ing, and potentially destructive “pop” reaching the speakers.
In any large system whose components present an inductive load to the AC line (including electric motors, power supplies, and power amplifiers of all kinds), sequenced powering can avoid excessive inrush currents that can cause circuit breakers to trip even though the steady-state currents are not excessive. Power sequencing is particularly suited to applications where large installations must be switched by inexperienced personnel.
The PS-PRO HT is controlled by a front panel key-operated switch to provide security from non-authorized users tampering with the system. The switch has three positions: OFF, REM, and ON, allowing for local or remote control. With remote control, one or more PS-PRO HT’s may be installed in remote locations with on/off con- trol and LED monitoring via low-voltage control wires. The PS-PRO HT interfaces with computer touch screen systems as well.
Besides its power sequencing capabilities, the PS-PRO HT contains many other conditioning and protection features. Both aspects of its func- tioning will be discussed in the next sections.
The PS-PRO HT rear panel provides one un- switched outlet pair and three switched outlet pairs. The switched outlet pairs are labeled Delay 1, Delay 2, and Delay 3. (The other pair of outlets on the rear panel and an additional single outlet on the front panel are unswitched.)
Here’s how the PS-PRO HT works: When an ON sequence is initiated, power is immediately applied to the Delay 1 outlets. Power is then applied to Delay 2 and Delay 3 outlets per the 1-60 second total delay setting you choose with the front panel Delay Adjust control.
The screwdriver-settable Delay Adjust controls the total delay time between the Delay 2 and Delay 3 outlets. For example, if the Delay Adjust control is set to 30 seconds, Delay 1 outlets will
go on immediately, Delay 2 outlets will receive power 15 seconds after Delay 1 outlets, and Delay 3 outlets will receive power 15 seconds after Delay 2 outlets. Therefore the total delay time is 30 seconds.
The order is reversed on an OFF sequence. For example, when an OFF sequence is initiated and the Delay Adjust control is set at 60 seconds, Delay 3 outlets lose power immediately, Delay 2 outlets lose power 30 seconds later and Delay 1 outlets lose power 30 seconds after the Delay 2 outlets have been shut off. The total delay time is 60 seconds.
In the event of a power out, of course all equip- ment plugged into a PS-PRO HT will lose power simultaneously. However, when power is re- stored, the delayed outlet groups will again turn on in the usual delayed sequence (Remains off in Momentary Mode).
Installation Recommendations: In home theater
installations, we recommend that power amps or receivers be powered last — plug them all into Delay 3 or divide them into two groups and plug one group through Delay 2 and the other through Delay 3. Low level equipment such as video and audio processors should use Delay 1. Equipment incorporating clocks or timers such as VCR’s, or equipment that must respond to wireless remote actuation, should use the unswitched outlets. We suggest keeping the front panel unswitched outlet free for equipment that is only in use temporarily.
The overall capacity of the PS-PRO HT is 20 amps. This refers to the combined steady-state current drawn by all devices plugged into all of its nine outlets. If this combined current level exceeds 20 amps at any time, the circuit breaker will trip, cutting off power to your rack. If this oc- curs, you must reduce the load by unplugging one or more units from the PS-PRO HT. Then push the white button on the circuit breaker (on
2
