K R11
1 33K R2
1 68K R3
2 100K R1, R10
1 150K R7
1 220K R9
Resistors
1 470K R4
1 KBU6J6A U1
1 3.5W 150V Zener D7
4 Zero Ohm Resistors D1, D2, D4, D5
2 1N4007 D3, D6
Semiconductor Devices
2 78S12 U2, U3
Variable Resistor
NOTE: This may be replaced with 2x 22K resistors
1 50K 500mW VR1
1 8 pin valve base Valve Bases
1 9 pin valve base
1 6X5 Tube Tubes
1 ECL82 / 6BM8 tube

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M2 Power Supply Board onstruction Steps
Installing t e Valve Bases
Lets start by installing the 8-pin valve base with correct orientation.
The 8-pin (octal) valve base is shown opposite.
It’s a fairly tight fit into the board so take you will need to
take your time and make sure all the legs are individually
positioned over the holes in the board.
Now, let’s make sure we have the correct orientation - note
the Notch on the valve base along with the Notch on the
CB. These need to line up - see next image.
Here you can clearly see the notches lined up – this is a
correct orientation of the 8-pin valve base.

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The next job is to solder the valve base into position – Once
you have fitted the octal into position I suggest you use a
cap or something to support the board so that it is nice and
horizontal.
The reason for this is so that the valve base will be
soldered into the board nice and level – you may want to
solder a pin on one side and then the opposite and then
double check that the valve base is nice and level see the
following images.
It is only necessary to solder half the
valve base whole – feel free to put
solder on the entire hole if you feel like
you need to do so – I usually pick one
side and solder the lead to the board –
you may want to pull on the lead to
make sure that it is all the way out –
sometimes a valve base lead can stick
in position.
Next step is to solder in the 9-pin valve base – this one only goes in one way so you can’t really make a mistake. I would
suggest using some tape though to make sure that the valve base is level to the board – then solder a pin on one side
and then the other to make sure the valve base is level and that you are on track. See pictures below: