Nady Audio SPA 850, Owner'S Manual

Page: 6 / 12

FRONT & REAR CONNECTIONS
6
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.
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.