Laney CA3000 Schematic

CA3000CA3000
Power Amplifer
Service Information
Laney www.laney.co.uk
SystemDiagram
CA Series Power Amplifiers
Traditionally, Class A and Class A-B amplifiers have dominated the amplifier marketplace. These purely analogue devices have low power efficiency and most integrated circuit Class A-B amplifiers fall short of true high-fidelity audio quality. Class D amplifiers however, solve the efficiency problem by using switching pulse-width modulation technology. However, this produces audio quality that is far inferior to class A or AB, so efficiency is gained at the expense of audio fidelity. The ‘Holy Grail’ of amplification: High audio quality AND high power efficiency has long eluded the market. Enter the CA range of power amplifiers delivering audiophile performance and very high efficiency.
If you have measured the output waveforms of CA amplifiers using traditional equipment and methods, you may have observed an unusual characteristic in the output waveform when the amplifier is driven close its maximum output. This characteristic appears to be a high frequency oscillation near the waveform peaks. In reality, this apparent oscillation is an audio quality enhancement characteristic of the CA amplifier. The apparent oscillations are well outside the audio bandwidth, and are a unique feature of the digital power processor.
As the input signal, to any conventional amplifier is increased, at some point the output of the amplifier will distort/clip i.e. ‘Square’ off. This is bad news because the for a split second the loudspeaker is not moving at all but still dissipating potentially huge power levels, this is the main cause of (expensive) compression driver failure. When the CA power amplifier goes into this distortion region, it exhibits high frequency break-up of the peaks as shown above. This is actually the amplifier resetting the control processor overloads at a frequency far above the audible range. This is not instability or oscillation, nor does it degrade the performance of the amplifier in any way. In addition the CA series power amplifiers also have the ability to run almost rail-to-rail, and thus will not lose negative feedback. In other words, it will retain control of the load at all times.
No Filtering on output
Measurement of THD%+N
Unless your distortion analyser is designed to reject out of band noise when measuring THD (And very few are), the THD measurement actually reflects harmonic distortion plus any noise present up to the bandwidth of the analyser and so is actually a measurement of THD+N. Since the CA range of amplifiers have energy far outside the audible frequency range (As do inferior class D amplifiers), a test designed for linear amplifiers (such as class A, AB) will not yield valid results when applied to a CA amplifier. A sharp cut-off low-pass filter must be inserted between the amplifiers outputs and the test equipment’s inputs prior to making any distortion measurements. Some measurement equipment (Such as Audio Precision2) have high quality low pass filters which can be used to limit the test bandwidth. Using these filters (as shown below) you will achieve what ‘looks’ like a high quality linear amplifier. Even though there appears to be ‘lots going on’ outside the audio bandwidth, the CA amplifier is designed to be well within current and future EMC guidelines, and as such is quieter than most linear amplifiers.
Output with 30Khz Low-pass filter
D:\RST\MISC\CA Series Ampifers THD measurement.doc Created by R&D3 On 07/11/00 Page 1/1
CA3000
CA3000 CARTON
1
SPECIAL MAINS LEAD
1
CA3000 CHASSIS ASSY
10462 10702 10959 CA SERIES MANUAL 1 7915/6
CA3000
CA3000 CHASSIS ASSY
10000UF 100V CAPACITOR/SAM
4
M3x25MM HEX SPACER
4
3A THERMAL RELEASE SWITCH
2
3MM SOLDER TAG
2
6mm SOLDER TAG
4
100mm TIE WRAP
30
M3*20 PLASTIC SPACER HEX
4
SHORT BOARD SPACER 12.7MM
4
B1/CA OUTPUT ASSY PCB 9333
-2
3mm HEX NUT
2
3*5mm PAN POZI
8
4mm HEX NUT
27
4*12mm PAN POZI
16
4*8 PAN POZI TAPTE
8
5*12mm PAN POZI
1
5mm BRASS HEX NUT
1
6 WAY END CONNECTOR
8
3 WAY IDC CONNECTOR
12
NO 4*1/4 PLASTITE
20
4mm NUTSERT
14
4 X 3/8 PAN POZI AB BLK PO
6
35A BRIDGE RECTIFIER
2
EARTH WARNING LABEL
1
HC25/50 4.8 FASTON
34
POZI LOCK NYLON BOOT
30
3*6mm PAN POZI Z/B
10
4*10mm SMALL F/H
12
M8 * 60 ROOFING BOLT
2
S/A SQUARE RUBBER FOOT20MM
4
50mm CAPACITOR CLAMP
4
ALUMINIUM SHEET
0.006
75MM CA HEATSINK EXT
-4
CA3000 FAC1A
-1
CA3000 REAR PANEL
-1
CHASSIS MOUNT MAINS FILTER
2
7915(/6)
->002022
->002204 680NF 250V 22.9mm 6
->005077
->005320
->005321 (->005324 5A THERMAL RELEASE SWITCH 2)
->005323 6A FILTERED MAINS INLET (1/2)
->005510
->005511 5MM SOLDER TAG 12
->005512
->005558
->005612 M3*8 METAL SPACER 2
->005632
->005659
->005666 RED P402 KNOB 4
->007906
->009150
->009151 3mm INT SHAKEPROOF 4
->009152
->009160
->009161 4mm INT. SHAKEPROOF 27
->009162
->009167
->009171 M5 INT SHAKEPROOF 8
->009173
->009181
->009183 WASHER 10MM O/D X 3 1/2MM 4
->009190
->009199
->009200 NO 6*3/8 FLANGE POZI 24
->009204
->009217
->009228 3*12 ZINC PAN POZI 2
->009235
->522032
->530027 DPST EQ MAINS SWITCH 2
->540038
->541004
->541053 1/4" LG RECEPTACLE 35
->541071
->581001
->582005 4*25 PAN POZI 18
->582007
->586002
->586023 8mm SHKPRF WASHER 2
->589020
->589041
->5P-50036 MX500 CAP STRAP -2
->->79052
->8P-5068
->8P-5073 CA3000 RACK WING -2
->8P-5074
->8P-5075
->8P-5076 CA3000 FACIA TRIM DRG 3151 -1
CA3000
CA3000 LID DRG 3158
-1
CA SERIES HANDLE DWG 3128
-2
CA3000 TRIP MOUNTING BRACK
-1
CA3000 MAINS TX + CRIMPS 2
-2
->8P-5077
->8P-9256
->8P-9257 CA SERIES HANDLE SPACER 2
->8P-9259
->8T-6148A
CA3000
B1/CA OUTPUT ASSY PCB 9333
-2
33R 6W(5W)
4
OR01 2W5 5% WIREWOUND RESI
8
18KSM 1206 1% RESISTOR
4
47R 5% RESISTOR
2
10K 5% RESISTOR
22
4K7 5% RESISTOR
8
47K 5% RESISTOR
6
1K 5% RESISTOR
4
10K 1W RESISTOR
2
680R 5W RESISTOR
2
ZERO OHM RESISTOR
2
1000UF 25V RADIAL
6
10UF 50V CAPACITOR
2
1UF 63V RADIAL
4
220UF 25V CAPACITOR
2
100UF 100V RADIAL CAP
4
220N 250V POLYPROPYLENE CA
4
1u63V 10% POLYESTER CAP'
4
100NF 400V 15MM
4
47PF 500V CERAMIC
4
1N4007 DIODE
12
15V 1.3W ZENER
2
1.5A 200V BRIDGE
2
3mm GREEN LED
4
5MM FERRITE BEAD
10
MPSA42/43 TRANSISTOR
4
STW38NB20 N CHANNEL MOSFET
8
LM7812 12V REGULATOR
2
BAS16 DIODE
14
BC857B TRANSISTOR
2
34072 IC (SMD TL072)
2
7815 IC VOLT'REGULATOR
2
7915 IC VOLT'REGULATOR
2
10K HORIZ PRESET
4
HEATSINK TV5
6
->007906
->->001067
->->001068 5R6 1W 5% WW RESISTOR 8
->->001069
->->001070
->->001300 ORO SHORTING LINK 4
->->001302
->->001306
->->001309 1M 5% RESISTOR 8
->->001312
->->001315
->->001318 6K8 5% RESISTOR 2
->->001327
->->001400
->->001511 1K 2.5W RESISTOR 4
->->001705
->->001920
->->002004 47UF 50V RADIAL 8
->->002009
->->002013
->->002014 100UF 35V RADIAL 2
->->002025
->->002029
->->002035 100N 100V 5MM BOX POLY 12
->->002036
->->002039
->->002041 100N 250V 5MM POLYESTER CA 4
->->002042
->->002410
->->002419 100NF 63V 5mm 16
->->002818
->->003000
->->003007 3V9 .5W ZENER DIODE 4
->->003014
->->003017
->->003018 10V .5W ZENER DIODE 2
->->003022
->->003041
->->003042 BYW100-200-FAST RECOVERY D 8
->->003411
->->003422
->->003423 TA0104A TRIPATH DIGITAL AM 2
->->003424
->->003500
->->003503 BC847B TRANSISTOR 6
->->003504
->->003508
->->003610 TIP31C TRANSISTOR 4
->->003901
->->003902
->->003905 7805 IC 2
->->004019
->->005030
->->005036 6 WAY LOCKING HEADER 2
CA3000
CA SERIES INPUT PCB 9339 A
-2
22K 1206 1% RESISTOR
12
ORO SHORTING LINK
22
100R 5% RESISTOR
4
ZERO OHM RESISTOR
4
56KSM 1206 1% RESISTOR
4
10UF 50V CAPACITOR
16
100NF 63V 5mm
12
100PF 50V 10% COG
4
470PF 50V 10% COG
4
5MM FERRITE BEAD
8
BAS16 DIODE
24
7815 IC VOLT'REGULATOR
2
7915 IC VOLT'REGULATOR
2
STEREO JACK SOCKET
4
HEATSINK TV5
4
XLR SOCKET FEMALE
4
3 WAY LOCKING HEADER
6
2 POLE 2 WAY (MX)
2
3 WAY IDC CONNECTOR
2
4P 3W SLIDE SWITCH
2
SHORTING LINK (IDC)
4
->007909
->->001071
->->001072 39K 1206 1% RESISTOR 4
->->001300
->->001303
->->001327 1K 5% RESISTOR 4
->->001920
->->001923
->->001924 10KSM 1206 1% RESISTOR 24
->->002013
->->002419
->->002602 47PF 50V 10% COG 2
->->002603
->->002605
->->003034 3mm LED YELLOW 4
->->003041
->->003500
->->003509 MC33078 IC 8
->->003901
->->003902
->->004019 10K HORIZ PRESET 4
->->005003
->->005030
->->005036 6 WAY LOCKING HEADER 4
->->005054
->->005063
->->005065 3 WAY NON LOCKING 4
->->005610
->->009199
->->009339 PCB ISSUE 2 2
->->530023
->->543508
CA3000
PCB 9342-VU ASSY
-1
1K .25W RESISTOR
1
10K .25W RESISTOR
1
ORO SHORTING LINK
3
10K 5% RESISTOR
5
470R 5% RESISTOR
4
ZERO OHM RESISTOR
3
10UF 50V CAPACITOR
4
220NF 250V 15MM DIPPED POL
4
5V1 .5W ZENER DIODE
1
SURGE GUARD SCK20-10-8A
2
3mm LED RED
8
BC847B TRANSISTOR
2
LB1413 BARGRAPH DRIVER
4
B10K 27.5MM POT
4
6 WAY LOCKING HEADER
2
3 WAY NON LOCKING
4
4.8MM TERMINAL SPADE
10
10 TURN CHOKE
4
SPEAKON SOCKET
6
->007971
->->001003
->->001005 2K2 .25W RESISTOR 1
->->001014
->->001300
->->001305 2K2 5% RESISTOR 1
->->001306
->->001311
->->001327 1K 5% RESISTOR 7
->->001920
->->002013
->->002401 22NF 400V 10MM 4
->->002402
->->003011
->->003022 3mm GREEN LED 13
->->003031
->->003033
->->003034 3mm LED YELLOW 4
->->003503
->->003805
->->004019 10K HORIZ PRESET 4
->->004110
->->005036
->->005047 16A 24V RELAY 2
->->005065
->->005686
->->009342 CA3000 VU/SS ARRAY PCB 1
->->571014
->->530066
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