MASTER
|
7
INTERNAL JUMPERS & ADJUSTMENTS
The motherboard has input cable shield ground selection jumpers to accommodate different grounding
schemes. It is recommended that all electrical equipment in the studio is properly grounded by making
sure that power cables have 3 pins and that the third pin is connected to ground. The use of ‘ground lifts’
to clear up a buzz problem is frowned upon by the international consortium of electrical safety agencies.
If a ground noise problem occurs, it may be cleared up by switching the jumper position on the connector
associated with the piece of gear that is having the buzz problem.
The shield lift headers have 2 posts. A jumper placed over both posts connects the chassis ground to the
cable shield. To lift a shield, pull the jump off of the posts. It is a good idea to put the ‘unused’ jumpers on
one of the posts to keep from losing the jumper.
MASTER should not need to be calibrated but in case it does, here is the procedure:
1. Obtain a calibrated oscillator and level measuring device. These should be lab quality (HP,
Tektronix, Neutrik, Audio Precision, etc.)
2. Place the Master on a clean, well lit table with a pad under it to prevent scratches.
3. Remove the top to expose the motherboard for calibration.
4. Hook up the power supply and turn on the unit.
5. Set all controls to unity gain with all Function and Insert switches out.
6. Set the oscillator for +4dBu and plug into Input 1. Feed both channels.
7. Activate ‘INSERT 1’ and measure the level coming out of the ‘SEND 1’ jacks.
8. Adjust P1 and P2 to m4dBu.
