Ashly MFA-6000, MFA-8000 manual Input Ground, Speaker Outputs Binding Posts, Normal/Bridging Switch

Operating Manual - MFA-8000 and MFA-6000 Power Amplifier

Input Ground

The CHASSIS GROUND terminal is internally connected to the chassis, the AC earth ground, and the power amplifier’s signal ground. The INPUT GROUND terminal is tied to the XLR pin 1 and the 1/4" jack sleeve. It is recommended that the input and chassis ground ter- minals remain connected with the factory-supplied jumper strap.

7.5Speaker Outputs - Binding Posts

Caution: This product can deliver enough energy to the output terminals to produce a lethal shock. Do not attempt to wire the amplifier when the power is turned on.

In situations where the power amp and its signal source are separated by great distances, a ground voltage difference may exist between the amp’s chassis ground and the input cable’s ground. Connection of these two grounds through the jumper strap may cause large ground currents to flow (which is known as a ground loop), caus- ing a hum noise in the amp’s output. Unless you have such a situation with a hum problem that cannot be solved by using balanced input connections, the ground jumper strap should remain in place.

7.2Normal/Bridging Switch

This switch selects between NORMAL mode in the “out” position where both channels are in-phase, and BRIDGING mode in the “in” position where channel 1 input is used to drive both channels, inverting the phase of channel 2. In BRIDGING mode, the channel 1 red bind- ing post is the (+) in- phase speaker output terminal and the channel 2 red binding post becomes the (-) out-of-phase speaker terminal. It is not necessary to depress the MONO switch in order to operate in BRIDGED mode. The BRIDGING switch overrides either setting of the Stereo/ Mono Switch.

7.3Stereo/Parallel Mono Switch

This switch selects between STEREO mode in the “out” position and PARALLEL MONO mode in the “in” position. In PARALLEL MONO mode, channel 1 and channel 2 inputs are internally tied together before the input attenuator, allowing discrete channel control of a mono signal. CAUTION: Be sure not to have two signal sources connected to ch.1 and ch.2 inputs when in paral- lel mono mode, as it would short-circuit these two signals

1+ is POS

1- is GND

an.1

n 1+, Pin1-

an.2

n 2+, Pin2-

al Channel nnector

dged

ono Mode:

n 1+ is pos

n 2+ is neg

1+ is POS

1- is GND

CHANNEL 1

OUTPUT

(-)

(+)

(+)

(-)

CHANNEL 2

OUTPUT

Ashly

Mad

MF

1

5

750 W

(+)1200 W

BRIDGE (-)

MDA 20A

Channel 2

and result in no output.

7.4Level Controls

The level controls allow attenuation (calibrated in dB) of the input signal. In PARALLEL MONO mode, channel 1 and channel 2 inputs are tied together, while still preserving independent level control per channel. In BRIDGED mode, use only channel 1 level control. It is recommended that the level controls be operated at full level (0 dB attenuation) in most situations to maximize the headroom in the signal source.

Figure 7.5: Output Section

A pair of dual banana binding posts provide the stereo speaker outputs. In BRIDGING mode, the channel

1red binding post is the (+) in-phase speaker output ter- minal and the channel 2 red binding post becomes the (-) out-of-phase speaker terminal.

CAUTION! NEVER CONNECT THE TWO RED BINDING POSTS TOGETHER OR CONNECT EITHER RED BINDING POST TO A BLACK BINDING POST!

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