The wall to the speaker, with the amplifier acting only as a “valve” in-between
to control its flow. This power supply’s remarkable efficiency at converting
energy from the AC line to a usable form for loudspeaker applications allows
many of the major components to be downsized, saving space, weight and
cost.
Unlimited Dynamic Range
Most power amplifiers utilize some form of current limiting in the audio
signal path. While a fairly reliable form of protection, this technique has some
disadvantages in that it can reduce the impact of musical transients by
prematurely limiting output current and therefore dynamics. Low frequency
signals may sound weak or distorted as a result. Stewart Audio amplifiers
have no current limiting in the audio path, and therefore reproduce the full
dynamics of the audio signal.
Absolute Protection
Stewart Audio power amplifiers employ circuits which fully protect
the amplifier while avoiding sonic compromise. For example, a unique
circuit monitors the current drawn from the power supply. The
amplifier’s output is not affected in any way until the load impedance
drops below 2? , indicating the presence of a short. Under these
conditions the power supply will simply shut down until the short is
removed, at which point the supply will slowly ramp up to full power,
protecting the load from a surge of high energy. In the event of an
amplifier malfunction this circuitry will also protect the speakers,
since the power is immediately disconnected from the amplifier.
Most other amplifier designs require the presence of relatively high
levels of signal in order to detect a short-circuit on the output. At low
levels, these amplifiers will continue to drive a short, causing rapid
heat buildup, thermal runaway, and finally amplifier failure. The
current-sensing circuitry in all Stewart World Series amplifiers is
capable of detecting a shorted output even at low program levels,
increasing reliability under conditions which could cause other
amplifiers to fail.
8
As direct boxes, tape recorders, etc.
Pinouts are standard (see diagram below), Pin 2 of the XLR and the Tip
of the 1/4” phone connectors are “Hot”, or
Positive.
Input connections should always be made with the amplifier’s power
turned off.
Balanced XLR Connections
are made with the following pin
assignments:
#1 = Ground
#2 = Positive (+)
#3 = Negative (-)
Unbalanced XLR Connections
are made with the following pin
assignments:
#1 = Ground
#2 = Positive (+)
#3 = Ground
(wire pins 1 & 3 together)
Balanced TRS ¼” Phone Connections
are made with the following pin
assignments:
Tip = Positive (+)
Ring = Negative (-)
Sleeve = Ground
Unbalanced TS Phone Connections
are made with the following pin
assignments:
Tip = Positive (+)
Sleeve = Ground
13
