LIVERPOOL Tube Compressor
Page 15
HUM
This unit is meant to use the third pin of the mains as the ground
reference. The GROUND TERMINAL is one method to reduce hum. Verify
that the terminal is connected with the ground strap or that the hum is
less with the strap off of the terminal. If that does not work, try a three pin
to two pin AC adapter for the AC plug.
The most common problem is the input/output cabling. Transformer
isolated balanced inputs and outputs are most immune to ground
problems. These balanced inputs and outputs will interface to unbalanced
inputs and outputs automatically. This is a prime benefit with
transformers.
Alternative ground schemes are common in studios. The two most used
are cutting shields at either inputs or outputs to prevent ground loops and
star grounding style. This method does not use any AC grounds but
supplies a separate ground wire from a central ground to each piece of
gear.
CHASSIS GROUND may be connected to the rack rails or not. Always try to
use pro gear that is designed to drive 600 ohms for this unit.
Another source of hum can be equipment mounted on top of one another.
This is not a good for hum or ventilation and should be avoided.
