Proel DIRECT100P - Manual (Page 2)

INTRODUCTION
The name DI box comes from direct injection box, that means exactly: To inject a signal directly or take an
audio signal from the source and send it directly to a mixer console or recorder. Direct boxes perform several
important functions: they are designed as impedance matching and signal balancing devices. This means that
they take the high impedance of a guitar or keyboard and ‘transform’ it to the low impedance used in balanced
sound systems. Balanced signals inherently cancel noise and, due to their lower impedance, are capable of very
long cable runs. Balanced signals are the norm in professional recording, broadcast and live sound. By properly
matching the impedance you will enjoy better sound, less noise and an extended frequency response.
DIRECT100P is a passive direct box with transformer and does not require any external power such as phantom
or batteries to work. Just plug-in and play!
The beauty of a transformer is that there is no electrical connection between the primary and the secondary.
The signal is ‘transformed’ from electrical energy to magnetic, then back to electrical; in effect, a ‘magnetic
bridge’. This provides two huge benefits: with no electrical path, ground loops are eliminated and a tremendous
reduction in common-mode noise is possible. The DIRECT100P features a mic level balanced output XLR
male connector and a high impedance (hi-z) jack input. To obtain both these features the transform ratio of
DIRECT100P is 20:1, so DIRECT100P has an insertion loss of 26 dB without any PAD switch depressed.
CONTROLS AND AUDIO CONNECTION
1. INPUT - unbalanced JACK
Connect the source instrument to this 1/4” jack to receive the signal. The input impedance depends on PAD
setting: > 250 Kohm with no pad, 47 Kohm with pad insertion.
2. LINK - unbalanced JACK
Connect this 1/4” jack to the input of the backline instrument or monitor amplifier. It is directly connected at
the input. NOTE: If you are using a tube amplifier power output (4, 8 or 16 ohm), you must connect always a
speaker of matched impedance in parallel, also using the LINK jack on DIRECT100P; for these connections you
have to use always jack-jack power cables avoiding jack-jack signal cables.
3. PAD - switch
The pad switch reduces the input signal to the circuit to ensure a clean and distortion-free signal.
Three steps are possible: 0, -20, -40 dB. Always use as little as attenuation as possible to get the best possible
signal with reference to the noise floor. The highest attenuations make possible to connect the DIRECT100P to
any amplifier output without saturate the mic input of your mixer desk.
4. GND LIFT - switch
Use the GND LIFT switch to either connect the ground pin of input and output or keep them completely
separated. Depending on the grounding of the connected devices linking or disconnecting will reduce hum
and buzz noises and prevent ground loops. NOTE: Always make sure the GND LIFT is pressed (no ground link)
when connecting to speaker terminals, this prevents accidental short-circuiting of the amplifier output. Also
make sure the TIP of the input jack is connected to the red wire and that the metal chassis of the DIRECT100P
has no contact with other equipment.
5. BAL OUTPUT - male XLR
This male XLR output connector is the balanced microphone level output of the DI and it is wired with pin-1
ground, pin-2 hot and pin-3 cold.
ENGLISH