Studio R Z.500 User manual

OWNER’S MANUAL
12/2006 - REV#3 / EN

1
INTRODUCTION:
Congratulations for purchasing a STUDIO R Z SERIES amplifier!
Our amplifiers are designed for many years of reliable operation at fixed or
movable facilities, under the strictest weather conditions.
Studio R 3-year warranty (valid for Brazil. Check with your dealer for local warranty):
A regular warranty usually covers the free repair of a product every time this fails
during a certain initial period of its lifetime. This procedure, although free of
charge, solves the problem of those components on the product which have aged
prematurely on a very costly and burdensome way for the customer. Many hours
are lost with the system inoperative and its transportation. Our concern with the
warranty covering our products has never been that of merely repairing them
promptly every time they present a fault, but also to prevent faults for a long
time during their lifetimes.
Studio R exclusive Burn-in:
Every Studio R amplifier is in-factory tested for three 3-hour cycles at full power
in a high-temperature oven. It is cooled and tested again at every interval. This
exclusive process in Brazil is the only internationally proven way of finding
components of a system which could deteriorate prematurely within the
equipment lifetime.
Our current fault rate is 2 out of every 1000 devices produced, with a 5-year
time of regular use between two faults.
Such kind of product really allows you to amortize your investments safely and
still make profit. This is why we say that your amplifier should operate almost
seamlessly, while keeping the sonic quality and performance characterizing the
Studio R products.
Although it is basically simple to operate, and having been designed to be
endurable, the improper use of this equipment can be dangerous!
FOR YOUR SAFETY, READ THE SECTIONS ON IMPORTANT PRECAUTIONS,
INPUT, OUTPUT, AND POWER CONNECTIONS.

2
DANGER: THE OUTPUTS OF THIS AMPLIFIER CAN PRODUCE LETHAL VOLTAGE
LEVELS. NEVER MAKE CONNECTIONS WHILE THE DEVICE IS ON.
Wait for at least 1 minute after the shutoff in order to carry out modifications in your connections.
 WARNING: THIS EQUIPMENT IS CAPABLE OF PRODUCING HIGH SOUND
PRESSURE LEVELS WHEN CONNECTED TO SPEAKERS AND SPEAKER SETS.
The continued exposure to high sound pressure levels may cause the permanent loss of or a
reduction in the hearing. Always work with your ears protected by appropriate attenuators.
1- IMPORTANT PRECAUTIONS: Read before operating your amplifier:
1.1 Keep this manual for future inquiries.
1.2 Follow all instructions printed on the chassis for the device proper
operation.
1.3 Make sure the power line is compatible with your device voltage by
checking on its back panel.
1.4 Do not spill liquids in or on the apparatus. Do not operate the
apparatus exposed to rain or with some spilled liquid. Such practice is
the main reason for lethal accidents caused by electric discharges.
1.5 Do not block the air inlet or outlet.Do not operate in locations liable to
preventing the normal air flow.
1.6 Do not use this equipment in case any wire is stripped or fractured.
1.7 It is recommended to keep your amplifier frame always connected to a
grounding system; do this by means of the chassis bolt on the back
panel.
1.8 Do not activate the inputs with a power supply greater than the required
for the amplifier at maximum output.
1.9 Never connect the output of a channel back to the input of another
channel.
1.10 Do not connect the outputs in parallel with the outputs of any other
amplifier.
1.11 Do not connect the outputs of this equipment with any other power
supply, such as batteries or power line, either the equipment is ON or
OFF.
1.12 Do not connect any positive terminal to the ground.
1.13 Do not remove the covers. On removing them you will be exposed to
dangerous voltages. Inside the equipment there is no useful parts for the
user. In case any problem occurs, call our nearest technical assistance.
Technical support and information by Internet or e-mail:
www.studior.com.br - [email protected]

3
2- INSTALLATION AND OPERATION:
2.1 Unpacking
Open the transportation packing carefully and check for any apparent damage.
Prior to leaving the plant all Studio R amplifiers are fully tested and inspected and
ought to reach you in perfect conditions. Should any damage be found on them,
please notify the carrier immediately. Only a forwarding agent may request the
carrier to take actions concerning the damage occurred during the
transportation. Make sure to keep all packing for inspection. It might be a good
idea to keep the packing even when your amplifier has come in perfect conditions.
Whenever it has to be transported, use the original packing or rack standard
CASE, with frontal bars.
2.2 Assembling
Your amplifier is designed to be assembled on a standard 19” CASE, with two
units/rack (88.5 mm). The ventilation on the apparatus rear portion and the front
air outlet are essential for its proper performance. This system provides enough
cooling for all load rates, assuming that the rack rear portion is open and
unblocked. On racks with a closed rear portion, it is vital to install additional fans
on same in such a way to pressurize them, ensuring a good air source for your
amplifier internal fan.
2.3 Operating precautions.
Make sure that the power line AC voltage is the same selected on the
amplifier. The warranty does not cover damages resulting from using the
device on the wrong voltage. Also check the fuse proper use on the table of
the following page.
Prior to making any connection, both of input and output, make sure that the
power switch is off. Even though the amplifier is fitted with overload protection as
well as a Soft Start (silent activation), it is recommendable to always keep the
gain controls low when turning it on. This operation will prevent any possible
damages to the speakers should there be an excess signal on the inputs. Seek to
acquire cables, connectors, and speaker of good quality and appropriate capacity.
Check the wiring capacity table (Section 2.5) to determine the appropriate
measures for different impedances and lengths of cables.
Most of the systems intermittences and faults occur
due to defective wires and connectors.
Use quality connectors, wires, and welding technique to ensure seamless operations.
Fuses Tables (110V / 220V):
Z.300 Z.500 Z.700 Z.900 Z1200 Z1600
4A / 2A 5A / 3A 6.3A / 3A 8A / 4A 15A / 8A 20A / 10A

4
BALANCED UNBALANCED
2.4 Connecting the inputs
The input/split connections are performed by
means of two 3-pin, XLR-type and two
“P10”- type connectors, located on the rear
panel. The connection orientation is:
Pin 1 - Ground.
Pin 2 – Positive (phase).
Pin 3 – Negative (counter-phase).
The fact of finding XLR-type connection cables on
devices or cables does not mean your connections are correct.
ALWAYS CHECK THESE DETAILS VERY CAREFULLY
The figures on the following pages show the basic diagram for the connections on
the rear of your amplifier in a sound system.
It is important on a stereo system to connect the mixer L channel to the amp
input 1, and the mixer R channel to the amplifier input 2.
The same precaution should be taken for connecting the speakers. The speakers
located on the right side of the stage should be connected to the right channel
(OUTPUT 2), and those of the other side to the left channel (OUTPUT 1).
The speaker polarity is also important. The speaker positive should be connected
to the amplifier (+) positive terminal, and the speaker negative, to the amplifier (-)
negative terminal.
BALANCED UNBALANCED
I I I
1 3 2
I I I
1 1 2
T
he Z SERIES amplifiers contain
balanced inputs and can be
powered either by balanced lines
or not, according to the figures.
You can connect up to two 8 Ohm speakers
or cabinets in parallel per channel, or only
one 4 Ohm speaker or cabinet per channel. If
you don’t respect these limits, you can
overload your amplifier and void the warranty.

5
2.5 Connecting the outputs:
The loudspeakers should be connected to the amplifier by wires which should,
first, provide the minimum current capacity necessary for the work.
Wire minimum gauge in mm2(Z.500)
A wire for each speaker 1mm2
A wire for every two speakers 1,5mm2
Wire minimum gauge in mm2(Z.700)
A wire for each speaker 1,5mm2
A wire for every two speakers 2mm2
Wire minimum gauge in mm2(Z.900)
A wire for each speaker 2mm2
A wire for every two speakers 2,5mm2
In addition to the current capacity of the speaker connecting wires, it is
important to know as well at what distance from the amplifier the speakers are.
We may have power and damping factor losses on long-distance connections,
even with the correct gauge wire.
The following example can provide us with a magnitude order in this regard:
An 8-ohm speaker placed at 50 meters from the amplifier and connected with
a pair of 2-mm2 wires results in a damping factor of 9 only.
A drop in the Damping Factor occurs on any amplifier, and it just takes the
presence of a wire between same and the speaker or speaker set.
On the following table see the power loss in percentage and, in parentheses, the
resulting damping factor:
(We can see in bold letters that the losses in long distances exceed 10%, and that the
damping factor also drops to below 10. For example, with a 12% loss on a 1000-W
amplifier, 120 watts are lost and the speakers receive 880 watts only.)
Length of the
pair of wires
(in meters)
Gauge
(mm2)
Power loss on the wires
for each speaker
(Damping factor)
Power loss on the wires
For each 2 speakers
(Damping Factor).
5 1 2,2% (45)
5 1,5 1,5% (67) 3% (34)
5 2,0 1% (90) 2,2% (45)
5 2,5 0,85% (114) 1,75% (57)
5 3 0,7% (140) 1,4% (66)
10 1 4,4% (23)
10 1,5 3% (34) 6% (16)
10 2,0 2% (46) 4,4% (25)
10 2,5 1,7% (57) 3,5% (28)
10 3 1,4% (66) 2,8% (33)
20 1 8,8% (11)
20 1,5 6,0% (16) 12% (8,3)
20 2,0 4% (22) 8,8% (11)
20 2,5 3,4% (28) 7% (10)
20 3 2,8% (33) 6% (16)

6
2.5.1 Speaker wire terminals (BINDING POSTS)
We should use wires with “banana” or “fork” connectors, the second (fork) being
more reliable in the long run (the “banana” terminal gets loose in a short time).
We can see that on each amplifier output channel there is a pair of lugs. The
speaker positive should be connected, and the terminal with red lug is to be
regarded as “hot”, which should never be connected directly to the ground. The
other side of the speaker should be connected to the black lug.
Never connect any wire directly between the left channel
lugs and those of the right channel and vice-versa.
2.6 Connecting the power of your 4-ohm Z series:
Your Studio R power cable has 3 wires with a 3-pin connector. The 4-ohm Z
Series amplifiers are designed to operate on 110 V or 220 V.
Under full power, with both channels set to 4 ohms (Two 8-Ohm speakers in
parallel per channel), your Studio R 4-ohm Z Series amplifier can “pull” a
considerable current. See on the following table the recommendable minimum
gauge to use on your AC electrical installation according to the number of
speakers to be used and the type of music.
SPEAKER OUTPUTS: This is
where the speakers should be
connected. Connect the
speaker positive to the
positive lug, and the negative
to the speaker negative.
Floating common: Your amplifier circuit ground is insulated from the frame. This allows
various safety configurations to be made for the system grounding.
WHEN WE SELECT THE LINE VOLTAGE ON
WHICH THE AMPLIFIER WILL OPERATE, IT IS
VITAL TO PLACE THE FUSE WITH THE PROPER
CURRENT VALUE. SEE THE CORRECT VALUE
ON THE FUSES TABLE.

7
 ATTENTION: Make sure that the power line AC voltage is the same
selected on the amplifier. The warranty does not cover damages resulting from
using the device on the wrong voltage. Also check the fuse proper to use on
page’s 4 table.
Your Z Séries amplifier will protect it self when connected to the wrong
voltage, by burning a safety device in its interior. In this case, your amplifier
will refuse to turn-on again. You must contact our technical assistance in
order to substitute the safety device and use your amplifier again.
NOTE THAT THE TABLE VALUES WERE CALCULATED FOR 110 VOLTS, WITH A
SETTING BETTER THAN 5% (WHICH IS A SATISFACTORY SETTING), ON AN
INSTALLATION WITH NO MORE THAN 50 METERS BETWEEN THE POWER FRAME
AND THE AMPLIFIER. AS TO THE 220-V LINE, WE CAN USE UP TO HALF THE
GAUGE.
When longer distance connections are required, such as for example 100 meters
(double the distance), we should use double the gauge as well.
In case of a sound system leasing company, where music is generally reproduced,
we should always size the AC system for the PINK NOISE rate:
PINK NOISE Z.300 Z.500 Z.700 Z.900 Z1200 Z1600
2 speakers p/ channel 0,5mm21mm21,5mm22mm22mm22,5mm2
1 speaker p/ channel 0,4mm20,5mm21mm21,5mm21,5mm22mm2
ROCK WITH
COMPRESSION
Z.300 Z.500 Z.700 Z.900 Z1200 Z1600
2 speakers p/ channel 0,5mm21mm21,5mm21,5mm22mm22mm2
1 speaker p/ channel 0,4mm20,5mm21mm21mm21,5mm21,5mm2
AMBIENT MUSIC Z.300 Z.500 Z.700 Z.900 Z1200 Z1600
2 speakers p/ channel 0,4mm21mm21mm21,5mm21,5mm22mm2
1 speaker p/ channel 0,3mm20,5mm20,6mm21mm21,5mm21,5mm2
 All of the Studio R Z Series amplifiers come with a power cable and
connector. The user should consult the consumption table and, according to the
intended use of his/her equipment, purchase the female connector with the
appropriate capacity for the extension.

8
2.7 Stereo Operation:
For stereo operation, place an audio signal on the channel “1” input with an
amplitude consistent with the amplifier sensitivity (selectable according to the
SDS table) in order to produce a signal output on channel “1” parallel lug, while a
signal in “2” will produce a signal output on the parallel connector in “2”.
SDS table (gain/sensitivity adjust):
Sensitivity Euro Version Regular Version
DS (centered gain - “DS” point) 26dB / 20x 1.55V
Maximum (gain at 10 position) 32dB / 40x 0.775V
IMPORTANT: The 1.55V level (in regular versions) is equal to -6dBm or -6 dBU. You must
always use this level, instead of 0.775V, when using digital processors. In other cases, adjust
according to your system sensitivity.
Both channels operate on a completely independent way, with their respective
input attenuators controlling the total levels. In order to distribute the signals to
other amplifiers we must use connectors parallel to the input connectors: “P10”
in case of input via “XLR”, and “XLR” in case of inputs via “P10”.
VOL/GAIN: Input signal attenuators. The controls operate
separately even on the parallel operation. “DS” position
(center) indicates 1,55V sensitivity. “10” position (max)
indicates 0
,
775V sensitivit
y
.
Inputs: XLR balanced or P10
balanced parallel. “1” is the left
channel, and “2” the right one.
Mode selector
STEREO or PARALLEL.

9
2.8 Parallel operation:
Both channels, on the parallel mode, can be fed by a single input signal source
without the need for any bridge. The signal applied on the “XLR” or “P10” of
channel 1 will activate both sides with the signal in phase. The output
connections are made in the same way as the stereo mode via the channel and
black lugs. Both input attenuators remain active, allowing for different levels for
the speakers of each channel.
The power specifications continue the same as on the stereo operating mode.
 Attention: With the input switch on the parallel mode we can feed the
amplifier inputs with distinct signals, as they will be short-circuited.
2.9 Input signal attenuators (VOL/GAIN).
The rotary controls located on the back panel of your Studio R, one for each
channel, allow the input sensitivity to be individually set with a reasonable
resolution. On the scale recorded on the panel from 0 to 10, the amplifier input
signal level on the stereo and parallel modes can be individually modified. When
fully turned on the clockwise direction, they will allow a signal on the input
sensitivity rate of 0,775V (or 32dB/40x - Euro Version only) to provide a maximum
power on a 4-ohm load. When at the center click point (DS), sensitivity rate will
be 1,55V (or 26dB/20x - Euro Version only).
IMPORTANT: As the attenuators are independent, the channels can be set
with different signal levels. This occurs when each one of the channels are
being used for different environments or on different frequency ranges such as
bass and treble. (The speakers always withstand more power than the drivers.
Be careful with the settings!).
VERY IMPORTANT 
THE INPUT SENSITIVITY CONTROLS OF THE Z SERIES AMPLIFIERS
ARE NOT POWER SETTINGS (A HEAVY-DUTY LINE EXCLUSIVENESS!).
The regular setting of these will never be able to protect delicate speakers
with power lower than that the amplifier is able to provide. In these instances,
an appropriate external limiter should be used.

10
2.9.1 Power Switch:
Studio R 4-ohm Z-series amplifiers are fitted with an on/off switch located on the
front panel. In the regular use, when the switch is pointing upward, this turns the
amplifier on and two green LEDs will light up on the panel.
ATTENTION 
Prior to turning your amplifier on make sure that the
power line voltage is same as selected on the apparatus.
This is statistically the only way of damaging a Studio R.
In addition, it is regarded as a misuse and is not covered by the warranty.
3 – INDICATORS:
The Studio R 4-ohm Z-Series amplifiers are equipped with LED-type light
indicators, individual for each channel, which report the user on the operating
condition. If the power is on or off, the green LEDs “CHANNEL...ON” will light
up. If a signal is present on the output, two green LEDs “SIGNAL” will flash
according to the signal on each of the channels. When the maximum output
power is reached, the blue LEDs (Signal processing) will light up according to the
intensity of the limiter acting and activation. See the following:
3.1 Signal processing indicators:
When the processing blue LED lights up, this indicates that the input signal
limitation has started. When the red LED flashes occasionally, a tolerable soft
limiting will be occurring. In case the input signal exceeds too much the input
nominal level, the limiter will start operating so as to avoid any distortions
greater than 2%.
Power switch
lever: Turns the
amplifier on or off.
Power indicator:
Lights up when the power
switch is turned on.
Signal indicators
on the amplifier output.
Signal processing indicators
to prevent distortions:
Flashing slightly when the amplifier
is under full
p
ower is normal.

11
4 - PROTECTION FEATURES (EPS)
The Studio R Z Series amplifiers incorporate several protection systems, both
for the amplifier and the speakers.
We seek to produce your amplifier on a “fail-safe” way, impenetrable by short-
circuits, open circuits, overloads, unequal loads, and damages due to overheating.
Under conditions where protection mechanisms are enabled, the operation stops
until the problem is cleared.
4.1 Impedance sensor:
All Studio R amplifiers are fitted with a system to assess the type of load on its
output. On an excess load, this limits the maximum output current without
causing any severe distortions.
4.2 Thermal Protection:
Studio R amplifier dissipator is one of the most effective available in the market.
It provides double the required thermal capacity and its fans will keep the
amplifier operating within the desired temperature limits under normal conditions.
Should the temperature (or heat dissipator) reach 95º C due to an improper air
supply, air input or output blocking, or else due to the breakdown of its own fan, a
thermal sensor will be enabled in such a way to protect each channel individually
until the temperature returns to an acceptable level.
4.3 Short circuit:
If a short-circuit is applied to an output, the limiting and thermal circuits will
protect the amplifier.
4.4 Fuses:
Assuming that an accident occurs in which the amplifier output electronics are
severely damaged, your amplifier still relies on an internal fuse which will not allow
the fault to propagate to other parts of the system.
Soft Start.
When you turn on a Studio R Z Series amplifier, its circuits are powered on a
symmetrical and totally silent way.
Soft Clip.
With the Z Series limiter, you will always be able to use your PA at full power
without any distortion. Even when the line voltage is quite altered, your Studio R
will know how to dispense the power in such a way to avoid any audible distortion.

12
- VARIABLE-SPEED FANS:
Three stages variable-speed fans automatically maintain internal temperatures
within a safe operating range, with minimum noise.
5 - SPEAKER PROTECTION METHODS:
All speakers present physical limits. The most critical ones are the thermal and
mechanical limits, which should be observed so as to avoid its operation
stoppage.
Studio R amplifiers contain energy enough to damage most of the speakers
existing in the market without much effort, if misused.
Make sure that the frequency range used is appropriate for the speaker,
particularly the subsonic frequencies which are not reproduced by the
speaker. Always set your crossover to the ideal frequencies. Check the
speaker manual for determining the maximum “X” and “f3”.
)TIP: Ask for the service leaflet to the speaker manufacturer
in order for your own technician to master the subject.
Never power DRIVERS and TWEETERS without
an appropriate series capacitor!
For drivers, an optimum value is 47 micro Faraday.
For most of the tweeters, a 5.6uF capacitor is appropriate.
6 – OPERATION ON AMBIENT SOUND:
All 4-ohm Z Series amplifiers can operate on the constant voltage line
configuration for ambient sound installations. This type of installation is quite
used successfully in bars, night clubs, churches, etc.
For example, The Z.500 operates as a 30Volts line amplifier. In this way, you can
connect up to five 15 watts speakers using Studio R transformers model AML
15/30. Consult for other models.

13
7 – MAINTENANCE:
Your Studio R amplifier does not require much maintenance, which is restricted
to its outer cleaning. Do not use any solvent, but only a cloth wet with water and
soap. During its lifetime the amplifier will not require any internal setting.
 NEVER BLOW COMPRESSED AIR INTO THE
AMPLIFIER ELECTRONICS OR ANY OTHER SIMILAR EQUIPMENT.
8 - USER RESPONSIBILITY:
YOUR AMPLIFIER IS QUITE POWERFUL
AND CAN BE POTENTIALLY DANGEROUS!
STUDIO R IS NOT RESPONSIBLE FOR ANY DAMAGE CAUSED TO HUMANS OR
SPEAKERS. FOLLOW CAREFULLY THE INSTRUCTIONS SET FORTH IN THE
MANUAL AND THE RELEVANT STANDARDS RELATED TO YOUR INDUSTRY.
9 – WARRANTY::
Studio R provides the purchaser of any Z Series amplifier with a warranty
against defects on the components and assembly for a 3-year*** time as of the
purchasing date (***Valid for Brazil. Please check with your dealer about local warraty).
IMPORTANT:
Studio R reserves the right to introduce changes or improvements into the
design and manufacturing of its amplifiers, without undertaking any obligation to
do so in the previously manufactured products.
Do not forget to send us the registration sheet already filled out to make it
easier for serving you and sending information and future novelties. Such
registration can also be made on our site: www.studior.com.br
In the event you are unable to install or to take the best profit you expect from
your equipment, get in touch with our International Technical Support:
[email protected]
STUDIO R Eletronica LTDA
Rua Lucrecia Maciel, 95 – Vl Guarani. CEP 04314-130
Sao Paulo, SP – Brazil
[phone].
Visit our website: http://www.studior.com.br
E-mail: [email protected]

14
General Specifications: 120V 60 Hz power line
CLASSIFICATION
AB Class
HARMONIC DISTORTION
1KHz @ 1/2 of rated power
0.05%, 4 ohms
0.02%, 8 ohms
HARMONIC DISTORTION
20Hz-20KHz@ rated power
lower than or equal to 0.2%.
FREQUENCY RESPONSE 20Hz a 20khz, +/- 0,7dB.
DAMPING FACTOR Greater than 2000 at 8 ohms @ 40Hz
NOISE 105 dBA relative to the maximum power.
SENSITIVITY 775mVRMS for the rated power or 1,55V (selectable).
INPUT IMPEDANCE 10 Kilohms balanced
CONTROLS
Front: power switch.
Rear: parallel/stereo switch, 110/220V selector, and rotary settings for the
input signal attenuation.
INDICATORS
Power - 2 green LEDs
Signal - 2 green LEDs
Processing - 2 blue LEDs
CONNECTORS
Line inputs and outputs: 2 XLR female connectors and 2 P10 female
connectors, balanced (pin 1 and 3 ground, 2” +”).
Chassis and floating common connecting bar.
Speakers: 2 pairs of 1/4’ lugs (one pair for each channel).
COOLING Aluminum duct with forced ventilation.
PROTECTION
Soft Clip, Soft Start, short-circuited or open output, reactive or mismatched
loads, and over the input signal. Independent thermal sensors for each
channel.
LOAD PROTECTION Silent on/off, output power limiter with reference to 2% of DHT.
OUTPUT CIRCUIT Linear complementary, Soft Clip.
POWER 110 or 220V AC (selectable)
PRECISE CONSUMPTION 1.65 times the output power used.
DIMENSONS
(height x width x depth)
88,5MM x 483MM x 320mm
WEIGHT/RATED POWER and
MAXIMUM CONSUMPTION
Z.500 – 5kg/ 500W, 110V; 5A / 220V; 3A
Z.700 – 5kg/ 700W, 110V; 6,3A / 220V; 3A
Z.900 – 5kg/ 700W, 110V; 8A / 220V; 4A
SINUSOIDAL POWER TABLE: Valid for 120V/60Hz line (standard IEC-60268-3).
For line voltage variations in the amount of 10%, the powers can vary up to + or – 22%.
Model 4 ohms - 2 channel 8 ohms - 2 channel 4 ohms - 1 channel 8 ohms - 1 channel
Z.500 500 watts RMS 340 watts RMS 300 watts RMS 190 watts RMS
Z.700 700 watts RMS 430 watts RMS 375 watts RMS 230 watts RMS
Z.900 900 watts RMS 500 watts RMS 480 watts RMS 270 watts RMS
Z1200 1200 watts RMS 720 watts RMS 660 watts RMS 400 watts RMS
Z1600 1600 watts RMS 1000 wattsRMS 880 watts RMS 540 watts RMS
ATTENTION: A 4-ohm Z Series amplifier should power no more than 2 speakers per channel. This is
this condition where it will provide its maximum stereo power.