6
7
Operating
(continued)
Power
RemoteMix 3.m is powered by two 9 volt alkaline batteries located
under the cover on the bottom of the unit. Under normal use, you
should get at least 30 hours of continuous use from a fresh set of
batteries.
To test the batteries, simply press the
Battery Test
button on the
front of the unit. If the LED lights, the batteries are still good. The
unit may still function if the LED does not light, but there will be
significant audio distortion and a loss of level as the batteries
continue to discharge.
The batteries are wired in parallel so it is important to replace both
at the same time with identical batteries. If two fresh batteries are
not available, it is better to run using only one good battery. The
two battery fixtures are wired in parallel so it does not matter which
one gets the single battery.
We also provide a high quality, regulated AC to DC adapter to
power RemoteMix 3.m when AC power is available. Simply plug it
into the back of RemoteMix 3.m and plug the transformer into a 110
VAC wall outlet. When the power connector is inserted into the
jack, the batteries are bypassed. The AC adapter does not charge
the batteries.
Hybrid Null Adjustment
(optional)
The receive side of RemoteMix 3.m has a hidden fine tuning control
which is adjusted by inserting a screwdriver into the back of the unit
just below the words
Null Adj
. and turning left or right. This is a ten-
turn potentiometer. This adjustment controls the level of transmit
audio that appears on the receive audio jacks. The null circuit
matches the characteristics of RemoteMix 3.m with the
characteristics of the telephone line. Although much of the transmit
audio can be removed, this is not the equivalent of a mix-minus
output.
Hybrid Null Adjustment
(optional)
The amount of transmit/receive isolation will depend on the quality
of the telephone line. This circuit is factory set to give a good mix
on an average telephone line, and is
therefore perfect for recording
both sides of a telephone interview.
To find the absolute null for any telephone line, follow this
procedure:
1.
Place a call to a quiet location.
2.
Send a signal down the line at moderate levels, this can be
a prerecorded tape of music or speech, or preferably a test signal.
3.
Connect the
Receive
line output to a meter or scope, or
listen to the receive signal over the headphones. Be sure to turn up
the
From Phone
or
Headphones
volume control depending on
which method you are using to monitor the receive signal.
4.
On the back of RemoteMix 3.m, below the words
Null Adj
.,
there is a hole for a small flat blade screwdriver. This is a 10-turn
potentiometer to allow for very sensitive adjustments. Try to
remember the position of the blade, and the number of turns you
are making as you first adjust clockwise, and then back to the
original position, and then counterclockwise.
The goal is to adjust the null signal until the receive signal
contains a minimum amount of transmit audio. However, if you
want a good mix of transmit and receive signals, you must have
someone on the far end speak or send audio down the line as you
adjust for the proper balance.
To Reset Null to Factory Setting:
Disconnect from phone line, switch the Phone Line switch to On
Hook, and the set the null to minimum. This presets the null to an
average phone line impedance.
