Timewave DSP-599zx, Operating Manual

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2 – Installation
2-4 March 6, 1997
Audio Input
Input Impedance Setup
The factory default input impedance of the DSP-599zx Channel
A
is 25
ohms. This impedance is appropriate for most radios when driven by the
speaker output of the radio. The factory default input impedance of the DSP-
599zx Channel
B
is 20k ohms. This impedance is appropriate for most radi-
os when driven by the speaker output of the radio and for other higher im-
pedance sources. The reason for the two choices of impedance is that some
radio output stages oscillate if you do not load them with a low impedance
source. Other radio output stages are stable with high or low impedance
loads. When using a radio, start with the radio loudspeaker output connected
to the DSP-599zx Channel
A
input. This should work for all radios. If you
are using a high impedance source, start with the source connected to the
DSP-599zx Channel
B
input. You can configure the DSP-599zx Channels
A
and
B
for a high or low input impedance by moving a shorting jumper.
Input Impedance Jumper Access
1. Loosen the two screws holding each of the bezels in place. Slide bezels
off the unit.
2. Remove four screws holding the front panel in place. Carefully discon-
nect the two ribbon cables from the rear of the front panel.
3. Remove the four screws holding the rear panel in place.
4. Turn unit over and remove the two screws from the bottom of the case.
5. Observing static precautions carefully turn unit upright and slide cir-
cuit board assembly about two thirds of the way out of the case.
6. Change the location of the jumper for the appropriate channel. Note
that channel B is the uppermost. Putting the jumper on the left and
middle pins sets the channel to high impedance. Putting the jumper on
the center and right pins sets the channel to low impedance.
B A
Headphones
H L
B
A
559-018
Audio Input
Impedance Jumpers