Cambridge Audio Azur 840W Schematic

1

840W Power Amp.

Issue Date: November 2008

SERVICE MANUAL – AP23914/1

Specifications:

Power Output – Stereo / Mono 200W per channel 8 Ohms

350W per channel 4 Ohms
Power Output – Bridged Mono 500W 8 Ohms

800W 4 Ohms
THD (unweighted) < 0.001% 1kHz

< 0.005% 20Hz – 20kHz

Frequency Response 5Hz – 80kHz – 1dB
S/N ration (ref 1W/8 Ohm) > 90 dB (unweighted)

Sensitivity Stereo or Mono =

(for 200W 8 Ohms) 1.5V rms unbalanced

1.5 + 1.5V rms balanced
Bridged Mono =

0.775V rms unbalanced

0.775V + 0.775V rms balanced
Input Impedances Balanced input 38 kOhm

Unbalanced input 68 kOhm

Damping factor > 125 at 1 kHz
Trigger In 5 – 12V AC or DC
Trigger Out 12V DC @ 100mA

Power consumption Maximum 2400W

Active (no signal) < 180W
Standby < 5W

Dimensions (H x W x D) 148 x 430 x 365mm
(5.8 x 16.9 x 14.4”)

Weight 19.6kg (33lbs)

Audio Partnership, Gall ery Court, Hankey Place, Lo ndo n, SE1 4BB, UK

Tel: [phone]
Fax: [phone]

2

CAMBRIDGE AUDIO AZUR 840W POWER AMP SERVICE MANUAL

TABLE OF CONTENTS

Specifications 1

Table of Contents

Front Panel Details

Rear Panel Connections 5

Safety Instructions 6

Service Adjustment Procedure_______________________________________________7

Exploded Drawing 8

Exploded Drawing Parts List 9

Power PCB Schematic

Power PCB Schematic (Revision 1)___________________________________________ 11

Power PCB Layout

Power PCB Layout (Revision 1)______________________________________________ 13

Power Board Bill of Materials

Power Board Bill of Materials (Updated Revision)________________________________ 15

Input PCB (Mains Circuitry) Schematic

Input PCB (Mains Circuitry) Schematic (Revision 1)______________________________ 17

Input PCB (Audio Right) Schematic

Input PCB (Audio Right) Schematic (Revision 1)_________________________________ 19

Input PCB (Mircrocontroller) Schematic

Input PCB (Microcontroller) Schematic (Revision 1)______________________________ 22

Input PCB (Audio Left) Schematic

Input PCB (Audio Left) Schematic (Revision 1)__________________________________ 23

Input PCB Layout

Input PCB Layout (Revision 1)_______________________________________________ 25

2 - 3

4

10

12

14

16

18

20

22

24

3

TABLE OF CONTENTS Cont

Input PCB Board Bill of Materials

Power Amp Schematic

Power Amp Power Supplies Schematic

Power Amp PCB Layout

Power Amp Module Bill of Materials

Control Bus PCB Layout

Control Bus PCB Schematic

Control Bus Bill of Materials

Control Bus Bill of Materials (Updated Revision)_________________________________ 36

Mode Switch PCB Schematic

Mode Switch PCB Layout

Mode Switch PCB Layout (Revision 1)_________________________________________ 39

Mode Switch Bill of Materials

Mode Switch Bill of Materials (Updated Revision)_________________________ _______ 41

On/Standby Switch Schematic

On/Standby Switch PCB Layout

On/Standby Switch Bill of Materials

26 - 27

28

29

30

31 - 32

33

34

35

37

38

40

42

43

44

Cambridge Audio Azur 840W Power Amplifier

4

Front panel controls

azur 840W

Class XD Power Amplifier

1

Standby / On

Left Right

2 3 4 2 3 45 6

1

Standby/On

Switches the unit between Standby mode (indicated by dim power LED)
and On (indicated by bright power LED). Standby mode is a low power
mode where the power consumption is less than 10 Watts. The unit

.esu ni ton nehw edom ybdnatS ni tfel eb dluohs

When the 840W is switched out of Standby mode it will automatically
check for faults and allow the power amplifier stages to stabilise before
un-muting the speaker outputs.

Note: The protection LEDs will flash whilst this check is being done.

2

Output

Indicates that the Left or Right output is active. The LED (light-emitting
diode) is on for an active output, off for inactive (i.e. muted).

3

Protection

If this LED is constantly on the 840W has detected a fault on either the
Left or Right channel and is protecting itself.

4

Clipping

This LED indicates that the 840W has detected that either the Left or
Right channel is being overdriven or clipped.

Clipping distortion is caused at high volume levels when the output
signal attempts to go outside the maximum voltage that the connected
pre-amplifier can provide, causing the tops of the signal to flatten off.

BridgedClippingOutput

MonoProtection

LED indicators

Stereo output:

Mono output:

Bridged Mono output:

Standby / On

Standby / On

Standby / On

Left

BridgedClippingOutput

MonoProtection

Left Right

BridgedClippingOutput

MonoProtection

Left Right

BridgedClippingOutput

MonoProtection

ClippingOutput Protection

azur 840W

Class XD Power Amplifier

Right

ClippingOutput Protection

Class XD Power Amplifier

ClippingOutput Protection

Class XD Power Amplifier

ClippingOutput Protection

Bridged Mono

azur 840W

Bridged Mono

840W

azur

Bridged Mono

Clippin g

When the 840W detects clipping this LED will briefly flash. If the clipping
reaches a dangerous amount that could damage the amplifier or
attached speakers the unit will then go into protection.

5

Bridged

This LED indicates that the 840W is being used in Bridged mode. (The
Mono LED will also be illuminated.)

6

Mono

This LED indicates that the 840W is being used in a Mono mode.

Front Panel Contols

Cambridge Audio Azur 840W Power Amplifier

5

In Loop

1 = Ground
2 =
3 =

Loudspeaker Terminals - Right

Impedance 4 - 8 ohms

Please ensure that loudspeaker terminals are fully tightened

1

Veuillez s'assurer que les bornes de l'enceinte sont entièrement serrées

Balanced Audio - Right Unbalanced

Audio - Right

Loop OutputInput

Input

Loop Output

IMPORTANT!

Only change modes

when unit is off.

Refer to Manual for

more information.

Stereo

Mono

Bridged

only!

Mono Mode

6

Bi-Amp

Bridged

Bridged

Use Left Input for

Bridged / Bi-Amp

operation.

Right

Input Type

Balanced Balanced

Balanced

Unbalanced

azur 840W Class XDTM Power Amplifier

5

2 3 4

1

Loudspeaker terminals

For normal wiring, connect the wires from your left channel loudspeaker
to the LEFT + & - terminals, and the wires from the right channel
loudspeaker to the RIGHT + & - terminals. In each case, the red terminal
is the positive output and the black terminal is the negative output.

Other dual mono schemes are also possible if two 840Ws are used.
Refer to later sections of this manual for more information.

Use speakers with a nominal impedance of between 4-8 ohms. Care
should be taken to ensure no stray strands of wire short the
loudspeaker outputs together. Please ensure that the loudspeaker
terminals have been tightened completely to provide a good electrical
connection. It is also possible for the sound quality to be affected if the
screw terminals are loose.

Audio input types

The 840W features either unbalanced (phono/RCA) or balanced (XLR)
input connections. Either type may be used but not both at the same
time. The balanced connection is the higher quality option and can
reject noise and interference in the cable when used with other
equipment that supports this function. An XLR connector is wired Pin 1

- Ground; Pin 2 - Hot (in-phase); Pin 3 - Cold (phase-inverted).

Use the Left and Right Input Type switch (Item 4) to select the
connection type you wish to use. When using either the balanced or
unbalanced input, make sure that no cables or equipment are
connected to the unused input, as this may degrade operation. The
unused input does not need to be terminated and this should not be
done.

2

Balanced Audio

For connection to the balanced XLR outputs of suitable pre-amplifiers
that have this kind of output (such as our own 840E model). The pre­amplifier used should be capable of providing at least 1V rms of output
per phase (i.e. at both of + and – terminals of the XLR, more is also
fine). Nearly all modern pre-amplifiers fulfill this requirement.

3

Unbalanced Audio

For connection to the normal (single ended) RCA/Phono outputs of a
suitable pre-amplifier (such as our own 840E model). The pre-amplifier
used should be capable of providing at least 1V rms of output (more is
fine). Nearly all modern pre-amplifiers fulfil this requirement.

Designed in London, England

www.cambridge-audio.com

11

Power AC

10

230V AC ~ 50Hz

:

Power Rating

Max Power Consumption : 1600W

CAUTION

AVIS

ACHTUNG

Risque de choc

Vorm öffnen

Risk of electric

electrique.

des gerätes.

shock.

Ne pas ouvrir.

Netzstecker ziehen.

Do not open.

When Mono mode has been selected, switches the 840W between Bi­Amped Mono and Bridged Mono. Refer to later sections of this manual
for more information.

In - Allows un-modulated commands from multi-room systems or other
components to be received by the unit.

Out - Loop out for Control Bus commands to another unit.

The 840W can also be switched between On and Standby mode by
connecting the Control Bus output of an 840E pre-amplifier to the
Control Bus input of the 840W. Refer to the ‘Power syncing’ section of
this manual for more information.

For Custom Install use, the 840W can be turned on and off (i.e. brought
in and out of Standby mode) by the presence of 5-12V DC at the Trigger
input. A trigger input will also produce an internally generated 12V DC
trigger output at the Output/Thru connection. Turning the 840W on from
the front panel also produces a 12V DC trigger output at the
Output/Thru connection. This can be used to turn on/Standby other
connected power amplifiers or other equipment if desired. Refer to the
‘Power syncing’ section of this manual for more information.

Allows modulated IR commands from multi-room systems or IR repeater
systems to be received by the unit. Commands received here are not
looped out of the Control Bus. Refer to the ‘Custom installation’ section
for more information.

Once you have completed all connections to the unit, plug the AC power
cable into an appropriate mains socket then switch on. Your unit is now
ready for use.

Switches the unit on and off. If the 840W is not going to be used for long
periods of time it should be turned off using this switch.

In

Control Bus

7

ffOnO

8

9

N1863

AЯ

46

6

Mono mode switch

7

Control Bus

8

Trigger In, Out/Thru

9

IR (Infra-Red) Emitter In

10

AC power socket

11

Power On/Off

Bridged

Out

In

Trigger

Out/Thru

IR Emitter

Audio - Left

In

Left

Input Type

Unbalanced

Loop Output

4 3 2

This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions:

2) This device must accept any interference, including interference that may cause undesired operation

Veuillez s'assurer que les bornes de l'enceinte sont entièrement serrées

only!

Input

Manufactured in an ISO9001 approved facility

1) This device may not cause harmful interference

Loudspeaker Terminals - Left

Impedance 4 - 8 ohms

Please ensure that loudspeaker terminals are fully tightened

Class 2 WiringClass 2 Wiring

Balanced Audio - LeftUnbalanced

1

Loop OutputInput

In Loop

1 = Ground
2 =
3 =

Input Type switch

4

Use to select a balanced or unbalanced connection type for the input.

5

Stereo/Mono mode switch

Switches the 840W between ‘normal’ Stereo operation (where one
840W is used for a pair of speakers) and Mono operation (where two
840W’s are used one for each speaker). Refer to later sections of this
manual for more information.

Rear Panel Connections

Cambridge Audio Azur 840W Power Amplifier

6

Important safety instructions

For your own safety please read the following important safety
instructions carefully before attempting to connect this unit to the mains
power supply. They will also enable you to get the best performance and
prolong the life of the unit:

1. Read these instructions.

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not use this apparatus near water.

6. Clean only with a dry cloth.

7. Do not block any ventilation openings. Install in accordance with the
manufacturer's instructions.

8. Do not install near any heat sources such as radiators, heat registers,

stoves, or other apparatus (including amplifiers) that produce heat.

9. Do not defeat the safety purpose of the polarized or grounding-type

plug. A polarized plug has two blades with one wider than the other.
A grounding type plug has two blades and a third grounding prong.
The wide blade or the third prong are provided for your safety. If the
provided plug does not fit into your outlet, consult an electrician for
replacement of the obsolete outlet.

10. Protect the power cord from being walked on or pinched, particularly

at plugs, convenience receptacles, and the point where they exit
from the apparatus.

11. Only use attachments/accessories specified by the manufacturer.

12. Use only with the cart, stand, tripod, bracket, or table

specified by the manufacturer, or sold with the apparatus.
When a cart is used, use caution when moving the
cart/apparatus combination to avoid injury from tip-over.

13. Unplug this apparatus during lightning storms or when unused for

long periods of time.

14. Refer all servicing to qualified service personnel. Servicing is

required when the apparatus has been damaged in any way, such
as the power-supply cord or plug being damaged, liquid has been
spilled or objects have fallen into the apparatus, the apparatus has
been exposed to rain or moisture, does not operate normally, or has
been dropped.

WARNING - To reduce the risk of fire or electric shock, do not expose
this unit to rain or moisture.

The unit is of Class 1 construction and must be connected to a mains
socket outlet with a protective earthing connection.

The unit must be installed in a manner that makes disconnection of the
mains plug from the mains socket outlet (or appliance connector from the
rear of the unit) possible. Where the mains plug is used as the disconnect
device, the disconnect device shall remain readily operable. Only use the
mains cord supplied with this unit.

Please ensure there is ample ventilation (at least 10cm clearance all
round). Do not put any objects on top of this unit. Do not situate it on a
rug or other soft surface and do not obstruct any air inlets or outlet
grilles. Do not cover the ventilation grilles with items such as
newspapers, table-cloths, curtains etc.

This unit must not be used near water or exposed to dripping or
splashing water or other liquids. No objects filled with liquid, such as
vases, shall be placed on the unit.

CAUTION

Risk of electric

shock.

Do not open.

The lightning flash with the arrowhead symbol within an equilateral
triangle is intended to alert the user to the presence of un-insulated
‘dangerous voltage’ within the product’s enclosure that may be of
sufficient magnitude to constitute a risk of electric shock to persons.

The exclamation point within an equilateral triangle is intended to alert
the user to the presence of important operating and maintenance
instructions in the service literature relevant to this appliance.

AVIS

Risque de choc

electrique.

Ne pas ouvrir.

ACHTUNG

Vorm öffnen
des gerätes.

Netzstecker ziehen.

WEEE symbol

The crossed-out wheeled bin is the European Union symbol for
indicating separate collection for electrical and electronic
equipment. This product contains electrical and electronic
equipment which should be reused, recycled or recovered and

should not be disposed of with unsor ted regular waste. Please
return the unit or contact the authorised dealer from whom you
purchased this product for more information.

CE mark

This product complies with European Low Voltage
(2006/95/EC) and Electromagnetic Compatibility

to this instruction manual. For continued compliance only Cambridge
Audio accessories should be used with this product and servicing must
be referred to qualified service personnel.

(89/336/EEC) Directives when used and installed according

C-Tick mark

This product meets the Australian Communications Authority’s

Radio communications and EMC requirements.

Ross Test Stamp

This product meets Russian electronic safety approvals.

FCC regulations

NOTE: THE MANUFACTURER IS NOT RESPONSIBLE FOR ANY RADIO OR
TV INTERFERENCE CAUSED BY UNAUTHORIZED MODIFICATIONS TO
THIS EQUIPMENT. SUCH MODIFICATIONS COULD VOID THE USER
AUTHORITY TO OPERATE THE EQUIPMENT.

This equipment has been tested and found to comply with the
limits for a Class B digital device, pursuant to Part 15 of the

FCC Rules. These limits are designed to provide reasonable
protection against harmful interference in a residential installation. This
equipment generates, uses and can radiate radio frequency energy and,
if not installed and used in accordance with the instructions, may cause
harmful interference to radio communications. However, there is no
guarantee 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 turning the equipment off and
on, the user is encouraged to try to correct the interference by one or
more of the following measures:

- Re-orient or relocate the receiving antenna.

- Increase the separation between the equipment and receiver.

- Connect the equipment into an outlet on a circuit different from that to

which the receiver is connected.

- Consult the dealer or an experienced radio/TV technician for help.

Safety Instructions

ServiceAdjustmentProcedure

7




The Bias should be 14mV when the 840W is up to temperature, this is measured
across each emitter resistor individually (R21/R22), as there is a single adjustment
for both get as close as possible. Because of the very large mass of metal in the
main heatsink, the power amplifier module
equilibrium. This table gives a guide to how the DC Bias voltage, as measured at
CN1, varies over time when the biasis setcorrectly. Thusif thebias is being set9
minutesafterturningthemoduleon,(9minutesisthe
procedure)settingthebias to 15mV will resultinthecorrectvalue of 14 mVbeing
reachedduringlong‐termoperation.





 takes a long time to reach thermal

averagedurationofthistest

Timein
minutes

Temp(°C)
Main
heatsink

Temp(°C)
Driver
Heatsink1

Temp(°C)
Driver
Heatsink2

VBias
(mV+/1mV)

0 26.0 25.6 25.6 40
1 27.8 31.0 30.8 25
5 31.0 37.8 38.0 17
9 32.4 40.8 41.6 15
13 33.0 41.4 42.4 14
17 33.8 42.4 42.4 14



8

Cambridge Audio Azur 840W Power Amp

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Drawing ref AP part num ber Factorycode Description

1 PY1228 7003-008010E002 Screw M3*8 M /C 1/K TORX RE CESS ZINC-PT
1 PY1229 7003-008010E001 Screw M3*8 M/C 1/K TO RX REC ESS BLACK -PT
2 PY1378 3200-073542E000 Azur 840W 230V MAIN TRANS FOR MER TI-073520
2PY1379 3200-073542E000 840W 115V MAIN TRAN SFOR MER T I-073542
3 PY1460 3200-074050E000 Azur 840W 230V STB TRAN SFO RME R T074050
3 PY1461 3200-077810E000 840W 115V STB TRAN SFOR MER T 07781
4 PY1464 6584-150006E000-01 Azur 840W MES H SIDE PANE L BLACK PAINTED
4 PY1462 6584-150006E000-02 Azur 840W MES H SIDE PANEL SILVER PAINTED
5 PY1465 6584-150009E000-01 Azur 840W TO P PANEL BLACK PAINTED
5 PY1463 6584-150009E000-02 Azur 840W TOP PAN EL SILVER PAINTED
6 PY1466 6584-150027E000-01 Azur 840W FRO NT PANE L-B A RTW O RK (metalwork only)
6 PY1467 6584-150027E000A01 Azur840W FRON T PANEL-S ARTWOR K (m etalwork only)

PY1468 8584-035000E301 Azur 840W BLAC K FRON T PANEL ASSY REV A
PY1469 8584-035010E301 Azur 840W SILVER FRO NT PAN EL ASSY REV A

7 PY1470 9484-035000E071 Azur-840W PO W ER PC BA REV A

7 PY1520 9484-035000E072 Azur-840W POWER PCBA * Surface Mount version

8 PY1471 9484-035000E091 Azur-840W M AIN AMP PCB ASSY REV A
9 PY1472 9484-035001E091 Azur-840W SU B MAIN AMP PCB ASSY REV A

10 PY1473 9484-035000E341 Azur-840W INPU T PCBA 230V REV A

10 PY1522 9484-035001E342 * Revised Input PCBA 115 V
10 PY1523 9484-035000E342 * Revised Input PCBA 230 V

11 PY1122 6074-150004E000 Azur 840A plastic footblack
11 PY1124 6074-150004E000A01 Azur 840A plastic foot silver

PY1262 6600-070166E000 Azur 840A foot pad

12 PY1118 2331-004909E301 Speak er binding post (set)

PY1521 9484-035000E112 Azur 840W ControlBus PCBA
PY1524 9484-035001E172 Azur 840W m ode switch PC BA

Note that production after the first lot use revised PCB layout an

*

Production after 0810 are the new build

Exploded Drawing Parts List

Cambridge Audio Azur 840W Power Amplifier

10

F3

T1AL

7.5 Vrms

0 Vrms

Slow Blow Fuse

F1

T1AL
Slow Blow Fuse

C18

10nF 250V
X1/Y1 Mains Rated

F2

T1AL
Slow Blow Fuse

R3

470R
1/4W Metal Film

D2

Blue Azur LED

C17

10nF 250V
X1/Y1 Mains Rated

10nF 250V
X1/Y1 Mains Rated

J4

TERMINAL

RED

J5

TERMINAL

ORANGE

STANDBY
TRANSFORMER

J1

TERMINAL

YELLOW

17 Vrms

J3

TERMINAL

GREEN

0 Vrms

17 Vrms

J2

TERMINAL

VIOLET

R1

470R
1/4W Metal Film

D1

Blue Azur LED

OUTPUT PROTECT CLIPPING

LEFT

© COPYRIGHT

The Audio Partnership

Gallery Court
Hankey Place
LONDON SE1 4BB

Tel : [phone]
Fax : [phone]

C20

C19

10nF 250V
X1/Y1 Mains Rated

R4

470R
1/4W Metal Film

D3

Blue Azur LED

1N4004
Rectier

1N4004
Rectier

D9

D11

D13

C1

100nF 100V
Mono Ceramic

100nF 100V
Mono Ceramic

D15

1N4004
Rectier

C5

100nF 100V
Mono Ceramic

C6

100nF 100V
Mono Ceramic

1N4004
Rectier

MICROCONTROLLER SUPPLY

L7805

R9

2R2
1/2W Carbon

1

C15

100nF 50V
Mono Ceramic

U2

1

VI

U1

VI

L7815
Regulator

Regulator

C24

4700uF 25V
Electrolytic

GND

2

VO

GND

2

+9V

RELAY SUPPLY

3

VO

C21

100nF 50V
Mono Ceramic

3

C23

100nF 50V
Mono Ceramic

OPAMP SUPPLY

C13

100uF 25V
Electrolytic

C12

47uF 16V
Electrolytic

+5V

1N4004
Rectier

100nF 100V
Mono Ceramic

C4

100nF 100V
Mono Ceramic

1N4004
Rectier

D10

D14

C2

C3

D16

C27

100nF 100V
Mono Ceramic

1N4004
Rectier

4700uF 25V
Electrolytic

C16

C25

1000uF 35V
Electrolytic

D18

Rectier
1N4004

R10

4K7
1/4W Metal Film

+15V

C7

100nF 100V
Mono Ceramic

D12

1N4004
Rectier

BRIDGED MONO

C11

1000uF 35V
Electrolytic

R5

270R
1/4W Metal Film

D4

Blue Azur LED

BRIDGING SWITCH

VI

2

U3

L7915
Regulator

MODE SWITCH PCB

AP20566x

1

GND

C22

VO

3

100nF 50V
Mono Ceramic

R6

270R
1/4W Metal Film

D5

Blue Azur LED

MONO SWITCH

+5V

C14

100uF 25V
Electrolytic

Q3

BC337-25
NPN Signal

D19

Rectier
1N4004

-15V

R7

470R
1/4W Metal Film

D6

Blue Azur LED

D17

1N4004
Rectier

+-

C26

4.7uF 50V
Electrolytic

MAINS FAIL DETECT

R14

22K
1/4W Metal Film

BRIGHTNESS CONTROL

R8

470R
1/4W Metal Film

D7

Blue Azur LED

RIGHT

R11

7K5
1/4W Metal Film

R12

3K0
1/4W Metal Film

R13

430R
1/4W Metal Film

Q2

BC337-25
NPN Signal

ON/STBY LED

R2

470R
1/4W Metal Film

D8

Blue Azur LED

OUTPUTPROTECTCLIPPING

+5V

Q1

BC337-25
NPN Signal

R15

430R
1/4W Metal Film

LO = NORMAL

CN2

1
2
3

3 Way
Straight Header

MAINS FAIL

+5V

P1

BLK

LED

P2

RED

SWITCH

P3

ORG

ON/STBY PCB AP20570x

+15V

-15V

+5V
+9V

MAINS FAIL

MONO SWITCH

BRIDGING SWITCH

C8

100nF 50V
Mono Ceramic

C9

100nF 50V
Mono Ceramic

C10

100nF 50V
Mono Ceramic

EMC

D18

Blue LED

CN1

1
2
3
4
5
6
7
8

9
10
11
12
13
14
15
16

16 Way
FFC Connector

TO INPUT PCB

P4

PAD

P5

PAD

P6

PAD

FRONT PANEL FIXINGS

SW1

ON/STBY SWITCH

BC337

EBC

123

+15V
0V AUDIO

-15V
0V LOGIC
+5V
+9V
MAINS FAIL (HI = FAIL)
ON/STBY SWITCH (HI = PRESSED)
MONO SWITCH
BRIDGING SWITCH
POWER LED BRIGHT (HI = BRIGHT)
OUTPUT LEDS L & R (HI = ON)
PROTECT LED L
CLIP LED L
CLIP LED R
PROTECT LED R

Power Circuit Board Schematic

Cambridge Audio Azur 840W Power Amplifier

11

F3

T1AL

7.5 Vrms

0Vrms

Slow Blow Fuse

F1

T1AL
Slow Blow Fuse

J4

TERMINAL

RED

J5

TERMINAL

ORANGE

STANDBY
TRANSFORMER

J1

TERMINAL

YELLOW

17 Vrms

J3

TERMINAL

GREEN

0Vrms

17 Vrms

J2

F2

T1AL

TERMINAL

SlowBlowFuse

VIOLET

R1

1206 Thick Film
470R

D1

Blu

eAzurLED

R3

1206 Thick Film
470R

D2

Blue Azur LED

OUTPUT PROTECT CLIPPING

LEFT

© COPYRIGHT

The Audio Partnership

Gallery Court
Hank

ey Place

LONDON SE14BB

Tel : [phone]
Fax : [phone]

C17

100nF 250V
Met Polyester

C18

100nF 250V
Met Polyester

R4

1206 ThickFilm
470R

D3

Blue Azur LED

D13

C1

S1D

Met. Polyester
39nF 250V

C4

Met. Polyester

D15

39nF 250V

S1D

D9

MBR1100RLG

C5

Met. Polyester
39nF 250V

C6

Met. Polyester

D11

39nF 250V

MBR1100RLG

MICROCONTROLLER SUPPLY

4700uF 25V

D14

Electrolytic

C2

S1D

Met. Polyester
39nF 250V

C3

Met. Polyester

D16

39nF 250V

S1D

D10

MBR1100RLG

C27

Met. Polyester
39nF 250V

C7

Met. Polyester

D12

39nF 250V

MBR1100RLG

C16

C15

100nF 50V
1206 Ceramic

R9

2R2
1/2W Carbon

U2

1

C25

2200uF 35V
Electrolytic

C11

2200uF35V
Electrolytic

R5

1206 Thick Film

BRIDGED MONO

270R

D4

Blue Azur LED

U1

1

VI

C24

4700uF25V
Electrolytic

L7815
Regulator

VI

2

VI

2

U3

L7915
Regulator

MODE SWITCH PCB

AP20566x

L7805
Regulator

GND

GND

2

1

GND

3

VO

+9V

RELAY SUPPLY

OPAMP SUPPLY

3

VO

C21

Met. Polyester
47nF 63V

C22

Met. Polyester
47nF 63V

VO

3

R6

1206 Thick Film
270R

D5

Blue AzurLED

MONO SWITCHBRIDGING SWITCH

C23

100nF 50V
1206 Ceramic

C13

100uF 25V
Electrolytic

C14

100uF 25V
Electrolytic

+5V

Q3

BC846
NPN SmallSignal

C12

10uF 16V
EL Capacitor SMT

DGND

FB1

On 24AWG Wire
1uH Ferrite

AGND

+5V

D18

S1D

D19

S1D

DGND

R10

1206 Thick Film
4K7

+15V

AGND

-15V

R7

1206 Thick Film
470R

D6

Blue Azur LED

D17

S1D

C26

4.7uF 50V
EL Capacitor SMT

DGND

MAINS FAIL DETECT

R14

1206 Thick Film
22K

DGND

BRIGHTNESS CONTROL

R8

1206 ThickFilm
470R

D7

Blue Azur LED

RIGHT

DGND

R11

1206 Thick Film
7K5

R12

1206 Thick Film
3K0

R13

1206 Thick Film
430R

Q2

BC846
NPN SmallSignal

ON/STBY LED

R2

hick Film

1206 T
470R

D8

Blue Azur LED

OUTPUTPROTECTCLIPPING

+5V

Q1

BC846
NPN SmallSignal

R15

1206 Thick Film
430R

LO = NORMAL

CN2

1
2
3

3Way
Straight Header

MAINS FAIL

DGND

+5V

P1

BLK

P2

RED

SWITCH

P3

ORG

ON/STBY PCB AP20570x

+15V

-15V

+5V

AGND

+9V

DGND

MAINS FAIL

MONO SWITCH

BRIDGING SWITCH

C8

100nF 50V
1206 Ceramic

C9

100nF 50V
1206 Ceramic

C10

100nF 50V
1206 Ceramic

Blue LED

LED

CN1

1

2

3

4

5

6

7

8

9
10
11
12
13
14
15
16

16 Way
FFC Connector

TO INPUT PCB

P4

PAD

C19

10nF 50V
X7R Ceramic

P5

0805

PAD

C20

10nF 50V
X7R Ceramic

P6

0805

PAD

C28

10nF 50V
X7R Ceramic
0805

D18

SW1

ON/STBY SWITCH

BC337

EBC

+15V
0V AUDIO

-15V
0V LOGIC
+5V
+9V
MAINS FAIL (HI = FAIL)
ON/STBY SWITCH (HI = PRESSED)
MONO SWITCH
BRIDGING SWITCH
POWER LED BRIGHT (HI = BRIGHT)
OUTPUT LEDS L&R (HI=ON)
PROTECT LED L
CLIP LED L
CLIP LED R
PROTECT LED R

123

Power Circuit Board Schematic (Revision 1)

Cambridge Audio Azur 840W Power Amp

12

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??

??

??

??

??

??

??

??

??

??

??

???

???

???

??

??

??

??
?

???

???

??

??

??

???

??

???

???

???

??

???

???

???

???

?? ??

??

???

???

??

??

??

??

?

??

??

???

???

???

? ??

???

??

??

???

???

??

???

??

??

???

???

???

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???? ?

???

??????

???

???

??

???

??

?

Power PCB Layout

Cambridge Audio Azur 840W Power Amplifier

13

J1

J2

J3

J4

D17

C26

R11

D6

R7

C19

P4

C8

D7D8

R2

R8

CN1

Q2

D19

D18

R15

R13

R14

R6

Q3

Q1

D5

C9

C20

R10

R12

R5

C3

P5 P6

D13

C1

D14

C2

D15

C4

D16

F3

J5

C16

C24

F2

C17

FB1

R9

C12

C13

C23

C15

U1

C18
C27

C7

C6

D10

C25

3D2D D4

R4

C14

C21

U2

C22

U3

F1

C5

D9

D11D12

R3

R1

C11

D1

CN2

C10

C28

Power Circuit Board PCB Layout (Revision 1)

Cambridge Audio Azur 840W Power PCB (AP20549/4)

23

Fuse Holder Cover

3

F1-F3

PTF78 (or equivalent)

20mm Pitch

4034-780000E000

14

RESISTORS

/12R21

mliFlateMW4/1R0744

lateMW4/15K77

CAPACITORS

C-8C7cimareConoMV05Fn00111

1C1citylortcelEV61Fu7431

1C2citylortcelEV53Fu000151

CONNECTORS

DIODES

eifitceRA1V00402

FUSES

21 T1AL Slow Blow Fuse 3 F1-F3 20mm

-

INTEGRATED CIRCUITS

TRANSISTORS

-

SETONN/PyrotcaFofnIegakcaPecnareloTNPnaMtnedItnenopmoCytQepyT/noitpircseDeulaV

hctiPmm21%019R1nobraCW2
hctiPmm01%16R,5R2mliFlateMW4/1R0722
hctiPmm01%151R,31R2mliFlateMW4/1R0343
hctiPmm01%18R,7R,4R-1R6
hctiPmm01%121R1mliFlateMW4/10K35
hctiPmm01%101R1mliFlateMW4/17K46
hctiPmm01%111R1mliF
hctiPmm01%141R1mliFlateMW4/1K228

100-490301-0111%0202C-71C4detaRsniaM1Y/1XV052Fn019

0401-6011hctiPmm5%0172C,7C-1C8cimareConoMV001Fn001V001Fn00101

100-46
000-340401-0011hctiPmm5%0132C-12C,51C,01

000-410074-2011aiDmm5%022
000-420101-2011aiDmm6%0241C,31C2citylortcelEV52Fu00141
000-430201-2011%0252C,1
100-420274-2011aiDmm61%0242C,61C2citylortcelEV52Fu007461

hguorhT61-VSS-001D1NC1rotcennoCCFFyaW6171

000E000087-1304hctiPmm02)tnelaviuqero(87FTP3F-1F3esaBredloHesuF22

22OT5197L3U1rotalugeRV51-62

100E105610-1032eloH

400-001300-0032hctiPmm5.2A-HX-B3B2NC1redaeHthgiartSyaW381

000-040041-104114OD4004N191D-9D11r

007E433050-8714022OT5087L1U1rotalugeRV5+42
006E203051-8714022OT5187L2U1rotalugeRV51+52
006E203051-97140

001-000733-003129OT52-733CB3Q-1Q3langiSNPNAm003V5472

aiDmm5000-440774-2011%0262C1citylortcelEV05Fu7.421

BCP

otesabDELgnicapsmm8300-030000-0013031-M369BFH8D-1D8mm3DELruzAeulB91

Note: resistors, capacitors and other 'generic' components are

Note: resistors, capacitors and other 'generic' components are

not usually stocked by the manufacturer. Please obtain these locally.

not usually stocked by the manufacturer. Please obtain these locally.