Mission 776 Pre-Amplifier
Mission 777 Power Amplifier
Con ratulations on your excellent choice! Your Mission pre-amplifier &/or power amplifier are precision
manufactured products & have been tested to the hi hest standards. A few minutes spent in readin
your instruction manual will ensure that you et optimum results from your system & your investment
will prove lon term.
IMPORTANT NOTES
1. Before switchin the equipment on, please ensure that it is correct for your local power supply. The
pre-amplifier & power amplifier are made in different versions for different parts of the world. Please
refer to the detailed instructions for each unit for more information.
2. Mission equipment is manufactured to the hi hest quality standards. All Mission pre-amplifiers &
amplifiers are warranted to be free of defects in materials & workmanship for a period of three years
from date of purchase.
3. Please retain packin materials. You may need them a ain for safe transport of the equipment.
INTRODUCTION
Traditionally, amplifiers are desi ned as mathematical models their characteristics measured under
steady-state conditions, & their quality jud ed by a simple set of specifications. This is inadequate for
an amplifier dynamically operatin to reproduce music. It is the dynamic behaviour of an audio
amplifier with complex interface (input/output) transducers when drivin reactive loads that hi hli hts
many obscure problems. Many "theoretically-perfect" desi ns suffer serious clippin distortions durin
musical transients; are unable to drive complex speaker loads; create poor interface with cartrid e
transducers; have inadequate power-supplies; use IC's in place of discrete components; & i nore the
detrimental effect of excessive switches & ad ets.
As for specifications, historically too much emphasis was placed on parameters such as THD or
bandwidth. This resulted in excessive use of overall feedback - enhancin specifications by reducin the
amplitude of low-order harmonics but eneratin hi h-order harmonics & listenin fati ue. A ain much
was made of bandwidth & speed of amplifiers. Fi ures of 1MHz were considered desirable. But such
fi ures do not reveal the critical ratio of power supply bandwidth to audio bandwidth; the amount of
feedback used to achieve such specifications; linearity with varyin power levels; & the respective
relationship between the closed & open-loop curves. Also, steady-state measurements i nore time
domain problems such as time & phase errors resultin in incoherent musical information.
The Mission desi ns are the result of a new look at the fundamental parameters & basic operatin
functions of an audio amplifier. Our research has been painstakin in careful evaluation & correlation of
subjective results with advanced & novel measurements.
Considerable effort was made to create inherently stable circuit desi ns capable of drivin all complex
loads & eliminatin conventional protection circuits, Zobel networks couplin capacitors, etc. The 777
achieves the unprecedented open-loop bandwidth of 230kHz resultin in 1.15MHz bandwidth with a
mere 14dB overall feedback:
Discrete components are used throu hout, switches & connectors kept to a bare minimum.
Exceptionally low output impedance power supply is utilised with some 70,000 filterin capacity.
A totally linear harmonic distortion pattern is achieved with rapidly diminishin hi h order harmonics.
Complex distortions measured over a lar e frequency band are ne li ible. The slewin rate of the 777 is
a sta erin 180 Volts per micro second, thereby eliminatin all dynamically induced distortions such as
TIM, with special attention iven to slewin behaviour at maximum output swin s.
The 777 is DC coupled throu h out, desi ned as a perfectly symmetrical class "A" amplifier, except for
the hi h technolo y H-FET output devices which operate in class "AB" mode.
10 of 20
