Martin Audio – MA1400 Amplifier
E
NGLISH
12
MA1 400
-4 0dB
PROTECT
CLIP
ON
8
OPERATION
8.1
Operating precautions
•
Make sure that the power switch is set to “OFF” before connecting any input or output or operating the
switches on rear panel. See pages
8
about installation.
•
Make sure that the AC mains voltage is correct and the same as the one printed on the rear panel of the
amplifier. See pages
8
, about operating voltage and power consumption.
•
Make sure that the switches on the rear panel for operation modes, gain-switch and clip-limiter switch are
in the correct position. See page
6
about operation modes and page
13
about clip limiters.
•
It is always a good idea to turn down the gain controls during power-up, to prevent speaker damage in
case a high signal is present at the input.
8.2
Powering up – Soft start
•
W he n yo u p ow e r up th e am p lifier it ta ke s a cou ple o f se con ds to self-che ck. T his is kno wn a s the "soft-sta rt"
o r "slo w -sta rt" seq u en ce . T he 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 gree n
L ED ’s illu min ate to sh ow th e am p lifie r is o p eration al.
8.3
Input attenuators
T he two in pu t level atte n ua to rs on th e fron t p an e l ad ju st th e sig na l leve l fo r the ir re sp ective a mp lifie r ch a nn el in a ll
m od es. T he y a re calibrate d in d B to h elp se tting up a ctive lo ud sp ea ker system s.
In brid g ed m o de , bo th co n trols m ust b e in th e sa m e po sitio n, so tha t the sp ea ke r loa d w ill b e sh a re d eq u ally be tw ee n
the cha n ne ls.
8.4
Indicators
T he yellow L E D's at th e top ind ica te if a ny prote ctio n circu its a re activated .
T he se a re de scrib ed on p a ge
1 3
.
T he C lip /lim it LE D's ind ica te w h en th e am plifier ou tp ut is clip ping or limiting . It
h as two diffe re nt in dica tio n sta te s
•
W he n th e clip lim ite r is en ga ge d it h as a sh ort tim e co n stan t a nd
illum in a te s b riefly.
•
When the clip limiter is not engaged it has an increased time constant
and it illuminates for a longer period.
Front Indicators
The ”-40 dB” LED’s illuminate if the output signal is greater than -40dB (with 0dB referenced to full output power).
These LED’s also act as signal present indicators.
The two bottom green ”ON” LED’s indicate when the power supply is operating normaly and the output circuits are
receiving the correct rail voltage.
All material © 2007. Martin Audio Ltd. Subject to change without notice.
