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
continuetodischarge.
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
twobattery fixturesare wiredin parallel so it does not matter which
onegetsthesinglebattery.
We also provide a high quality, regulated AC to DC adapter to
powerRemoteMix 3.m when AC power is available. Simply plug it
intothebackofRemoteMix3.mandplugthetransformerintoa110
VAC wall outlet. When the power connector is inserted into the
jack,thebatteries are bypassed. TheACadapterdoesnotcharge
thebatteries.
HybridNullAdjustment (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
onanaveragetelephoneline,andisthereforeperfectforrecording
bothsidesofatelephoneinterview.
To find the absolute null for any telephone line, follow this
procedure:
1. Placeacalltoaquietlocation.
2. Send a signal down the line at moderate levels, this can be
aprerecordedtapeofmusicorspeech,orpreferablyatestsignal.
3. Connect the Receive line output to a meter or scope, or
listentothereceivesignalovertheheadphones. Besuretoturnup
the From Phone or Headphones volume control depending on
whichmethodyouareusingtomonitorthereceivesignal.
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
originalposition,andthencounterclockwise.
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
adjustfortheproperbalance.
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.
