Stereo Power Amplifier
• 380 watts per channel at 8 ohms;
600 watts per channel at 4 ohms;
and 850 watts per channel at 2 ohms
at 1 kHz
• 1,200 watts bridged at 8 ohms;
1,700 watts bridged into 4 ohms
at 1 kHz
• State-of-the-art limiters driven by a
sophisticated input/output comparator ensure freedom from amplifier
• High-current Neutrik Speakon® output
connectors for channels A, B and
bridged operation for loss-free
• Active-balanced XLR-type input and
paralleled XLR-type output connectors provide easy signal routing
• Rear-mounted dB-scaled detented
level controls for easy control of gain
The Electro-Voice Q66 amplifier is a very
high-quality power amplifier designed to
elicit excellent performance from any
speaker system. Its low distortion and substantial headroom ensure that program material will be accurately amplified.
Each channel of the Q66 delivers more
than 300-watts continuous average power
into 8 ohms, 500 watts into 4 ohms and
650 watts into 2 ohms over the full audio
frequency range. In the bridged mode, the
amplifier can deliver more than 1,200 watts
into 8 ohms and 1,700 watts into 4 ohms at
less than 1% THD. The power supply with
its large torodial transformer gives the amplifier impressive headroom and current output capability.
The Q66 contains 20 high-power output devices with 5,000 watts of dissipation capability. These devices are protected from overheating by two, three-speed temperature-sensitive fans. The fans are quiet enough to permit use of the Q66 in noise-sensitive applications such as recording studios and houses
of worship.
The output devices are mounted to two large,
extruded aluminum heat sinks that are engi-
neered to minimize thermal gradients and
allow the amplifier to operate safely into lowimpedance loads. The output devices have a
maximum junction temperature of 200o C
(392o F), so high operational temperatures
present no problems. The output devices are
mounted directly to the heat sinks without
mica insulators to ensure better dissipation
of heat.
The Q66 has sophisticated protection circuits
that guard it and the load from problems.
Protection circuits guard against overload,
over-temperature, shorted outputs, radio-frequency interference and dc faults. The output devices are protected against damage
from the reverse feeding of electrical energy
(back EMF) from the load and are switched
on via relays to avoid transients which could
damage speakers.
The Q66 has built-in limiters to protect
speakers from the deleterious effects of amplifier clipping. The limiter’s action is controlled by very sophisticated input/output
comparators which are designed to preserve
the sonic integrity of the source.
The Q66 has electronically-balanced XLRtype input and signal output connectors that
allow easy, problem-free connections and
signal routing. The amplifier has an input
routing switch that allows selection of either
normal dual-channel operation or parallel
mono operation, which routes an input to
both channels but still allows independent
level control.
The Q66’s professional Neutrik Speakon®
output connectors provide sturdy, reliable
connections and allow use of heavy wire for
loss-free signal transmission. There are separate output connectors for channels, A and
B, and for the bridge mode. The bridge mode
connector is sealed with a plastic cover to
prevent connection errors.
To prevent ground loops from occurring, the
Q66 is equipped with a ground-lift switch.
When the amplifier is operated in a rack with
units of different ground potential, the switch
may be adjusted to eliminate hum.
Separate potentiometers on the rear panel of
the Q66 allow easy regulation of gain. There
is easily readable nomenclature to ensure
easily repeatable control settings.
The Electro-Voice Q66 is an excellent choice
for high-quality professional sound system
applications which require excellent sound
quality, speaker protection and the highest
level of construction quality and long-term
Q66 Stereo Power Amplifier
Q66 Stereo Power Amplifier
Architects’ and Engineers’
The power amplifier shall be a dual-channel
model of solid-state design employing highpower output devices in a true-complementary-symmetry output circuit. It shall be capable of operating from a 120/220/240-V, 50/
60 Hz ac line. The power amplifier shall meet
various worldwide safety standards including Underwriter’s Laboratories UL-813 standard, Canadian Standards and CE standards.
The power amplifier shall contain a limiter
circuit driven by a high-quality input/output
comparator to protect the load from damage
by amplifier clipping. The amplifier shall
contain sensing circuitry to provide protection for the output transistors against
overtemperature, excessive output voltage,
shorted loads, excessive phase shift and
back-EMF current. The load shall be similarly protected against start-up/shutdown
transients, low ac line voltage and dc.
Rear-mounted controls shall include detented
level potentiometers for each channel, an
input routing switch for selecting dual/stereo or parallel mono operation, a switch for
selecting dual/stereo or bridged operation
and a chassis groundlift switch. Rearmounted input connectors shall include a 3pin female XLR-type connector wired in
parallel with a male 3-pin XLR-type output
connector for signal routing. Output connectors shall be Neutrik Speakon NL4MP’s for
channels A and B, and another for bridged
Front-panel indicators shall include power
on, a protection indicator and separate signal present and limiter indicators for each
channel. Front-panel controls shall include
a power on switch.
The power amplifier shall meet the following performance specifications: rated output
power from 20-20,000 Hz at less than 0.2%
THD, each channel 300 watts into 8 ohms,
500 watts into 4 ohms and 650 watts into
2 ohms. In bridged mode at 1 kHz, the
amplifier shall deliver 1,200 watts into
8 ohms and 1,700 watts into 4 ohms. Hum
and noise shall be at least 103 dB
(A weighted) below rated output power;
damping factor shall be greater than 300
at any frequency up to 1 kHz in any mode
with an 8-ohm load; THD (total harmonic
distortion) shall be less than 0.05% at 1 kHz
at rated output power; crosstalk shall be better than -80 dB at 1 kHz at rated output
power; transient intermodulation distortion
(DIM 30), shall be less than 0.03%. Dimensions shall be 132.5 mm (5.25 in) high x 483
mm (19.0 in) width x 385.5 mm (15.7 in)
deep. Net weight shall be 16 kg (35.2 lb).
Color shall be light gray.
The power amplifier shall be the ElectroVoice Q66.
Limited Warranty
Electro-Voice products are guaranteed
against malfunction due to defects in materials or workmanship for a specified period,
as noted in the individual product-line
statement(s) below, or in the individual product data sheet or owner’s manual, beginning
with the date of original purchase. If such
malfunction occurs during the specified period, the product will be repaired or replaced
(at our option) without charge. The product
will be returned to the customer prepaid. Exclusions and Limitations: The Limited
Warranty does not apply to: (a) exterior finish or appearance; (b) certain specific items
described in the individual product-line
statement(s) below, or in the individual product data sheet or owner’s manual; (c) malfunction resulting from use or operation of
the product other than as specified in the
product data sheet or owner’s manual; (d)
malfunction resulting from misuse or abuse
of the product; or (e) malfunction occurring
at any time after repairs have been made to
the product by anyone other than Electro-Voice
Service or any of its authorized service representatives. Obtaining Warranty Service:
To obtain warranty service, a customer must
deliver the product, prepaid, to Electro-Voice
Service or any of its authorized service representatives together with proof of purchase
of the product in the form of a bill of sale or
receipted invoice. A list of authorized service representatives is available from ElectroVoice Service at 600 Cecil Street, Buchanan,
MI 49107 (800/234-6831 or FAX
616/695-4743). Incidental and Consequential Damages Excluded: Product repair or replacement and return to the customer
are the only remedies provided to the customer. Electro-Voice shall not be liable for
any incidental or consequential damages including, without limitation, injury to persons
or property or loss of use. Some states do not
allow the exclusion or limitation of incidental or consequential damages so the above
limitation or exclusion may not apply to you.
Other Rights: This warranty gives you specific legal rights, and you may also have other
rights which vary from state to state.
Electro-Voice Electronics are guaranteed
against malfunction due to defects in materials or workmanship for a period of three
(3) years from the date of original purchase.
Additional details are included in the Uniform Limited Warranty statement.
For warranty repair or service information, contact the service repair department
at: 616/695-6831 or 800/685-2606.
For technical assistance, contact Technical
Support at 800/234-6831 or 616/695-6831,
M-F, 8:00 a.m. to 5:00 p.m. Eastern Standard Time.
Specifications subject to change without
Q66 Stereo Power Amplifier
Figure 1—Front and Rear Panels
Q66 Stereo Power Amplifier
Figure 2—Block Diagram
Q66 Stereo Power Amplifier
Q66 Stereo Power Amplifier
1. 0 dBu= 0.775 V rms.
2. Dual-mode ratings are for each
channel both operating, unless
3. 120-volt ac line voltage maintained
throughout testing.
Continuous Rated Output Power (20 –
20,000 Hz at less than 0.2% THD,
both channels driven per EIA RS490),
Dual Mode, 2 Ohms:
650 watts
Bridged Mode, 4 Ohms:
1,300 watts
Dual Mode, 4 Ohms:
500 watts
Bridged Mode, 8 Ohms:
1,000 watts
Dual Mode, 8 Ohms:
300 watts
Continuous Rated Output Power
(1 kHz, 1% THD, both channels
driven per EIA RS-490),
Dual Mode, 2 Ohms:
850 watts
Bridged Mode, 4 Ohms:
1,700 watts
Dual Mode, 4 Ohms:
600 watts
Bridged Mode, 8 Ohms:
1,200 watts
Dual Mode, 8 Ohms:
380 watts
Maximum Single Channel Output
Power (1 kHz burst, 20 ms on, 480 ms
off, per IHF-A),
2 Ohms:
950 watts
4 Ohms:
880 watts
8 Ohms:
460 watts
Power Bandwidth (+0, -1 dB, reference 1 kHz), Any Mode, 4 Ohms:
10 – 50,000 Hz
Frequency Response (+0, - 3 dB,
reference 1 Khz/1 watt):
13 – 45,000 Hz
Input Sensitivity, 1 kHz, Dual Mode
for 500 watts into 4 Ohms:
0 dBu (775 mV)
Input Impedance (per channel, 20 –
20,000 Hz), Balanced:
20,000 ohms
Total Harmonic Distortion (at rated
output power, measurement bandwidth 80 kHz):
IMD (SMPTE) (60 Hz/7 kHz, typical,
at rated power):
DIM 30 (composite square-sine wave
bandwidth-limited to 30,000 Hz):
Slew Rate, Any Mode:
30 V/microsecond
Damping Factor, Any Mode,
(at 100 Hz / 1 kHz):
>300 / >200
Amplifier Protection:
Audio limiters; over-temperature; dc,
excessive hf, excessive back-EMF; inrush current limiters; shorted loads;
peak current limiters
Load Protection:
Start-up/shutdown transients; dc fault;
Low ac line voltage; nonlinear signal
Cooling System:
Front-to-rear airflow with two 3-speed
Output Topology
True complementary symmetry with
ungrounded collectors (no mica
insulators for better heat transfer)
Output Devices,
Total Number: 20 devices
Pd (max) Rating: 250 watts
Ic (collector current): 20 amps dc
Tj (max): 200o C (392o F)
Controls and Switches,
Two calibrated level controls; input
routing (Dual/Parallel); chassis
ground switch (Grounded/Ungrounded); bridged mode switch
Power switch (On/Off)
Front-Panel Indicators:
Two LED’s per channel (4 total) for
signal present and limiter on, protect
indicator and power on
3-pin female XLR-type connectors
for each channel in parallel with a
3-pin male XLR-type output
connector for easy signal routing;
the XLR connectors are wired
according to the IEC 268 standard:
pin 1 shield, pin 2 positive, pin 3
Neutrik Speakon NL4MP for
channels A, B and for bridged mode
16-gauge 3-wire IEC standard
removable power cable
Operating Voltage:
120 V, 60 Hz ac
Power Consumption (both channels
operating in dual mode at 1/8 maximum output power at 4 ohms:
870 watts
Dimensions, (see Figure 1),
132.5 mm (5.25 in)
483 mm (19.0 in)
385.5 mm (15.17 in)
Light gray
Net Weight:
35.2 lb (16 kg)
600 Cecil Street, Buchanan, MI 49107
616/695-6831, 616/695-1304 Fax
©Telex Communications, Inc. • 1998 • Litho in U.S.A.
Part Number 535034 — 9817
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