ATI Audio SDA200 - Manual (Page 4)

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An electrostatic shield is mounted to the PC board just behind the panel to shield
the low level circuitry. To achieve optimum shielding, SYSTEM 10K modules
should be mounted side-by-side starting on the left side of the rack frame with no
spaces left between modules. Panel retaining screws should be tight to
effectively ground the panel to the frame.
All parts with the exception of panels, shields and PC boards are standard
distributor items but are also available from ATI stock. A1 and A4 are National
LF347N quad bi-fet ICs interchangeable with TI TL074 and others. A2 and A3
are Signetics, TI or Exar NE5532AN dual, high output audio opamps. The output
boost transistors are GE D44C3 (NPN) and D45C3 (PNP).
INSTALLATION
A mating connector assembly is included with each amplifier module. The
connector assemblies may have been pre-assembled to the RM100 rack frame if
ordered together. If not, they should be mounted to the rear of the frame using
the (4) M2.5X6mm screws supplied. Install modules starting from the extreme left
(opposite power supplies); leave no spaces between modules to achieve the
most effective shielding. Plug on the DC power buss connector to the polarized
3-pin receptacle at the top of the connector assembly.
To make a connection to the 3.5mm modular connectors using Belden #8451
cable or equivalent cable with 22 to 24 gauge inner conductors, strip back the foil
shield about 1" to 1 1/2" exposing the inner conductors and shield drain wire.
Remove shield and cut off the drain wire. All connectors and 3.5mm modular
connectors are marked clearly for function and polarity.
The output ground connections "G" are used for connecting the LO side of
unbalanced, single ended, one-side grounded loads. They must NOT be used to
terminate the shields of the cables connected to the outputs or inputs since this
would degrade the RF immunity of the system by routing intercepted RF and
other noise pickup directly into the module. Cable shields should instead be tied
to studio ground at a punch block, Christmas tree block or jack field interconnect
point and allowed to float at the input and outputs of the DA.
All inputs, whether balanced or unbalanced should be treated and wired as
balanced sources to achieve maximum immunity to hum, noise and RF which
may be picked up on the input wiring. All inputs should use two-conductor-plus-
foil shielded cable. Connect source HI to DA input HI, connect source LO or GND
to the DA input LO, tie cable shield to source or studio ground (allow shield to
float at the DA) and make sure there is a connection from the source chassis to
the studio ground.