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CONTENTS
8.2
Powering up – Soft start
W he n yo u p ow e r up th e amp lifier it ta ke s a c ou ple o f se c on ds to s elf-c he c k. This is k no wn a s the "s oft- s ta rt"
o r "s lo w -s ta r t" s eq u en ce . The fa ns th en b lo w a t h ig h sp e ed b e fo re g o in g into "id le " a nd the fo ur bo ttom
g re en L ED's illumin a te to s ho w the a mplifie r is o pe ra tio na l.
8.3
Input attenuators
The fou r inp u t le ve l a tte nu ator s o n the fro n t pa n el a dju st th e sign a l le v el for th eir r es pe c tive amplifier
c ha nn el's in all mo d es o f o pe ra tio n. Th ey a r e ca lib ra te d in d B' s to he lp th e se tting up o f a ctiv e lou ds p ea ke r
s ys te ms .
In br id g ed mo de , bo th le v el a tte nu ato rs mus t b e in th e s ame p os itio n , so th at th e lo u ds pe ak e r lo a d will be
s ha re d e qu ally be tw e en th e ch an n els.
8.4
Indicators
The y ellow L ED' s on th e fro nt p a ne l ind ic ate if a ny p ro tec tio n circ u its a re a ctiva te d . Th es e a re de sc rib ed o n
4.
p ag e
1
The C lip/limit L ED' s ind ic ate s wh e n th e a mp lifie r ou tpu t is clip p in g o r limitin g. It h as tw o d iffe re n t in d ic atio n
s ta te s:
• W he n th e c lip limite r is en ga ge d it h as a s h or t time co n stan t a nd illu min ates b r ie fly .
• W he n th e c lip limite r is no t en g ag ed it h as an in cr ea se d time c on sta nt a n d illu min ate s fo r a lon g er
p er io d.
The "- 40dB" LED's illuminate when the output signal is greater than -40dB (with 0dB referenced to full
output power). These LED's also act as signal present indicators.
The four bottom green "ON" LED's indicate when the power supply is operating normaly and the output
circuits are receiving the correct rail voltage.
9
PROTECTION FEATURES
Eac h Ma r tin Aud io MA s er ies a mp lifie r h as ma ny a d va nc ed pr ote ctio n fea tu r es , th a t will pr ote ct b o th the
a mp lifie r an d the lo ud sp e ak er s c on ne c te d to it, s ho uld a fau lt co nd ition ar is e. Un de r n or ma l u se th es e
fea tu re s a re in au dib le . All p ro tec tio n circ u its o pe ra te in de p en de ntly.
9.1
Output Limiter
An ou tp u t limiter is inc lud ed to a vo id amplifier clip pin g. W h en a n a mp lifie r is se ve r ely ov e rd riv en , its o utp ut
w av efor m is c lipp ed (its pe ak s a re s q ua re d o ff) – r ed uc ing th e cr es t fac tor . In ex tr e me c as e s, th e wa ve for m
c an a pp r oa ch th at o f a s q ua re w a ve . An amplifier is n or mally ca pa ble o f p ro du cin g fa r mor e p ow er un de r
the se c o nd ition s th a n its n or ma l u nd istor te d r ate d ou tp u t po w er .
The limite r w or ks b y mon ito ring th e o utpu t a nd c o mp ar in g the distor tio n p ro du ce d b etw ee n th e inp u t an d
o utpu t o f th e a mp lifie r. If the disto rtio n e xc ee d s 1%TH D for an y re a so n ( vo ltag e o r c ur re nt clip p in g) , the
PRINT
PROTECT
PR OTECT
CLIP
CLIP
- 40dB
-40 dB
ON
ON
CH.A
CH.B
CH.C
CH.D
- 12 - 10 - 7
- 10
- 10 - 7
-10
-12
-7
- 12
- 12
-7
- 16
- 5
-16
- 5
- 16
- 5
- 16
- 20
- 3
- 20
- 3
- 20
- 3
-40
- 1
- 40
- 1
-40
- 1
- 40
-1
- 80
dB 0
-80
0
- 80
dB 0
-8 0
0
dB
dB
MA200Q
Martin Audio – MA200Q Amplifier
-5
- 3
14
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