Tascam M-200 Series Owner's Manual page 15

The condition of the AC circuit that you in-
tend to use with your mixer i s very important.
IVoise and safety problems can be both annoying
and dangerous. There are a couple of inex-
pensive tools that you should have with you
whenever and wherever you set up your mixer:
an AC Outlet Tester, AC AdapterIGroud Lift,
and an AC Neon Lamp tester (better yet,
a
VoltIOhm Meter).
Outlet Tester
Neon Lamp Tester
VoltIOhm Meter
AC Adapter
The AC Outlet Tester is very easy to use, just
plug it into the outlet and its.LEDs will signal
whether or not the circuit is properly wired.
If it is not, do not under any circumstances use
that outlet. Faulty wiring in an AC circuit is
potentially hazardous.
AC AdapterIGround Lifts are used in two
ways. They are useful if you are using older
equipment that uses two prong plugs that are
not properly grounded. Your Series 200 uses a
two prong plug, but it will present no gounding
problems by itself. The wire on the two t o
three prong adapter must be connected to the
grounding screw on the outlet. These adapters
are also useful as ground lifts. A ground lift is
used in the event that a "ground loop" is created
within the wiring of al1 the elements of your
system. A ground loop will create a hum or buzz
that will not go away no matter what remedy
is used. Ground lifts should only be used as a
last
resort, since failure to have equipment
properly grounded can create safety problems.
A Neon Lamp Tester, or VoltIOhm Meter can
be used to check the grounding of individual
instruments and amplifiers. Guitar and bass
amps are particularly vulnerable to grounding
and shock problems when the guitarist or
bassist is also using a microphone. Check the
grounding by putting one of the tester or
meter's probes on the metal chassis of the
amplifier, or the strings of the guitar or bass
and touching the other probe to the micro-
phone. If the lamp or meter registers the pos-
sibility of a shock, reverse the ground of the in-
strument's amplifier by using the amplifiers
polarity switch or reversing i t s AC plug. If the
amp has a three prong plug and doesn't provide
a
polarity switch, which i s rare, use one of your
AC AdapterIGround Lifts t o reverse the plug.
"Snakes" are very helpful when your mixer is
used in a sound reinforcement application. A
snake uses a connection box on one end of a
properly shielded cable with individual cables and
connectors on the other end. Snakes are very
convenient, but the shielding in the cable
can be damaged if the cable i s bent, or kinked.
Keep snakes out of the way so that people and
equipment aren't banging them about.
All your wiring should be neat. A snake is
obviously neat and convenient, but provides
an additional advantage. When cables that carry
a
similar signal (input, output, effects, etc.)
are grounded together, there is less danger of
creating a noise source called a ground loop. We
mentioned an AC ground loop above, and a
similar situation can be created with your audio
cables. I t follows that cables that carry different
kinds of signals should be kept away from one
another. A neat arrangement of cables also keeps
them from being damaged by keeping them out
of the way of the performers and audience.
Damaged cables are the most frequent problem
you will encounter during sound reinforcement.
So keep the cable layout neat, and always
have spare cables on hand.