Prisma 750 Monoblock 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.
i Introducing the Perreaux 750 Power Amplifier Congratulations on your Perreaux 750 purchase. To realise the full potential of your unit you need to appreciate all aspects of its operation. Before installing the 750 into your system, read the entire manual carefully. Endeavour to understand every detail by familiarising yourself with the controls and features as you read. You will find it easier to install using the relevant sections of this manual as a reference.
ii Important Safety Instructions Note: All safety and operation instructions should be read carefully before the 750 is operated. Keep the Owners Manual in a safe place for future reference. The 750 should not be used near water, for example near a bathtub, kitchen sink, in a wet basement, near a swimming pool, etc. M ounting to a wall or ceiling should be via a heavy-duty bracket or shelf designed for audio equipment use.
DO NOT attempt to repair the 750. In the event of a problem, please contact your Perreaux dealer. DO NOT operate this product in an explosive atmosphere. Caution! The 750 is an extremely high powered, convection cooled amplifier. The finned outer heat sinks may become very hot when delivering high volume levels – to avoid injury; care should be taken not to touch the heat sinks during operation.
iii Table of Contents i ii iii 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Introducing the Perreaux 750 Power Amplifier ........................................................3 Important Safety Instructions ........................................................................................4 Table of Contents ..............................................................................................................6 Unpacking and Placement..................................................................
1 Unpacking and Placement The 750 is packaged for maximum protection. Please carefully read the instructions below before proceeding to unpack the unit. Be extremely careful. Unpacking Procedure Note: 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.
Ventilation Requirements Note: The 750 is a high-powered amplifier. For optimal performance, the unit M UST 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 750 directly onto carpeted surfaces.
2 Instant Install If you are like us, the first thing you will want to do is to play your favourite piece of music through your new 750. The following instructions are written to enable you to achieve this as quickly as possible. These are not comprehensive instructions, but are designed to enable you to play music now! Note: Please take the time to read the 750 manual thoroughly as it incorporates many features, which will enhance its operation.
Start your source component Switch on the source component both at the wall and on its front panel. Ensure you have some source material inserted and press play. Increase the volume Slowly increase the preamplifier volume control to achieve a comfortable listening level. CONGRATULATIONS! Now that you have achieved your first objective, sit back, relax and please read the rest of the manual at your own pace, in your favourite armchair, whilst sipping a glass of wine.
3 Front Panel Functions Power Indicator The indicator light is an LED that shows the status of your 750 monoblock power amplifier. Off This indicates that the amplifier is either not connected to the mains supply, or the unit is in standby. The unit not being connected to the mains supply could be due to the power switch at the rear of the unit being set to the OFF position, or power not being supplied to the mains power cord (e.g. unplugged, switched OFF at the wall socket, tripped circuit breaker, etc.
4 Rear Panel Functions Caution! Please make all changes at minimum volume setting. Only increase the volume after the connections have been made. Serial Number The serial number is unique to your 750. Please record this number and store it in a safe place. For any service related enquiry, please be prepared to quote the product serial number to Perreaux personnel or their service representative.
Fuse Rating The fuse rating displayed here, refers to the rating of the mains inlet fuse. For more information on fuse ratings, please refer to Chapter 13 “Specifications”. Caution! Never replace the fuses with any other ratings other than the one specified. AC Mains Input An IEC-standard mains input is provided at the rear of the unit. The AC cord set is removable, allowing you to upgrade to a cord set of your preference.
The plug must follow the specifications as per the following diagram: Slave Trigger Output A parallel slave trigger output is provided to switch on or off any connected peripherals to the 750. The slave trigger output is designed to accept a 3.5mm diameter male plug. The voltage rating is +12V DC level ON and 0V DC level OFF. The plug must follow the specifications as per the diagram below: Power Switch Set this switch right (I) to turn power ON.
Refer to Chapter 13 “Specifications”, for detail on input sensitivity and impedance. Note: Please set the input configuration switch to the appropriate setting.
5 Special Design Philosophies Perreaux has been designing and manufacturing only the highest quality audio componentry for more than a quarter of a century. Technology has continued to evolve rapidly over that time and our knowledge and application of design, materials and manufacturing techniques has advanced in tandem with this. Today’s Perreaux range comes closer to fulfilling our shared vision than at any other time in the past.
“Form and function” are both tough masters. That is why our amplifier heat sinks are not hidden, but instead feature prominently in all our designs. We make no excuses for producing some of the most distinctive high-end audio products on the planet. We let “form and function” blend together in perfect harmony. This surely is the essence of true minimalist utilisation.
6 Special Design Features Rugged Build Quality M echanical strength has been a hallmark of Perreaux products since the company first started production back in 1974. The concept behind the physical design and construction is that each structural member should contribute to both rigidity and performance. Ultra Stiff Power Supply The 750 incorporates a massive custom designed, toroidal power transformer, employing unusually heavy gauge wire that reduces copper losses to a minimum.
DC Offset Protection This system senses if any direct current (DC) is present at the 750 output terminals and disconnects the output to avoid potential speaker damage. DC may be present due to ancillary equipment feeding DC into the input or an amplifier fault. Short-Circuit/Overdrive Protection This system senses if there is a short circuit across the 750 output terminals and disconnects the output to avoid amplifier damage.
7 Interconnects and Speaker Cables Maximising System Potential An often-ignored area in high fidelity systems is the cabling connecting the various 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.
The rejection ratio achieved is described in minus dB. The CM RR of a system follows the formula 20Log(Voutput/Vinput). In other words a CM RR of –40dB means that all garbage entering the unit will be made 100 times smaller. The piece of equipment with poorest CM RR will effectively determine the hum and RFI level of the system. Effectively the weakest link in the chain. Highest quality audio systems should quote a CM RR figure of –80dB or better.
8 The Power MOSFET Today with the vast number of technical achievements 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, to the audiophile at least, is that of the power MOSFET device.
their much smaller size, no filaments and greater reliability with reduced vulnerability to physical damage. Audio Applications When used in an audio 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.
High Frequency Response Probably, from the sonic quality point of view, the most important improvement is the power M OSFETs vastly superior high frequency response. A large proportion of the power transistors used in modern hi-fi amplifiers start to show a decline in efficiency from 10kHz upwards. The efficiency of the power MOSFET does not start to decline until about 2M Hz and is only down 3dB at 30MHz.
9 Care and Maintenance The 750 has been designed to provide many years of trouble free enjoyment. It’s important to keep the exterior of the unit clean and to periodically ensure that the air-cooling grills remain clear from obstruction. Note: Please switch the unit off and remove the cord-set from the rear of the amplifier before attempting to clean your 750 in the manner described below. Never apply liquid directly to the 750. Never use abrasives. Never rub in a circular motion.
10 Warranty Information and Obtaining Service 1 Year Limited Warranty The Perreaux 750 is warranted to be free from defects in material and workmanship under normal use to the original purchaser for a period of 1-year (365) days from the date of purchase from an authorised dealer or distributor.
11 Extended Warranty Registration Form Please complete this form and either fax, mail or scan and e-mail it to Perreaux Industries Ltd. Fax: +64 3 489 2976 M ail: Perreaux Industries Ltd PO Box 305 M osgiel Dunedin 9053 New Zealand E-mail: info@perreaux.com Alternatively, complete the online Warranty Registration Form on our website – www.perreaux.com.
12 Cause and Elimination of Hum Faultfinding Your System Hum is a particularly annoying form of noise in any high fidelity system and at some time has been experienced by many of us. Hum may result from a number of different situations and to make matters worse maybe caused by a seemingly illogical combination of circumstances. One or more of three specific causes creates hum in the system.
When a piece of equipment is supplied with a three pin mains/line supply 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 supply of any piece of equipment.
Step 1 – Loudspeakers PREAMPLIFIER 750 750 A B Change the loudspeaker leads from one loudspeaker to the other. If the fault remains in loudspeaker ‘A’, then loudspeaker ‘A’ is at fault, go no further. If the fault now appears in loudspeaker ‘B’ then the problem lies further up the line. M ove on to step 2.
If the fault stays in loudspeaker ‘A’, then it is probable that the fault may exist within the amplifier. Caution: Changing of any connectors must be carried out at a minimum volume setting. Only increase the volume after the connections have been changed. Step 3b – Inputs (Interconnects) PREAMPLIFIER 750 A 750 B Change the interconnect leads completely from left channel to right and from right channel to left by now swapping them at the source component’s output.
Faultfinding Flowchart Fault in loudspeaker A Swap loudspeaker connections Fault in loudspeaker A? YES Loudspeaker A at fault YES Loudspeaker cable at fault NO Loudspeaker cable at fault NO Input source at fault NO Swap amplifier outputs Fault in loudspeaker B? NO Restore speaker cables to original connections Swap amplifier source input channels Fault in loudspeaker A? YES Swap source output channels Fault in loudspeaker A? YES Amplifier at fault 32
13 Specifications The 750 specifications are detailed in brief and then subsequently in more detail. In the detailed version, we attempt to explain the significance of each specification. The correlation between published specifications and sonic unreliable. A list of numbers reveals virtually nothing. measurements must be subject to qualitative as well interpretation. M easurements of the 750 reveal excellent standards.
Power Consumption Idle................................................................................................................... 65W M aximum .................................................................................................... 1400W (at 4Ω rated output) Mains Input Voltage 100V, 110V, 120V, 220V, 230V or 240V AC at 50Hz or 60Hz (Set within the 750 at time of manufacture) Dimensions Width...............................................................................................
The amount of amplification the amplifier is asserting on the input signal. Gain can be calculated by dividing the rated output by the input sensitivity. Dynamic Headroom .................................................................................>1.1dB This indicates the 750 can provide more than enough extra power to cope with the sharpest musical transients. Without adequate headroom, an amplifier can become unstable under clipping conditions.
14 Physical Dimensions 36
15 Contact Details For more information please contact your Perreaux dealer, or contact: Perreaux Industries Ltd PO Box 305 M osgiel Dunedin 9053 New Zealand Ph: +64 3 489 2975 Fax: +64 3 489 2976 E-mail: info@perreaux.com Internet: www.perreaux.
Installation Notes 38
