Adjusting The Gain; Troubleshooting Guide - MTX Thunder4122 Owner's Manual

AMPLIFIERS

Adjusting the Gain

1. Turn the gain control on the amplifier all the way down.
2. Turn up the volume control on the source unit to
approximately 3/4 of maximum.
3. Adjust the gain control on the amplifier until audible distor-
tion occurs.
4. Adjust the gain control down until audible distortion
disappears.
5. Follow steps 3-4 for other gain control settings.
(THUNDER4244)
6. The amplifier is now calibrated to the output of the
source unit.
Definitions of Common Terms
The following list of terms with their definitions is offered as
help in understanding the set-up and operation of your
amplifier.
1. Crossover (xover) - an electrical filter with high-pass or
low-pass characteristics that divides the frequency range
into playable bands for certain speakers. Subwoofers, mid-
bass, midrange and tweeters are all designed to play differ-
ent frequencies and should do so to avoid damage. The
xover point is where the playable frequencies cross from
one speaker to the next at -3dB below reference level.
2. Full-range - refers to signals which cover the entire audio
frequency span from 20Hz to 20kHz.
3. High-pass - simply put, this blocks lower frequencies
which damage smaller speakers, and passes the higher
frequencies for smaller speakers like the midrange and
tweeter.
4. Low-pass - you got it, this is the inverse of a high-pass. It
blocks higher frequencies and passes the playable lower
frequencies to the larger speakers, like subwoofers.
Typical Speaker
Wiring
Configurations
Stereo Amplifier
Bridge Mode Application
Impedance Requirement
4 ohm bridge minimum
2 ohm stereo minimum
4 ohm
8 ohm
8 ohm 4 ohm
+ - - + + - - +
L L R R L L R R
AMP AMP
Two 8 ohm Speakers Two 4 ohm Speakers
not
OK
ok
5. Impedance - the resistance to the flow of current in an
alternating current circuit (such as with music). Line level
circuits are typically a high impedance of several thousand
ohms, while speaker level circuits are usually a low imped-
ance of a few ohms.
6. Line level - the type of signal produced at the outputs of
tape decks, CD tuners, preamplifiers, etc., with a typical
value of a volt or less in a high impedance circuit.
7. Speaker level - the type of output that is meant to drive
speakers. These signals are sometimes called high level
and are usually connected by two conductor speaker wires.
8. Signal - the signal of an audio system is what is heard
from the speakers. These signals may be high pass, low
pass or full-range.
We don't have enough space for Electronics 101, so if you
have a good, bad or amusing question, please call us TOLL
FREE at 800-CALL MTX! (800-225-5689)

Troubleshooting Guide

Read this if you wanna be a do-it-yourselfer or give us a call at 800-CALLMTX.
Problem Cause
No LED indication No +12V at remote connection
No +12V at Power connection
Insufficient ground connection
Blown power fuse
LED on, no output Volume on head unit off
Speaker connections not made
Gain control on amplifier off
Signal processing units off
All speakers blown
Output distorted Head unit volume set too high
Amplifier gain set too high
Balance reversed Speakers wired L + R reversed
RCA inputs reversed
Some balance reversed Some Speakers wired L + R
reversed
Some RCA inputs reversed
Bass is weak Speakers wired out
of phase
Not using MTX woofers
Blowing fuses Excessive output levels
Amplifier defective
Solution
Supply +12V to terminal
Supply +12V to terminal
Verify ground connection
Replace fuse
Increase volume on head unit
Make speaker connections
Turn up gain
Apply power to signal processor
Replace speakers
Lower head unit volume
Lower amplifier gain
Wire speakers with correct orientation
Reverse RCA inputs
Wire speakers with correct orientation
Reverse appropriate RCA inputs
Wire with correct phase
Buy MTX woofers
Lower volume
Return for service