UNiKA PRO 148 Pro Series Audio Interface Single Active Direct Box User Manual
- June 13, 2024
- UNiKA
Table of Contents
UNiKA PRO 148 Pro Series Audio Interface Single Active Direct Box User
Manual
GENERAL PRECAUTION BEFORE USE
Thank you for purchasing the UNiKA PRO SERIES AUDIO INTERFACE. Before using, please read this manual carefully and pay attention to every detail that you must pay attention to. If you use a mixer to connect to this interface, please turn off the mixer power and +48V phantom power before connecting, and then turn on the power and phantom power after inserting the signal cables. For passive models, please do not turn on the phantom power to avoid leakage or damage the equipment.
If using a model with a volume knob, turn the volume knob to the minimum. During use, please do not plug or unplug the wires arbitrarily to avoid signal loss. Please refer to the following instructions for the soldering method of the plugs to ensure the expected level and keep the signal smooth.
If you need further installation or operation guidance, please directly contact UNiKA’s dealer or distributor, or write to the following mail address for help:
PRODUCT OVERVIEW
PRO 148 is an active single-channel DI box. Unlike traditional DI, PRO 148 uses +48V phantom power instead of the traditional 9V dry cell battery, so users can use it on the mixer or external phantom power supply. Power is supplied to PRO 148, the power supply circuit and the output signal line are shared, and no additional power cord is required. The +48V indicator is set on the upper cover. The +48V circuit specially selects the British OEP PT-4 pulse transformer.
PRO 148 has a built-in UNiKA-PROTM EI30A10E 1+1:1+1 isolation transformer, which has a special copper foil layer and a dedicated ground layer, which allows this device to restore high signal/noise ratio and dynamic sound, and can avoid unnecessary leakage caused by radio frequency interference, ground interference and potential difference. PRO 148 is especially suitable for electronic musical instruments, recording studios and fixed installation projects by using mixers.
The PRO 148 uses a balanced/unbalanced combo socket on the input, and a TRS through out is convenient for musician to pass the direct signal to the instrument amplifier. In addition, it is equipped with a 0/-20dB attenuation switch and LED indicator, which is suitable for various types of audio signals with high and low impedance. The output terminal is also equipped with a GND/LIFT button to quickly eliminate ground noise.
CAUTION
This product has undergone rigorous inspection before leaving the factory. If customers encounter failures during use, please contact your local dealer or distributor for replacement or repairing, do not disassemble the case or replace parts by yourself, which will invalidate the warranty.
For details, please refer to the warranty regulations in the enclosed warranty card, and fill in the details, and get a valid stamp or signature of the d ealer or distributor.
PARAMETER TEST CONDITIONS
In the development and manufacturing process, Audio Precision’s 2700 series and 500 series are used to test and verify electrical characteristics.
FEATURES
- Power by external +48V phantom power
- Built-in UNiKA-PROTM EI30A10E isolation transformer
- Use British OEP PT-4 1:1 audio pulse transformer in phantom power circuit
- +48V status indicator on the upper cover
- The input socket uses Combo jack
- Use TRS jack as through out terminal
- At 0dB input, the set load impedance is 260KΩ, which can clearly show the high frequency overtones, harmonic and graininess of electric guitars or electric bass
- 50Ω ultra-low impedance output, suitable for various types of mixers and pre-amp equipment
- There is 0dB/-20dB input signal attenuation switch with status indicator
- The output is equipped with a GND/LIFT switch
APPEARANCE PARTS & FUNCTIONS
- Signal output: XLR terminal, isolated balanced output of the transformer, need to turn on +48V phantom power supply for PRO 148 proper working after connecting to the mixer.
- Output grounding/floating switch: when the switch is not pressed, the first pin (PIN-1) of XLR is grounded. PIN-1 will be disconnected from ground after pressing. This button should depend on the system. Used in the situation, in order to isolate the ground loop noise or leakage.
- +48V phantom power indicator: When ISO OUT receive +48V phantom power, the indicator will be shinning the blue color
- Signal input: One combo jack be able to input balance and unbalance signal by TRS/ TS and XLR plug.
- Input attenuation switch: Provide 0/-20dB two option, when inputting signals of various impedances and levels. It can be attenuated by 20dB to avoid overload or clipping.
- Attenuation active indicator : When the PAD attenuation switch is pressed (-20dB), the indicator light will be shinning the yellow color.
- Signal through out: TRS socket, convenient for musicians musical instrument speakers or other DI and peripheral equipment.
ISO TRANSFORMER SCHEMATIC
PULSE TRANSFORMER SCHEMATIC
OEP PT-4
INPUT PAD ATTENUATION
The most widely used DI box is to connect electronic musical instruments, sound source of A/V equipment and computers, convert their output signals into balanced signals and then extend the transmission distance.
The most ideal state is to set the attenuator to 0dB position (button up) for musical instrument. For some other type of signals, you can press the button to make the signal is attenuated by 20dB to avoid clipping caused by signal overload. W
hen the button is pressed, the PAD indicator on the right will light up.
POWER SUPPLY
PRO 148 is an active DI box and requires +48V phantom power. It can work normally when it is powered, but no additional power supply is required. Just use balanced wires to connect the device to the mixer’s input channel, and turn on the +48V power switch of the mixer, similar to connect a condenser microphone to the mixer. When the +48V power supply is suppling properly, the +48V ACTIVE indicator light on the upper cover will light up.
Before connecting the device, do not turn on the +48V switch of the mixer.
ELIMINATING GROUND LOOP NOISE
The built-in channel independent balanced isolation transformer has solved the potential difference leakage problem. When the system causes a ground loop due to poor wiring, the noise can be eliminated through the GND/LIFT button.
The GND/LIFT button determines whether pin 1 of the output XLR is grounded, grounded when it bounces, and disconnected from ground when pressed.
CONNECTION GUIDE
XLR-TRS Combo input
The unbalanced connection, pin-2 is hot, pin-3 is shield paralleled with pin-1.
TRS Balance plug
TS Unbalance plug
SPECIFICATIONS
PRO 148
Circuit principle: Active low-noise op-amp with Transformer balance
output
Input connector: 1 x Combo
Thru connector: 1 x TRS
Input pad switch/indicator: 0/-20dB push button with LED
Power supply: +48V Phantom power through output
connector with: LED indicator on top cover
Output connector: 1 x Male XLR through ISO Transformer
Output GND/LIFT switch: Push button
Input impedance: 260KΩ / 0dB, 50KΩ/-20dB
Output impedance: 50Ω
Max. input level before clipping: +10dB
Max Output level: +10dB
Frequency response: 20Hz-20KHz, +0.3/+0.6dB
S/N ratio @20Hz~20KHz un-weight >95dB
T.H.D. @1KHz 0dBV output: <0.02%
Transformer Ratio: 1:1+1:1
Chassis: 1.6mm/1.2mm steel cabinet and chassis
Surface finished: Durable complex painting
Dimension: (W x D x H) 78 x 124 x 46 mm
Weight: 0.56kg
Shipping weight: 0.59kg
Packing per carton: 20pc/12.40kg
Shipping dimension per carton: 305 X 283 X 195 mm
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