JK Audio RemoteMix C+ User Manual

RemoteMix C+

Portable Mixer for

Remote Telephone Broadcasts

User Guide

JK Audio

Introduction

RemoteMix C+ is a professional audio mixer and headphone
amplifier designed to interface with any standard analog
telephone line. This telephone hybrid operates on batteries
or AC power.

Simply plug your audio equipment into RemoteMix C+ and
connect to a phone line. You can now put on headphones,
plug in a microphone, and you are ready to broadcast the
game or talk up a taped interview. The RCA type jacks on
RemoteMix C+ are equivalent to the jacks found on most
home tape recorders, CD players, and receiver/amplifiers.
There are two balanced XLR microphone inputs and the first
one can be switched for mic or line level input. The balanced
line level XLR output jack provides a high quality connection
to mixers and professional tape gear. The adjustable hybrid
circuit provides control over the mix of transmit and receive
audio at the output jacks.

Cellular Telephones

Use our Daptor One to connect the standard 3-conductor,

2.5 mm micro-jack on your digital wireless telephone to the
RJ-11 phone jack on the RemoteMix C+. Then you will con­tinue to use your wireless phone to dial or answer the call,
but you will use the microphone and headphones plugged
into your RemoteMix C+ during the call.

RemoteMix C+ was also designed to work well with a data
interface (fax / modem adapter) connected to your older ana­log cellular telephone or bag phone. These are available
through your cellular dealer. These adapters turn your
cellular telephone into an RJ-11 equivalent jack which
replaces the wall jack in this picture.

2

Connection

Microphones
2 XLR jacks

Headphones or small
speaker, 2 jacks 1/4”
stereo or mono

to RJ-11
Analog wall jack

Tape recorder or audio
equipment input or
output, RCA or XLR

1. Connect your audio equipment, microphones and
headphones to the input and output jacks on the
RemoteMix C+.

2. Connect the jack marked "Phone Line" to any standard
analog telephone line or to the Fax/Modem adapter on a
cellular telephone.

3. Turn on the power switch, flip the "Phone Line" switch to
"Dial/Talk" and dial your call. You are now ready to
broadcast or record a telephone interview.

3

Operation

Send Side (To Phone Line)

There are separate volume controls for the two XLR
microphone inputs and the RCA line input (To Phone Line)
jack. You can use all three inputs at the same time. Mic 1

also has a Mic/Line
level selector switch
which lowers the gain
on the Mic 1 XLR
jack by 30 dB to
allow a balanced line
level input.

Receive Side (From Phone Line)
The receive side has separate controls for headphone output
level and line output level. The Line Out control adjusts the
signal going out the RCA and XLR jacks marked From
Phone Line. This is a mix of both sides of the telephone call.

Headphones

The built-in headphone amplifier is strong enough to power
two pair of headphones or a small desktop speaker. The left
and right channels contain the same mono signal, but are
powered by separate amplifier channels. These jacks will
drive either two 1/4” stereo plugs or two 1/4" mono plugs.

Handset Jack
The handset jack on the side
of RemoteMix C+ allows you
to plug in a telephone handset
and quickly set up a call before
you connect your microphones
and headphones. The handset
microphone volume is
adjusted using the Line In knob. The earpiece volume is
adjusted using the Headphone level knob. All telephone
handsets are different, so if yours is not compatible, try an
AT&T, Sony, or Radio Shack residential phone handset.

4

Operation

Ringer

RemoteMix C+ has an audible internal ringer for incoming
calls. This can be turned off using the switch on the side of
the unit.

Phone Line

Connect this RJ-11 jack to the wall jack of a standard, single­line analog telephone line.

Keypad

The telephone keypad is
for tone or pulse dialing.
You may use the keypad
at any time during a call
but keep in mind that both
transmit and receive
audio are muted during a
keypress.

Phone Line Switch
This switch acts as the
switch-hook for the
telephone line. The Hang
Up position is the normal
on-hook position when

you are not using the line
or you are waiting for a call. When you want to place a call,
or when a call comes in, switch to the Dial/Talk position.

Tone / Pulse Dialing
RemoteMix C+ is equipped with a switch to select tone
(DTMF) dialing or pulse dialing. The switch is located
underneath the battery door. With the switch towards the
volume control knobs, the unit is in the “pulse” mode. When
in “pulse” mode the “*” key will set the unit to transmit digits
as tones regardless of the switch position. To return to pulse
dialing turn the power off and back on.

5

Operation

Power

RemoteMix C+ 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 alkaline 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 may be
significant audio distortion and a loss of level as the batteries
continue to discharge. It is important to replace both batteries
at the same time with identical batteries. If two fresh batteries
are not available, it is better to use only one good battery.
Since the two battery fixtures are wired in parallel it does not
matter which one gets the single battery.

We also provide a high quality, regulated AC to DC adapter
to power RemoteMix C+ when AC power is available. Simply
plug it into the back of RemoteMix C+ 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.

Null Adjust (optional)

The RemoteMix C+ can be adjusted to control the amount of
transmit audio that appears on the receive audio jacks. The
recessed fine tuning control 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.
The null circuit matches the characteristics of RemoteMix C+
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.

The amount of transmit/receive isolation will depend on the
quality of the telephone line. This circuit is factory set to give
an equal mix on an average telephone line, and is therefore
perfect for recording both sides of a telephone interview.

6

Null Adjust (optional)

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 prerecorded music or speech, or a test signal.

3. Connect the From Phone line output to a meter or scope,

or listen to the receive signal over the headphones. Be
sure to turn up the Line Out or Headphones volume
control depending on which method you are using to
monitor the receive signal.

4. On the back of RemoteMix C+, below the words Null A dj.,

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. If, on the
other hand, 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.

5. Factory Setting: To reset to the factory setting, set the

phone line switch to On-Hook, and adjust to find the null.
We have installed a terminating resistor in the On-Hook
position that simulates the average phone line connection
and gives the right mix of transmit and receive audio.

The best tools for this task are 1) an oscilloscope connected
to the From Phone Line output, and 2) a 1 kHz sine wave
generator connected to the To Phone Line input jack.
However, the above procedure will work with a little patience.

7

FAQs

? The output from Mic 1 is very low but the other mic is

fine.

! Check the position of the Mic/Line switch near Mic 1. This

first input can be switched to accept a line level signal from a
mixer or other equipment.

? Can I wire a stereo mini output into the XLR input of a

RemoteMix C+?

! Yes. You need to wire the tip to pin 2, the sleeve to pin 1,

and leave the ring and pin 3 floating. You should use the mic
1 input since it is mic/line switchable, and use mic 2 for an
additional microphone.

? I know that Daptor One allows Remote Mixers to con-

nect to digital cell phones with a 2.5 mm headset jack,
but what about older cellular phones?

! RemoteMix C+ is a standard telephone line interface. Electri-

cally, it is similar to a telephone with a lot of audio jacks. A
cellular telephone can be used like a portable wall jack if you
purchase the proper adapter. Contact your cellular phone
dealer and ask about a Fax / Modem adapter or Data Inter­face for your current cell phone. Do not mention remote au­dio broadcasting as it is guaranteed to confuse them. The
Fax / Modem, or Data Interface is a little box that plugs into
the bottom of the cell phone and converts it into an RJ-11
jack. You can then plug any "telephone" like device into this
RJ-11 jack such as a fax machine, modem, or... get this... a
JK Audio RemoteMix C+. Data interfaces run anywhere from
$60 to $300, depending on the manufacturer and type of
telephone. Our customers tell us the older analog bag type
phones are the best, they have the strongest signal, longest
battery duration, and typically sound better.

8

FAQs

? Can I use the RemoteMix C+ with a digital PBX phone

system if there is no analog line available?

! No. If you need compatibility with digital PBX or ISDN phone

systems you should step up to a RemoteMix 3 or RemoteMix
Sport. These units will work virtually anywhere.

? Will RemoteMix C+ provide phantom power for my con-

denser microphone?

! No, this device will not provide phantom power. If you are

connecting your microphone directly to a JK Audio Remote
Mix C+, you should use a dynamic mic.

? I've lost the power supply for my RemoteMix C+ unit. I

have another power supply that fits from a different
product. Can I use this instead?

! NO! Never use a power supply other than the one that was

supplied by your manufacturer. Power supplies are available
in either AC or DC output with many combinations of voltage
and available current. DC supplies carry either positive or
negative center pin output and may or may not be
"regulated". If you connect a negative center pin power sup­ply to a positive center pin jack, it's just like hooking up the
battery cables to your car backwards. Obviously you would
not want to do this to your car or your expensive audio
equipment. "Regulation" is the tolerance to the specified volt­age of your DC power supply. All of our DC power supplies
have a low noise 5% tolerance. This means that our 9V DC
power supplies will always output 9 volts +/- 5%, whether
you are using no power at all or applying a full load. Most
consumer power supplies are not regulated. A non-regulated
9V, 800 mA power supply could actually output 16V until an
800 mA load is applied. This could invariably damage your
equipment, and also create a great deal of noise. There is
also no standard for the size of your power jack. This means
that a 16V AC power supply and a 1.5V DC power supply
could both have the same 2.1 mm jack.

9

Specifications

Inputs:
Unbalanced: Connector RCA phono jack
Input Impedance 50 k ohms
Level 250 mV RMS
Microphone: Connector (2) Female XLRs
Input Impedance 1000 ohms
Mic/Line: Line switch on Mic 1 -30 dB
Handset: Modular 4pin/4wire handset jack
Electret /dynamic microphone bias.

Outputs:
Unbalanced: Connector RCA phono jack
Output Impedance 50 ohms
Level 250 mV RMS
Balanced: Connector Male XLR
Output Impedance 200 ohms
Level 500 mV RMS
Headphone: Connector 1/4" stereo jacks
Output Impedance 8 ohms
Power 1 watt per channel

Phone Line: Connector RJ-11C
Isolation 1500 volts
Ringer (REN) 1.2B

Keypad: DTMF (Dual Tone Multi-Frequency) or
Pulse Dialing

FCC Part 15 Compliance

This equipment has been tested and found to comply with the limits for a
Class A digital device, pursuant to Part 15 of the FCC Rules. These
limits are designed to provide reasonable protection against harmful
interference when the equipment is operated in a commercial
environment. This equipment generates, uses, and can radiate radio
frequency energy and, if not installed and used in accordance with the
instruction manual, may cause harmful interference to radio
communications. Operation of this equipment in a residential area is
likely to cause harmful interference in which case the user will be
required to correct the interference at his own expense.

Changes or modifications not expressly approved by JK Audio can void
the user's authority to operate the equipment.

10

FCC Registration

Your new JK Audio product has been registered with the Federal
Communications Commission (FCC). This product complies with the
standards in Part 68 of the FCC rules.

1. Connection and use with the nationwide telephone network
The FCC requires that you connect this telephone equipment to the

national telephone network through a USOC RJ-11C modular
telephone jack.

This equipment may not be used with Party Line Service or Coin

Telephone Lines

This equipment is hearing aid compatible.

2. Information for the telephone company
Upon request from your local telephone company, you are required to

provide the following information:

a) The "line" to which you will connect the telephone equipment (that is,

your telephone number), and

b) The telephone equipment's FCC registration number. This can be

found on the bottom of your telephone equipment, and,
c) The ringer equivalence numbe r (REN) for this equipment.
The REN is used to determine the quantity of devices which will be

connected to the telephone line. Excessive RENs on the telephone line
may result in the devices not ringing in response to an incoming call. In
most, but not all areas, the sum of the RENs should not exceed 5.0. To
be certain of the number of devices that may be connected to the line,
as determined by the total RENs, contact the local telephone company.

3. Repair Instructions
If it is determined that your telephone equipment is malfunctioning, the

FCC requires that it not be used and that it be unplugged from the
modular outlet until the problem has been corrected. Repairs to this
telephone equipment can only be made by the manufacturer or its
authorized agents or by others who may be authorized by the FCC.
For repair procedures, follow the instructions outlined under the
warranty section of the manual.

4. Rights of the telephone company

If telephone equipment is causing harm to the network, the telephone

company may temporarily discontinue your telephone service. If
possible, they'll notify you before they interrupt service. If advanced
notice isn't practical, you'll be notified as soon as possible. You'll be
given the opportunity to correct the problem, and you'll be informed of
your right to file a complaint with the FCC.

Your telephone company may make changes in its facilities,

equipment, operations or procedures that could affect the proper
functioning of your JK Audio product. If such changes are planned,
you'll be notified by your telephone company.

11

Warranty

RemoteMix C+ is covered by a 2 year warranty to be free
from defective workmanship and materials. In the event that
the RemoteMix C+ needs repair, you must call us to get an
authorization, and then carefully pack and ship it to us. You
will pay for shipping to us and we will pay for return back to
you, UPS ground. No free repairs will be made if the defect
was caused by misuse, weather conditions, or other cause,
except for defective workmanship or materials. THERE ARE
NO EXPRESSED OR IMPLIED WARRANTIES WHICH
EXTEND BEYOND THE WARRANTY HERE MADE.

03/07

JK Audio, Inc. 1311 E 6th Street, Sandwich, IL 60548 USA

Voice: [phone] Toll Free: 800-JK-Audio Fax: [phone]

[e-mail] www.jkaudio.com

Copyright © 2007 JK Audio, Inc. All Rights Reserved.