Manual

AtlasSound.com – 10 –
Owner’s Manual
AA50PHD
50W Mixer Amplifier
1601 Jack McKay Blvd. • Ennis, Texas 75119 U.S.A.
Telephone: [phone] • Fax: [phone]
Rear Panel
16. Amplifier Outputs
For loudspeaker connections, connect as follows or proceed to the setup section for typical wiring schemes.
• COM - Speaker common or negative connection
• 4Ω - Connect to direct coupled loudspeakers
• 25V - Connect to transformer coupled loudspeakers
• 70V - Connect to transformer coupled loudspeakers
17. Power Cord
Connect this grounded power cord to 120VAC circuits only. Serious damage may result otherwise.
18. Ground Terminal
Connect this terminal to electrical ground as required by local codes.
Using the PHD Mixer Amplifier Diagnostic System
The AAPHD Series features a patent pending Amplifier Self Diagnostic System. The PHD (Push Here Diagnostic) is simple to use and
is very effective running a 70V distributed system diagnostic test to assure the amplifier has the proper load applied. The proper load
will assure you a long lasting trouble free audio experience with your new AAPHD Series amplifier. Many amplifiers fail because an
incorrect load is applied to the amplifier. This is especially true when using the amplifier in a 25V or 70V distributed audio speaker
system. There are a few common failure points that can occur during system installation that are listed below.
Common Amplifier Failure Conditions, also see “How to Trouble Shoot Your Speaker System if the Limit LED is Illuminating”.
1. A short in the speaker wiring.
2. Improper load selection or power tap setting on 70V speaker systems. It is very common when using many speakers to
have one of the speakers tapped accidently at 8Ω. This error will definitely be very hard on a 70V amp and in most
cases cause the amp to fail within a few days. This kind of error is easy to make, time consuming to find and costly to fix.
3. Too many speakers attached or the wrong power taps are selected. If a 100 watt amp is used in a 70V system and it has ten
speakers all tapped at 10W, but three of the speakers are accidently tapped at 30W, that comes up to 160W of power
required to drive the system properly. While it may work at low levels, as soon as the system needs to be louder the
amp will be strained and could fail over time.
Most amplifier failures are caused by improper installation on the speaker side. There are two known ways to test the speaker system
after everything is installed.
A. Measure the speaker system using a true audio frequency impedance meter. These are the best way to see if your speaker
system is wired correctly for the amplifier.
B. Run the PHD Self Diagnostic test.