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OWNERS MANUAL / GUIDE D' OPERATION
LTD. is not responsible for any damage which may result as a consequence of
exceeding such a speaker’s power handling capability. In any case, Yorkville’s two year
unconditional warranty does not cover any consequential damages to other equip-
ment. Please consider these facts carefully before you choose to run your AUDIOPRO
3000 in bridged mode.
The AUDIOPRO 3000 features a specially designed subsonic filter which effectively
transfers the wasted energy from the band below 30 Hz to the band between 35 and
70 Hz. The filter provides an 18 dB/Oct skirt below 40 Hz and a 3.6 dB boost at 50 Hz.
This is achieved with a five pole network designed to minimize phase shift down to 40
Hz. We recommend using this filter in conjunction with most subwoofers and with high
power full range cabinets. Engaging this filter immediately produces the perception of
a better “bottom end”, while excessive and possibly damaging excursions of the
speaker cone are restrained. See Fig, #2- 1
The PROTECT LED will glow steadily if the Energy Management System is activated.
In the event of a shorted load or a load which is of too low an impedance for the amplifier
to handle, (less than 2 ohms), the PROTECT LED will flash alternately on and off at
about one second intervals. The sound may come on and off at the same rate. In this
case, the fault in the speakers or the speaker cables should be located and remedied.
No reset of the AUDIOPRO 3000 is required to restore proper operation.
The AUDIOPRO 3000 is fully protected against all possible passive load conditions. It
can operate with a “dead” short continuously without damage. The output stage uses
a unique triple slope VI limiting scheme which is sophisticated enough to remain inert
during transient 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. (You may have read that current limiting can affect
the sound of an amplifier. Our answer to this is that it only gets in the way of the sound
if it is not done properly. In the AUDIOPRO 3000, its done right!)
In the unlikely event of the AUDIOPRO 3000 outputs “going DC”, a thyristor circuit will
short the output and divert all potentially harmful currents away from your speakers.
The CLIP LEDS on the front panel are of the pulse stretching type. Any excursion
beyond the dynamic headroom of the amplifier - no matter how short - is trapped and
converted into a visible pulse of light.
The AUDIOPRO 3000 represents a significant advance in the art and science of analog
power amplifier design. It incorporates MOSFETS where they should be used - in the
driver stage where their immunity from secondary breakdown lets them reliably drive
bi-polar output devices which can present an essentially capacitive load at high
frequencies. The unique design of the output stage uses four supply voltages. This
greatly reduces internal power dissipation. Rather than switching between the various
supply voltages, the AUDIOPRO 3000 smoothly directs its output stage to the appro-
priate supply. The output is free of the “glitches” that plague other multiple supply
PROTECT L.E.D.
DC PROTECTION
SUBSONIC FILTER
OTHER DESIGN
DETAILS
CLIP L.E.D.'S
