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Heater Core
Q: What wiring do I need to hook up my amplifier
A: Amplifiers generally do not include the wiring necessary to hook them up. However, There's a
number of wiring kits that will provide everything you need to send signal and power to your amp.
You need enough
power cable to run from your car battery's positive terminal through the firewall to the amplifier. Be sure to install an
in-line fuse or circuit breaker near the battery. Without one, an accidental short circuit could pose a fire hazard and damage
your amp (not to mention your car).
You also need another length of the same gauge cable to serve as your ground wire.
You won't need as long a ground wire because your grounding point should be relatively close to the amplifier.
The
last wire you need for powering the amp is a turn-on lead. It doesn't need to be as thick as the power and ground wires (18
gauge should be fine). It runs from the remote turn-on lead at the back of your receiver to the remote terminal on the amp.
When connecting these wires, be sure to use crimp-on spade or ring terminals to get the best signal transfer.
The
audio signal travels from the back of your receiver to your amplifier through an RCA patch cable. Your patch cable should
be long enough to reach the amp but not so long that it has a lot of slack and could become kinked over time.
At the
other end of the amp, you'll need speaker wire. Generally 14, 16, or 18 gauge wire should be sufficient. Keep in mind that
current flows more easily through thicker wire. (The lower the gauge number, the thicker the wire.)
Q: How much power do I need for my subwoofers?
A: That depends on what sort of bass impact you
hope to achieve. If you just want to hear a bit more bass than your regular stereo speakers can put out, you can get what
you need with an efficient 6-1/2" subwoofer driven by as little as 30 watts RMS. But when you're looking for really big bass,
you'll need at least a 10" or 12" subwoofer and a minimum of 150 to 200 watts to drive it. Low bass notes are power hungry,
and the more wattage you feed them, the better they sound. In general, the larger your subwoofer and the harder you want it
to hit, the more power you'll need.
Remember, if you're driving one sub, you can "bridge" a 2-channel amp to get a
significant increase in output.
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Q: What's the biggest amp I can hook up to my car's electrical system?
A: Your car's alternator
ampere rating determines how powerful an amplifier you can install. Multiply the ampere rating by 40%, and you'll get a rough
idea of how much power demand your car's system can handle. An alternator capable of producing 55-65 amperes is usually adequate
for systems up to 350 watts RMS. A Japanese car with a 35-amp alternator can accommodate around 125 watts of power, while
a German car with a 90-amp alternator can handle a 500-watt system. A capacitor can help if your system is drawing a little
too much power. Car audio competitors often replace their vehicle's alternators with heavy-duty upgrades to accommodate big
power demands.
Q: What's the difference between "parallel" and "series" wiring?
A: When you wire a pair of speakers
in parallel, you connect the positive (+) leads of both speakers to the amp's positive (+) terminal and the negative (-) leads
of both speakers to the amp's negative (-) terminal. If you parallel wire two 4-ohm speakers, the amp sees a 2-ohm
load. This lower ohm load (lower resistance) pulls more power from the amp and causes the amp to run hotter. Amps that can
handle this additional heat build-up are considered 2-ohm stable. Series wiring works the same way as flashlight batteries;
the positive end of one speaker is connected to the negative end of the other speaker. Wire from the positive terminal of
the amplifier to the positive terminal of one speaker. Then wire from the negative terminal of the first speaker to the positive
terminal of the second speaker. Finally, run a wire from the negative terminal of the second speaker to the negative terminal
of the amplifier. If you series-wire two 4-ohm speakers, the amp will see an 8-ohm load. This higher ohm load (higher
resistance) inhibits the flow of current out of the amp. You get less power, but the amp runs cooler and is more stable.
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Q: What's the story on the different amplifier "classes?"
A: An amplifier's circuit design determines
its class of operation. Class A amplifiers are desirable for the high quality of their sound, but the design is not
particularly suited to car applications because of inefficiency and high heat production. Car amplifiers that boast Class
A design are usually a Class A/Class AB hybrids. The Class AB design is most commonly used for car amplifiers because
it combines reasonable efficiency, low distortion, and reliability.
Class D amplifiers ("D" does not stand
for "digital") boast higher efficiency, produce less heat, and draw less current than traditional Class AB designs, but they
tend to have more distortion. Since low-frequency distortion is almost impossible to detect, compact Class D amps rule the
bass kingdom. Class T amplifiers combine characteristics of conventional Class AB and cutting-edge Class D designs
for great power, compact size, and minimal production of heat
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Q: How do I hook up multiple amplifiers?
A: You must supply power from your battery to every
amplifier in your system. You could run a separate power wire to each amplifier, but a power distribution block will give
you a cleaner installation with less potential for noise problems.
Let's say that you want to install a 200-watt mono
subwoofer amp, a 75W x 4 amp for your door and rear deck speakers, and a 30W x 2 amp for your dash speakers 560 watts of total
system power. Run a single 4-gauge power wire from your battery to a 3-way (or 4-way) distribution block next to your amps.
From the block, 8-gauge cables supply power to your subwoofer and multi-channel amplifiers, while a 10-gauge wire feeds the
30 x 2.
Ground your amplifiers in reverse fashion one 10-gauge and two 8-gauge ground cables run from the three amplifiers
to a grounding block. A 4-gauge ground cable connects the grounding block to your vehicle's chassis. You'll need a relay on
the turn-on lead to protect your receiver. A relay connected to the power antenna lead draws little current from the receiver,
but supplies enough power to turn on all your amps simultaneously.
You can use RCA patch cables to send signal from
your receiver to your amplifiers. A receiver with 3 sets of preamp outputs can provide signal for your front, rear, and subwoofer
amps. If your receiver has only one set of preamp outputs, you'll have to use a Y-adapter to provide signal to a multi-amp
set, or look for amps with built-in preamp outputs (allowing you to daisy chain the signal from one amp to the next).
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