Crown Audio STUDIO AMPLIFIER owner manual Controls, Circuit Breaker

Studio Reference I & II Professional Studio Amplifiers

former than in the output devices. This can overheat the transformer and activate its protection system.

Studio Reference amplifiers are designed to keep work- ing under conditions where other amplifiers would fail. But even when the limits of a Studio Reference amplifier are exceeded, it still protects itself—and your invest- ment—from damage.

4.3.4 Circuit Breaker

A back panel circuit breaker is provided to prevent ex- cessive current draw by the high-voltage power sup- plies. A Studio Reference I configured for 100 to 120 VAC has a 30 amp circuit breaker, while the 220 to 240 VAC version has a 20 amp circuit breaker. A Stu- dio Reference II configured for 100 to 120 VAC uses a 20 amp circuit breaker, and the 220 to 240 VAC ver- sion has a 10 amp circuit breaker. With rated loads and output levels, this breaker should only trip in the incred- ibly rare instance of a catastrophic amplifier failure. The ODEP system keeps the amplifier safe and operational under most other severe conditions. The breaker can also trip in situations where extremely low-impedance loads and high output levels result in current draw that exceeds the breaker’s rating. Again, this should only be possible when operating outside rated conditions, like when the amplifier is used to drive a 1 ohm load, or when an input signal is clipped severely.

4.4 Controls

The front panel enable switch is used to turn the ampli- fier on and off. If you ever need to make any wiring or installation changes, don’t forget to disconnect the power cord first. Please follow these steps when first turning on your amplifier:

1.Turn down the level of your audio source. For example, set your mixer’s volume to – • (off).

2.Turn down the amplifier’s level controls.

3.Turn on the enable switch. The enable indicator be- side the switch should glow. During the four second turn-on delay that immediately follows, the indica- tors will flash as described in Figure 4.2. After the delay, the ODEP indicators should come on with full brilliance and the IOC and signal presence indica- tors should function normally.

4.After the turn-on delay, turn up your source to the maximum desired level.

5.Turn up the amplifier’s level controls until the maxi- mum desired sound level is achieved.

6.Turn down the level of your audio source to its normal range.

Each of the front panel level controls has 31 detents for accurately repeatable settings. In Bridge-Mono and Parallel-Mono modes, the channel 2 level control should be turned down.

The meter switches are located behind the front panel. They make it possible to switch between the dy- namic range and signal level display modes for the meters, or you can turn the meters off. From the factory, the meters automatically display dynamic range (which is computed as the ratio of peak to average out- put power). To change these switches, you will need to remove part of the front panel. A phillips screwdriver will be needed, and it will help to remove the amplifier if it is mounted in a rack. Follow these steps:

1.Make sure the amplifier is turned off and its power cord is disconnected from the AC mains source.

2.Remove the two screws that hold each end cap in place and remove both end caps (see Figure 3.2).

3.Remove the six screws that hold each handle in place and remove each handle (see Figure 4.3).

4.Remove the dust filter by gently pulling it away from the front panel.

5.Remove the two screws that secure the lower half of the front panel and remove the lower front panel.

6.Locate the meter switches as shown in Figure 4.4. Set the switches as desired. The left switch is used to turn the meters on and off, and the right switch is used to change display modes.

7.Reassemble the front panel, handles and end caps in reverse order of disassembly.

8.Install the amplifier and reconnect power.

AMPLIFIER TOP VIEW

(FRONT LEFT CORNER—END CAP REMOVED)

To remove the handle, pull firmly from the side.

Fig. 4.3 Removing a Handle

Page 22