Studio Technologies Mic-Pre - Manual (Page 15)

Mic-PreEminence User Guide Issue 5, April 1994
Studio Technologies, Inc. Page 17
Appendix B
Enabling the Output Coupling Capacitors
As shipped from the factory, the Mic-Pre-
Eminence balanced and unbalanced output
circuits are directly coupled to the output
connectors. In rare instances, capacitor
coupling of the outputs may be required.
With this in mind, output capacitor pairs
(100uf in parallel with 0.33uf) have been
installed in the circuit board. The Mic-Pre-
Eminence is shipped from the factory to
achieve direct coupling, and these capacitor
pairs have been shunted with 0 ohm resistor
jumper wires. To put the capacitors in the
circuit, carefully remove the 0 ohm resistor
jumper wires. Later, the shunts can easily
be added to return the Mic-PreEminence
to the stock configuration.
The following procedures must be
performed by a qualified technician.
Operating the Mic-PreEminence with
the top and/or bottom cover removed ex-
poses the technician to points in the power
input section with hazardous voltages.
1) Ensure that the AC mains cord is re-
moved from the Mic-PreEminence AC
mains input connector on the back panel.
2) Remove the top and bottom cover (four
Phillips head screws for each cover).
3) Refer to the schematic at the back of
this manual for the part ID numbers of
the 0 ohm resistor jumper wire(s). The
ID numbers will start with the letter R
followed by a number. Two ID numbers
are found for each output channel.
4) Carefully cut out the appropriate 0 ohm
resistor jumper wire(s) with diagonal
cutting pliers.
5) Return the top and bottom cover to
their correct location and put the
screws back in.
6) Check the Mic-PreEminence for correct
operation.
Appendix C
Replacing the 0.33uf Coupling
Capacitors
This procedure involves removing the exist-
ing 0.33uf coupling capacitors and replacing
them with ones of your choice. Physically,
polypropylene capacitors are much larger
than film types and may be tricky to install.
The Mic-PreEminence circuit board should
not be drilled, or otherwise cut up to fit in
the new capacitors. The leads of the new
capacitors should be bent and adjusted to
fit into the existing printed circuit board holes.
The following procedures must be
performed by a qualified technician.
Operating the Mic-PreEminence with
the top and/or bottom cover removed ex-
poses the technician to points in the power
input section with hazardous voltages.
1) Ensure that the AC mains cord is re-
moved from the Mic-PreEminence AC
mains input connector on the back panel.
2) Remove the top and bottom cover (four
Phillips head screws for each cover).
3) Refer to the schematic diagrams at the
end of this manual for the part ID of the
coupling capacitors that are to be re-
placed. The ID will start with the letter
C followed by a number. There are four
0.33uf coupling capacitors in each chan-
nel (six if the output coupling capacitors
have been enabled).