Speaker Connections; Trouble Shooting - Redback PHASE 5 A 4264 Operating Manual

SPEAKER CONNECTIONS

Speakers fitted with 100V line transformers may be connected to the corresponding terminals on the rear of the amplifer.
Always ensure the total load of the fitted speakers does not exceed the rated output of the amplifier (ie 60 watts)
otherwise damage may result. When fitting speakers with line transformers the impedance of the load cannot be
measured using a standard multimeter. An impedance meter is required. Fig 2 lists the impedance at certain loads of
speakers fitted with 100V line transformers. So for a total load of 60 watts using 100V line transformer fitted speakers the
impedance of the speaker load should be 166Ω.
i
About 70V & 100V Line Speaker Systems
Wiring speakers in parallel for 70/100V line: Where several speakers are to
be used at one time, on one circuit, it becomes necessary to use speakers tted
with line-matching transformers. This is to overcome the effects of connecting
speakers in parallel and cable losses. The ampli er generally has an output
voltage of 100 volts (70 volts is typically used in North America, however
operation is similar). In this con guration the total wattage load on the ampli er
is derived from adding all the line transformer primary tap ratings together. For
example, 70 one watt speakers will have a total speaker load of 70 watts. Or
alternatively, it is conceivable to connect 100 one watt speakers to a 100 watt,
100 volt line ampli er.
Measuring 70/100V Line Speaker Impedance: To measure ampli er system
load, you must use an impedance meter in order to measure the ac resistance
of the connected speaker network. Impedance cannot be measured with a
standard multimeter, as this measures the dc resistance. Use the Altronics
Q 2001 or similar impedance meter.

TROUBLE SHOOTING

If the REDBACK Phase 4 amplifier fails to deliver the rated performance, check the following:
No Power, No Lights
Make sure amplifier power switch is on. Make sure mains power switch is on at the wall. Check the mains and
DC fuse. Replace with only the correct type and rating. Over rated fuses will invalidate warranty.
Distorted Output
Check that the speaker type is correct for the output that you are using (ie. 4-16Ω, 70V or 100V line). Check for
any short circuits on the speaker line.
Very Low Output Volume
Make sure that the input is the correct level (check for shorted connectors). Check for any short circuits on the
speaker line.
Check if power LED's on the front panel is lit to indicate there is signal. If it is not lit there is no signal present.
Continually Blows Fuses
Make sure that the speaker line is not shorted. Check speaker types, ratings and if on correct output.
Amplifier Keeps on Cutting In & Out
Make sure that there is adequate ventilation around the amplifier. Check the vent slots on the front,top and sides
are not covered or blocked and the fan on the rear is functioning correctly. Check also speaker types, ratings and
for any short circuits on the speaker line.
No Output From 24V DC
Make sure the 24V DC Out connector is wired correctly.
www.altronics.com.au
A 4264
Load 70V 100V
0.5W 9.4k 20k
0.66W 7.12k 15k
1W 4.7k 10k
1.25W 3.76k 8k
2W 2.35k 5k
2.5W 1.88k 4k
3W 1.56k 3.3k
5W 940 2k
7.5W 626 1.3k
10W 470 1k
15W 313 666
20W 235 500
30W 156 333
40W 117 250
60W 78 166
100W 47 100
125W 37 80
250W 19 40
500W 9.4 20
Redback® Proudly Made In Australia
4 x 60 Watt Power Amplifier
Fig 2
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