JK Audio Inline Patch - Manual (Page 5)

8
?
There is a small amount of hum in the background of my
recordings made from the Inline Patch. What’s wrong?
!
Try turning up the “From Line” volume control knob to
around 2:00. That should decrease line resistance and
help eliminate the hum.
? I recently purchased the Inline Patch, which works great,
but I don't seem to be getting as much volume out of the
XLR output as promised in your catalog. What's wrong?
!
Check your XLR Cable. Some Sound Engineers are in the
habit of connecting the "ground wire" (pin 1) and the
"negative wire" together. This is sometimes done to con-
vert transformer output signals into a single ended output.
Inline Patch uses an active differential output so ground-
ing one of the hot pins will drop the output in half. Sepa-
rate these two wires and you should hear a difference.
?
There is a hum on the output of my Inline Patch, even
when nothing else is connected. What else could it be?
!
Make certain you are using the power supply that was
shipped with the unit. Power supplies are not all the
same.
?
We purchased an Inline Patch to take callers on our radio
show. It functions just as promised but we've now found
that 20 dB of separation really isn't enough for us. What
can we do?
! The Inline Patch was designed primarily for interview re-
cording and telecom demos. If you're looking for some-
thing to put callers on the air for a radio show you should
purchase a digital hybrid instead. Our Broadcast Host and
innkeeper 1x digital hybrids typically provide greater than
50 dB separation between send and receive and have
great sound quality.
FAQ’s
5
Operation
Output Jacks
The Inline Patch has three audio output jacks on the back
panel. The 3.5 mm stereo jack has the phone line audio on
the left channel and your voice on the right channel. The sec-
ond 3.5 mm jack has both sides of the call combined on both
left and right channels. You may use either a mono or stereo
plug in this jack. The third output is a balanced male XLR
jack. The XLR jack contains only the audio coming from the
phone line with a nominal 20 dB of trans-hybrid loss (your
voice will be mixed with the caller’s audio, but about 20 dB
lower).
There are three output controls on the front of the Inline
Patch. From Phone adjusts the level of your voice on both
output mini jacks. From Line adjusts the level of the audio
coming from the phone line on all three output jacks.
The Separation control is used to achieve the best match be-
tween your voice and the audio coming from the phone line.
When you send your voice into the phone line it comes back
to you mixed in with the audio from the other side of the call,
although it will be about 20 dB lower than your original trans-
mit level. This means that if your audio is sent at 0 dB, and
you receive the caller’s audio at –10 dB, then you would have
10 dB of separation between your voice and the caller audio.
The goal is to have a minimum amount of your voice coming
back to you from the phone line.
To fine tune the separation, first connect your audio equip-
ment (powered speakers, mixer with a VU meter, etc.) to the
mixed mono output jack on the back of the Inline Patch. Next
turn the From Phone control all the way down and the From
Line control all the way up. Now place a phone call. Without
any audio coming from the other end of the call, hold down a
touch tone on your telephone while adjusting the Separation
control to find the most quiet position. Now turn the From
Line control to about 12:00 and use the From Phone control