ATI Technologies MMA400-800 Betriebs- und Wartungshandbuch - Seite 7

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ADJUSTMENTS
It is sometimes difficult to maintain good noise performance when using a
high output amplifier to drive medium level console inputs (-20dBm) or IHF
(-10dBu, .25V) equipment inputs. You may have found it necessary in the past to
insert attenuator pads to allow the amplifier to operate at a high enough level to
maintain a good signal to noise ratio. The MAA will reduce its already low noise
as you turn down its gain pot and in the lowest output gain position will provide a
comfortable S/N ratio even at -20dBu out. In the absence of high RF levels, you
can distribute levels from 0 to -20dBm, and avoid building, trimming and repairing
all those nasty little attenuator pads.

MAINTENANCE

Power supply voltages are + and - 15VDC nominal.
IC output DC voltages under no signal; shorted input conditions should remain
within .1VDC of ground. Greater deviation is a good sign of IC or circuit
problems.
Five to ten years from now replace all the aluminum electrolytic capacitors.
Keep 250W soldering guns out of the amplifier.
If hit by lightning, replace U1 through U12 and anything else that has turned
black or smells bad.
MODIFICATIONS
Your MAA is wired for 115VAC, 50/60Hz operation unless otherwise
requested at the time of ordering. It can be easily modified for 230VAC operation
by removing the power transformer primary jumpers J17 and J19 and inserting a
jumper in J18
Different types of attachment plugs or line cords may be required for
connection to alternate supply voltages.
If your name is CBS, you can convert the transformer outputs to 150 ohms
line impedance by removing jumpers J13, J14, J15 and J16 and replacing each
with two jumpers from the original jumper terminals to the immediately adjacent
terminals on either side of the original pairs.
Audio Technologies Inc.
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856-719-9900
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www.
audio.com