Crown PH-1A Datasheet
PH-1A
he Crown® PH-1A is a single-channel,
battery- or AC-powered phantom
power supply for condenser microphones.
T
Battery power provides 17V phantom and AC
power provides 24V phantom.
The unit can be AC powered by using a 24V
AC/DC adaptor (not included). This adaptor
plugs into a 120V AC wall outlet and provides
24V DC to the PH-1A.
When using external power, the PH-1A provides
+24V DC nominal loaded voltage on pins 2 and
3 with respect to pin 1 of the microphone input
connector.
With battery operation, the PH-1A provides
+17V DC nominal loaded voltage. “Loaded
voltage” is the phantom voltage available with a
microphone plugged in.
The PH-1A includes suffi cient hum fi ltering for
extremely quiet operation and is transformer
isolated. If AC power fails, the batteries automatically take over.
The rugged steel and aluminum chassis is designed to withstand daily abuse in professional
applications.
Operation
To use your phantom supply, follow this procedure:
1. For AC powering, purchase a 24V AC/DC
adaptor with a 1/8 inch (3.5mm) phone plug.
Connect the adaptor to an AC outlet providing
120 VAC, 60 Hz. Connect the adaptor's phone
plug to the 1/8 inch (3.5 mm) phone jack in the
PH-1A phantom supply.
2. For battery powering, unscrew the two large
captive screws on the underside of the phantom
supply; open the chassis, and install two 9V
alkaline batteries (Duracell MN1604 or equivalent). Replace the cover.
3. Plug the cable from your microphone into the
MIC IN connector.
4. Plug the cable going to the input of your
mixer or recorder into the OUTPUT connector.
This cable can be unbalanced because the phantom supply is transformer isolated.
5. To prevent ground loops, be sure that the
phantom supply is resting on its rubber feet.
6. To avoid draining the batteries after use,
unplug the mic cables and unplug the AC/DC
adaptor from the phantom supply. There is no
battery drain when all cables are unplugged
from the supply.
SINGLE CHANNEL
BATTERY OR AC POWERED
PHANTOM POWER SUPPLY
Features
Supplies a single channel of clean phantom
power to a condenser microphone
Powered by internal 9V batteries or external
24V power supply (not included)
Supplies 17V phantom with battery power
and 24V phantom with AC power
Specifi cations
Phantom voltage supplied: 24V with AC
powering; 17V with battery power. Each voltage is nominal loaded voltage on pins 2 and
3 with respect to pin 1 of microphone input
connector.
Number of channels: 1.
Microphone input connector: Female 3-pin
professional audio connector (XLR-type).
Output connector: Male 3-pin professional
audio connector (XLR-type).
DC power input connector:
phone jack, positive tip.
AC/DC adaptor: Not included. Use a 24V AC/DC
adaptor with 120V AC input, 24V to 31V DC
output,
1/8 inch (3.5 mm) phone plug con-
nector with positive tip.
J1
1/8 inch (3.5 mm)
Rugged construction for professional
use
If AC power fails, the batteries automatically take over
Transformer-isolated signal
Battery powering: Two 9V alkaline cells
(Duracell MN1604 or equivalent). Batteries
not included.
Battery life: 525/I hours, where I = current
drain of microphone in mA. 350 hours typical.
Hum fi ltering (inside phantom supply): 50 dB
at 60 Hz; 62 dB at 120 Hz.
Dimensions: 5.0 x 2.325 x 1.750 inch LWH
(12.7 cm x 5.91 cm x 4.44 cm).
Weight: 1¼ lb. (0.57 kg).
+
PH-1A Schematic
PH-1A
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:
E
= E
- RI
L
U
where
EL= loaded phantom voltage
E
= unloaded phantom voltage (30.7V with
U
Crown PS-24 AC/DC adaptor)
R = 983 ohms (typical internal resistance of PH1A when used with an AC/DC adaptor)
I = current drain of microphone in amperes.
For battery powering, the loaded phantom
voltage is:
E
= E
- RI
L
U
where
E
= loaded phantom voltage
L
= unloaded phantom voltage (18V with two
E
U
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’ Specifi cations
The model shall be the Crown PH-1A. It shall be
a single-channel, battery or AC powered, 17- or
24-volt 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 connector. With battery power, it shall provide 17V
DC nominal loaded voltage.
The supply shall include suffi cient hum fi ltering for extremely quiet operation, and shall be
transformer isolated. If AC power fails, the batteries shall automatically take over. The Crown
model PH-1A is specifi ed.
Warranty
Crown professional microphones are guaranteed against malfunction for a period of three
years from date of original purchase. See
enclosed warranty sheet for additional information.
Service
If the unit fails to operate, plug your AC/DC
adaptor 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 on the phoneplug tip with respect to the phone-plug sleeve.
If the AC/DC adaptor is working correctly, plug
it into the phantom supply. Measure the DC
voltage between pins 2 and 1 of the microphone
input connector. With no microphone plugged
in, you should measure at least 24V DC. If not,
return the PH-1A 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 original 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
©
2008 Crown Audio®, Inc. Specifi cations 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.
6/08 103292-9
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