Mackie SR40.8 Owner's Manual page 76

DO
If you are plugging in a condenser micro-
phone, do verify that your microphone can
be phantom powered.
Ensure that the microphone's output is low
impedance, balanced and floating. This is
especially important for vintage ribbon
microphones like the RCA 44BX and 77DX.
Mute the sound system when turning the
phantom power on or off, or when connect-
ing or disconnecting microphones. If you
forget, the resulting loud, nasty POP may be
your last.
Microphones that do not require power sim-
ply ignore the DC present between pin 2/pin 3
and pin 1. If you measure with a voltmeter
between pin 2 and pin 3, you will read 0 Volts
DC. This is what your dynamic microphone
sees. Measuring between pin 2 and pin 1, or
between pin 3 and pin 1, you will read the
phantom power voltage, usually 48V, without a
microphone connected. The dynamic micro-
phone, as well as your balanced mixer input,
ignores this voltage.
Lately, the term phantom power has been
perverted to refer to any remote powering
system. In the strict sense of the DIN standard,
this is not true. Furthermore, microphones or
transducers that claim to use this system are
not compatible with the DIN standard and will
almost certainly be damaged if connected into
such a system. Fortunately, these systems use
tip-ring-sleeve phone plugs or miniature XLR
connectors and they are usually associated
with instrument pickup applications
Phantom powering is defined in DIN standard
45 596 or IEC standard 268–15A. Your Mackie
Designs mixer conforms to this standard.
What works?
To be compatible in a phantom powered
system, a device (microphone, preamp with a
microphone-style output, or direct box) must
have a balanced and floating, low-impedance
2 There is another remote powering system called A-B or
T-system powering. It uses pins 2 and 3 to carry both power and
audio. It is not compatible with dynamic microphones or phan-
tom-powered microphones.
76
PHANTOM POWER DO & DON'T CHART
2 .
DON'T
Don't worry about your other microphones as
long their outputs are balanced and floating.
Don't connect microphones or devices that do
not conform to the DIN 45 596 standard.
Don't connect A-B or T-system microphones
(another remote powering system) without
suitable adaptors.
output. This includes all microphones com-
monly used for sound reinforcement and
recording, such as the Shure SM58, SM57,
Electro-Voice RE-15, RE-16, RE-20, ND series,
Beyer M160, M500, AKG D224, D12, D112, and
many others.
If you are fortunate enough to own any tube
condenser microphones, such as the AKG C12,
Neumann U47 or U67, these microphones may
be connected in a phantom powered system
and will operate without regard to the pres-
ence or absence of phantom power. They will
always require their external power supply
(which must be plugged in and turned on).
What doesn't work?
The list is short:
1. Microphones with unbalanced outputs.
2. Microphones with grounded center-tapped
outputs. Many old ribbon microphones were
supplied connected this way. Have a
technician lift the ground from the center
tap.
3. High-impedance microphones.
4. Microphones that exhibit leakage between
pin 2 or pin 3 and pin 1. These micro-
phones will sputter and crackle when
phantom power is applied and will work
fine when you turn off the phantom power.
Get the microphone repaired.