Crown Audio PH-1A Loaded Phantom Voltage, Architects’ and Engineers’ Specifications, Warranty

Loaded Phantom Voltage

When you plug a microphone into a phantom power supply, the supply voltage drops due to the load of the microphone. The higher the current drain of the microphone, the more the voltage drops.

The loaded phantom voltage is the phantom voltage available when a microphone is plugged into the phantom supply. You can calculate the loaded phantom voltage for the PH-1A as described below:

For AC powering, the loaded phantom voltage is:

EL= EU - RI where

EL= loaded phantom voltage

EU = unloaded phantom voltage (30.7V with Crown PS-24 AC/DC adaptor)

R = 983 ohms (internal resistance of PH-1A when used with Crown PS-24 AC/DC adaptor)

I = current drain of microphone in amperes.

For battery powering, the loaded phantom voltage is:

EL = EU - RI where

EL = loaded phantom voltage

EU = unloaded phantom voltage (18V with two 9V batteries)

R = 743 ohms (internal resistance of PH-1A when used with battery powering)

I = current drain of microphone in amperes.

Architects’ and Engineers’ Specifications

The model shall be the Crown PH-1A. It shall be a single-channel, battery or AC powered, 17- or 24-volt DC phantom power supply for condenser microphones.

With AC power, the supply shall provide 24V DC nominal loaded voltage on pins 2 and 3 with respect to pin 1 of the microphone input con- nector. With battery power, it shall provide 17V DC nominal loaded voltage.

The supply shall include sufficient hum filter- ing for extremely quiet operation, and shall be transformer isolated. If AC power fails, the bat- teries shall automatically take over. The Crown model PH-1A is specified.

Warranty

Crown professional microphones are guaran- teed against malfunction for a period of three years from date of original purchase. See enclosed warranty sheet for additional informa- tion.

Service

If the unit fails to operate, plug the AC/DC adap- tor into a 120V AC power outlet and measure its DC output voltage between the tip and sleeve of the 1/8 inch (3.5 mm) phone plug. You should measure at least 24V DC (approximately 31V DC for the Crown model PS-24 AC/DC adaptor). If not, return the model PS-24 AC/DC adaptor to Crown’s Service Department.

If the AC/DC adaptor is working correctly, plug it into the phantom supply. Measure the DC

PH-1A

voltage between pins 2 and 1 of the microphone input connector. With no microphone plugged in, you should measure at least 24V DC (ap- proximately 30.7V DC with Crown model PS-24 AC/DC adaptor). If not, return the PH-1A phan- tom supply to Crown’s Service Dept.

If both the AC/DC adaptor and phantom supply are working correctly, check your microphone cables and batteries.

Also check your microphone data sheet under “operating voltage” to make sure it will operate on the voltage supplied by the PH-1A.

If service is required, return the unit in its origi- nal packaging to: Crown Factory Service, 1718

West Mishawaka Road, Elkhart, IN 46517- 9439. A Service Return Authorization (SRA) is required for product being sent to the factory for service. An SRA can be completed online at www.crownaudio.com/support/ factserv.htm.

For further assistance or technical support call

800-342-6939.

Crown International 1718 W. Mishawaka Rd. Elkhart, IN 46517-9439 TEL: 574-294-8000 FAX: 574-294-8FAX www.crownaudio.com

©2007 Crown Audio®, Inc. Specifications subject to change without prior notice. Latest information available at www.crownaudio.com. Crown and Crown Audio are registered trademarks of Crown International. Printed in U.S.A.