Mackie FAST RECOVERY M-1200, Service Manual

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VERSIO N 1.1
SYSTEM O VERVIEW
3
SYSTEM O VERVIEW
This se c tio n p ro vid e s a q uic k sum m a ry o f the M•1200/ M•1400’ s m a jo r fe a ture s. It is no t
inte nd e d to ta ke the p la c e o f the o w ne r’ s m a nua l. It is inc lud e d he re to he lp se rvic ing
te c hnic ia ns fa milia rize the mse lve s with the M•1200/ M•1400.
DIFFERENC ES BETWEEN THE M•1400, M•1400i AND M•1200
The M•1200 a nd M•1400 a re e le c tro nic a lly id e ntic a l p ro d uc ts w ith the fo llo w ing
e xc e p tio ns:
1. The M•1400 ha s 12,000uF ma in filte r c a p s, whe re the M•1200 a nd M•1400i ha ve
10,000uF.
2. The M•1400 a nd M•1400i use a mo re p o we rful fa n tha n the M•1200.
3. The M•1400 ha s Sp e a ko n

c o nne c to rs whe re the M•1200 a nd M•1400i ha ve ¼”
sp e a ke r o utp uts (b o th in a d d itio n to b ind ing p o sts).
The M•1200 wa s d isc o ntinue d in 1998 a nd re p la c e d b y the M•1400i.
Exp o rt M•1400’ s a lso ha ve a “ So ft Sta rt” c irc uit tha t is no t insta lle d o n Am e ric a n units.
FAST REC O VERY DESIG N
So lid sta te p o w e r a m p lifie rs ha ve a re p uta tio n fo r so und ing ha rsh w he n d rive n into
c lip p ing . The usua l e xp la na tio n is o d d ha rm o nic s g e ne ra te d b y ha rd c lip p ing , b ut In
fa c t m uc h o f the unp le a sa nt so und is c a use d b y la tc hing a nd p a ra sitic o sc illa tio ns tha t
o c c ur a s the a m p lifie r re c o ve rs fro m c lip p ing .
TYPIC AL AMPLIFIER MAC KIE FR SERIES

ARTIFACTS C AUSED BY
LATCHING AND PARASITIC
O SCILLATIO N
Ma c kie ’ s Fa st Re c o ve ry d e sig n re c o ve rs fro m c lip p ing q uic kly w itho ut g e ne ra ting a ny
und e sira b le a rtifa c ts. This p e rfo rm a nc e is a c hie ve d b y tw o uniq ue d e sig n e le m e nts; the
Full Sym m e try Dua l Diffe re ntia l fro nt e nd p ro vid e s e xc e lle nt line a rity w hile m inim izing the
ne e d fo r ne g a tive fe e d b a c k, a nd the Ba ke r C la m p p re ve nts o utp ut/ d rive r d e vic e
sa tura tio n. Ho w the se c irc uits o p e ra te is c o ve re d in d e p th in the c irc uit the o ry se c tio n.