Millennia HV-3C Stereo Microphone Preamplifier - Manual (Page 8)

HV-3C
(4) SIGNAL INDICATORS "OL" & "SP" LEDs
The green "signal present" (SP) LED indicates that a nominal signal is present at the microphone
input. It is set to illuminate in the neighborhood of -35 dBu. The red "overload" (OL) LED has
been set to illuminate when the balanced output reaches a level of +25 dBu. However, the
HV-3C can produce unclipped, undistorted levels over twice this voltage. Hence, the overload
LED is not an indication of preamp clipping. Rather, it is a general reference showing a nominal
"system" peak level. If clipping is occuring in your recording path, check all devices connected
after the HV-3C and reduce system gains accordingly. In the event that B&K (DPA) 4004 or
4012 microphones are used with hazardous sound pressures (over 130 dB, SPL), an attenuator
may be required between microphone and preamp.
(5) PILOT INDICATOR LIGHT
LED which, when illuminated, shows that the HV-3C unit is powered up and active.
(6) POWER SWITCH "POWER"
Rocker switch for switching AC line power on and off.