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Prisma 750 

Monoblock Power Amplifier 

Owners Manual 

Summary of Contents for Prisma 750

Page 1: ...Prisma 750 Monoblock Power Amplifier Owners Manual...

Page 2: ...change products or specifications detailed herein at any time without notice and does not make any commitment to updatethe information contained herein No licenses to patents or other intellectual pr...

Page 3: ...m and electronic reliability with a functional yet elegant appearance that reflects the care and craftsmanship applied during all stages of construction Features at a Glance Balanced and Unbalanced in...

Page 4: ...posing the 750 to extremely high or low temperatures The 750 should be connected to a mains power supply only of thetype described in the operating instructions or as marked on the rear of the unit DO...

Page 5: ...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...

Page 6: ...ons 11 4 4 4 4 Rear Panel Functions 12 5 5 5 5 Special Design Philosophies 16 6 6 6 6 Special Design Features 18 7 7 7 7 Maximising System Potential 20 8 8 8 8 The Power MOSFET 22 9 9 9 9 Care and Mai...

Page 7: ...lifier could be tipped upside down and the bottompackaging removed If opened in this manner please ensure that you turn the contents over again Note Be very careful to secure the unit if you are plann...

Page 8: ...h a cloth or similar Please do not mount the 750 directly onto carpeted surfaces As a rule of thumb allow 80 100mm 3 4 inches around all sides of the product and mount the 750 on a flat surface ensuri...

Page 9: ...unbalanced RCA input at the rear of the 750 and set the input configuration toggle switch at the rear to the correct position Note Try to keep all interconnect cables as far from loudspeaker cables as...

Page 10: ...he 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 re...

Page 11: ...e 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 Standby occurs when the unit is connected to the mains supp...

Page 12: ...important that the 750 be operated from the correct AC mains voltage This unit is factory set for the voltage applicable to the original country of destination The 750 will operate satisfactorily with...

Page 13: ...itch DOWN connects the internal signal earth to mains earth and is the normal position Setting to UP disconnects the signal earth from the mains earth Note Activating this switch has no effect on chas...

Page 14: ...outputs The connectors are high quality gold plated sockets which are highly conductive corrosion resistant and provide less potential for corrosion induced distortion Refer to Chapter 13 Specificati...

Page 15: ...mising System Potential Speaker Output Terminals The 750 is equipped with two sets of output terminals to enable easy hook up for bi wiring of loudspeakers or additional loudspeakers All terminals are...

Page 16: ...design perspective only The concept of less equating to more has been at the heart of all Perreaux audio designs for more than a quarter of a century Minimalist Electronics We wish to maximise the qu...

Page 17: ...products on the planet We let form and function blend together in perfect harmony This surely is the essence of true minimalist utilisation Minimalism in a Wider Context John Pawson writes Clearly si...

Page 18: ...crossover notch distortion and the resulting odd order harmonics present to some degree in all other classes of operation The devices used in the 750 output stage are MOSFETs which with high quiescen...

Page 19: ...hs only meeting at a central starred point Earth Isolation Switch The toggle switch on the rear of the 750 allows the internal circuitry to be isolated from the mains earth whilst still maintaining an...

Page 20: ...e input sensitivity so that when the same input signal is provided to each of them the output level will be exactly the same This can often be done with one power amplifier connected to the tweeters a...

Page 21: ...e with your 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 models and if at all po...

Page 22: ...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 i...

Page 23: ...s in a power transistor This is related to thermal runaway In order to understand this one must imagine that the chip silicon inside the power transistor is in fact many smaller transistors connected...

Page 24: ...slow This means the distortion products in the signal of say a fast transient will not travel through the negative feedback system into the output stage fast enough to cancel at exactly 180 degrees o...

Page 25: ...o the surface 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 effected area Front Panel The 750...

Page 26: ...it will be repaired or replaced at our option without charge for either parts or labour The warranty does not apply to any unit that has been misused abused or altered Any unit that is not performing...

Page 27: ...ail 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 Ext...

Page 28: ...must be employed to negate these effects on low level signal equipment Another good practice to adopt is to keep all signal leads away from power leads The practice of neatly tying excess leads togeth...

Page 29: ...experiencing a problem such as one channel not working or a noise in one channel it is good practice to adopt a method of isolating the problem to a specific item or area This practice will assist in...

Page 30: ...ow swapping them at the amplifier output If the fault now appears in loudspeaker B then that loudspeaker lead is at fault go no further If the fault appears in loudspeaker A then loudspeaker leads are...

Page 31: ...ut at a minimum volume setting Only increase the volume after the connections have been changed Should the fault prove to be in the amplifier it will be necessary to determine where the fault actually...

Page 32: ...estore speaker cablesto original connections Fault in loudspeaker B Swap amplifier source input channels Loudspeaker A at fault YES NO Loudspeaker cable at fault Fault in loudspeaker A Swap source out...

Page 33: ...at 0 040 THD 1300WRMS into 4 continuous driven from 20Hz 20kHz at 0 070 THD Frequency Response 5Hz 40kHz 0 25dB Total Harmonic Distortion THD N Typically 0 008 1kHz into 8 20Hz to 20kHz 0 040 into 8...

Page 34: ...everyone is familiar Actually frequency response is a misnomer technically it should be called amplitude response versus frequency for it describes how uniform the amplitude or strength of signals of...

Page 35: ...ak the 750 can easily meet any challenge music can present to it whether instantaneous or continuous To be specific it can deliver high power into low impedance loads and provide great dynamic headroo...

Page 36: ...36 14 14 14 14 Physical Dimensions...

Page 37: ...ails For more information please contact your Perreaux dealer or contact 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...

Page 38: ...38 Installation Notes...

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