Vision manual page:29
10.0 Installation - Electrical Local Electrical Voltage
Before connecting the Vision, check the AC supply voltage setting by looking at the sticker on the back of the rack
mount power supply. This should be 115V for use in areas with an AC supply between 100V and 120V,
and 230V for use in areas with an AC supply between 220V and 240V.
The main fuse is a 10 amp with a 250 volt rating. After replacing a blown fuse with the correct size and rating, turn
the power supplies on and check the three LED indicators. If you are still missing one or more of the power rails, turn
off the power supply and call the D&R Technical Support Department. DO NOT REPLACE THE FUSE WITH ANY OTHER
TYPE AS THIS CAN BECOME A SAFETY HAZARD AND WILL VOID THE WARANTY.
Electrical Wiring
To take full advantage of the excellent signal to noise ratio of the Vision, it is necessary to read this part of the manual
carefully.
Hum, radio frequency interference, buzzes and instability are often caused by improper wiring and poor grounding.
Sometimes the incoming electrical ground is inadequate and a dedicated ground would need to be installed
for the audio equipment.
Your local electric power company will provide you with all local electrical codes and safety regulations. There are some
grounding rules to follow. All signals in a recording studio are referenced to ground.
This ground must be clean and free of noise. A central point should be selected as the main grounding point and all
grounds should originate from this point. This is commonly referred to as a “star ground system”.
In some instances electrical contractors will daisy chain ground connections. This is unsuitable for a studio. Ideally, run a
separate ground wire from each outlet and a separate ground wire for each piece of equipment. A separate wire
from each equipment rack to the dedicated ground point is useful in cases where AC outlet grounds are not
satisfactory. The dedicated ground point should be located at the rear of the console or equipment rack. Separate
and identify “clean” and “dirty” AC outlets. Use clean outlets for audio equipment and the dirty ones for lighting, air
conditioning, freezers etc. Do not intermix these two types of outlets. AC interference can be greatly reduced by
using an
isolation transformer (Juice Goose) to power clean outlets. Ground this transformer directly to the dedicated ground
point or as close as possible to the incoming ground.
All equipment should be physically located as far as possible from the main breaker panel. Unbalanced equipment may
require isolation from the equipment rack so that ground loops are avoided.
10.1 Installation - audio
10.2 Interface CRM Levels
The Vision in its standard configuration can interface with all available equipment.
Attention concerning the CRM output must be noted. This output delivers a n4 dBu level which is sometimes
too high for power amps rated at 300mV sensitivity for full output. In some instances an input attenuator at the
power amp's input is required to reduce this +4 dBu level
by up to 12 dB. Contact the D&R Technical Support Department for details.
NOTE
:
This alignment is imperative in order to avoid damage to the speakers, or in some cases, damage to the ears of
the listener.
10.3 The Initial Hook-Up
First connect the rack-mounted power supply to the console. All faders, monitors, and effect returns must be in the
“down” or “off” position. In order to ensure the best signal to noise ratio for your system, the next steps should be
performed in the order they are printed.
Connect the CRM outputs (located on the master module back plate) to the inputs of your control room speaker
power amps. Now turn on the console power supply and then turn the power amp on and check for any hum,
buzz, or interference. Slowly turn the CRM control clockwise until it is wide open while listening for excessive noise.
You should only hear a faint “hiss”. If everything is O.K., continue. If any hum or excess noise is present, stop and try
different ground and shielding arrangements until the system is clean. After checking the main power amp and speakers,
check CRM 2.
Before making any other connections move each monitor fader to the 0 dB position with the tape switch
depressed on each monitor section. Connect the multitrack outputs to the tape return connectors, then connect
each connector on the tape output of your multitrack. Check for hum or noise after each track has been hooked up.
”Hiss” will normally increase slightly with each track. Connect the tape send output jacks to the inputs of the
multitrack. Carefully listen for excessive noise or hum. If after hooking up an input or output excessive noise or hum is
detected, stop and take corrective action before proceeding.
Do not hook up all 16, 24, 32, or 48 tracks and then listen.
You may need to rewire the entire cable harness to make
