Mackie Compact Mixer Benutzerhandbuch

Even though microphones produce alter-

nating current (AC), they have a defi nite 
polarity orientation. Be sure that you don’t 

reverse the wires between pins 2 and 3.

Did you pick up a cool retro mic at a yard sale that 

has a 1/4" phone plug instead of an XLR? Chances are 
it’s a high impedance mic and it will require a match-
ing transformer in order to sound its best with your 
mixer. Plug-in transformers available from several 
sources will not only match the impedance and signal 
level, but will adapt the plug too.

Most condenser mics require phantom power, a 

system whereby the mixer supplies a DC voltage to 
the mic’s electronics through the same wires that 
carry audio. 

The phantom power on all Mackie mixers (except 

the Onyx series) is globally controlled by the PHAN-
TOM switch on the rear panel (one switch for each 
group of 8 mics on the 8-Bus). A PHAMTOM LED on 
the front panel will remind you that phantom power 
is turned on. The Onyx mixers have a 48V switch and 
LED indicator on each channel for selective control of 
phantom power.

“Phantom” owes its name to the ability to disappear 

when it’s not needed, like when connecting dynamic 
mics (Shure

®

 SM57/SM58, for instance) that don’t 

require external power. 

 The most common phantom power supply is 48 

volts. All Mackie mixers have a 48 volt phantom 
supply with the exception of the PPM series, which 
provide 15 volts. Some microphones will operate just 
fi ne on lower voltages while others require the full 48 
volts. Check your mics’ specs. 

Here’s what the phantom powering circuit looks 

like:

There’s 48 volts between pins 1 and 2 and between 

pins 1 and 3. Since pins 2 and 3 are both at the same 
DC potential, the voltage difference between them is 
zero. That’s why an unpowered mic doesn’t “see” the 
voltage.

People have thought highly of Mackie mic pre-

amps for a long time, so when it was time to put the 
engineers to work on some new designs, they brought 
us the Onyx series, which includes the 800R. This an-
swers a popular customer request for a rack-mounted 
unit with eight mic preamps, but no other mixer 
features. The 800R has a few neat tricks up its sleeve 
which we’ll discuss later, but we wanted to mention it 
in this discussion about microphone preamps. 

Dynamic and ribbon mics don’t like to 

see DC voltage applied to their sensitive 
insides. Normally it won’t be, but a shorted 

or miswired mic cable can cause the full voltage to 
appear across the sensitive microphone element. Be 
sure that your cables are in good condition before ap-
plying phantom power. 

Also, unless you know for certain that it is safe to 

do so, never plug single-ended  (un bal anced) micro-
phones, instruments, or electronic  devices into the 
MIC input jacks if the phantom power is on.

Practice safe phantom powering! Plug in 

your mics with phantom power switched 
off! The XDR preamps used in many Mackie 

mixers have extra protection against damage from 
“hot plugging,” but your mics don’t. Get into the habit 
of plugging mic cables in with the phantom power off, 
then turning it on. 

Line inputs on Mackie mixers are on 1/4" TRS (tip-

ring-sleeve - the parts of the mating plug) jacks. All 
Mackie line inputs are balanced and present a mod-
erately high impedance load, around 10 k

Ω, depend-

ing on the model and the particular input. As we’ve 
seen from our block diagram tour, LINE IN jacks on 
channels with both line and mic inputs share circuitry 
(but not phantom power) with the mic preamps. 

You can use these inputs for virtually any line-level 

signal. With proper adjustment of the TRIM control, 
they’ll accept signals over a range of approximately 
–45 to +16 dBu. 

Some Mackie mixers are equipped with stereo line 

inputs. These have two line-level input jacks which 
share a common set of controls. To learn how signals 
are routed from these inputs, consult the block dia-
gram or quick start guide for your mixer, or check the 
Controls section of this manual.

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