Crown Official Manual for Power Amplifiers: CT 4150, CT 8150, CT 875, and CT 875 Models

CT Power Amplifiers

8 Amp Configuration

8.1 70Hz HPF (High Pass Filter)

On the back panel, one 2-position high-pass filter switch will only allow signals above 70Hz to be amplified. This is to prevent transformer saturation. The HPF, when turned on, is activated for all channels. The filter is a 2nd order 12 dB/occ t filter.

8.2 Limiter

The limiter reduces amplifier gain to allow over drive without harsh clipping at output.

When Amp Configuration Switch #5 is set to on (pushed up), the amplifier will utilize the limiter feature.

9 Operating Modes

DriveCore Amplifiers can work in a variety of power modes.

9.1 Normal

The amplifier automaticaly operates full output power.

9.2 Green Power

Green mode utilizes Crown’s adaptive rail technology for higher efficiency or power on demand. When Amp Configuration DIP switch #4 is set to on, the amplifier will operate in green mode.

For low input signal levels (less than –40dBu) the amplifier will operate with minimum power.

The amplifier will increase to full power if either of the following occurs:

1 - The input signal goes above -40dBu

2 - There is a single clip event from any of the channels

Likewise, if the amplifier is operating with full power, the amplifier will decrease the operating rails to minimum power if the input signal drops

below -40dBu.

Through the use of Green Power, the efficiency of the amplifier dramatically increases for lower audio signal reproduction. The adaptive rail technology used in the CT amplifiers can increase the efficiency of the amplifier by up to 10% with low signal levels.

9.3Deep Sleep See Section 10.1

Is green mode	NO	Full Power
DIP switch on?

Y

E

S

Lower voltage rails

Is there a clip	NO	Minimum Power
event?

Y

E

S

Increase rails to Full Power

Figure 9.2.1 How Green Power DIP switches work

page 12 Operation Manual