D-fend SA300 User Manual - page 27
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D-fend™ SA300 User Manual
4. Verify that the calculated current is below the SA300 ratings:
For direct drive scenarios without the use of step-up transformers, the previously determined current (I) will be the
current flow propagated through the SA300; therefore:
I = 3.53 Arms, which is well below the SA300 rated current handling capability.
For step-up drive scenarios where the SA300 is placed before a step-up transformer (see figure 2.5 on page 13), the current
passed through the SA300 will be higher than the calculated current (I) present on the 70V line. Therefore, use the step-up
transformer turns ratio to determine the operating current seen by the SA300. In this scenario the turns ratio is taken to be
1.5, so I = 3.535 Arms x 1.5 = 5.3. This is well within the current limits of the SA300.
Troubleshooting
Following are the most common technical issues. If you do not see an answer to your issue, please visit the FAQ page at
http://www.d-fend.net/support/faqs/, or you may e-mail us at dfend@eminence.com, or call 502-845-5622.
Issue: I have no sound at all.
If you have connected the D-fend SA300 and have not heard ANY audio at all:
Make sure you have made the proper connections (i.e., input cable in the input connector, output cable in the output
connector, sound source properly connected to amp).
Issue: An audio signal was present, but disappeared during performance.
1. You may have tripped the Over Voltage/Current protection circuitry. This circuitry is designed to stop the flow of
excess voltage and current to protect your D-fend unit. If this is the case, reduce the gain of the amplified signal
and the unit will recover. Please see the specifications chart on page 5 for further information on the voltage and
current limitations of the D-fend SA300.
2. You may have reached the thermal limits of the D-fend SA300. D-fend incorporates built-in thermal protection
circuitry which will temporarily disable the unit in the event the thermal limit has been reached or exceeded.
Failure to mount the device in the recommended orientation will increase the likelihood of reaching this limit
(see Mounting Recommendation on page 17). Reaching the temperature threshold signifies the SA300 is being
subjected to extremes beyond what it is rated for, and/or there is an issue with the protected system or the
system demands.
Issue: The speaker sounds unnatural.
Pumping, pulsing or breathing:
If the speaker has a “pumping” “pulsing” or “breathing” sound, you may need to adjust the attack and release
settings for your LF protection. If the LF protection turns on too fast it will create this “pumping” sensation. If you
are experiencing this, we would recommend allowing for longer attack and release times. Adjust the unit in small
increments and listen again. Continue adjustments until you have reached the optimal settings for your enclosure.
Missing LF or HF content:
If the speakers seem to have lost their LF or HF content, you may have your thresholds set too low. The goal is to
only protect your speaker when protection is needed. Premature protection will reduce the overall quality of the
LF or HF content. Slowly adjust your threshold until the LF or HF content returns but make sure you have given
adequate protection.
Limited output:
If you have programmed the D-fend unit yet you believe that your enclosure does not play as loud as before, you
may have the thresholds set too aggressively. If you are familiar with the cabinet you are protecting, slowly raise
the thresholds until the cabinet sounds like it should, yet make sure you have adequate protection.