Input Polarity - Peavey GPS Series Operating Manual

"bridge" mode, place the Mode Switch to the "in" position where the switch remains down. The amp is
now a mono amplifier and only requires a single input. Plug your input signal into Channel A only for
"bridge" mode operation. Channel B input must not have anything connected.
NOTE FOR GPS 900 AND 1500:
When these models are switched to "bridge" mode, the Power LED (3) for Channel B
will no longer illuminate.
NOTE: Refer to the Outputs section for an explanation of how the Mode Switch affects the speaker
outputs.
INPUTS
5. CHANNEL A COMBINATION INPUT
GPS 900 AND 1500
These GPS Series amplifiers offer both XLR electronic balanced and phone jack quasi-balanced
inputs for each channel using Neutrik
The female XLR inputs are connected to dual OP AMP circuitry which offers very low noise and
extremely high common mode rejection ratio to minimize outside interference!
The female 1/4" phone jack input in the center of the "combo" connectors are also connected to a
unique "quasi-balanced" input circuitry. When used, these 1/4" jacks are not "chassis grounded" but
connected to ground through a relatively low impedance circuit which is part of a "ground loop"
elimination circuit associated with the input. This will normally allow "hum free" operation when
relatively short 1/4" cable patches are made to this input by various outputs from other equipment that
share the same rack with this amp. This "quasi-balanced" circuit is "automatic", and is virtually
invisible in normal usage. It cannot be defeated. Use only a two-conductor (TS) phone plug when
connecting to the 1/4" input of this connector.
GPS 2600, 3400 AND 3500
These GPS Series amplifiers offer both XLR electronic balanced and phone jack balanced/unbalanced
inputs for each channel using Neutrik's new "combo" connector to save panel space.
The female 1/4" phone jack input in the center of the "combo" connectors is also connected to a
unique balanced/unbalanced input circuitry. When used, these 1/4" jacks can accept both unbalanced
two-conductor (TS) and balanced three-conductor (TRS) inputs. Balanced operation is always
recommended for optimum signal-to-noise. If unbalanced operation is a required, always keep the
input cable to a minimum length to avoid excessive noise.
6. CHANNEL B COMBINATION INPUT
This connector is identical to the Channel A Combination Input (5) except it is not used during
"bridge" mode [See Mode Switch (4).]
7.

INPUT POLARITY

Located between the Channel A and Channel B Inputs is a recessed Input Polarity switch (7) that
allows the user to select the desired polarity (phase) of the XLR inputs. This switch is a push-push type
and a small diameter "tool" is required to select the desired position. Set to the out (default) position,
the polarity is pin #3 positive, pin #2 negative, and pin #1 ground. This is the polarity found on most
Peavey power amplifiers. Although this is not the world "standard" (IEC) polarity, it was chosen by
Peavey more than 20 years ago, and thus we offer this polarity to be consistent with products both past
and present. If this amplifier is used with other competitive products which use the IEC standard
polarity, then the "in" position of switch (7) should be selected yielding pin #2 positive, pin #3
negative, and pin #1 ground. As with any electronic gear, polarity (phasing) is important because the
® 's new "combo" connector to save panel space.
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