Mackie 1202 VLZ Owner's Manual page 41

tinnitus
The ringing in the ears that is produced
with prolonged exposure to high volumes. A
sound in the ears, such as buzzing, ringing, or
whistling, caused by volume knob abuse!
trim
In audio mixers, the gain adjustment for the
first amplification stage of the mixer. The trim
control helps the mixer cope with the widely
varying range of input signals that come from
real-world sources. It is important to set the
trim control correctly; its setting determines
the overall noise performance in that channel
of the mixer. See mic preamp.
TRS
Acronym for Tip-Ring-Sleeve, a scheme for
connecting three conductors through a single
plug or jack. 1 ⁄ " phone plugs and jacks and
4
mini phone plugs and jacks are commonly
wired TRS. Since the plug or jack can carry
two signals and a common ground, TRS con-
nectors are often referred to as stereo or
balanced plugs or jacks. Another common TRS
application is for insert jacks, used for insert-
ing an external processor into the signal path.
In Mackie mixers, the tip is send, ring is re-
turn, and sleeve is ground.
TS
Acronym for Tip-Sleeve, a scheme for con-
necting two conductors through a single plug
or jack. 1 ⁄ " phone plugs and jacks and
4
phone plugs and jacks are commonly wired TS.
Sometimes called mono or unbalanced plugs
or jacks. A 1 ⁄ " TS phone plug or jack is also
4
called a standard phone plug or jack.
unbalanced
An electrical circuit in which the two legs of
the circuit are not balanced with respect to
ground. Usually, one leg will be held at ground
potential. Unbalanced circuit connections
require only two conductors (signal "hot" and
ground). Unbalanced audio circuitry is less
expensive to build but under certain circum-
stances is more susceptible to noise pickup.
unity gain
A circuit or system that has its voltage gain
adjusted to be one, or unity. A signal will
leave a unity gain circuit at the same level at
which it entered. In Mackie mixers, unity
gain is achieved by setting all variable
controls to the marked "U" setting. Mackie
mixers are optimized for best headroom and
noise figures at unity gain.
VLZ
Acronym for very low impedance. (Impedance
is measured in ohms represented by the
bol, which is the last letter of the Greek alphabet.
This is how the letter Z is used instead of I.) VLZ
1 ⁄ " is one of the most important reasons why inher-
8
ent noise levels on Mackie mixing boards are so
minuscule. Thermal noise is something that's
created by all circuitry and usually transistors
and resistors are the worst culprits. The basic
rule with thermal noise is: the higher the imped-
ance, the more the noise. Mackie's VLZ design
reduces thermal noise by making internal imped-
ances as low as possible in as many places as
possible within the console. VLZ is achieved by
scaling down resistor values by a factor of three
or four – resulting in a corresponding reduction
in thermal noise. This is especially true for the
1 ⁄ " mini console's mixing buses.
8
volume
Electrical or sound level in an audio system.
Perhaps the only thing that some bands have
too much of.
VRMS
See RMS.
wet
With added reverberation or other effect
like echo, delay or chorusing.
XLR connector
See Cannon.
sym-
41