Electro-Voice 7300 User manual

ElecfroVoice'
7300
STEREO POWER AMPLIFIER
OWNER’S MANUAL
7300
STEREO POWER AMPLIFIER
MASTER COPY

I. INTRODUCTION
The EV 7300 was designed to deliver exceptional
performance and reliability at an affordable price. Each
channel delivers 200 watts of power into 8 ohms, and
300 watts into 4 ohms over the full audio frequency
range. In the mono bridge mode, the 7300 can deliver
over 600 watts.
The APX octal crossover accessory provides the
convenience of on-board, bi-amp capability. The APX
module has 24 preset selectable crossover frequencies
from 50 Hz to 10,000 Hz. Simply plug the module into
the octal sockets provided on the rear of the amplifier
and your system is bi-amp ready.
The 7300 is an addition to the growing family of
Electro-Voice electronic products. We would appreciate
any comments you have regarding the performance,
features or reliability of the 7300.

Table of Contents
7300 STEREO POWER AMPLIFIER
TABLE OF CONTENTS
I INTRODUCTION
1. DESCRIPTION — FRONT PANEL
IA. Power Switch
IB. Power Status Indicator
IC. Channel Attenuation
ID. Clip Indicator
IE. Protect Indicators
2. DESCRIPTION — REAR PANEL
2A. Input Connectors
2B. Octal Input Sockets
2C. Dual Bridge Mode
2D. Output Connectors
3. SPECIFICATIONS
4. INSTALLATION
4A. Operating Cautions
4B. Input Connections
4C. Output Connections
4D. Grounding
4E. Ventilation
5. OPERATION
5A. Dual/Stereo Mode
5B. Bridge Mode
5C. APX Crossover Option
5D. Alternate Operating Voltage
6. TROUBLESHOOTING
6A. Protection
7. SCHEMATIC
8. SERVICE/WARRANTY INFORMATION
*** WARNING ***
The service information contained within this document is for use
only by Electro-Voice, Inc. authorized warranty stations and
qualified service personnel.
one

Description
7300 STEREO POWER AMPLIFIER
DESCRIPTION
1. Front Panel
1 A. Power Switch — The power switch turns the
amplifier on and off.
IB. Power Status Indicator — This LED indicates
when the unit is on.
IC. Input Attenuators — Clockwise rotation increases
the amount of amplifier gain.
ID. Clip Indicators — When the amplifier is driven into
clipping, the clip indicator will illuminate. To avoid
distortion reduce the input level until the LED’s no
longer light.
IE. Protect Indicators — The protect light illuminates
when the amplifier overheats or when shorted
loads or dc is detected on the amplifier output.
A relay automatically disconnects the load from
the channel when a problem is detected. The
amplifier will reset itself when the problem is
corrected. See the Troubleshooting section for
problem solving.

Description
7300 STEREO POWER AMPLIFIER
FIGURE 2 — Back Panel View
DESCRIPTION
2. Back Panel
Input Connectors — Located on the left side are
two 3-pin-XLR-type connectors and two balanced
quarter-inch phone jacks. The inputs can also be
unbalanced. See Figure 3 for typical input
connections.
Octal Accessory Sockets — Located above the
input jacks, accessory octal sockets are provided
for the APX crossover module. Twenty-four
crossover frequencies are available from 50 Hz
to 10,000 Hz.
Dual/Mono Bridge Mode — The mode switch
located to the right of channel 1 input selects
stereo mode or bridge-mode without any
additional patching.
Output Connectors — The speaker connectors
are heavy-duty five-way binding posts. For
protection, there is a bracket on each side of the
binding posts.
thriwi

7300 STEREO POWER AMPLIFIER Specifications
SPECIFICATIONS
CONDITIONS —
1 0 dBu - 0.775 V rms.
2. Dual-mode ratings are for each channel.
3. Both channels operating at rated output power unless noted.
A 120 volt ac line voltage maintained throughout testing.
CONTINUOUS RATED OUTPUT POWER —
(20 Hz, reference 1 kHz)
Dual Mode, 4 Ohms: 300 watts at <0.10% THD
Bridge Mode, 8 Ohms: 600 watts at <0.10% THD
Dual Mode, 8 Ohms: 200 watts at <0.05% THD
Bridge Mode, 16 Ohma: 400 watts at <0.05% THD
MAXIMUM MIDBAND OUTPUT POWER —
(reference 1 kHz, 1% THD)
Dual Mode, 4 Ohms: 400 watts
Bridge Mode, 8 Ohma: 800 watts
Dual Mode, 8 Ohma: 250 watts
Bridge Mode, 16 Ohma: 500 watts
DYNAMIC HEADROOM (reference 1 kHz) —
Dual Mode, 4 Ohma: >1.25 dB
Bridge Mode, 8 Ohma: >1.25 dB
Dual Mode, 8 Ohma: >1.0 dB
Bridge Mode, 16 Ohma: >1.0 dB
POWER BANDWIDTH (+0, -3 dB, reference 0 dB at 1 kHz) —
Dual Mode, 4 Ohma: 7 Hz-70 kHz
Bridge Mode, 8 Ohma: 7 Hz-60 kHz
Dual Mode, 8 Ohma: 7 Hz-85 kHz
Bridge Mode, 16 Ohma: 7 Hz-65 kHz
VOLTAGE GAIN (reference 1 kHz) -
Dual Mode: 32.0 dB
Bridge Mode: 38.0 dB
INPUT SENSITIVITY FOR RATED OUTPUT POWER -
(reference 1 kHz, ±0.3 dB)
Dual Mode, 4 Ohma: 0 dBu (0 775 V rms)
Bridge Mode, 8 Ohma: 0 dBu (0.775 V rms)
Dual Mode, 8 Ohma: -t-3 dBu (0 902 V rms)
Bridge Mode, 16 Ohma: + 1 . 3 dBu (0.902 V rms)
MAXIMUM INPUT LEVEL (reference 1 kHz) —
+ 20 dBu (7.75 V rms)
INPUT IMPEDANCE (per channel, 20 Hz-20 kHz) —
Balanced: >30 kilohms
Unbalanced: >15 kilohms
PHASE RESPONSE (at rated output power, any mode) —
at 20 Hz: +15 degrees
at 20 kHz: -15 degrees
THD (at rated output power) —
Dual Mode, 4 Ohma, 20 Hz-20 kHz: <0.10%
Bridge Mode, 8 Ohma, 20 Hz-20 kHz: <0.10%
Dual Mode, 8 Ohma, 20 Hz-1 kHz: <0.01%
Dual Mode, 8 Ohms, 1 kHz-20 kHz: <0.05%
Bridge Mode, 16 Ohma, 20 Hz-1 kHz: <0.01%
Bridge Mode, 16 Ohma, 1 kHz-20 kHz: <0.05%
IMD [SMPTE] (at rated output power) —
Dual Mode, 4 Ohma: <0.05%
Bridge Mode, 4 Ohms: <0 05%
Dual Mode, 8 Ohma: <0.03%
Bridge Mode, 16 Ohms: <0.03%
TIM [DIM 100] (at rated output power) —
Dual Mode, 4 Ohms: <0.05%
Bridge Mode, 8 Ohms: <0.05%
Dual Mode, 8 Ohms: <0.03%
Bridge Mode, 16 Ohms: <0.03%
RISE TIME (10% to 90%, at rated output power) —
Dual Mode, 4 Ohms: <5 Msec
Bridge Mode, 8 Ohms: <6 Msec
Dual Mode, 8 Ohms: <4.5 Msec
Bridge Mode, 16 Ohms: <5.5 Msec
SLEW RATE (at rated output power) —
Dual Mode, 4 Ohms: >20 V/m sec
Bridge Mode, 8 Ohma: >30 V/Msec
Dual Mode, 8 Ohma: >30 V/m sec
Bridge Mode, 16 Ohma: >60 V/m sec
DAMPING FACTOR —
Dual Mode, 4 Ohms, 20 Hz-1 kHz: >100
Dual Mode, 4 Ohma, 20 kHz: >40
Bridge Mode, 8 Ohma, 20 Hz-1 kHz: >200
Bridge Mode, 8 Ohma, 20 kHz: >50
Dual Mode, 8 Ohms, 20 Hz-1 kHz: >200
Dual Mode, 8 Ohma, 20 kHz: >80
Bridge Mode, 16 Ohma, 20 Hz-1 kHz: >400
Bridge Mode, 16 Ohma, 20 kHz: >100
CHANNEL SEPARATION -
(below rated output power, single channel operating)
>80 dB at 1 kHz
NOISE (below rated output power, A-weighted, any mode) —
>100 dB
AMPLIFIER PROTECTION —
Excessive output voltage
Shorted loads
Excessive phase shift
LOAD PROTECTION -
Startup/shutdown transients
dc fault
COOLING —
Heatsink: Thermally equalized Ms-inch aluminum,
black anodized heatsink
Dual-Speed Fan: 106 CFM (high speed), minimum life rating of
20,000 hours at 72 “C, or 43,500 hours at
25°C ambient temperature
OUTPUT TOPOLOGY —
True complementary symmetry
OUTPUT TYPE —
Dual Mode: Unbalanced, each channel
Bridge Mode: Balanced
OUTPUT DEVICES —
Sixteen 250-watt, 250-V/16-A, TO-3 transistors
CONTROLS AND SWITCHES —
Input level controls (two), rear
Mode switch, rear
Power switch, front
FRONT-PANEL INDICATORS —
Power LED
Clip LED's (two)
Protect LED's (two)
CONNECTIONS -
Input: 6-terminal barrier strip, female XLR-type connectors (two)
Output: 4-terminal barrier strip
Power: 8-foot, 3-wire, 17-GA power cord with NEMA 5-15 plug
POWER REQUIREMENTS -
100, 120, 200, 220, 240 V ac, 50/60 Hz, 900 watts
POWER CONSUMPTION/HEAT PRODUCED —
(both channels operating dual mode with 1 kHz Input signal at
stated output power into 4 ohms, or bridge mode Into 8 ohms)
Idle: 130 watts/0 442 kBTU/hr
% Power: 900 watts/2.380 kBTU/hr
Yt Power: 1060 watts/2.584 kBTU/hr
Rated Power: 1430 watts/2.822 kBTU/hr
Maximum.MIdband Power: 960 watts/1.564 kBTU/hr
OPERATING TEMPERATURE RANGE —
Up to 60®C (140 o F) ambient
DIMENSIONS —
Height: 13.3 cm (5% in.)
Width: 48.2 cm (19 in.)
Depth: 32.4 cm (12% in.)
COLOR — Gray/biack
ENCLOSURE -
Rack mount chassis, 16-GA steel bottom/sides. Winch
aluminum top/back, Winch 6061-T6 aluminum front panel
SHIPPING WEIGHT — 21 8 kg (48 lb)
NET WEIGHT - 17.7 kg (39 lb)
RF interference
Over temperature
Infrasomc signals
Low ac line voltage

HEADROOM vs. FREQUENCY
NOISE va. FREQUENCY
c

7300 STEREO POWER AMPLIFIER
Installation
4. INSTALLATION
4A. Operating Cautions
a. Do not operate the amplifier in a completely ciosed,
unventilated housing.
b. Do not connect the outputs of the channels in parallel.
c. Do not connect the output terminals to a battery, power
supply, or the power mains. Damage caused by such
hookup is not covered by the warranty.
d. Be careful when making connections, selecting signal
sources and controlling the output level.
e. Do not ite the input signal ground to the ground lead
of an output. Ground-loop-induced oscillations may
occur.
f. Ensure that the main ac power is within 10% of
selected voltage and frequency. Failure to operate the
unit within these limits voids the warranty.
g. Use only the proper size mains fuse for the selected
ac voltage.
h. Do not connect either side of the loudspeaker cable
to ground when operating the unit in bridged mode.
The bridged mode is balanced to ground.
i. Make certain that test equipment is not ground
referenced when testing the unit in the bridged mode.
j. Tampering with the circuit or repair by unauthorized
personnel will void the warranty of the unit.
4B. Input Connections
Two conductor shielded low-impedance cable is recom¬
mended for input lines to the amplifier input. Pin 2 of the
XLR-type connector is high (+), pin 3 is low (-), and
pin 1 is ground. The Winch jack may be used as a low
impedance input. Tip is high ( + ), ring is low (-), and the
sleeve is ground. See Figure 3.
High impedance lines may be connected to the amplifier
inputs with a single-conductor low capacitance sheilded
cable of 30 feet or less in length. A two conductor Vi-inch
plug will automatically unbalance the input. To help avoid
hum or buzz in the output, be certain that all input cables
are physically separated from power wiring or power
transformers.
4C. Output Connections
Binding posts are provided for speaker terminations, the red
post is high (+) and the black post is low (-). The preferred
connector is a high quality dual banana plug. See Figure 4
for typical output configurations.
Before making output connections, the input attenuators
should be turned off (full counterclockwise), doing so will
eliminate any chance of loud blasts or damage to the
loudspeaker.
Power loss in the speaker wire. The impedance of the
speaker connecting wire would ideally be zero, so all of the
amplifier output power would be delivered to the speaker
load. However, the impedance of the speaker wire can
become a significant percentage of the speaker impedance.
Thus, part of the amplifier power is "lost" in the wire (in the
form of heat) and the power delivered to the speaker system
six

Operation 7300 STEREO POWER AMPLIFIER
AWG
Size
Resistance
(ohms/1000 feet)
Impedance
40
60 160
10
1.00 120 240
480
12
1.59 75 150 300
14 2.50 48 96 190
16 4.02 30
60 120
18
6.39 19 38 75
20 10.1 12
24 48
22
16.2
7
15 30
TABLE I — Cable Selection Chart
is correspondingly reduced. Wire impedance is higher when
using long wire runs and small wire sizes.
Table I shows the two-wire cable (copper) lengths
permissable for a number of wire sizes and speaker
impedances, to avoid a loss of more than 0.5 dB For a loss
of 1 dB (basically imperceptible) lengths may be doubled.
For a 2-dB loss, the lengths would be multiplied by 4.4.
In general, note that the higher load impedances allow much
longer smaller-gauge wiring to be used.
4D. Grounding
The chassis of the unit should be grounded. Connecting the
chassis grounds of additional audio equipment to the chassis
ground of the amplifier may help reduce noise and hum.
4E. Ventilation
In order to offset the heat generated by the power amplifier,
it is necessary to provide ample ventilation around the unit.
Avoid blocking or impeding the vent slots of the chassis.
Locate the unit where it is free from direct sunlight, humidity,
dust or vibration to help prevent problems which might be
caused by the environment.
5. O PERATION
5A. Dual/Stereo Mode:
In the dual or stereo mode the channels may be operated
independently. Before hook-up make sure that the mode
switch is in the dual position and that the level controls are
down (FCCW). Connect the inputs and outputs (See
Figures 3 and 4). Turn the power amp on and slowly
increase level until the desired output power is obtained.
If either (clip) LED illuminates, reduce the output with the
input attenuators or reduce the source signal level.
5B. Bridge Mode:
Input connection should be made into channel 1 only. Do
not make any input connections into channel two. Move the
mode switch to bridge mode and make sure both level
controls are down (FCCW). Connect the speaker across the
two red binding posts. Channel 1 red post is high ( + ),
channel 2 red post is low (-). Do not make a connection
to either of the black binding posts. Switch power on and
slowly increase amplifier channel 1 level control until the
desired output power is obtained. If the clip LED indicators
come on, reduce the power amp level control or the source
signal level.
5C. APX Crossover Option:
The APX crossover is a 24 dB per octave Linkwitz-Riley filter
network. There are 24 selectable frequencies from 50 Hz
to 10,000 kHz.
*•* CAUTION ***
No user serviceable parts inside. Hazardous voltage
and currents may be encountered within the chassis.
To avoid electric shock, do not perform any servicing
unless you are qualified to do so.
5D. Alternate Primary Voltage
The amplifier can be powered with line voltages other than
120 volts by altering the primary wiring of the power
transformer. Table II lists the primary wire color, the terminal
block (TB), and the position of the TB the wire should be
located in for operation at the desired voltage.
To alter the transformer primary wiring configuration use the
following procedure:
1. Disconnect the amplifier from the ac power source.
2. Remove the ten screws securing the top cover. There
are three screws on each side, two screws on the rear
along the bottom edge, and the two innermost screws
inset into the top strip on the front panel. See Figure 5
for exact screw locations.
3. Discharge each large capacitor carefully through a
150-ohm, 2-watt resistor for at least one minute.
See Figure 6.
4. Locate the two voltage-selection terminal blocks
mounted next to each other on the side of the chassis
, between the power transformer and the large capacitor.
5. The transformer has six primary leads. Disconnect the
primary leads of the power transformer by pulling each
wire firmly to disengage it from the terminal block.
Note: The primary lead colors are black, brown, white,
black/white, brown/white and white/black.
6. Select the desired operating voltage on Table II and
reconnect the wires accordingly. Push each wire firmly
into the block until it snaps into place.
7. Relocate the fan wires according to the wiring chart.
8. Install the correct line fuse (values in Table III).
9. Plug the amplifier into a variac and sweep the mains
voltage from zero to full operating voltage while monitor¬
ing the amplifier's dc rail voltages. The dc rail voltage
should be ± 78 V dc, ± 5% at the selected primary
voltage.
10. Reinstall the top cover with the ten screws.

C5J 7300 STEREO POWER AMPLIFIER
Permanent Connections*
TBI TB 2
lo Ho I
(BLK) LINE CAP
(BLK) FUSE
(BLK) PWR SW
(BLK) PWR SW
1 LINE CAP (BLK)
2 NEUTRAL (WH)
o o
Factory Wiring (120 V)
TB1 TB2
lolol
T) 4 T) 4 BLK/WH
• n 5 n 5 FAN (YL)
brn Jn & Jd 6
BRN/WH ID 7 Jn 2
(YL) FAN T] a T] 0
M WH/BLK
o ifo
T81 TB2
[olo"
3 BLK
4 BLK/WH
5 FAN (YL)
6
7 FAN (YL)
8 BRN/WH
9 BRN
olfo
200 V
TB1 T82
roiicn
220 V
TBi TB2
folfo
240 V
TBI TB2
fo Ho
3 BLK/WH
4 FAN (YL)
5
6 BRN/WH
7 FAN (YL)
ol WH/BLK
ro io
3 BLK/WH
4 FAN (YL)
5
« BLK
7 BRN/WH
8 FAN (YL)
9
’0 WH/BLK
lo [IO
3 BLK/WH
4 FAN (YL)
5
8 BLK
7 BRN/WH
B FAN (YL)
9
'C WH/BLK
O O
• DO NOT MOVE THESE WIRES, THEY ARE COMMON TO ALL PRIMARY VOLTAGES
TABLE II
Primary Power Conversion Chart for 100-, 120-, 200-, 220-, and 240-V, 50/60-Hz Operation
\ /
UPPER 2 SCREWS
FIGURE 5 — Top Cover Removal
Line Voltage
Line Fuse,
314 Series
Normal-Bio
100 Vac
10 A/250 V
120 Vac
10 A/250 V
200 Vac
5 A/250 V
220 Vac
5 A/250 V
240 Vac
5 A/250 V
TABLE III
Main Fuse Selection Guide
FIGURE 6
Capacitor Discharging
eight