Crest audio HD User Manual

PROFESSIONAL POWER AMPLIFIERS

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OWNER’ S MANUAL

Important Precautions

This symbol is used to alert the operator to follow important operating procedures and precautions detailed in documentation.

This symbol is used to warn operators that uninsulated “dangerous voltages” are present within the equipment enclosure that may pose a risk of electric shock.

1.Save the carton and packing material even if the equipment has arrived in good condition. Should you ever need to ship the unit, use only the original factory packing.

2.Read all documentation before operating your equipment. Retain all documentation for future reference.

3.Follow all instructions printed on unit chassis for proper operation.

4.Do not spill water or other liquids into or on the unit, or operate the unit while standing in liquid.

5.Make sure power outlets conform to the power requirements listed on the back of the unit.

6.Do not use the unit if the electrical power cord is frayed or broken. The power supply cords should be routed so that they are not likely to be walked on or pinched by items placed upon or against them, paying particular attention to cords and plugs, convenience receptacles, and the point where they exit from the appliance.

7.Always operate the unit with the AC ground wire connected to the electrical system ground. Precautions should be taken so that the means of grounding of a piece of equipment is not defeated.

8.Mains voltage must be correct and the same as that printed on the rear of the unit. Damage caused by connection to improper AC voltage is not covered by any warranty.

9.Have gain controls on amplifiers turned down during power-up to prevent speaker damage if there are high signal levels at the inputs.

10.Power down & disconnect units from mains voltage before making connections.

11.Never hold a power switch in the “ON” position if it won’t stay there itself!

12.Do not use the unit near stoves, heat registers, radiators, or other heat producing devices.

13.Do not block fan intake or exhaust ports. Do not operate equipment on a surface or in an environment which may impede the normal flow of air around the unit, such as a bed, rug, weathersheet, carpet, or completely enclosed rack. If the unit is used in an extremely dusty or smoky environment, the unit should be periodically “blown free” of foreign matter.

14.Do not remove the cover. Removing the cover will expose you to potentially dangerous voltages. There are no user serviceable parts inside.

15.Connecting amplifier outputs to oscilloscopes or other test equipment while the amplifier is in bridged mode may damage both the amplifier and test equipment!

16.Do not drive the inputs with a signal level greater than that required to drive equipment to full output.

17.Do not connect the inputs / outputs of amplifiers or consoles to any other voltage source, such as a battery, mains source, or power supply, regardless of whether the amplifier or console is turned on or off.

18.Do not run the output of any amplifier channel back into another channel’s input. Do not parallelor series-connect an amplifier output with any other amplifier output.

Crest Audio is not responsible for damage to loudspeakers for any reason.

19.Do not ground any red (“hot”) terminal. Never connect a “hot” (red) output to ground or to another “hot” (red) output!

20.Non-use periods. The power cord of equipment should be unplugged from the outlet when left unused for a long period of time.

21. Service Information E q u i p m e n t should be serviced by qualified service personnel when:

A.The power supply cord or the plug has been damaged;

B.Objects have fallen, or liquid has been spilled into the equipment;

C.The equipment has been exposed to rain;

D. The equipment does not appear to operate normally, or exhibits a marked change in performance;

E.The equipment has been dropped, or the enclosure damaged.

22.To obtain service, contact your nearest Crest Audio Service Center, Distributor, Dealer, Crest Audio at 201.909.8700 (USA).

Power Amplifier Owner’s Manual

				Table of Contents
				Introduction				5
				Unpacking				5
				Installation and Mounting				5
				Front Panel				6
				Back Panel				7
			Internal Configuration and Control					8
				Operation				9
			Connecting Power / Circuit Size Requirements					9
				Cooling Requirements				9
				Connecting Inputs				10
				Connecting Outputs				10
				Mode Selection				11
			Stereo /Parallel/Bridged Mono Connections					12
			TourClass® Protection Features					13
				User Precautions				14
				Speaker Protection				14
			Recommended Speaker Cabling					14
				Maintenance				15
				User Responsibility				15
				Service and Repair				15
			Appendix A	Specifications
			Appendix B	HD Block Diagram
			Appendix C	Wire Gauge Charts
			Appendix D	Rear Panel Symbols - Legend
			Appendix E	HD18 Special Functions
			Appendix F	Warranty Information

Crest Audio HD Series Power Amplifiers	Page 3
Models HD2, HD4, HD6, HD9, HD12, HD18

HD12, 18 Front View

Front height 5.25"

133mm

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Front width 19" / 483mm

HD2-9

Front View

Rear height 3.5" 89mm

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Front width 19" / 483mm

Rear/Side Views HD2-9 (Top), HD12, HD18 (Bottom)

			A			A
+	A
			AB		•	•		3.5"
+	A	A
	B					+		89mm
		A B	A	B	• •
+
	B
			A B			B
								2+
							1
								3-
17.9"/437mm (19"/483mm to rack ears)
						1	2+
							3-
						A
			A					5.25"
+	A				•	•
			AB					133mm
		A
+	A					+
	B	A B A B			• •
+
	B		A	B
						B

CA2

CA4

CA6

CA9

1.375"

18"/457mm 35mm

CA12

CA18

See appendix E for detailed drawing and information regarding model HD18

Page 4	Crest Audio HD Series Power Amplifiers
	Models HD2, HD4, HD6, HD9, HD12, HD18

Introduction

Congratulations on your purchase of a new HD Series professional power amplifier, and thank you for your confidence in Crest Audio products. You are among the growing number of audio professionals who have made Crest Audio one of the world’s leading suppliers of professional and commercial/industrial audio systems.

For your safety, please read the Important Precautions section before installing and operating the amplifier.

The Crest Audio HD Series is based on the same advanced circuit topologies that have made Crest amplifiers the choice of touring professionals worldwide. HD Series amplifiers are designed for high operating efficiency and accurate sonic performance across the full audio bandwidth, even under stressful conditions. In order to maintain strict quality assurance standards, all HD Series amplifiers are built in Crest’s state-of- the-art USA manufacturing facility. Internal components are the finest available, and key sub-assemblies are pre-tested before final assembly. Finally, each amplifier is “burned in” and thoroughly tested (using precision audio test equipment) before shipping. In addition, all HD Series amplifiers incorporate Crest’s exclusive TourClass protection features to safeguard both internal circuitry and connected loudspeakers.

This proven combination of advanced design, quality construction, and comprehensive circuit protection is your guarantee of fail-safe reliability. You can depend on consistent, stable performance even when your HD Series amplifier is subjected to punishing extremes in the most demanding fixed or mobile sound reinforcement applications.

Unpacking

Please inspect the amplifier carefully immediately after unpacking. If you find any damage, notify your supplier/dealer immediately. Only the shipper may file a damage claim with the carrier for damage incurred during shipping. Be sure to save the carton and all packing materials for the carrier’s inspection.

If your packing materials are in good condition, please save them. If you ever need to ship the unit back to Crest Audio or an authorized service center, you should use only the original factory packing.

Installation and Mounting

Four HD Series amplifiers are 2-rack-space units: models 2, 4, 6, and 9. The HD Series models 12 and 18 are 3-rack-spaces high. All mount in standard 19-inch racks. Four front-panel mounting holes are provided on each amplifier. Rear mounting ears give additional support, and use of rear supports is highly recommended in all mobile and touring sound systems. Optional rack-mount handles are available. Dimension drawings are included on page 4.

Crest Audio HD Series Power Amplifiers	Page 5
Models HD2, HD4, HD6, HD9, HD12, HD18

Front Panel

1	2	3	4	5	6	7	8	9
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1. Rack Mounting Ears.
Two front panel mounting holes are provided on each mounting ear.								Never try to hold the
2. Optional Rack Handles.								circuit breaker/power
								switch in the “ON”
Available from your authorized supplier.
								position if it won’t stay
3. Fan Outlet Grills.								there itself!

Granit Line amplifiers are cooled by two, rear-mounted fans. Cool air flows over the heat sinks and exhausts through the front grills. Make sure these outlets remain clear to allow unrestricted air flow.

4. AC Power Switch/Circuit Breaker.

Granit Line amplifiers have a front-panel combination AC switch and circuit breaker. (No fuses are used.) If the switch shuts off during normal use, push it back to the “ON” position once. If it will not stay on, the amplifier needs servicing.

5. Active LED.

Indicates that AC power is connected and the amplifier is turned on.

6. Protect LED.

Indicates that the channel is in Protect mode (speakers disconnected by output relay).

7. Clip LED.

Illuminates at the clipping threshold. Continuous illumination also indicates that

ACL (Active Clip Limiting) protection circuitry is engaged.

8. Signal LED.

Illuminates to indicate that a signal (above a minimum threshold) is present at the amplifier input, and that the signal is being amplified.

9. Input Attenuators.

Two input attenuators adjust level for their respective amplifier channels. In Bridged Mono Mode, both attenuators are used to control signal level and must be adjusted to the same setting.

Page 6	Crest Audio HD Series Power Amplifiers
	Models HD2, HD4, HD6, HD9, HD12, HD18

Never connect a “hot” (red) output to ground or to another “hot” (red) output!

Rear Panel See Appendix E for information specific to model HD18.

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

AVIS : RISQUE DE CHOC ÉLECTRIQUE—NE PAS OUVRIR

WARNING TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK DO NOT

EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE.

ATTENTION! POUR ÉVITER LE RISQUE D'INCENDIE OU DE CHOC ÉLECTRIQUE, NE PLACEZ PAS CET APPAREIL SOUS LA PLUIE OU Á L'HUMIDITÉ

+

+

+

A

A

B

B

A A

• •

A B

A

		+
A B	B • •
A
A	B	B

Designed & manufactured in the USA by:

Crest Audio Inc.

100 Eisenhower Dr.

Paramus, New Jersey 07652 USA

1 2+

3-

10

11

12

13

14

15

10. Output Connectors

Your amplifier is supplied with 5-way Output Binding Posts. Connection to the binding posts can be made with bare wire, banana plugs, or spade lug terminations. Make connections to both the Channel A and Channel B terminals for Stereo or Parallel Mode, or a single connection across the red (“hot”) terminals only of Channels A and B for Bridged Mono Mode. See Appendix D and the section on Mode Selection for more information. NOTE: on the HD18, two pairs of 5-way binding posts are provided for each channel, so that paralleling of speakers is possible.

11. Mode Selection Switch.

This recessed, three-position switch configures the amplifier for Stereo, Parallel or Bridged Mono Mode operation. Amplifiers are factory-configured for Stereo Mode. See Appendix D and the section on Mode Selection for more information.

12. Signal Ground Lift Switch.

The recessed signal ground lift switch is factory-set to the ‘ground’ (bottom) position, which electrically connects the signal ground to the chassis/AC ground. The top position lifts the amplifier’s signal ground. In a properly designed system (for safety purposes and to minimize noise), the amplifier should be connected to ground through the AC line cord. Also, whenever possible, the signal source equipment should share the same AC ground as the amplifier. In some cases this may not be possible, and a ground loop results. If this happens, the first step is to move the ground lift switch to the top (‘lift’) position. In this position, the signal ground is lifted and completely isolated from the chassis/AC ground. Do not change the switch to the ‘lift’ position if the amplifier and the signal source equipment are on the same AC ground. Should the ground loop problem persist after the ground lift switch has been set to the ‘lift’ position, then the shield on balanced input lines should be grounded at one end only (usually the signal source).

Crest Audio HD Series Power Amplifiers	Page 7
Models HD2, HD4, HD6, HD9, HD12, HD18

13-14. Balanced 1/4" (TRS) & XLR Input Connectors.

These connectors accept input signals on balanced TRS and XLR input plugs. See the figure at the left for information on polarity. Connectors for each channel are in parallel; the unused connectors may be used for “loop through” connection to other amplifiers.

Note: Unbalanced “Tip/Sleeve” plugs may be used with the balanced TRS

“Tip/Ring/Sleeve” connectors. The “ring” terminal or negative input will be connected to ground internally. When using three-pole (‘stereo’) TRS connectors, make sure that the ring connection is made either to the cold (–) output of the source equipment, or to ground. Incorrect connections may cause a 6dB loss in level.

15. Fan Inlet Ports & Filters.

Tip - Positive (+)

Ring - Negative (-)

Sleeve - Ground ()

+

1 - Ground ()

3 - Negative (-)

2 - Positive (+)

Cooling air enters the amplifier through the fan inlet ports located on the rear of the amplifier chassis. Be sure not to block these ports when installing the amplifier or other associated equipment. Air must flow unimpeded through these ports. Removable fan filters are provided to minimize entry of dust and dirt.

Internal Configuration and Control

Input XLR Polarity

HD Series amplifiers are supplied standard with the XLR configured as “Pin 2 hot” (+). On models HD2, HD4, HD6, HD9 and HD12, an internal jumper makes it possible to alter the amplifier to “Pin 3 hot” (+).

NOTE: This jumper is NOT user configurable. Please consult your supplier or lohdl Crest Audio service center if you wish to have the input XLR polarity changed

On the HD18, an external XLR polarity switch is featured. (See Appendix E).

Input Sensitivity

The HD Series amplifiers have a standard input sensitivity of .775 Volts for rated power at 8 Ohms. Models HD2, HD4, HD6, HD9 and HD12 are fitted with an internal jumper which allows optional gains of X20 or X40. Model HD18 features an external voltage gain/input sensitivity switch (See Appendix E). Standard and optional voltage gains/input sensitivities are detailed below.

HD2

HD4

HD6

HD9

HD12

HD18

Gain

Sens

Gain

Sens

Gain

Sens

Gain

Sens

Gain

Sens

Gain

Sens

Std.

X45

.775V

X61

.775V

X68

.775V

X86.5

.775V

X97.5

.775V

X115

.775V

Opt. 1

X40

.866V

X40

1.12V

X40

1.32V

X40

1.66V

X40

1.87V

X40

2.24V

Opt. 2

X20

1.73V

X20

2.24V

X20

2.65V

X20

3.32V

X20

3.74V

X20

4.47V

NOTE: This jumper is NOT user configurable. Please consult your supplier or local Crest Audio service center if you wish to have the voltage gain / input sensitivity changed.

Page 8	Crest Audio HD Series Power Amplifiers
	Models HD2, HD4, HD6, HD9, HD12, HD18