Electro-Voice CPS-1, CPS-2 Service manual

SERVICE MANUAL

CPS 1 / CPS 2

CINEMA PRECISION SERIES

SPECIFICATIONS

Technical Specifications: CPS1, CPS2

Amplifier at rated conditions, both channels driven with 8 ohms loads, unless otherwise specified.

CPS1 CPS2

Load Impedance 8 Ω 4 Ω 2 Ω 8 Ω 4 Ω 2 Ω Maximum Midband Output Power 280W 450W 650W 380W 600W 850W

THD=1%, 1kHz Rated Output Power 230W 350W 450W 300W 500W 650W

THD < 0, 2%, 20Hz ... 20kHz Maximum Bridged Output Power 900W 1300W ——— 1200W 1700W ———

THD=1%, 1kHz Maximum RMS Voltage Swing 56V 64V

THD=1%, 1kHz Voltage Gain 34dB 35dB

at 1 kHz

Slew Rate 25V/µs 30V/µs Power Consumption 690W 870W

at 1/8 maximum output power @ 4 Ω Input Sensitivity 0dBu ( 775mV)

at rated output power @ 4 Ω, 1 kHz THD at rated output power, < 0.05 %

MBW=80kHz, 1 kHz IMD-SMPTE < 0.08 %

60 Hz, 7 kHz DIM30 < 0.03 %

3.15kHz, 15 kHz Crosstalk <-80 dB

ref. 1kHz, at rated output power

Frequency Response

-1dB, ref. 1 kHz 13Hz ... 45kHz

Power Bandwith

THD=1%, ref. 1kHz, half power @ 4 Ω 10Hz ... 50kHz

Input Impedance

20Hz ... 20 kHz, balanced 20kΩ

Damping Factor

at 100Hz / 1kHz >300 / >200

Signal to Noise Ratio

A-weighted 103dB

Power Requirements 120V, 50Hz ... 60Hz Protection Audio limiters, High temperature, DC, HF, Back-EMF,

Peak current limiters, Inrush current limiters, Turn-on delay

Cooling Front-to-Rear, 3-stage-fans Safety Class I Dimensions (W x H x D), mm 483 x 132.5 x 385.5 Weight 15kg 16kg

MEASUREMENT SPECIFICATIONS: CPS1 & CPS2 complete appliance

printed board assembly names and their corresponding EDP-numbers:

Printed board assembly EDP-number

120V 230V

CPS1 CPS2 CPS1 CPS2

84183 84184 84181 84182

Printed board assembly Index

Main PCB 1

Supply PCB 4

Input PCB 2

LED PCB 3

measuring condition; if not otherwise specified:

- tolerance of measured values: ∆X = ±1.5 dB

- measuring frequency: f = 1 kHz

- stated levels refer to: U = 775 mV (0 dBu)

- level controls set to their clockwise limits

- pin assignment of the XLR-type connectors: PIN 1: ground / shielding PIN 2: + INPUT PIN 3: - INPUT

- source resistance for the induction via the XLR-type connector: R(Q) = 50 Ω

- the AMPLIFIER PCB printed board assembly is provided with service connectors

CNS1 CNS2 CNRC

PIN assignment PIN assignment PIN assignment

1 -Vcc 1 LIM A Switch 1 LIM Out A 2 BIAS +A 2 -15V 2 LIM Out B 3 BIAS -A 3 LIM B Switch 3 Standby via RC 4 FAN Voltage 4 +15V 4 Standby LED 5 +Vcc 5 AGND 5 -Vss 6 BIAS +B 6 Speaker Out A 6 +Vss 7 BIAS -B 7 Relais/Protect 7 n.c. 8 Temp Heatsink 8 Speaker Out B 8 n.c.

1. Operating voltage: U(B) = 120V, 230V, 240V 50Hz ... 60Hz

2. Deviation limit of the operation voltage: -30% .... +10%

3. Power consumption (both channels driven) f = 1kHz

CPS1 CPS2

Idling power consumption 30-60W 40-80W Nominal power consumption (RL=4Ω) Standard power consumption (RL=4Ω) Maximum power consumption (RL=4Ω) Power consumption at 1/8 of the maximum output power 690W 870W

1400W 1900W

430W 600W

1650W 2100W

4. Settings / adjustments

4.1. IDLING CURRENT ADJUSTMENT

Connect the DC-volt meter at the BIAS measuring points (see service connector) and adjust the idling current via the trim potentiometer VR101/VR301 (on the main PCB printed board assembly). Adjust both channels of the power amplifier A&B to a value of U(DC) = 7.5 mV. Adjusting the idling current has to be performed at normal room temperature. In case the power amplifier was previously in operation, it needs several hours for cooling off.

4.2. VCA - OFFSET

Rhythmically open and short-circuit the CNS2.1 and CNS2.2 on the main PCB printed board assembly for channel A; respectively CNS2.3 and CNS2.2 for channel B. Use VR100 respectively VR300 for adjusting the power amplifier outputs to their minimum offset (with oscilloscope to minimal peak value or to the audible minimal volume of the interfering pulse).

5. Testing of functions

5.1. OUTPUT - offset voltage

DC-voltage measuring at the SPEAKER A/B outputs with U(DC) ≤ ±10 mV.

5.2. LIMITER

5.2.1. attenuation test

Channels separately driven with a 1 kHz signal up to U(A) = 42.4 volts, respectively U(A) = 49 volts (without load). Increase the input voltage by 10 dB. The LIMITER LED lights and the output voltage increases by about 2 dB to approx. 58 volts – respectively 64 volts; with slight clipping. The distortion rate of the limited signal is at THD = 1.0 … 1.5 %. Increasing the input signal up to a value of +20 dBu should not result in remarkably higher clipping.

5.2.2. attack and release times

separately test both power amplifier channels: testing without load resistors

1.) Drive the power amplifier input with a burst signal (f = 1 kHz, 10 cycles, rate: ≈ 0.5 sec.)

2.) and U(E) = +10 dBu.

2.) Monitor the output signal via oscilloscope. After 4 - 5 signal periods, the limiter controlled the major

distortion down to a minor residual distortion (THD = 1.0 … 1.5 %). attack time: 4 - 5 mS release time: 40 - 50 mS

5.3 POWER-ON DELAY

Signal present at the power amplifier input. Use the power-on switch to switch the power amplifier's power on. Approximately 2 seconds after switching the power on, the signal is present at the amplifier's output.

5.4 FAN CONTROL

Upon powering-on the power amplifier, the fans will run for about 2 seconds and then stop; presuming that the amplifier's temperature is not too high. In idling condition (power-on, no signal present) the fans are switched between the SLOW and OFF (0 V) mode, depending on the heat sink's temperature. When CNS1.8 is connected via a 5k1 ohms resistor to +15 V, the fans will run in SLOW mode. Fan-voltage of 16.8 V DC measured between Pins CNS2.4 and CNS1.4. Disconnecting the plug CN5 results in the fans running at FAST speed. Fan-voltage of 28 V DC measured between Pins CNS2.4 and CNS1.4

5.5. SOAR-PROTECTION CIRCUIT TEST

Channels separately driven on 4 Ω up to 49 volts; respectively 42.2 volts. Parallel connect a 1 Ω resistor. The protection circuit reacts and tries continuously to re-start! The protect-LED lights. Repeat the test with a 2 Ω resistor; the power amplifier should not switch off.

5.6. SHORT-CIRCUIT CURRENT-LIMITING TEST

separately test both power amplifier channels without load:

- drive the channel with a burst signal (f = 1 kHz, 1 - 3 cycles, rate ≈ 1 sec.) with U(E) = 1Vrms

- connect a load resistor of 1 Ω the short-circuit current-limiter limits the output voltage at the load resistor

symmetrically (monitor via oscilloscope) to a peak voltage value of 35 V, respectively 27 V ( approx. 35 A respectively 27 A maximum peak output current).

5.7. DC-VOLTAGE PROTECTION CIRCUIT TEST

separately test both power amplifier channels:

- drive the power amplifier with a test signal (f = 7 Hz) and without load

- at an input voltage of approx. 3 Vpeak the protection circuit reacts and tries continuously to re-start!

The protect-LED blinks with the same frequency.

- Repeat the test with f = 14 Hz; the power amplifier should not switch off.

5.8. HF-PROTECTION CIRCUIT TEST

Caution: it is mandatory to drive the power amplifier without load resistors connected.

Drive the power amplifier with a +20 dBu sine burst signal (40 mS ON, 960 mS OFF) f = 100 kHz applied to each channel at a time. The protection circuit should react. The power amplifier tries to re-start continuously. The PROTECT LED blinks with the same frequency. Repeat the test with f = 50 kHz; the power amplifier should not switch off.

5.9. LED INDICATOR TEST

Apply a 1 kHz sine signal and increase its level. At approximately -30 dBu the SIGNAL LEDs will light and at about +1dBu the LIMIT LEDs light.

6. Level CHANNEL A B

6.1. voltage amplification

Unit Input U(E) Measure point U(A) Load resistor Test

frequency

CPS1 CH. A/B 1Vrms SPEAKER A/B 42V CPS1 CH. A 1Vrms BRIDGED OUT 84V CPS2 CH. A/B 1Vrms SPEAKER A/B 49V CPS2 CH. A 1Vrms BRIDGED OUT 98V

6.2. MAXIMUM INPUT LEVEL: U(E) = +20dBu

7. GROUND LIFT switch

The circuit ground (at the input or the output connector) is measured versus the common ground of the enclosure (contact at the ground terminal, located on the rear panel - or common ground of the mains cord). position of the switch: GROUNDED : R = 0 Ω

UNGROUNDED : R = 5 Ω

8. Amplitudes - non-linearities

- testing with load resistor 8 Ω, dual mode

- MDW = 80 kHz

Measuring at nominal output remarks

CPS1 CPS2 THD+N ( f = 1kHz ) IMD-SMPTE DIM 30

<0.05% <0.05% <0.08% <0.08% 60Hz, 7kHz <0.03% <0.03% 3.15kHz, 15kHz

∞ ∞ ∞ ∞

1kHz 1kHz 1kHz 1kHz

9. Frequency response

the frequency response is linear. (please take the cut-off frequencies into consideration)

low cut-off frequency high cut-off frequency

-3dB fu < 10Hz fo = 110kHz

-1dB fu < 10Hz fo = 57kHz

10. Factory default

BRIDGED MODE switch set to NORMAL INPUT ROUTING switch set to DUAL/STEREO LEVEL controls set at their clockwise margin.

11. Noise interference

- U(F) = external voltage un-weighted with B = 22 Hz … 22 kHz, effective value (IEC 268-1)

- U(G) = noise voltage, frequency-weighting filter according to CCIR-468-3, quasi peak weighted (IEC 268-

- U(A) = interference voltage A-weighted, dB(A), effective value (IEC 268-1)

- Signal-to-noise ratio referring to maximum output voltage at 4 Ω and A-weighted interference voltage

Power Amp output U(F)

LEVEL controls set to their clockwise margin CPS1 SPEAKER

OUT A&B -67 -56 -69 32.5 -102.5 105

CPS2 SPEAKER

OUT A&B -67 -56 -69 33.5 -102.5 105 LEVEL controls set to their counterclockwise margin CPS1 SPEAKER

OUT A&B -68 -57 -70 / / / CPS2 SPEAKER

OUT A&B -68 -57 -70 / / /

12. Dimensions and weight

Power amplifier weight Dimensions in mm

CPS1 15kg 483 x 132.5 x 385.5 CPS2 16kg 483 x 132.5 x 385.5

dBu

U(G)

dBu

U(A)

dBu

GAIN

IN(A)

dBu

S/N-R.dBremarks

INPUT A&B R(Q) = 50Ω INPUT A&B R(Q) = 50Ω

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