Nady Systems SPA 850 Installation, Inspection, Contents, Rack Mounting, Amplifier Cooling

FRONT & REAR CONNECTIONS

11. L/R CHANNEL OUTPUT CONNECTORS

Connections are as depicted on the rear panel and in the follow- ing CONNECTIONS section on page 7 of this manual.

12.BALANCED INPUT CONNECTORS (1/4" TRS & XLR) These 1/4" (6.3mm) TRS (Tip/Ring/Sleeve) phone jacks and XLR jacks are compatible with balanced inputs and are wired as Tip/ Pin 3 = (+), Ring/Pin 2 = (-), and Sleeve/Pin 1 = Ground. Normal maximum input level at clipping is 1.15V RMS (+ 4dB). Input impedance is 10K Ohms. Since the TRS phone jacks and XLR jacks are wired internally in parallel, you can parallel this unit with another amplifier by using either the LINE 1/4" jack or the XLR jack (depending on which you’re using to input your signal) to output the signal to the input jack of the other amplifier.

The 1/4" TRS phone jacks can also be used for unbalanced inputs. For TRS phone plugs, simply connect the unused side of the balanced input to ground. For 1/4" TS phone plugs, no change is necessary for compatibility with this input. Balanced input signals are recommended as they are less prone to AC hum. For long cable runs a source of less than 600 ohms output impedance is needed to avoid signal loss. For short cable runs an unbalanced signal input should be suitable.

For stereo (two-channel) operation, use the inputs for both CH-A and CH-B; for parallel or bridged mono operation, use only CH-A input. (See MODE SELECTOR SWITCHES below for more explanation.)

13.MODE SELECTOR SWITCH

The XA Series amplifiers offer 3 modes of operation: PARALLEL, STEREO & BRIDGED. Slide the switch to one of the three positions for you application.

•PARALLEL (MONO) INPUT - This mode allows both chan- nels to operate in parallel with the same signal and without requiring a Y-cord. In this mode the inputs for both channels are

internally connected, so that you only need to feed a signal into one of the channels. This still allows independent control of each channel. (Note: Do not select this “Parallel” mode when feeding the amplifier 2 separate signals.)

(Note: Do not use both unbalanced and balanced cables in the same set-up as that can unbalance the connections resulting in hum.)

•STEREO INPUT - This is the most common mode generally used, and allows independent control of 2 separate signals such as stereo playback, main and monitor live mixes, and bi- amp operation (highs in one channel and lows in the other).

•BRIDGED MONO - This mode combines the power of both channels to drive a single speaker. In this mode the amp produces 4 times the peak power and 3 times the sustained power into a 4 or 8 ohm speaker than each channel can deliver separately in stereo or parallel mode.

(CAUTION: In this mode the amplifier can deliver high power into a speaker. Make sure that the speaker, connectors and wiring can handle this output. Note that for prolonged overdriven outputs into a 4 ohm speaker the breaker may trip, so care must be taken not to overload the amplifier in such operation.)

Connect the input signal to CH-A input for bridged mono operation.

14.FANS

The two dual-speed fans switch between idle speed and high speed automatically to maintain the proper internal operating temperature.

INSTALLATION

To ensure years of enjoyment from your NADY AUDIO XA-900/1100, please read and understand this manual thoroughly before using the unit.

INSPECTION

Your XA -900/1100 was carefully packed at the factory in packag- ing designed to protect the units in shipment. Before installing and using your unit, carefully examine the packaging and all contents for any signs of physical damage that may have occurred in transit.

(Note: Nady Systems is not responsible for shipping damage. If the unit is damaged, do not return to us, but notify your dealer and the shipping company immediately to make a claim. Such claims must be made by the consignee in a timely manner.)

CONTENTS

•Instruction manual

•XA-900/1100 (verify that the unit’s serial number is same as shown on shipping carton)

•AC Power cord

•Warranty Card

RACK MOUNTING

The XA Series amplifiers are designed for standard 19" rack mounting as well as “stack” mounting without a cabinet. Use 4 screws and washers for mounting to the front rack rails. It is also a good idea to support the amps also in the rear, especially for mobile use where the amps will be subjected to shocks.

AMPLIFIER COOLING

Also pay close attention to the cooling requirements. Never block the air vents in the back side and front of the amplifier if the load seen by amplifier is less than 4 ohms and the amplifier is being run at high output levels. For best results, in such high output power applications you should augment the amplifier’s air flow with a rack cooling system.

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