©American Audio® - www.americanaudio.com - VLP Series™ Power Amplifier User Manual Page 13
Mono Subwoofer -
This operation is similar to the Stereo Subwoofer operation but in mono. When running subwoofers it is usually
recommended to run them in mono mode to achieve a cleaner tighter low end. This operation allows you to run several subwoofers
down to a minimum of 4 ohms. To avoid amplifier overheating, never run the amplifier below 8 ohms in this mode. Set up this mode
as you would a standard stereo set up. Be sure both channels are set to “SUBWOOF” and the mode switch is set to “MONO.” In this
mode you may use the frequency adjustment on the rear of the amp, to control the bass frequency output level. Frequencies may be
adjusted from 20Hz to 200Hz.
One Channel Normal/One Channel Subwoofer (BI-AMP) -
You may also use your amp to bi-amp your system. You may use one
side of the amp to power a subwoofer and the other side to power a full range speaker. Follow the set up guides listed above to mix
and match your operations.
PROTECTION:
Limiter -
Only the VLP 1500 and 600 come with a built in limiter. When the input signal overloads, the “CLIP LED’s” indicate a sig-
nal overload, at this time, the master volume should be lowered to reduce distortion. If the input gain level is not reduced the built-in
limiter will activate. During signal overload, the limiter will reduce the input audio signal enough to minimize the amount of clipping.
A limiter takes the gain of an overloading signal and reduces it, the reduction in gain reduces distortion that can cause damage to
your speakers and amplifier. During normal operation below clipping, and momentary clips on peaks, the limiter does not affect the
audio signal and is inaudible. It will allow brief clipping of peaks and will only activate when continuous, hard clipping occurs. During
excessive clipping the limiter will reduce the audio signal enough to minimize the amount of clipping. When the input signal decreases
enough that clipping ends, the limiter will deactivate and cease its gain reduction. The limiter has a fixed threshold and can not be
adjusted.
Safe Power Levels at Different Output Loads:
8-Ohm Loads:
The amplifier can operate at practically any power level without risk of overheating. However, if it is pushed hard
enough to continually light the “CLIP ” indicator, the amplifier’s average output power can reach 150 watts.
4-Ohm Loads:
If the “CLIP” indicator flashes occasionally, the amplifier is approaching its maximum long-term power capacity. If it is
lit about half the time, the amplifier channel will probably go into thermal protection within a few minutes.
Short Circuit Protection -
The VLP Series
™
amplifiers all come with built-in Output Short Circuit Protects. The Output Short Circuit
Protection protects the output devices of the amplifier from short circuits and stressful loads. If your speaker lines short, the amplifier
automatically detects this problem and discontinues operation for that channel. If one side of your
amplifier becomes shorted and goes into protect mode, the other side will continue to operate nor-
mally. During short circuit protection, the "Clip" LED and “Protect" LED will light simultaneously indi-
cating amplifier fault. All channel output during the “Short Circuit Protection" will be interrupted (i.e.
no sound out
