Yorkville Sound Pulse PS218P Manuel De L'utilisateur page 4

5. INPUT & PARALLEL THRU Connections
and Balancing
The inputs to the PS218P's dual power amplifiers
are arranged in LEFT and RIGHT parallel pairs.
Internally, the amplifiers share these inputs. In
other words, the signal coming into either of the
INPUT jacks goes to both amplifiers at the same
time (i.e. not separately) and therefore both
speakers are powered. The LEFT/RIGHT INPUT
arrangement simplifies connecting a stereo
source. For example you may simply connect
your left and right stereo amplifier outputs to the
PS218P's INPUT jacks and they will be mixed
down into mono internally to feed the amplifiers.
Meanwhile, the PARALLEL THRU jacks can be
used to feed the stereo signals to another
PS218P's inputs or to a pair of full-range PA
enclosures. On the other hand, if you only have a
mono signal from a mixer or amplifier, or chained
over from another speaker, either one of the
INPUT jacks will do - no need to patch to the
other INPUT jack. The adjacent PARALLEL THRU
jack may then be used to deliver the signal to
another PS218P or, if speaker-level signal is
driving the INPUT jack, to a full-range speaker
enclosure. Additionally, all connectors are
balanced when the push-button is in the LINE
position. The 1/4-inch TRS inputs are wired; tip =
in phase, ring = reverse phase, sleeve = ground
(see under UNGROUNDED/GROUNDED Push-
button re: grounding). Because the input
impedance is very high ( >17k Ohms) any
amplifier driving the PS218P in parallel with
external speakers will not encounter a low load
impedance situation caused by the PS218P. Only
the number and impedance of external speakers
determines the overall impedance.
Note: The PS218P built-in stand mounting adapter can be used with Yorkville SW-Teletube
accessory to support our E160 cabinets. The support tube can be adusted up to it's full 5'4"
extension safely as long as the PS218P is not inclined more than 10°.
WARNING: Larger or heavier cabinets should not be used with the stand mount!
6. The Power Amplifiers
Both amplifiers are rated at 300 watts into 4
Ohms and feature comprehensive protection
from both thermal and input overloads.
Additionally, they are regulated by full-time
electronic limiting and automatic equalization
(see below). The heatsink fins on the back panel
should be kept well away from walls or anything
which could restrict air flow around them. If the
amplifiers overheat, their output power will be
reduced by the limiter to compensate.
7. Internal Subwoofer Limiter and
Automatic Equalization
In order to achieve maximum utilization of the
subwoofer amplifiers and speakers, the amplifiers
are regulated by a sonically transparent limiter
and an automatic equalization circuit. Together
they respond to a variety of potential situations
including excessive heat and clipping distortion
in the amplifier as well as excessive cone
excursions and even voicecoil overheating in the
speakers. The EQ additionally ensures extended
deep bass down to 45Hz at low to moderate
operating levels and, to protect the woofers at
higher operating levels, bass pre-emphasis is
reduced whenever the limiter cuts in. At very
high limiting levels, the EQ will actually cut the
response below 60Hz to ensure that there will be
no distortion or subwoofer cone damage. This
still permits maximum clean sound pressure in
the above-60Hz range for bass drum kicks.
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