Short Circuit Protection; Thermal Protection - YORKVILLE VTC Pro Audio V42 Manuel De L'utilisateur

7. Subsonic Filter Switch
The VTC Pro Audio V42/V44 features a specially designed subsonic filter which effectively
blocks potentially destructive energy in the band below 40 Hz. The filter provides a 12 dB/octave
skirt below 40 Hz. It is implemented with a two pole network designed to minimize phase shift
down to 40 Hz. We recommend using this filter in conjunction with some subwoofers and with
all high power full range cabinets. When the subsonic filter is disabled, the V42/V44 is flat (down
to 20 Hz) and rolls off at 12dB/Oct below that.
8. Limiter Switch
With the internal limiters activated, the V42/V44' s gain is continuously adjusted to fit the signal
within the available dynamic range. Occasional clipping is permitted. The limiters will not only help
to protect your system' s horns but will automatically make the best use of the available dynamic
headroom. With the limiters activated, all you need to do is turn up the signal level until you start
to see some clipping. The limiters will make sure that you are getting the maximum clean power
output at all times. Setting the switch to the IN position completely disables both limiters.
9. Protect LED
In the event of a shorted load or a load which is of too low an impedance for the amplifier to handle
the PROTECT LED will flash alternately on and off at about 3 second intervals. The sound may
come on at ½ second intervals. In this case, the fault is in the speakers or the speaker cables and
should be located and remedied. No reset of the V42/V44 is required to restore proper operation.
The PROTECT LED will stay on if the amplifier has overheated. Check the speaker load impedance
and any restrictions to air flow at the air intake or exhaust vents of the amplifier.

10. Short Circuit Protection

The V42/V44is fully protected against all possible passive load conditions. It can operate into a
dead short continuously without damage. (However, we don't recommend that you short your V42/
V44 "just for fun." Shorts do create a lot of stress on the output devices). The output stage uses a
unique triple slope VI-limiting scheme which is sophisticated enough to remain inert during tran-
sient currents in excess of 100 Amperes and phase angles of more than 45 degrees, yet is capable
of protecting the output stage from damage due to accidental short circuits and improper loads.
11. DC Protection
In the unlikely event of the V42/V44's outputs going DC, a thyristor circuit will short the output
terminals and divert all potentially harmful currents away from your speakers.

12. Thermal Protection

In the unlikely event that the V42/V44 overheats, the signal will be sporadically cut off the
audio signal and the PROTECT LED will stay on. The V42/V44 is designed and tested to op-
erate under "worst case" conditions without shutting down, so if you experience a thermal
shut down you should check for blocked air flow.
13. Cooling
The fan draws air in from the front and expels hot air through the rear vents. This is compatible
with most installations. Since hot air rises, the heated air forcibly expelled from the back tends
to rise away from the equipment rack. This draws cool air from the floor upwards into the front
of the rack. In some cases where the rear of the rack is obstructed, it may be necessary to install
rack fans to aid cooling. If there are no obstructions, no secondary cooling is required.
14. Clip LEDs
The CLIP LEDs on the front panel will visibly indicate any signal excursion beyond the dy-
namic headroom of the amplifier.
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