Prisma 350
Stereo Power Amplifier
Owners Manual
Perreaux Industries Limited makes no warranty for the use of its products, other than those
expressly contained in the warranty detailed herein. The Company assumes no responsibility for
any errors which may appear in this document, reserves the right to change products or
specifications detailed herein at any time without notice, and does not make any commitment to
update the information contained herein. No licenses to p atents or other intellectual prop erty of
Perreaux are granted by the Company in connection with the sale of Perreaux products, expressly or
by implication.
mboob^ru® is a registered trademark of Perreaux Industries Ltd.
Terms and product names in this document may be trademarks of others.
2
Congratulations on your Perreaux 350 purchase. To realise the full potential of
Before installing the 350 into y our system, read the entire manual carefully.
erstand every detail by familiarising y ourself with the controls
and features as you read. You will find it easier to install using the relevant
ly and
concisely. In the event that something is still unclear to you, your Perreaux
Read this manual, install your unit correctly and realise the sonic signif ican ce of
ucts are design ed to provide the utmost in sonic realism and
electronic reliability with a functional y et elegant appearance that reflects the
To maintain the consistently high quality that you expect from us, and we exp ect
on, through
Because we too listen to our products, we know that with your Perreaux you will
ited, thank you for choosing the
iiii
Introducing the Perreaux
350 Power Amplifier
your unit y ou need to appreciate all asp ects of its operation.
Endeavour to und
sections of this manual as a refer ence.
We have attempted to explain every feature and op erational facet clear
dealer will be happy to assist you further.
your investment in Perreaux.
Perreaux prod
Features at a
Glance
care and craftsmanship applied during all stages of construction.
Balanced and Unbalanced inputs
Rugged build quality
Ultra-stiff power supply
Soft-Start circuit
Hybrid Class A/AB output stages
MOSFET output devices
High p ower output
Dual binding posts per channel
Remote trigger input and output
Multiple protection systems
Advanced PCB design and earthing techniques
Earth isolation switch
from ourselves, Perreaux p roducts are essentially handcrafted.
We maintain the human-link throughout, from design and constructi
to the ultimate test, your music, your system, your ears.
discover many more of the musical secrets we strive to reveal.
From all of us at Perreaux Industries Lim
Perreaux Prisma Series 350 power amplifier.
3
ii
All safety and operation instructions should be read carefully before the
ure
The 350 should not be used near water, for example near a bathtub, kitchen
ii
iiii
Note:
Important Safety Instructions
350 is operated. Keep the Owners Manual in a safe place for fut
reference.
sink, in a wet basement, near a swimming pool, etc.
Mounting to a wall or ceilin g should be via a heavy-duty bracket or shelf
designed for audio equipment use.
The 350 should be situated away from heat sources such as radiators,
stoves, or other appliances that produce excessive amounts of heat.
Always ensure the 350 heat sinks have adequate ventilation enabling air
circulation both above and below.
DO NOT place the 350 directly onto carpeted surfaces.
Avoid exposing the 350 to extremely high or low temperatures.
The 350 should be connected to a mains power supply only of the type
described in the operating instructions, or as marked on the rear of the unit.
DO NOT disconnect the mains earth from the system.
The mains p ower supply cord should be routed so that it is not likely to be
walked on or pinched by items placed on or against it.
The power cord of the 350 should be unplugged from the mains outlet
when the unit is to be left unused for long periods or when attemp ting to
connect or disconnect cables and before cleaning your unit.
Care should be taken so that objects and/or liquids do not accidentally fall
inside the 350.
Please keep electrical equipment out of reach of children.
Please unplug sensitive electronic equipment during electrical storms.
Please replace any fuse with the value and typ e sp ecified.
Avoid operating the 350 with the cover removed.
DO NOT bypass any fuse.
4
The 350 is an extremely high powered, convection cooled amplifier. The
elivering high
to avoid injury; care should be taken not to touch the
DO NOT attempt to repair the 350. In the event of a problem, please
contact y our Perreaux d ealer.
DO NOT operate this product in an explosive atmosphere.
Caution!
finned outer heat sinks may become very hot when d
volume levels –
heat sinks during operation.
5
iii
iii
iiiiii
iiii
Introducing the Perreaux 350 Power Amplifier ........................................................3
ii
ii
Important Safety Instructions ........................................................................................4
iiii
iii
iii
Table of Contents ..............................................................................................................6
iiiiii
1111
Unpacking and Placement..............................................................................................7
2222
Instant Install......................................................................................................................9
3333
Front Panel Functions................................................................................................... 11
4444
Rear Panel Functions.....................................................................................................12
5555
Special Design Philosophies ........................................................................................ 16
6666
Special Design Features................................................................................................18
7777
Maximising System Potential ...................................................................................... 20
8888
The Power MOSFET.......................................................................................................22
Table of Contents
9999
Care and Maintainance................................................................................................ 25
10
10
Warranty Information and Obtaining Service........................................................26
1010
11
11
Extended Warranty Registration Form ....................................................................27
1111
12
12
Faultfinding Your System............................................................................................. 28
1212
13
13
Specifications................................................................................................................... 33
1313
14
14
Physical Dimensions ...................................................................................................... 36
1414
15
15
Contact Details................................................................................................................ 37
1515
6
1
fully read the
Be very careful to secure the unit if you are planning to flip the package
The 350 should generally be placed close to your preamplifier, keeping the
We strongly recommend keeping the 350 on it’s own sep arate shelf to allow for
1
11
The 350 is p ackaged for maximum protection. Please care
instructions below before proceeding to unp ack the unit. Be extremely careful.
Unpacking and Placement
Unpacking
Procedure
Note:
Remove the two white polystyrene p rotectors off either side of the
Inspect both ends of the cardboard box and open at the end without the
central staple by slitting the reinforced tape at either side.
Fold back the flaps and tip the package on end and the inner box will
slide out.
Lay the inner box down flat and upright, op en it conventionally by
separating the top tray from the bottom.
The product can now be removed from the bottom packaging. This will
be easier if you have someone to help y ou by holding the base of the
box.
Alternately, the bottom tray and amplifier could be tipped upside down
and the bottom packaging removed. If opened in this manner, please
ensure that y ou turn the contents over again.
upside down.
amplifier, leaving the black material covering.
Pull back the material and r emove the protective black tissue from the
front p anel.
Note:
Box
Contents
Placing
Your 350
The amp lifier is now unpacked and ready for further installation.
Please retain all packaging material for future transport.
1 x 350 Power amplifier
1 x 350 Product manual
1 x Detachable AC p ower cord
3 x Performance analy sis charts
interconnect cabling short.
proper ventilation.
7
Please take all necessary steps to ensure that the unit receives adequate
Ventilation
Requirements
Note:
The 350 is a high-p owered amplifier. For optimal performance, the unit MUST
receive adequate ventilation.
Please do not install in a sealed cabinet.
Please do not stack products directly on top of the unit.
Please do not cover the product with a cloth or similar.
Please do not mount the 350 directly onto carpeted surfaces.
As a “rule of thumb”, allow 80-100mm (3-4 inches) around all sides of
the product and mount the 350 on a flat surface, ensuring that the unit
has adequate access to free flowing air.
In the event that the 350 is to be incorporated into custom cabinetry,
please refer to Chapter 14 “Physical Dimensions”.
ventilation
8
2
If you are like us, the first thing y ou will want to do is to play your favourite
piece of music through your new 350. The following instructions are written to
enable y ou to achieve this as quickly as possible. These are not comp rehensive
Please take the time to read the 350 manual thoroughly as it incorporates
ll be achieved when placed
a carpeted floor
This minimises the potential to damage any other components when connecting
) inputs at the rear of the 350 and set the input configuration
keep all interconnect cables as far from loudspeaker cables as
We recommend using h igh quality connectors for y our speaker cables, spade
are the preferable option as they combine a larger surface area with the
possibility of a strong mechanical connection; however, high quality banana
right, and
Turn on the preamplifier and set the volume to the minimum level. Select the
After checkin g the supp ly voltage compatibility with the voltage rating on the
set supplied into the rear of the unit and
into the wall. Switch on the socket at the wall and p ower up the 350 using the
2
22
instructions, but are design ed to enable y ou to play music now!
Note:
many features, which will enhance its operation.
Placement
The 350 is a high-power amplifier and best results wi
on a solid surface with adequate ventilation. DO NOT place on
or cover the amplifier!
Turn off associated components
Instant Install
your 350 into the system.
Connect preamplifier to 350
Connect the outp ut of y our preamplifier to either the balanced (XLR) or unbalanced (RCA
toggle switch at the rear to the correct position.
Note:
Connect speaker cables to the left and right speaker terminals
Note:
Switch on preamplifier
Try to
possible and well away from all AC mains leads.
lugs
terminals are also acceptable.
Be careful to maintain channel integrity, i.e. left to left, right to
phase integrity, positive (+) to positive (+), negative (-) to negative (-).
respective input to which your source component is connected.
Switch on 350
350 rear panel, insert the p ower cord-
switch on the rear p anel.
9
Start your source component
Switch on the source component both at the wall and on its front panel. Ensure
ntrol to achieve a comfortable
Now that you have achieved y our first objective, sit back, relax and please read
the rest of the manual at y our own p ace, in y our favourite armchair, whilst
u’ll find the whole exp erience much more
you have some source material inserted and press play .
Increase the volume
Slowly increase the p reamplifier vo lume co
listening level.
CONGRATULATIONS!
sipping a hot cup of coffee. Yo
pleasurable whilst listening to music.
10
3
, or
could be due to the power
or power not being
wall
Standby occurs when the unit is connected to the mains supply with the power
connected via the remote trigger
To bring the unit out of standby the
For more information on the remote trigger, please refer to Chapter 4 “Rear
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33
Front Panel Functions
Power Indicator
The indicator light is an LED that shows the status of your 350 power amplifier.
Off
This indicates that the amplifier is either not connected to the mains supp ly
the unit is in standby.
The unit not being connected to the mains supply
switch at the rear of the unit being set to the OFF p osition,
supplied to the mains power cord (e.g. unplugged, switched OFF at the
socket, tripp ed circuit breaker, etc.).
switch being set to ON and a master device,
input at the rear of the unit, is set to OFF.
master device needs to be set to ON.
Panel Functions”.
Blue
When the LED is blue, the amplifier is ON and ready to be used.
11
4
Please make all changes at minimum volume setting. Only increase the
in a safe p lace. For any service related enquiry, please be prepared to quote the
he correct AC mains voltage. This
unit is factory set for the voltage applicable to the original country of
The 350 will operate satisfactorily within a voltage variation of up to ±5% of
uire the voltage setting to be altered, e.g. relocation to another area,
city or country, or extraordinarily high or low voltages, please contact your
to connect the unit to the incorrect voltage. Severe
4
44
Rear Panel Functions
Caution!
volume after the connections have been made.
Serial Number
The serial number is unique to your 350. Please record this number and store it
product serial number to Perreaux personnel or their service representative.
Input Voltage and Fuse Rating
Input Voltage
It is important that the 350 be operated from t
destination.
that voltage at which the unit has been set.
If you req
Perreaux dealer. Qualified service personnel can only perform this modification.
Caution!
Never attempt
damage can result from applying incorrect voltage to the unit.
12
e refer to Chapter 13
Caution!
Never replace the fuses with any other ratings other than the one
standard mains input is provided at the rear of the unit. The AC cord set
Prior to connection to the AC mains, please check the voltage label on
the rear panel to ensure that your unit conforms to the power supply in
rect voltage.
This switch enables the user to isolate the internal signal earth of the amplifier
etting this
switch DOWN connects the internal signal earth to mains earth and is the normal
Activating this switch has no effect on chassis earth, maintaining the
The 350 is equip ped with a user serviceable AC mains fuse. In the event of fuse
failure, always replace with the same type and value fuse. Remember, fuses do
re should be
For more information on fuse ratings, please refer to Chapter 13
Never replace the fuses with any other ratings other than the one
Always ensure your 350 is disconnected from the mains supply before
The remote trigger system is designed to switch on or off the 350 and any
ipherals. If the 350 is switched on or off via the remote input
trigger, any peripherals connected via the slave trigger outp ut will also be
Fuse Rating
The fuse rating disp layed here, refers to the rating of the mains inlet fuse.
For more information on fuse ratings, pleas
“Specifications”.
specified.
AC Mains Input
An IECis removable, allowing you to upgrade to a cord set of y our p reference.
Caution!
your area. Never attempt to connect the unit to the incor
Severe damage can result from applying incorrect voltage to the unit.
Earth Lift Switch
from the mains earth and is useful if sy stem hum is a p roblem. S
position. Setting to UP disconnects the signal earth from the mains earth.
Note:
connection to mains earth.
Mains Fuse
not usually blow without a reason. Any doubts about fuse failu
conveyed directly to your Perreaux dealer.
Caution!
“Specifications”.
This is the ONLY user accessible fuse.
specified on the rear panel.
attempting to change the mains fuse.
Remote trigger input and output
connected p er
switched on or off.
13
Master Trigger Input
0 in and
out of standby . The master trigger input is designed to accept a 3.5mm diameter
male p lug. The voltage rating is +5V to +12V DC level ON and 0 V DC level
is p rovided to switch on
or off any connected peripherals to the 350. The slave trigger output is designed
to accept a 3.5mm diameter male plug. The voltage rating is +12V DC level ON
) to turn p ower ON. Mute relay circuitry is employed in
Set
) to turn the unit off, at which time the outputs will be
The 350 is equipped with two sets of output terminals p er channel, to enable
l loudspeakers. All
terminals are clearly marked and colour coded RED Positive (+) and BLACK
). This polarity must be observed when connecting loudspeakers, i.e.
positive terminal of the 350 to the p ositive terminal of the loudspeaker and
Never connect the amplifier’s output terminals to any device other than a
one amplifier to the output terminals of
The master trigger input (leftmost 3.5mm socket) is used to take the 35
OFF.
The plug must follow the specifications as per the following diagram:
Slave Trigger Output
A parallel slave trigger outp ut (rightmost 3.5mm socket)
and 0V DC level OFF.
The plug must follow the specifications as per the diagram below:
Power Switch
Set this switch right (I
the 350 so output is muted momentarily after the power switch is actuated.
the switch left (O
disconnected.
Caution!
Speaker Output Terminals
easy hook-up for bi-wiring of loudspeakers or additiona
Negative (-
negative terminal of the 350 to the negative terminal of the loudspeaker.
loudspeaker.
Please do not short circuit the amplifier’s output terminals.
Never connect the output of
another amplifier.
Do not over-tighten the binding posts on your amplifier.
For more information, please refer to Chapter 7 “Maximising System Potential”.
14
Balanced Inputs
ier with balanced outputs via a high quality
The use of good quality balanced line cable into the balanced
input cause the input signal to be relatively immune to noise and external effects
ps reduce hum loop noise and
Refer to Chapter 13 “Specifications”, for detail on input sensitivity and
Please refer to the operating manuals of your balanced output line level
rce to verify that the pin assignments of the output connectors
correspond to the 350 balanced inputs. In the event that they are not
cts, please refer to Chapter 7
ended input pair (RCA) from preamplifiers with
ended outputs. The connectors are high quality gold plated sockets which
tive, corrosion resistant, and provide less potential for
corrosion induced distortion. Inputs are clearly marked Left and Right, indicated
by a black and red ring resp ectively. Care should be taken to maintain channel
cifications”, for detail on input sensitivity and
Input leads should be connected to one type of input only, i.e. do not
Accepts a signal from a preamplif
XLR connector.
caused by the use of long interconnect cables, hel
aids in the cancellation of distortion products.
impedance.
Note: Please set the input configuration switch to the appropriate setting.
The pin assignments of the balanced XLR connectors are as follows:
Pin 1: Signal ground
Pin 2: Signal + (non-inverting)
Pin 3: Signal – (inverting)
Shield ground: Chassis ground
Note:
sou
compatible, the interconnecting cable will need to be altered to suit.
For more information regarding balanced interconne
“Maximising System Potential”.
Unbalanced Inputs
Accepts a standard singlesingleare highly conduc
integrity.
Refer to Chapter 13 “Spe
impedance.
Note: Please set the input configuration switch to the appropriate setting.
Input Configuration Switch
This toggle switch allows selection of either the balanced or unbalanced inputs.
Note:
connect to both the unbalanced and balanced inputs at one time.
15
5
Perreaux has been d esigning and manufacturing only the highest quality audio
mponentry for more than a quarter of a century. Technology has continued to
evolve rapidly over that time and our knowledge and app lication of design,
materials and manufacturing techniques has advanced in tandem with this.
loser to fulfilling our shared vision than at any
To follow is a discussion on some of Perreaux design philosophies that have
Perreaux has historically embraced the minimalist ethic from an audio design
perspective only. The concept of “less equating to more” has been at the heart
We wish to maximise the quality of your listening pleasure by keeping the
componentry and signal path as uncluttered, short and clean possible. All
ose of the highest quality have an effect
on the signal, thereby altering the quality of the reproduction in some way. Our
aim is to recreate in its entirety, the original performance by not adding or
We carefully study the user interface and par down the number of buttons and
associated clutter leav ing just the essential and no more. How tempting it has
have made it p ossible. That is one of the reasons why our older products still
have such a high resale value today. The user interface has and always will
eal to those who seek the ultimate in audio exclusivity, namely
5
55
Special Design Philosophies
co
Today’s Perreaux range comes c
other time in the past.
been incorporated into the entire range.
Minimalist
Design
Leading British architect, John Pawson, writes:
“The Minimum can be defined as the perfection that an object
achieves when it is no longer possible to improve it by subtraction.
This is the quality that an ob ject has when every component, every
detail, and every junction has been reduced or condensed to the
essentials. It is the result of the omission of the inessentials”.
of all Perreaux audio designs for more than a quarter of a century .
Minimalist Electronics
components in the signal p ath, even th
subtracting anything, irrespective of the source.
Minimalist User Interface
been over the y ears to loose sight of our core values as technology or trends
remain simple, free from adornments, clean and uncluttered.
Minimalist Aesthetics
Our p roducts app
the perfect blend of “form and function”.
16
“Form and function” are both tough masters. That is why our amplifier heat
esigns. We
end audio
products on the p lanet. We let “form and function” blend together in perfect
sinks are not hidden, but instead feature p rominently in all our d
make no excuses for producing some of the most distinctive high-
harmony. This surely is the essence of true minimalist utilisation.
Minimalism in a Wider Context
John Pawson writes:
“Clearly simplicity has dimensions to it that go beyond the purely
aesthetic: it can be seen as the reflection of some innate, inner
quality, or the pursuit of philosophical or literary insight into the
nature of harmony, reason, and truth”.
17
6
Mechanical strength has been a hallmark of Perreau x products since the
company first started production back in 1974. The concept behind the physical
tural member should contribute to both
The 350 incorporates a massive custom designed, toroidal p ower transformer,
employing unusually heavy gauge wire that reduces copp er losses to a
static shield prevents AC line borne interference from
entering the signal p ath. The power supply filter capacitors, totaling 60,000µF
(30,000µF p er channel), have exceptionally low inductance and internal
e to load demand far more
rapidly than conventional storage capacitors and are capable of delivering the
instantaneous current required by the outp ut stages, providing op timum dy namic
output
boards is designed for unimpeded transmission of the required current and
voltage and utilizes heavy gauge, tinned copper wire cables. Since power supp ly
leads radiate at sign al frequencies, all wiring is carefully loomed to minimise
polar transistors used in the 350 are run in Class A mode. This avoids the
order harmonics p resent, to
some degree, in all other classes of operation. The devices used in the 350
output stage are M OSFETs, which with high quiescent current circuitry, are run
in the equivalent of Class A to 10 watts. Beyond this p oint the output class is
technically Class AB (hence the hybrid nomenclature), but with a major
ion of MOSFET characteristics and their application in
The 350 output stage takes full advantage of the unique qualities of MOSFET
polar transistors. A major
advantage is their tendency to draw less current over a large section of the power
bandwidth as their temperature rises (Negative Temperature Coefficient), hence
polar transistors draw more current as their
temperature rises (Positive Temp erature Coefficient) and p rotection circuits
become mandatory to p revent thermal runaway and eventual self destruction.
the amplifier’s internal DC
rail" devices. Using M OSFETs
encourages the highest performance from the balance of the internal amplifier
6
66
Rugged Build
Quality
Ultra Stiff
Power Supply
Special Design Features
design and construction is that each struc
rigidity and performance.
minimum. An electro
resistance. They charge and discharge in respons
range and transient resp onse. The wiring from the power supplies to the
Hybrid Class
A/AB
MOSFET
Output Stage
this effect.
The bicrossover notch distortion and the resulting odd-
difference. The combinat
this circuitry , result in crossover distortion so minimal that it is virtually non-
existent.
devices and in many ways they are superior to bi-
self stabilising thermally, whereas bi-
MOSFETs have the ability to swing fully across
voltage and are therefore true "rail-to-
circuitry.
18
p rotection systems, isolated from all
couplers, to protect both itself and ancillary
This system senses if any direct current (DC) is present at the 350 output
output to avoid p otential speaker damage. DC
may be p resent due to ancillary equipment feeding DC into the inp ut or an
This system senses if there is a short circuit across the 350 outp ut terminals and
disconnects the outp ut to avoid amplifier damage. It also senses if the 350 is
being driven outside acceptable op erational parameters. An example of this
e is removed, the 350 must be
This system senses if the 350 is overheating and disconnects the output until a
atically
Perreaux engineers p ay p articular attention to designing the p roduct to ensure
maximum separation between internal signal and power earths, only meeting at a
gle switch on the rear of the 350 allows the internal circuitry to be
isolated from the mains earth, whilst still maintaining an earth connection to the
set with
grade
components, are used throughout the 350. This p rovides added stability under
al loads and assures maximum signal integrity,
wiring of sp eakers to be
ect the fuses and/or circuit breakers in
your home’s mains power supply . Without this circuit, the huge inrush current
required to charge the 60,000µF of power supp ly smoothing capacitance can
), the
350 is highly powered. Utilising eight high current Toshiba MOSFETs p er
Multiple
Protection
Systems
Note:
The 350 is equipped with a number of
signal carrying circuits via op to-
equipment.
DC Offset Protection
terminals and disconnects the
amplifier fault.
Short-Circuit/Overdrive Protection
would be driving a 1Ω speaker at very high levels.
After the short circuit or overdrive sourc
turned off then back on to reset and resume operation.
Thermal Protection
safe operating temperature is reached, at which time the unit will autom
resume normal operation.
Earthing
Earth
Isolation
Switch
Highest
Quality PCBs
and
Components
Bi-Wiring
Made Easy
Soft-Start
Circuitry
Highly
Powered
central starred point.
The tog
chassis. This ensures the potentially fatal p ractice of using an AC cordno earth connection, to alleviate system hum, is not required.
Quality fibreglass PCBs, featuring heavy copp er tracks and high-
variable thermal or electric
separation and product life.
Dual pairs of binding posts per channel allow biconducted easily.
The 350 utilises soft-start circuitry to prot
blow the fuses or trip the circuit breakers.
Capable of continuously delivering 350W
into 8Ω (600W
RMS
into 4Ω
RMS
channel, the 350 handles even the most difficult loads with ease.
19
7
ignored area in high fidelity systems is the cabling connecting the
components. Interconnect leads should be high quality cable with
substantial terminations. Gold plate is inherently resistant to corrosion, and an
excellent conductor. The presence of corrosion induces distortion and poor
conductivity will seriously interfere with sound quality. Terminations must plug
snugly into sockets to maintain maximum conductivity and to avoid annoying
ker cabling is equally critical. Use only solidly constructed cable of high
purity copper or silver content. Again, gold p lated terminations are
recommended, of the spade or banana plug typ e. Use cables of equal length and
in uniform electrical resistance at the lowest
possible level. If your amplifier is closer to one of your speakers than the other,
avoid coiling the longer lead as this can create inductance, with the p otential of
all connections clean, firm and
tight. The traditional adage that a chain is only as strong as its weakest link
amping uses two similarly powered amplifiers, with exactly the same input
o that, when the same input signal is p rovided to each of them, the
output level will be exactly the same. This can often be done with one p ower
amplifier connected to the tweeters and another to the woofers, as it spreads the
amping can achieve greater
control, dy namics and resolution than if you try to run everything from a single
The use of the balanced signal inputs and outputs can have the effect of cleaning
hums, buzzes, radio frequency interference (RFI) and general extraneous
rubbish that can enter an audio system. A balanced signal input system operates
on the principle of differential amplification. The p ositive and negative inputs
st one another and the difference between them is amplified.
Noise entering the sy stem is imposed equally on the positive and negative
the effect is called Common M ode
Rejection Ratio (CM RR). CM RR is an equipment and sy stem specification,
which describes how well unwanted common mode signals are counteracted
when used in conjunction with balanced connections. CM RR action prevents
gress and build up of extraneous hum; buzzes and RFI when analogue
signals are conveyed down cables and between equipment powered from
7
77
Maximising System Potential
Interconnects
and Speaker
Cables
Bi-amping Bi-
An oftenvarious
earthing problems.
Spea
as short as p ossible to mainta
reduced high frequency performance. Keep
most certainly applies to audio sy stems.
sensitivity s
Balanced
Interconnects
power requirement between the two amplifiers. Bi-
stereo amp lifier.
up
are contrasted again
signals and therefore will not be amplified, as no differential voltage exists.
The term used to describe the quality of
the e
different locations and is widely used in professional audio app lications.
20
The rejection ratio achieved is describe
d in minus dB. The CMRR of a system
40dB
means that all garbage entering the unit will be made 100 times smaller. The
e hum and
RFI level of the system. Effectively the weakest link in the chain. Highest
cord, decks) is
important. To avoid airborne frequency peaks, place them well away from your
s
are generally the worst situation. Everything which constitutes your listening
area, including the materials used in its construction, will affect the sound itself
and the sound stage created. Equally, y ou have to live with y our system and
mpromises will have to be made in line with y our particular
priorities. The best advice we can give concerning the choice of loudspeakers is,
establish clearly in your mind your requirements; listen to many makes and
n your preferred choice in y our own
ordinarily, the amp lifier should
er than the
, 8Ω speakers
, 8Ω speakers
that is, the
High fidelity systems are an investment deserving of careful thou ght and
personal time. Your preferences, priorities and constraints will dictate the
rameters of your p urchase, your ears will tell y ou what is the right choice for
you. Our exp erience tells us that the bitterness of dissatisfaction lingers long
–
follows the formula 20Log(V
output/Vinput
). In other words a CM RR of –
piece of equipment with poorest CMRR will effectively determine th
quality audio systems should quote a CMRR figure of –80dB or better.
Positioning
Positioning of your source equipment (tuner, video, disc, tape, re
Ancillary
Equipment
Loudspeaker
loudspeakers and not in the corners of your listening area.
Loudspeaker placement is a controversial issue; suffice to say that room corner
Placement
therefore co
models, and if at all p ossible auditio
listening area and trust your own ears.
Matching
Amplifier and
Speaker
Ratings
Note:
When matching sp eakers to amplifier wattage –
have a continuous RM S outp ut power rating the same as or high
speakers at the same impedance rating. For example, 350W
driven by a 350W
driven by a 350W
at 8Ω amplifier is not as ideal as 250W
RMS
at 8Ω amplifier.
RMS
RMS
RMS
350 Watts is twice as loud as 35 Watts, not ten times as loud.
Perreaux equipment is designed with substantial headroom built in –
reserve necessary to rep roduce musical peaks without clipping.
Final
Thoughts
pa
after the fragrance of cheap price is forgotten, hence our use of the term
investment.
21
8
Today with the vast number of technical ach ievements occurring around the
world, many discoveries are overshadowed or obscured by some that may
appear more important to the general media. One such discovery of importance,
The field effect transistor (FET) and then the M OSFET transistor have been
handling device, mostly
ons equipment. The electrical
fi. If only
what a benefit to the
ing reasonably
hence power.
MOSFET stands for “Metal Oxide Silicon Field Effect Transistor”, this in turn
but the
that controls the power flow through the device is insulated from the
remainder of the device by a metal oxide insulating layer and the controlling of
the p ower is achieved by the develop ment of an electrostatic field between the
In a transistor, the control of the p ower through the device is effected by the
application of a smaller, but nevertheless, significant amount of power to the
controlling element. Whereas in the power MOSFET, the control of the power
through the device is affected by the application of a very small and very
in fact, only the
amount required to create a small electrostatic field. This makes the operation of
There are basically three ty pes of p ower field effect d evice, they are: the
junction FET, the vertical FET and the p ower MOSFET, all of which were
t manufacturers in
The first of these was the junction FET, the second the vertical FET and lastly,
the p ower M OSFET. Although all these devices are vast improvements over
sistors, the junction FET and vertical FET cannot compare with the
power MOSFET, in terms of simplicity of the supporting driver stages and
The power MOSFET, though having similar characteristics to the valve, can be
channel and
channel. Broadly sp eaking only one of these types exists in valve operations.
can be
rity of operation than can be
achieved with valves. In addition, further advantages over the valve include
8
88
The MOSFET
The Power MOSFET
to the audiophile at least, is that of the power MOSFET device.
around for a number of years, but only as a small signalemployed in radio tuners and communicati
advantages of these have long been r ealised by manufacturers of hithey could be made to handle large amounts of power –
audiophile.
The term p ower M OSFET describes a device capable of handl
large amounts of electrical energy as an amplifier itself –
means that the device is constructed of Silicon. Similar to a transistor –
part
Other Field
Effect
Devices
controlling element and the conducting element.
insignificant amount of power to the controlling element –
a power M OSFET similar to that of a valve.
independently developed by three different hi-fi equipmen
Japan and all were major technological breakthroughs in their own right.
power tran
power supp ly requirements.
divided into 2 types of polarities of device – PNThis means that complementary power MOSFETs – P and N channel –
used in an audio outp ut stage p roviding greater linea
22
their much smaller size, no filaments and greater reliability with reduced
vulnerability to p hysical damage.
io power amplifier, the advantages of the power MOSFET
over the power transistor are much more difficult to describe and would require
greater complexity than can be gone into here. However, they can be
that the p ower MOSFET
has a negative temperature coefficient whereas the p ower transistor has a
positive temperature coefficient. This means that when a power transistor is
handlin g p ower it heats up further and consumes more p ower. This
called thermal runaway, will result in the destruction of the power
transistor if some means is not provided to control it. The power MOSFET on
the other hand, although heating up due to the power flow through the device,
d more power just because its temperature has
provided adequate head
sinking is available to remove the heat generated during normal operation.
d for a similarly p ower rated
Then there is the appearance of secondary breakdown and ‘hot spots’ in a power
transistor. This is related to thermal runaway. In order to understand this, one
chip silicon inside the power transistor is in fact many
smaller transistors connected in parallel. Now, if one of these smaller transistors
or a sp ot on the chip has a greater gain (or amplification factor) than the rest,
er and to a gr eater temperature than the remainder
of the transistor chip. This means that whole power dissip ation capability of the
transistor has been severely reduced and is a major cause of these unexp lained
The p ower MOSFET is largely immune to this problem because if a small part
of this chip has a higher gain than the rest then its temperature will rise slightly
wer is
more evenly distributed throughout the chip and therefore reliability is
It can be seen from the above that the transistor p ower amplifier has to have a
much larger margin of power dissipation capability and heat sinking in its output
can require a driver
stage capable of delivering 10W at 1kHz and up to 20W at 20kHz into the input
um of 0.01W
so a major saving in driver stage componentry and associated noise and
Audio
Applications
Secondary
Breakdown
When used in an aud
summarised as follows – the most important p oint is
characteristic,
does not continue to draw more an
risen. But in fact has a tendency to stabilize itself –
Incidentally this is less heat sinking than is require
standard transistor.
must imagine that the
then that spot will heat up fast
output stage failures in large power amplifiers, i.e. over 80 W
rm s
.
causing that sp ot to reduce gain and hence stabilization occurs. The p o
maintained.
stage than the power MOSFET amplifier.
The transistor p ower amplifier of 100W
output into 8Ω
rm s
of the output device. The power MOSFET only requires a maxim
distortion can be eliminated.
23
High
Probably, from the sonic quality point of view, the most important improvement
ior high frequency resp onse. A large
fi amplifiers start to show
a decline in efficiency from 10kHz upwards. The efficiency of the p ower
own 3dB at
30MHz. This is due to the energy transfer being accomplished with minority
charged carriers in the p ower MOSFET as opposed to majority charged carriers
within the transistor, and results in hole storage at high frequencies causing the
r to dissip ate increasing amounts of energy within itself as the frequency
Further sonic degradation of the transistor p ower amplifier occurs due to hole
storage of the output transistors. As the output distortion increases with
l frequency, it is obvious that the distortion products in the
Because the negative feedback sy stem is employed to reduce distortion by
cancellation, at high frequencies it causes even more p ower to be consumed
Transient intermodulation (TIM ) is also more prevalent in transistor power
amplifiers because the signal transition in time is relatively slow. This means
ay, a fast transient will not travel
through the negative feedback system into the output stage fast enough to cancel
resulting in the amplifier being overloaded.
Further sonic improvement is achieved in power MOSFET amplifiers due to
reduced crossover distortion, as p ower M OSFETs have a sharper “knee” than
off and provide a greater linearity when crossing over from one
other. Because crossover distortion is a major cause of odd order
harmonic distortion in transistor amplifiers (be it small, i.e. 0.05% total) they are
usually considered to sound more harsh than v alve amplifiers which generally
order harmonic distortion up to 5% and are thought
However, which is more accurate? The valve amplifier at 5% THD with a
pleasant sound and even order harmonics; the transistor amplifier with 0.05%
unp leasant sound with even and odd harmonic output, or a
power MOSFET amplifier with 0.02% THD and relatively pleasant even order
harmonic distortion? In our opinion, the power MOSFET amplifier because the
er harmonic distortion total
It can be seen that power M OSFETs are here to stay and that there are major sonic
Frequency
Response
is the power M OSFETs vastly super
proportion of the power transistors used in modern hi-
MOSFET does not start to decline until about 2M Hz and is only d
transisto
increases.
increasing signa
negative feedback path also increase.
within the output transistor just to cancel out the distortion.
Other
Advantages
the distortion products in the signal of, s
at exactly 180 degrees out of phase –
This is not p ossible in power M OSFET amp lifiers.
transistors at cutdevice to the
have large amounts of even
to sound more pleasant and musical.
THD with relatively
THD generated is virtually all second or even ord
0.02% or less at 20kHz and down to 0.004% or less at 1kHz.
and electrical improvements to be had over other output devices.
24
9
The 350 has been designed to provide many years of trouble free enjoyment.
It’s important to keep the exterior of the unit clean and to p eriodically ensure
set from t he rear of the
amplifier before attempting to clean your 350 in the manner described
coat finish. To remove finger
If the dirt is not removed, dip your cloth in a mild solution of soap and water,
Stubborn dirt may be removed by the application of a small quantity of
methylated spirits, applied directly to the cleaning cloth only and reworking the
me the
surface may retain finger marks and may need to be cleaned to restore it to
Gently wipe the front panel with a very clean cotton cloth. Wipe across the
Only attempt this infrequently, as too regular or vigorous application may
Apply a small quantity of any car polish containing carnauba wax to a very clean
e polish will therefore
Gently wip e over the front panel in lateral motion, allow to dry and then gently
9
99
Care and Maintenance
that the air-coolin g gr ills remain clear from obstruction.
Note:
Cover The cover features a durable, high qu ality powder-
Front Panel The 350 front p anel features a high quality electroplate finish. Over ti
Please switch the unit off and remove the cord-
below.
Never apply liquid directly to the 350.
Never use abrasives.
Never rub in a circular motion.
marks and dirt, lightly rub the surface with a soft cloth.
squeeze excess moisture from it and then gently reapply to the surface.
effected area.
original condition.
Regular Cleaning
surface and never in a circular motion.
Removing Stubborn Marks
damage the surface.
cotton cloth.
Note:
The car polish must state “Safe for Clear Coats” as th
contain the absolute minimum amount of abrasive compound.
wipe off with a very clean cotton cloth.
25
10
The Perreaux 350 is warranted to be free from defects in material and
year
To extend the warranty on y our Perreaux 350 to five (5) y ears from d ate of
purchase, please return a fully completed warranty registration form along with a
Perreaux Industries Ltd may, at its discretion, allow the warranty on this p roduct
info@perreaux.com requesting a
If during the warranty period the Perreaux 350 exhibits defects in materials
and/or workmanship, it will be repaired or replaced, at our option, without
abour. The warranty does not apply to any unit that
Any unit that is not p erforming satisfactorily may be returned to the factory in
New Zealand for evaluation. Return authorisation must first be obtained by
lling or writing to Perreaux prior to shipp ing the unit. Perreaux
Industries Ltd and it’s authorised distributors and dealers shall not be held liable
for any freight or insurance charges. Freight and insurance charges to and from
There is no other exp ress warranty on the 350. Neither this warranty nor any
other warranty , exp ress or implied, including any implied warranties of
e warranty period. No
In the event that y ou are experiencing difficulty with the 350, please as a first
fter following this
10
1010
1 Year
Limited
Warranty
5 Year
Extended
Warranty
Warranty Information
and Obtaining Service
workmanship under normal use to the original purchaser for a p eriod of 1(365) days from the date of p urchase from an authorised dealer or distributor.
copy of the original receipt of purchase to:
Perreaux Industries Ltd
PO Box 305
Mosgiel
Dunedin 9053
New Zealand
Warranty
Transfer
Information
on the 350
Warranty
For the Extended Warranty Registration Form, please refer to Chapter 11.
to be transferred. Please contact Perreaux on
transfer.
charge for either parts or l
has been misused, abused or altered.
either ca
the Perreaux factory will be the sole responsibility of the owner of the unit.
merchantability of fitness, shall extend beyond th
responsibility is assumed for any incidental or consequential damages.
Obtaining
Service
step , follow the faultfinding procedures in Chapter 12. If a
procedure, you require further assistance, please contact your Perreaux dealer.
26
11
mail it to Perreaux
11
1111
Extended Warranty
Registration Form
Please complete this form and either fax, mail or scan and e-
Industries Ltd.
Fax: +64 3 489 2976
Mail: Perreaux Industries Ltd
PO Box 305
Mosgiel
Dunedin 9053
New Zealand
E-mail: info@perreaux.com
Alternatively , complete the online Warranty Registration Form on our website
– www.perreaux.com.
5 Year Extended Warranty Form
Name:
Address:
Suburb:
City:
Country :
Telephone:
E-mail:
Website:
Product Purchased:
Serial Number:
Dealer:
Purchase Date:
d d m m y y y y
P R I S M A 3 5 0
/ /
27
12
Hum is a particularly annoying form of noise in any high fidelity system and at
Hum may result from a number of different situations and to make matters
Hum can be induced into the system from one or more sources and is generally
Hum and noise can be radiated from any object or system involving AC voltage
and current such as power supp lies in amplifiers, motors, switching equipment
ay be induced into any p art of the system, so there are no sp ecific
instructions that can be given which will offer a guaranteed cure. A good
level signal equipment such as p hono systems,
vel signal equipment such as power
amplifiers. Alternatively, careful designs must be employed to negate these
level signal equipment. Another good p ractice to adopt is to keep
tying excess leads together for a tidy looking installation
Earth loops are a particularly annoying cause of hum in the sy stem. Earth loops
equency current flowing in the screen of signal leads and
becomes apparent with the lack of adequate earthing between the various pieces
fi sy stem. This is further compounded by the
ions vary between different
Perreaux products used with equipment manufactured by other manufacturers
may cause an earth loop situation, but Perreaux products used with other
tion p rovided the following
outlet. This will ensure that each piece of the sy stem shares the same earth
all br ands of equipment.
A preamplifier or power amplifier may be operated from an extension cord
12
1212
Elimination
Induced Hum
Cause and
of Hum
Faultfinding Your System
some time has been experienced by many of us.
worse may be caused by a seemingly illogical combination of circumstances.
One or more of three specific causes creates hum in the system.
associated with the radiation of noise from one system into another.
etc. All of these may be found in your hi-fi system or within y our own home.
Hum m
practice to adopt is to keep lowtuners etc. well away from h igh-le
effects on lowall signal leads away from power leads.
The practice of neatly
should be resisted, as this could be the cause of induced hum in the system.
Earth Loops
are cr eated by mains fr
of equipment making up the hifact that the equipment earthing considerat
manufacturers and countries.
Perreaux p roducts will not cause an earth loop situa
precautions are observed:
The entire hi-fi system must be connected to the same mains/line power
or ground. This rule applies to all installations of
plugged into the same mains/line outlet.
28
When a piece of equipment is supplied with a three p in mains/line supp ly
This is a common cause of hum and noise in the sy stem. In many instances, the
eliminate the p ossibility of hum problems arising through a broken
earth connection somewhere in the system is to physically check every
se in
one channel, it is good p ractice to adopt a method of isolating the p roblem to a
specific item or area. This practice will assist in diagnosing, curing, or at least
advising y our technician of the p roblem and result in a saving of time, money
A logical approach to isolating the probable cause of the p roblem is to start at
the loudspeakers and work back to the music source, eliminating each piece of
ings. Please make all
changes at minimum volume setting. Only increase the volume after the
Check that the entire system is connected in the prop er manner and that the
one loudspeaker ‘A’ and the
B
lead all three pins must be connected in the correct fashion - see your
dealer if in doubt.
Check all interconnecting signal leads for good connections, both internal
connections and firm contact with the sockets. While the centre pin may
make firm contact, it is very important that the outer contact is also firm.
Never remove the earth/ground wire from the mains/line supp ly of any
piece of equipment. This could be hazardous.
Broken Earth Connections
only way to
connection.
Identifying
When experiencing a p roblem, such as one channel not working, or a no i
and Isolating
Problems
and perhaps frustration.
equipment in turn.
Caution!
Observe precautions regarding volume control sett
connections have been made.
mains/line supp ly is connected and switched on.
For clarity during this section, we have labelled
other loudspeaker ‘B’. In this example, loudspeaker ‘A’ app ears faulty.
Initial system connections
PREA MPLIFIER
350
A
29
Step 1 – Loudspeakers
B
Change the loudsp eaker leads from one loudspeaker to the other. If the fault
If the fault now appears in loudspeaker ‘B’ then the problem lies further up the
B
Change the loudsp eaker leads completely from left channel to right and from
right channel to left by now swapping them at the amplifier output. If the fault
ker ‘B’, then that loudspeaker lead is at fault, go no
If the fault app ears in loudspeaker ‘A’ then loudspeaker leads are OK. M ove on
B
Change the input p lugs on the rear of your amplifier, as follows: Change each
input source in turn by swapp ing the p lugs left to right and right to left. If the
e selected inputs, then that
A
remains in loudsp eaker ‘A’, then loudspeaker ‘A’ is at fault, go no further.
line. M ove on to step 2.
Step 2 – Loudspeaker Leads
A
PRE AMPLIFIER
350
PREAMPLIFIER
350
now app ears in loudspea
further.
to step 3.
Caution!
Restore the loudspeaker leads to their original connections at both ends.
Step 3a – Inputs (Channels)
A
PREA MPLIFIER
350
fault changes to loudspeaker ‘B’ on any one of th
particular inp ut source is p ossibly at fault. Move on to step 3b.
30
If the fault stays in loudsp eaker ‘A’, then it is probable that the fault may exist
within the amplifier.
ut at a minimum volume
setting. Only increase the volume after the connections have been
B
Change the interconnect leads completely from left channel to right and from
to left by now swapping them at the source component’s output. If
the fault stays in loudsp eaker ‘B’, then the interconnect lead is at fault, go no
any connectors must be carried out at a minimum volume
setting. Only increase the volume after the connections have been
Should the fault p rove to be in the amplifier it will be n ecessary to determine
s has been done, for instance, y ou now
know what input/s and what channel is affected. This information will assist
been localised to
the amplifier, it will be necessary to determine whether or not the noise increases
with the volume control; whether or not the noise exists when no input at all is
ample,
low frequency hummin g noise or high frequency hissing noise. This
information will also assist y our service p erson in making repairs or
Caution:
Changing of any connectors must be carried o
changed.
Step 3b – Inputs (Interconnects)
A
right channel
further.
If the fault appears in loudspeaker ‘A’, then the interconnect lead is OK.
Caution!
Changing of
PRE AMP LIFIER
350
changed.
where the fault actually lies. M ost of thi
your Perreaux dealer or service person when or if any service is required.
If the apparent fault is noise in one or both channels and has
connected to the amplifier; and what typ e of sound the noise is. For ex
adjustments.
31
B?
A?
cable at faul t
at fault
at fault
Faultfinding
Flowchart
Fault i n
loudspea ker A
Swap loudspe ake r
connect ions
Fault i n
loudspea ker
A?
NO
Swap am plifi er
output s
Fault i n
loudspea ker
NO
Restore speaker
cables t o ori ginal
conne ctions
Swap am plifi er
source input
cha nnels
YES
YES
Loudspea ker A
at fault
Loudspea ker
cable at faul t
Fault i n
loudspea ker
YES
Swap source
output channels
Fault i n
loudspea ker
YES
Ampli fier
NO
NO
Loudspea ker
Input sourc e
32
13
n subsequently in more detail.
In the detailed version, we attempt to explain the significance of each
The correlation between p ublished specifications and sonic quality can be
technical
measurements must be subject to qualitative as well as quantitative
interpretation. Measurements of the 350 reveal excellent results by any
13
1313
The 350 specifications are detailed in brief and the
Specifications
specification.
unreliable. A list of numbers reveals virtually nothing. All
standards. Tested at 115V and 230V after a 10 minute warm up p eriod.
Specifications
In Brief
Rated Power Output:.................................................................. 350W
(continuous, per channel, both channels driven f rom 20Hz-20kHz at < 0.020% THD)
................................................................................................. 600W
(continuous, per channel, both channels driven f rom 20Hz-20kHz at < 0.035% THD)
Frequency Resp onse:.......................................................... 5Hz – 40kHz ±0.25dB
Total Harmonic Distortion ( THD+N)
Typically:.....................................................................0.004%, @ 1kHz into 8Ω
20Hz to 20kHz: ....................................................................... <0.020%, into 8Ω
Voltage Gain: .............................................................................................. 30.7dB
Dynamic Headroom (r ated wi th musi c):............................................................ >1.1dB
Voltage Swing: ............................................................................................197V
Maximum Current Output:............................................................80A per channel
Damping Factor:.................................................................>700, @ 1kHz into 8Ω
Signal to Noise Ratio
Rated Output ( unweighted):............................................................................ 100dB
Input Sensitivity
Unbalanced:.............................................................................................1.5V
Balanced: .............................................................................................±0.78V
Input Impedance
Unbalanced:.................................................................................................22kΩ
Balanced: ....................................................................................................3.3kΩ
Smoothing Capacitance:...........................................................................60,000µF
(30,000µF per channel)
Driver Stage:............................................................................................... Class A
Output Stage: ........................................................................................Class A/AB
Audio Inputs
Unbalanced:.....................................................................1 p air RCA connectors
Balanced: ......................................................................... 1 pair XLR connectors
Audio Outputs:.................................. 2 pairs of speaker binding posts per channel
into 8Ω
RMS
into 4Ω
RMS
p-p
RMS
RMS
Other Connections
1 x IEC AC mains input receptacle
1 x 3.5mm “mini” jack for master remote input (5 – 12V DC)
1 x 3.5mm “mini” jack for slave remote output (12V DC)
33
Power Consumption
30.0kg (66.1lb)
34.0kg (74.8lb)
The 350 has been designed around the industry standard 8Ω load. The 350
into
4Ω loads. The 350 will also handle complex and 2Ω loads with stability and
This is the “standard” specification with which everyone is familiar. Actually,
“frequency response” is a misnomer: technically, it should be called “amplitude
response versus frequency” for it describes how uniform the amp litude or
h of signals of various frequencies is maintained. It is generally thought
that a difference of 1db is the least that can be perceived by ear. To better that
by a wide margin, the 350 is specified four times higher, thus far exceeding the
Measurements are made with fixed, purely resistive loads. However, since
speakers are not purely resistive, an amplifier’s distortion specifications do not
will be with the actual loads presented by speakers.
Perreaux distortion measurements hold for any conditions presented by any
Idle................................................................................................................... 80W
Maximum .................................................................................................... 1300W
Mains Input Voltage
100V, 110V, 120 V, 220V, 230V or 240 V AC at 50Hz or 60Hz
(Set within the 350 at time of manufacture)
Dimensions
Width...............................................................................................430mm (16.9”)
Height ................................................................................................194mm (7.6”)
Depth...............................................................................................486mm (19.1”)
Fuse Ratings
Mains inp ut fuse
100 – 125V:..........................................................................2SB slow blow 15A
200 – 250V:..........................................................................2SB slow blow 10A
Internal DC rail fuses ...................................................4 x 2AG normal blow 10A
(at 4Ω rated output)
(user servi ceable)
(NOT user serviceable)
Specifications
Explained
Weight
Net:..................................................................................................
Gross:...............................................................................................
Rated Power Output
delivers a staggering 350W
(per cha nnel)
continuously into 8Ω loads and 600W
RMS
............................................ 350W
RMS
into 8Ω
RMS
ease.
Frequency Response ....................................................5Hz to 40kHz ±0.25dB
strengt
audible range of the human ear.
Total Harmonic Distortion
(THD+N)
........................... 0.004%, @ 1kHz into 8Ω
indicate what p erformance
known speaker. Further, any measurable distortion in the Perreaux is secondorder harmonics – the least offensive to the ear.
34
Voltage Gain............................................................................................. 30.7dB
The amount of amplification the amplifier is asserting on the input signal. Gain
become unstable under clipping conditions. Perreaux amplifiers are intrinsically
Loud transients call for a sudden burst of p ower from the amplifier to drive the
speakers. This force is voltage. Peak to p eak voltage is a more useful
Current is the p ower reserve in the amplifier necessary to deliver the burst of
changin g audio signal. With more than adequate
peak, the 350 can easily
whether instantaneous or
impedance loads
Ω
of sp eaker systems, which are difficu lt to drive. Perreaux power
The ratio of desired signal to noise sign als p resent in the output. This figure is
account all potentially
Indicates the amount of input voltage required to drive the unit to its rated output
The resistance “load” that is p resented to the component that is driving it. The
high value indicates that the power amplifier will not load down the outp ut of
can be calculated by dividing the rated outp ut by the input sensitivity.
Dynamic Headroom .................................................................................>1.1dB
This indicates the 350 can provide more than enough extra power to cope with
the sharpest musical transients. Without adequate headroom, an amplifier can
stable under all dynamic conditions.
Voltage Swing ......................................................................................... 197V
p-p
specification than Watts when it comes to delivering power to a sp eaker.
Maximum Current Output......................................................80A per channel
voltage required by the evercontinuous current per channel and high volts peak-to-
meet any challen ge music can present to it –
continuous. To be specific it can deliver high power into lowand provide great dynamic headroom.
Damping Factor .............................................................. >700, @ 1kHz into 8
Another specification not always provided. One reason p erhaps, this
specification is important when indicating an amplifier’s ability to control the
cone behaviour
amplifiers have high damping factors. Thus exerting massive control over the
speaker sy stem.
Signal to Noise Ratio
(unweighted)
.............................................................. 100dB
referenced to the rated output of the 350, taking into full
annoying hum components.
Input Sensitivity....................................................................................... 1.5V
power (350W
into 8Ω).
RMS
Input Impedance..........................................................................................22kΩ
most high quality preamplifiers.
RMS
35
14
14
1414
Physical Dimensions
36
15
15
1515
For more information please contact y our Perreaux dealer, or contact:
Contact Details
Perreaux Industries Ltd
PO Box 305
Mosgiel
Dunedin 9053
New Zealand
Ph: +64 3 489 2975
Fax: +64 3 489 2976
E-mail: info@perreaux. com
Internet: www.p erreaux.com
37
Installation Notes
38
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