ULN-2 Users Guide
156
As with all electronic devices, when connecting an external power source to the ULN-2, you should first
connect the power source to ULN-2 while it is in an unenergized state (e.g. not connected to the mains or
switched off). After the connection to ULN-2 has been made, you should energize the power source.
If you connect an energized power source to the ULN-2’s 2.1mm power connector you may see a small
spark when you make the connection. This is due to surge current and is normal if you connect a power
source in this way. While this will not damage the ULN-2 in any way, to avoid the spark just connect the
power connector to ULN-2 before connecting the power source to the wall.
ULN-2 Specifications
Mic Inputs
Stepped Gain Range
+6 dB – +72 dB (6 dB Steps)
Gain Range with Trim
-14dB – +70 dB
Input Impedance
3.3k Ω
• Harmonic Distortion @1kHz
• (+9dBu in @ 6 dB Gain)
0.0005%
• Intermodulation Distortion 1k component
• (19 kHz/20kHz @ +8dBu)
-96 dBu
Table 7.1. Mic Inputs
Equivalent Input Noise (E.I.N.)
150 Ω Source
-130.5 dBu
50 Ω Source
-132.0 dBu
0 Ω Source
-134.0 dBu
Table 7.2. ULN-2 Equivalent Input Noise (E.I.N.) 20 Hz – 20 kHz Flat @ 72 dB Gain
Frequency Response
18 Hz – > 20 kHz
± 0.1 dB
8 Hz – > 50 kHz
-± 1.0 dB
3 Hz – >100 kHz
± 3.0 dB
Table 7.3. ULN-2 Frequency Response
Crosstalk @1kHz
trim link engaged
-107 dB
trim link disengaged
-132 dB
Table 7.4. ULN-2 Crosstalk @1kHz
Maximums
Max Gain
72 dB
Preamp Headroom
20 dB above Digital Clip
Phantom Power
+48v Regulated, high current, individually switch-
able, P48 test compliant, short circuit/ hot-swap
protected
Table 7.5. ULN-2 Maximums
