PoE Series Audio Amplifiers Operations Manual Rev E
Page 7
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Table of Contents
All models:
2.
Power LED
– This LED illuminates when power is present
3.
4Ω/8Ω Switch (low impedance model only)
– Position this switch to match the impedance of your
loudspeakers. If this switch is positioned improperly, the amplifier may not deliver full output power,
or the PSE may remove power from the amplifier port and renegotiate the connection.
4.
Output Connector
– Connect loudspeakers using the 5mm Euro-style terminal blocks provided. Strip
the loudspeaker leads ¼” and insert into the connector, observing proper polarity. With a small flat-
blade screwdriver, tighten the screw until the leads are securely in place. Inspect carefully for
possible shorts or broken wires.
Use 4Ω or 8Ω speakers for the low impedance models (AV8-2-LZ-D and AV20-2-LZ-D) and position
the switch ③ to match the loudspeaker impedance.
1
Because the audio power is limited by the PoE
standard, use high sensitivity and SPL loudspeakers for best performance. Stewart Audio
recommends using high-quality, heavy-gauge speaker wire. Use the following as a guide to select the
appropriate wire gauge.
Distance
Wire Gauge
Up to 25 ft (7.6m)
16 AWG
26-40 ft (8-12m)
14 AWG
41-60 ft. (8.5-18m)
12 AWG
Use high impedance speakers for the constant voltage models (CVA16-1-CV-D and CVA40-1-CV-D).
Because the current flow in constant voltage systems and speakers is much lower than in 4/8Ω
systems, higher gauge (thinner diameter) wire can be used. Connect the loudspeaker wires to either
the 70V or 100V pair of terminals, observing proper polarity. Care should be used when working
around the speaker terminals. Although not officially recognized as a shock hazard in the UL60065
Safety Requirements, touching these terminals can be quite unpleasant and should be avoided. Use
the following as a guide to select the appropriate wire gauge.
Distance
Wire Gauge
Up to 500 ft (<150m)
22 AWG
500-1000 ft (150-300m)
20 AWG
Over 1000 ft. (300+m)
18 AWG
The sum of the tapped wattage for all high impedance loudspeakers must not exceed 16W for the
CVA16-1-CV-D and 40W for the CVA40-1-CV-D.
The constant voltage amplifier models are equipped
with an internal 100Hz corner frequency highpass filter to minimize the possibility of saturating the
transformer in the high impedance loudspeakers.
1
Low
impedance models can deliver up to 16W
rms
for the AV8-2-LZ-D, and up to 32W
rms
for the AV20-2-LZ-D
into a
single
4Ω speaker by connecting the speaker to either output and positioning the switch to the 8Ω
position. The amplifiers will not drive an 8Ω speaker above 8W
rms
/ 20W
rms
. Connecting two 4Ω speakers with
the switch set to 8Ω may result in a power disruption at the PoE port.
Caution: The DC voltage on the speaker output connectors is approximately 12VDC. Do not
connect any speaker output to ground. Do not connect speakers across speaker outputs.
(Bridge mode is not supported.)
