ATI Audio P1000-1 User Manual

Page 3

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Another design consideration is the presence of large low frequency input
signals, which originate in record warp and seismic pickup from people walking,
bumping studio desks etc. The signals are strongest in the neighborhood of the
cartridge/tone arm resonant frequency, typically 6 to 10 Hz. In studio
applications these signals can overload subsequent amplifiers, overdrive limiters
and damage loudspeakers. Previous attempts at Rumble Filters noticeably roll
off low frequency audio when operated and therefore must remain switched out
of the circuit most of the time.

The MicroAmp incorporates an active two pole, subsonic filter bridged around the
RIAA equalization network. The Q of this filter is designed to allow the
preamplifiers response to follow the RIAA curve precisely to approximately 28 hz,
drop only 3 db at 20 hz then plunge quickly to –18 db at 10 hz and achieve
approximately 30 db rejection at 6 hz. Thus, excellent subsonic rejection is
attained without low frequency degradation. Hi Boost and Hi Cut switches are
included.

Our power supply incorporates a couple of unique regulation devices called
zener diodes. In contrast to most fancy three terminal IC regulators these
devices will live through line transients and simultaneously protect your
expensive circuitry.

INSTALLATION

MOUNTING

Your MicroAmp may be desk mounted on its suction cup feet and left out for
everyone to see since it is so pretty. If you want to keep knob twirlers away, you
can bury it inside your turntable cabinet using the two angle brackets provided.
Place them at diagonal corners under the lower cover mounting screws. Avoid
magnetic fields from the turntable motor. Make sure your cartridge leads reach
the preamp before permanently mounting.

Rack Mounting Kits are available. P/N 20021-501 mounts a single MicroAmp.
P/N 20024-501 mounts two MicroAmps side by side in 1 ¾” vertical rack space.

WIRING

The third wire ground can cause a ground loop with your station ground. If you
are sure your station ground will provide adequate protection to personnel in
case of an AC line short to the chassis, a 3 to 2 AC line adapter can be used to
isolate the power line ground. We recommend that the adapter be removed and
the power line ground reconnected prior to any service work requiring removal of
the station ground connection from the MicroAmp chassis.

This manual is related to the following products:

P1000-2