Hm-54 features, Front panel, Main input level – MACKIE HM-54 User Manual
Page 8: Phones jack, Source select switch, Level control, Power switch, Hm-54

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HM-54
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MAIN INPUT
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PHONES
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PHONES
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HM-54
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1
HEADPHONE MIXER/AMPLIFIER
HM-54 Features
Front Panel
All four headphone amplifiers share the same features:
• Dual-sources for each channel 
• Individual front panel level controls 
• Front and rear panel phone outputs for each channel 
• Balanced inputs
1. MAIN INPUT LEVEL
This adjusts the main mix input signal level coming
into the HM-54 LINE INPUT and PHONES INPUT jacks 
on the rear panel.
2. PHONES Jack
Plug your headphones into this jack. It carries the
same signals that appear on the rear panel PHONES 
OUTPUT jacks [8].
You can also connect an in-ear monitor (IEM) system to
the PHONES jack to provide an individual monitor mix.
Note: Since the PHONES output delivers a higher signal
level than a standard line-level output, you may need to 
turn thePHONES LEVEL control down more than usual.
Note: Plugging headphones into the front panel
PHONES jack automatically disconnects the signal from 
the rear panel PHONES jack.
WARNING: The headphone amps 
are designed to drive any standard 
headphones to a very loud level. 
We’re not kidding! They can cause 
permanent hearing damage. Even 
intermediate levels may be painfully 
loud with some headphones. 
BE CAREFUL! Always start with the PHONES level 
turned all the way down before connecting headphones 
to the PHONES jack. Keep it down until you’ve put on 
the headphones. Then turn it up slowly. Why? Always 
remember: 
“Engineers who fry their ears, find
themselves with short careers.”
3. SOURCE Select Switch
This switch allows you to select either the main mix
input signal or the direct input signal for the headphone 
amp source.
CAUTION: Make sure the main mix 
input signal and the direct input 
signal are roughly equivalent in 
volume before switching between 
the two. If you have the headphone 
amp LEVEL control [4] adjusted for one, and the other 
signal is considerably louder, you could damage your 
hearing. Follow the procedure described in “Set the 
Levels” on page 5.
4. LEVEL Control
This adjusts the volume for each individual
headphone output. It affects both PHONES OUTPUT 
jacks (front and rear panel).
5. Power Switch
This one is self-explanatory. When the power switch is
turned ON (up), power is supplied to the HM-54 and the 
power ON indicator lights up.
