HXM-1 Hx Series Microphone Preamplifier User’s Guide
Volume: this control is a fader between the tube microphone preamplifier and the balanced line driver.
It’s setting does not effect overload. It should be set near its maximum setting and used only for fine
tuning signal level or for fades in or out.
Meter: this switch controls the sensitivity of the VU LEDs and is calibrated for +4 dB out and -10 dB in.
Overload: this LED indicates if the signal level of the tube amplifier is near reaching its distortion level.
it is set to start flickering 6 dB before distortion is reached. A little flickering is fine. The gain must be
lowered or Microphone Pad engaged if the LED is constantly on.
Phantom LED: this yellow LED indicates that phantom power is being provided to the microphone input.
VU: This row of LEDs indicate the output level going to the balanced line output jacks in standard vol
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ume units. The level is indicated above each LED. There is no distortion if you go past 3 VU. The micro
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phone preamplifier has over 18 dB more headroom above the meter’s highest indication.
REAR PANEL
Voltage Selector: selects mains voltage 115 volts U.S.A. and 230 volts for Europe. WARNING: damage to
this equipment will occur if this switch is improperly set.
Fuse: 1 amp @ 115 volts and .5 amp at 230 volts regular blow.
Output: balanced three pin XLR connector and balanced TRS 1/4” phono jacks. WARNING: do not hook
up output connectors to any inputs that have 48 volt phantom appearing on them. This will damage the
units output circuitry.
Input: balanced Jensen transformer inputs on both three pin XLR and TRS 1/4” phono jacks. WARNING:
turn off 48 volt phantom when using TRS 1/4” jacks. Damage will occur to the microphone when using
unbalanced microphone input cables.
HOOKUP TIPS
1. Make sure that the tube microphone preamplifier is connected to inputs that are designed to operate
at line level, otherwise distortion could result.
2. Avoid ground loops. If hum occurs it may be necessary to telescope some grounds. This is done by
cutting the ground wire on only one side of the three pin XLR connector.
3. Keep wiring short and neat.
4. Make sure AC grounds are properly connected.
5. Don’t hesitate to call the factory or your Demeter dealer with any questions. We are here to help.
6990 Kingsbury Road | Templeton, CA 93465 | 805-461-4100 | http://www.demeteramps.com/
