HV-3C
(5) POWER ENTRY "IEC Power Receptacle"
An IEC-type AC line-power receptacle for use with removable cords. Use only the power cord
provided with the HV-3C unit or equivalent U/L approved type SV, SVT, SJ, or SJT AC power
supply cord. Do not defeat the third pin earth ground.
HV-3C FRONT PANEL
(1) HIGH RESOLUTION GAIN CONTROL
Detented, 36-position gain control employing a superior quality Grayhill mil-spec gold plated
rotary switch. Switch gain is approximately 1.5 dB per step and is inter-channel matched to bet-
ter than 0.08 dB at all settings. After a brief warm-up period, adjustment of this switch is virtu-
ally silent. Two illuminating pushbutton switches (Green and Amber) determine the gain "range"
of the rotary switch. When the pushbutton switches are not depressed (non-illuminated), the
mic preamp gain provided is as printed on the front panel (9.0 dB, 10.5 dB, 12.0 dB, etc..).
When the green pushbutton switch (only) is depressed and illuminated, add 18 dB to the gain
settings as printed on the front panel. When the green and amber switches are both depressed
and illuminated, add 36 dB to the gain settings as printed on the front panel. For example, with
both pushbutton switches depressed and the rotary switch at 12:00 o'clock position, the preamp
gain would be 54 dB (18 + 36).
(2) PHANTOM POWER SELECT SWITCH ("+48V")
Illuminating pushbutton switch which provides phantom power (+48VDC) to the microphone
inserted into that channel. When this switch is depressed (illuminated red), phantom power is
applied simultaneously through dual 6.81k ohm resistors to pins 2 and 3 of the three pin female
XLR input. Use phantom power with condensor and other microphones requiring traditional
phantom supply. CAUTION: Applying phantom power to ribbon microphones could damage
them. Do not use phantom with ribbons, moving coil, and other microphones which do not
require phantom power. Use care, as well, to not insert or extract mic cables from the HV-3C
when phantom power is active.
(3) HIGH VOLTAGE SELECT SWITCH ("+130V") Optional
Illuminating pushbutton switch which selects the four pin XLR input (+130VDC) for B&K
(Danish Pro Audio) high voltage microphones type 4003, 4004, 4009, and 4012. When this
switch is depressed (illuminated amber), the HV-3C receives mic-level audio from the four pin
XLR input. If you are using a B&K (DPA) high voltage microphone with four pin XLR con-
nectors, depress this switch so that it illuminates. If a conventional microphone is used, do not
depress this switch.
The HV-3C will not combine ("mix") both conventional and high voltage microphones on one
channel. NOTE: The HV-3C is designed to provide uninterrupted DC power to B&K (DPA)
high voltage microphones, regardless where this switch is set. Use care that high voltage micro-
phone cables are not inserted or extracted from the unit when power is on.
(...continued on page 8)
