Crown Audio STUDIO AMPLIFIER owner manual Use Good Connectors, Output Connection

Studio Reference I & II Professional Studio Amplifiers

power cables and power transformers. We also recom- mend using shielded or twisted pair wire. With loose wires, use tie-wraps to bundle together each pair of in- put wires. This helps reduce magnetically-induced current by minimizing the cross-sectional area be- tween conductors that could bisect the magnetic field.

Ground loops often occur when the input and output grounds are tied together. DO NOT CONNECT THE INPUT AND OUTPUT GROUNDS TOGETHER. Tying

the damping factor decreases as the cable resistance increases. This is very important because the ampli- fier’s excellent damping factor can be easily negated by using insufficient cable.

Use the nomograph in Figure 3.14 and the procedure that follows to find the recommended wire gauge (AWG or American Wire Gauge) for your system.

the grounds together can also cause feedback oscil- lation from the load current flowing in the loop. To avoid this problem, use proper grounding, isolate the inputs, and isolate other common AC devices. When using the input phone jacks, the signal grounds can be isolated from the AC mains ground with the ground lift switch located on the amplifier’s back panel (see Fig- ure 2.2 and Section 4.4).

3.3.5 Output Connection

Consider the rated power-handling capacity of your load before connecting it to the amplifier. Crown is not liable for damage incurred at any time due to overpow- ering. Fusing loudspeaker lines is highly recom- mended (see Section 3.3.6). Also, please pay close attention to Section 4.1, Precautions.

You should always install loudspeaker cables of suffi- cient gauge (wire thickness) for the length used. The resistance introduced by inadequate output wiring will reduce the amplifier’s power to and motion control of the loudspeakers. The latter problem occurs because

Use Good Connectors

1.Male connectors on loudspeaker cables should not be exposed to prevent possible short circuits.

2.Connectors which might accidentally cause the two channels to be tied together when making and breaking connections should not be used. (A common example is the standard three-wire stereo phone plug.)

3.Connectors which can be plugged into AC power receptacles should never be used.

4.Connectors having low current-carrying capacity should not be used.

5.Connectors having any tendency to short should never be used.

40

30

20

15

10

9

8

7

6

5

4

3

2

1.5

1

0.9

0.8

0.7

0.6

0.5

RL

LOAD

RESISTANCE

(ohms)

			.0002					RS
								SOURCE
								RESISTANCE
				.0004				(ohms)
				.0006
						.001
	RL
	RS		.002
DAMPING
FACTOR
20,000				.004
10,000
				.006
						.01
5,000
			.02
2,000									8000		COPPER
1,000				.04
									5000			WIRE
				.06								(AWG)
500								(ohms/1000 ft.)
200						.1		2-COND.	1000
								CABLE	500
100			.2					(feet)
								1
								2	100			#28
50								5
			.4							#26
			.6					10	50			#24
20								20				#22
								50				#20
						1		100	10			#18
10								200				#16
									5			#14
								500				#12
5		2						1000				#10
								2000	1			#8
2				4				5000				#6
									.5			#4
1				6								#2
												#0
							10		.1			#00
												#0000
					20				.05
									.01
					40

Example Shown:

RL = 8 ohms; RS = 0.016 ohms or D.F. = 500;

Cable Length = 10 ft.; answer: #8 wire

Fig. 3.14 Wire Size Nomograph

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