Crown Audio STUDIO AMPLIFIER Facilities, A. Level Controls, B. ODEP Indicators, C. IOC Indicators

Studio Reference I & II Professional Studio Amplifiers

A B C DD C B A E F

®

GH

Fig. 2.1 Front Facilities

2 Facilities

A. Level Controls

Each channel’s output level can be adjusted accurately using the 31-position detented level controls on the front panel (see Section 4.4).

B. ODEP Indicators

During normal operation of the amplifier, the ODEP (Output Device Emulation Protection) indicators glow brightly to show the presence of reserve thermody- namic energy. They dim proportionally as energy reserves decrease. In the rare event that energy re- serves are depleted, the indicators turn off and ODEP proportionally limits the output drive so the amplifier can safely continue operating even under severe conditions. These indicators also help to identify more unusual op- erating conditions (see Figure 4.2).

C. IOC Indicators

The IOC (Input Output Comparator) indicators serve as sensitive distortion indicators to provide proof of distortion-free performance. Under normal conditions, the indicators remain off. They flash if the output waveform differs from the input by 0.05% or more (see Section 4.2). If the input signal level is too high, the indicators will also flash brightly with a half-second hold delay to show input overload or output clipping. Note: The channel 2 IOC indicator stays on in Parallel-Mono mode. See Section 4.2.

D. Signal Presence Indicators

These indicators flash synchronously with the amplifier’s audio output to show signal presence. Note: These indi-

cators may not flash at very low input signal levels. See Section 4.2.

E. Enable Indicator

This indicator lights when the amplifier has been “en- abled” or turned on, and AC power is available.

F. Enable Switch

This push button is used to turn the amplifier on and off. When turned on, the output is muted for about four sec- onds to protect your system from start-up transients. This is why a power sequencer is rarely needed for mul- tiple units. (The turn-on delay can be changed. Contact Crown’s Technical Support Group for details.)

G. Dust Filter

The dust filter removes large particles from the air drawn in by the cooling fan. In most cases, the fan will not run so the filter will remain clean. If the filter becomes dirty, it can be removed for easy cleaning (see Section 4.5).

H. Dynamic Range / Level Meters

A five-segment output meter is provided for each chan- nel. The meters are factory-set to show dynamic range of the signals in dB, which is computed as the ratio of peak to average output power. Also, the meter can op- tionally be set to show output levels (see Section 4.4).

❏Meter Switches

Two switches behind the front panel can be used to customize the output meters (H). By default, the meters display dynamic range. To make the meters display sig- nal levels or to turn them off, see Section 4.4.

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