zapco Reference Series 2 User manual

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Contents
Mission Statement 3
The Reference Series 4
Sonic Purity 6
SymbiLink™Balanced System 7
Specifications You Can Hear 8
Warnings 10
Wire Size 11
Installation Guidelines 12
Reference Series Accessory 13
Reference Series 2 Channel Amplifiers 21
Reference 200.2 22
Reference 350.2 26
Reference 750.2 30
Reference Series Monaural Amplifiers 36
Reference 500.1 38
Reference 1100.1 42

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Reference Series Multi-Channel Amplifiers 47
Reference 360.4 48
Reference 1000.4 54
Reference 650.6 60
System Diagrams 67
Technical Assistance 92

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Mission Statement
Committed to excellence
ZAPCO is dedicated to the pursuit of audio fidelity. Our prime
objectives are to design and manufacture audio products of unsurpassed
quality, to provide unparalleled support and service for these products, and
to conduct business in a manner that will enhance the quality of life for all
involved.
Experience:
Knowledge from doing
There is absolutely no substitute for experience; that is a simple fact
of life. Another simple fact is that ZAPCO has, for over thirty years, been the
leader in defining quality standards for the car audio industry. These years
of experience have led to a thorough understanding of the challenges that
are unique to the world of car audio. ZAPCO's relentless quest for sonic
purity consistently yields imaginative designs that utilize the most innovative
technologies. The resulting products set the criteria by which all others in
the industry are judged.

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ZAPCO
The Reference Series
The Reference series (originally called AG) marked ZAPCO’s first
effort to bring the high quality that built the ZAPCO legend to an amplifier
line that everyone can afford. The response has exceeded the company’s
wildest expectations. Why has the line been received so well? We think the
answer is simple. The Reference Series amplifiers sound as good as, or
better than, other brands best amplifiers. This is possible because we took a
very different approach in the design of our Reference Series.
Rather than follow the crowd and build a less expensive amplifier
around cheaper components, ZAPCO chose to develop a more efficient way
to build the best, high voltage, amp on the market. The Reference Series
was modeled after the Studio Series including the same circuit design, Op-
Amps, Gate Drive Boost circuit, 1%, metal film resistors and high current, Bi-
Polar outputs devices. One major improvement was the addition of
SymbiLink™balanced line inputs.
Did we make any sacrifices to achieve this new Series? Certainly,
and these fall in two areas. First, we gave up a certain amount of headroom.
In the Studio Series, every model was overbuilt by 100%. The Studio
amplifiers had twice as many output devices as it needed to run full power
on all day long. The Reference Series amplifiers have only 1½ times the
outputs devices required. We still overbuild the Reference Series by 50%,
just not as much as the Studio. This is a difference that will almost never be
heard. The other sacrifice we made was in size. The Studio 500, for
example was probably the world’s smallest, 900-watt (only 19”L x 5.75W),
class A/B, amplifier. The Reference 1100.1 is 23”L x 7.5”W, which is more in
line with what people might expect from that much power. While the smaller
size can be more convenient, it took much more time to build.
So! We gave up a little headroom and we had to deal with a larger
footprint. In return, we got a very neat design with an inordinate amount of
extremely clean power at a price that made it an incredible value. While the
great price and clean power made the Reference an obvious choice, we
were not content to just make a more affordable series.
The Reference amplifiers received all of the features that we felt
were missing from the older Studio design. Every Reference amplifier has a
fully variable electronic crossover that can be switched to high pass or low
pass, and an input switch for stereo, summed mono, or bridged use. Every
Reference amplifier has an adjustable bass EQ control. And, perhaps most
significant difference is the addition of SymbiLink™Balanced Line inputs for
a lower noise floor, better dynamic range, and less signal loss on long runs.

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We also include with every model of amplifier our SLDIN-T.F
(transmitter line driver) providing a method of changing an unbalanced
signal to balanced and the ability to increase line level voltage up to 4-times
the output. The only accessory item to complete your system is the proper
length cable from the transmitter to the amplifier. Everyone will get
balanced…for free!
What’s next? Only time will tell. But here’s one thing you can count
on. As ZAPCO finds new ways to improve the state of the art, we will bring
them to you immediately, in all our products.
So! Enjoy this manual. We hope you will read it thoroughly. We
have tried to include all the necessary information for proper installation and
set up so that you can enjoy the full potential of your ZAPCO Reference
Series amplifier.

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Sonic Purity
Our Dedication to Sonic Purity Requires the Highest Quality Internal
Components are used.
•Resistors
All resistors (other than power resistors) are 1% precision low noise
metal film. This is a key reason why ZAPCO products have the industries’
best low noise specifications, and why you won’t see as much fluctuation in
our test certificates as you will other brands. Precision resistors also reduce
distortion and improve channel matching.
•Capacitors
Capacitors are similar to batteries. Like a battery, they store energy
and have electrolyte (internal fluid). Also like a battery, a capacitor can have
a very limited life. “Computer grade” capacitors for example, are reliable
only in cool environments with very little current applied to them. Only the
best high current and high temperature capacitors should be used in an
auto-sound application. Although these capacitors typically cost five times
as much as those commonly used in other brands, ZAPCO insists that no
audio degradation will occur over time.
•Transistors
Two types of transistors are used in ZAPCO products, bipolar and
MOSFET. MOSFET transistors are rugged, high current output devices that
are best suited as switches. They are the choice for switching power
supplies. They are however, very non-linear and are not suitable for use as
audio outputs. They cannot be matched and their inherent distortion
requires too much feedback to achieve reasonable distortion levels. Bipolar
output transistors are used exclusively in the audio stage of all Reference
Series amplifiers. The audio performance of a bipolar transistor heavily
outweighs any minor advantages a MOSFET might offer regarding
durability. We solve the durability concerns by simply using more output
devices than the amplifier requires. This gives us a bulletproof amp with the
sound quality we demand of a ZAPCO product.
•Transformers
Most of the transformers used in our products are hand-wound to
ensure maximum quality. This provides a guarantee that current capability,
efficiency, and radiated noise are all kept within our demanding parameters.
Another critical aspect of the transformer is mounting; all transformers are
securely mounted in their respective chassis. Transformers are massive,
and if not securely mounted can cause failure among internal components
due to vibration.

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•Power Supplies
Regulated or Unregulated? For years amplifier designers have
debated which type of power supply is best. What’s the truth about power
supplies? They each have advantages and disadvantages and there is no,
one, best type. Limiting yourself to one type of power supply limits your
amplifier design flexibility. ZAPCO uses both types of power supplies
depending on the intended use of each amplifier, as well as expected
current demands and operating environment.
SymbiLink™Balanced System
The most natural configuration for an audio system in the
automobile places the signal source in the dash with the amplifiers located
some distance away, usually under the seat or in the trunk of the vehicle.
The reality of this arrangement dictates the necessity to make long runs of
low level signal cable usually from the front to the back of the car. The
electrical environment in an automobile is one that is inherently noisy and
filled with conditions that threaten to degrade signal fidelity at every turn.
Capacitive loading due to the long cable lengths, the potential for ground
loops, alternator charging currents or currents generated by the amplifiers
themselves are all factors that induce noise and distortion into the signal
cables. By no means is this an ideal situation. Thankfully, ZAPCO has found
the solution.
SymbiLink™components convert a standard unbalanced audio
signal into the fully balanced domain usually reserved for expensive
professional audio equipment found in recording studios or at your local
concert venue. After this conversion is made, the audio cabling becomes
virtually immune to electrical interference in the surrounding environment
and is much less susceptible to signal degradation over long cable runs. It is
for this reason that balanced signal cables are common in professional or
industrial applications. ZAPCO has made this technology available for your
car. ZAPCO engineers also discovered that the pulsating D.C. current in the
automobile chassis and amplifier power wiring caused a significant amount
of low frequency distortion. ZAPCO's balanced SymbiLink™technology
completely eliminates this distortion.

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Specifications You Can Hear
Our dedication to sonic purity, and to the concept of cumulative
error demands that we design and build our amplifiers and processors to be
the cleanest in the industry. ZAPCO amplifiers are the standard by which all
other amplifiers are measured. However, it concerns us when one
specification THD (Total Harmonic Distortion) that can’t be heard in most
modern, high-end amplifiers becomes the only meaningful specification
manufacturers seem to publish. THD is only one of a number of
specifications that make ZAPCO amplifiers sound better than other brands.
Of the four primary specifications, it is probably the least obvious in normal
use.
Damping Factor:
The most common misconception about ZAPCO amplifiers is that
we drastically under-rate our power output. Not true, it just sounds that way.
Today’s music, of all genres, has a great deal of bass content. Damping
describes the amps ability to control a woofer. An amp with poor damping
will leave bass notes sounding soft and undefined, regardless of its power.
In most amp lines, the largest units have damping factors between 100 and
200. Since rock solid bass is perceived as a function of power, our 100-watt
amp sounds like other brands 300-watt amps.
Slew Rate:
A similar situation exists in the higher frequencies. Ever turn up the
volume and hear cymbals sounding like fingernails on a blackboard? That’s
because the amplifier simply wasn’t fast enough to accurately reproduce the
high frequency tonality of the cymbals. A higher slew rate means a faster
amplifier, which means crystal clear high frequency reproduction. ZAPCO
amps have the highest slew rates in the industry. Once again, clear defined,
sound is perceived as a function of power.
Signal to Noise Ratio:
Noise is an ever-present problem in auto sound reproduction.
ZAPCO approaches this problem in two ways. The first is at the input
source. All Reference amplifiers can use the SymbiLink™balance line
inputs, which drastically reduce the noise coming into the amp. Secondly,
ZAPCO amps are built with the highest quality, lowest noise components
available. We have the highest signal to noise ratios in the industry. The
extra money we spend on better components is directly rewarded with better
sound.

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Stereo Separation:
The ability of an amplifier to maintain the separation between the
right and left channels is what allows an amplifier to reproduce an accurate
sound stage. Music is recorded with each instrument in its own location on a
sound stage. You should hear it the same way in your vehicle.
Results:
To assure that no ZAPCO product ever fails to meet our level of
expectation, we must build all products to exceed our specifications by a
comfortable margin. Our superior design and construction give our
amplifiers advantages that go beyond power output and provide a sound
quality difference you will hear the moment you turn your system on.
A WORD ABOUT “WEIGHTED” SPECIFICATIONS
Most of the time, when you see specifications, they will be preceded
by the term “A” weighted. “A” weighting is a way of coloring numbers to
make specifications look better.
About the only place you can find specs that aren’t “A” weighted is
in ZAPCO manuals and literature. We publish only “raw” specs at ZAPCO. If
we don’t like the specifications of one of our products we’ll make it better,
not try to make the numbers look better.

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Warnings
ZAPCO highly recommends that a fuse or circuit breaker be placed
within 18" of the battery. Although products have adequate internal
protection, it is possible that a pinched power wire between the component
and the battery may result in a fire. The protection device should be placed
where it can be accessed easily and all wiring should be routed safely and
correctly according to the following guidelines:
Do not run wiring close to hot or spinning objects.
Always use wire grommets when routing wire through the firewall or
any other metal panels.
Make sure that the potential for pinched wiring is avoided by routing
all wires away from moving hinges and seats. This also includes brake, gas
and clutch pedals, hood and trunk hinges, etc.
Caution:
Continuous exposure to excessive sound pressure levels may
cause permanent hearing loss. ZAPCO strongly advises that you use
common sense when setting volume levels. If you experience ringing
in the ears, it could cause permanent hearing damage!
CAUTION!
When connecting our amplifiers to pre-wired stock speakers, care
must be taken that there are no common connections between left and right
speaker wires, i.e. minus to minus or plus to plus connections, as this will
cause the amplifier to go into immediate protection or may cause damage to
the amplifier. Output connections are not common chassis ground. Please
follow the hookup instructions in this owner’s manual. Any questions should
be directed to your local ZAPCO dealer or call us at 209-577-4268.

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Wire Size
Most people understand the importance of a clean signal source for
good sound reproduction. But, what about your 12 volt power source? It’s
often surprising how many people (even professional car audio people) will
obsess about signal wire but routinely provide the amplifier only a fraction of
the current it needs to do its job. The most common wire gauge used in car
audio is 10-gauge. The most common location for amplifiers is in the trunk.
Take a look at the chart below. If you want to have any respectable
amount of power for your amp, you need an 8-gauge wire to the trunk as a
bare minimum. If you want enough power to drive woofers, you’re going to
need at least a 4-gauge wire to the rear.
Length of Run
0-4 -7 -10 -
13 -
16 -19 -22 -
Current Demand
4 Ft
7 Ft
10 Ft
13 Ft
16 Ft
19 Ft
22 Ft 28 Ft
0 -20 amps 14 12 12 10 10 888
20 -35 amps 12 10 886664
35 -50 amps 10 8866444
50 -60 amps 88644442
65 -85 amps 66442220
85 -105 amps 66422220
105 -125 amps 44422000
125 -150 amps 22220000
Lets look at a fairly small system. If you use a Reference 200.2 (25
amps) for the highs and a Reference 350.2 (40 amps) for the woofers, you
need at least a 4-gauge wire to provide 65 amps at the trunk. Anything less
and your car won’t go boom. It’ll just go Blap!
It takes lots of current to make lots of power!
And remember! An electrical circuit is just that…a circuit. For current
to travel, you must complete the circuit from the positive terminal to the
negative terminal. Whatever you use for power (B+) you must also use for
Ground (B-). 4-gauge power wire…4-gauge ground wire!
So! Use this supplied chart! Add up the fuse values on the
amplifier(s) then choose the proper size wire based on the distance from the
car battery to the amplifier location. Very important, always use the same
gauge wire for the main ground as you do for the main power. Always make
your ground as short as possible and attach to a clean solid surface.

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Installation Guidelines
Mounting your Reference Amplifier is easy. Keep in mind the
following guidelines:
•The amplifier may be mounted in any direction, on wood, metal or
carpet.
•The metal case of the amplifier may be grounded or left isolated.
•The amplifier requires adequate ventilation. Position the amplifier with
sufficient surrounding area for proper cooling.
•Keep fan and vent endplates clear for proper internal cooling.
•Keep the amplifier out of the engine compartment and other locations
that may cause excessive heat or moisture.
•Do not mount the amplifier to a subwoofer enclosure or any
other place that may have excessive vibration!

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Reference Series Accessory
We believe the new textured pewter finish aluminum cover makes
the Reference Series of amps among the best looking products available
today. To dress up your installation and protect the connections from stray
hands and feet we have connection covers available for all Reference
Series amplifiers.
ZAPCO’s legend hasn’t always been built on the appearance of our
products, but on technical innovations and sound quality. On the next
several pages we will show you some of the differences that go beyond
appearance, which affect the versatility and performance of the Reference
Series amplifiers.

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In –Line SymbiLink™ Transmitters
ZAPCO was the first Car Audio manufacturer to embrace balanced
line signal transmission. There is a good deal of information in this manual
that explains the how and why of SymbiLink™ balanced line technology.
While Pro-Audio and High-End Home Audio manufacturers have
adopted balanced line technology, the car audio market is still supporting
the outdated RCA cable system. If SymbiLink™ is substituted for RCA the
potential built into our products will go unrealized by many users.
To ensure that every ZAPCO Reference Series amplifier can realize
its full potential we provide an SLDIN-T.F Balanced Line Transmitter with
every amplifier. Built into this transmitter is also a line driver capable of
boosting signal input up to 12dB (4-times) the output voltage of the source.
This balanced line conversion will improve noise rejection, lower the
inherent system noise floor, reduce distortion, and provide up to 16 volts of
signal output.
Simply attach the SymbiLink™ cable to the transmitter in the length
that fits your system and enjoy the sonic purity of SymbiLink™ Balanced
Technology.

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Dynamic Bass Control
ZAPCO offers a remote knob and mount for our bass equalization
circuitry. The Reference 500.1, 1100.1 and 1000.4 amplifiers have a “Bass
Boost” port on the control plate. Simply plug in the optional DBC (Dynamic
Bass Control) and you can make instantaneous changes in the bass contour
from the dash.

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ZAPCO Reference Controls
Reference Series Inputs
Some Reference Series amplifiers accept two distinct types of
signal inputs.
The first is the standard RCA type of signal input. While they are not
the best type of signal transmission, they certainly are the most common.
RCA cables were the first standardized transmission system for audio
signals, and have been around since the early days of phonographs and
tape recorders.
RCAs work quite well for home systems, where you have short
cable runs and few, if any, sources of induced noise. In a car environment,
however, they have some very real problems. These problems include
induced noise, harmonic distortion, system noise, and signal loss, due to the
long cable runs common in car audio systems. Despite these drawbacks,
RCAs have been around a long time and are very common, so, ZAPCO has
provided them as a convenient option on some Reference Series amplifiers.
ZAPCO also gives you a better sounding option. A 6-pin Mini DIN
connector that allows you to use the high voltage SymbiLink™balanced line
technology with all Reference Series amplifiers. Manufacturers of
professional audio equipment and high-end home products discovered
years ago that the problems inherent with RCAs could be eliminated, by
using differential preamps in combination with balanced line transmission.
ZAPCO one of the early adopters of balanced line technology incorporated
our SymbiLink™ balanced line transmission system into all Reference
Series amplifiers.

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Setting Your Gains
Proper gain setting is one of the most important factors in setting up
a stereo system. At the same time, gain setting is most often done wrong.
Turning up the gain of an amp is the very last thing you should ever do to a
system.
An amplifier is a step up transformer. Period. Any signal you put in
is boosted by a fixed factor. Music, hiss, or any other noise, it doesn’t
matter.
A large number of noise problems are simply a matter of improper
gain settings. The goal of gain setting is to achieve the maximum amount of
musical output from the amplifier while getting the least amount of hiss or
noise from the system.
Your Reference Series amplifier accepts an extremely wide range of
input levels. As little as .25 volts on the RCAs to as much as 16 volts with
SymbiLink™balanced inputs. The basic gain setting is very simple and
requires no special tools. Whether you have a simple system with a deck
and an amp, or a system with a deck, line driver, equalizer, crossover, and
amp, the procedure is always the same.
First, hook up the system with all gain controls at minimum (turn the
gain pot fully counter-clockwise with a small screwdriver). Then turn on the
head unit and turn up the volume. If you achieve clean sound, and, more
volume than you want, you don’t need to make any adjustments. However, if
you turn up the volume and begin to hear distorted sound before it becomes
loud, you are clipping (distorting) the deck (probably a little over ¾ volume).
Turn the deck down just enough to hear clean sound again, and then move
to the next component in your system. With the deck playing at “maximum
clean volume” adjust the gain of the next component to its “maximum clean
volume”. If you adjust your gains this way, always starting at the head unit
and working down the line to the amplifier, you will get the most
performance out of your amplifier(s) with the least amount of unwanted
distortion and noise.

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Signal Mode Switch
The Signal Mode Switch determines how the amplifier will treat the
input signal. You’ll notice that this is a three-position switch. The left position
is the “Stereo” setting. The center position is the “Bridged R Ch In ” setting.
The right position is the “L+R Sum Mono setting.
The Stereo setting is the most common. This is the position you will
use when the amplifier is going to drive both left and right speakers in a
stereo system. While this will account for 90% of our users, ZAPCO has
provided the Mode switch so the Reference Series amplifiers may also be
used in more advanced systems.
The second most common setting is the far right position, “L & R
Sum Mono”. In this position, the input stage will combine the left channel
and right channel information into a single mono channel, and feed that
information to both sides of the amplifier. You can then bridge the outputs
into a single bass channel or a single center channel. In both uses you will
have a single channel with the information from both channels of input.
NOTE: Left & Right Sum Mono is the position you will always use to drive
woofers only.
The third (center) position is “R Bridged”. This is the least common
setting, and is used primarily in large competition systems. This setting
takes information from the right input channel only and sends it to both sides
of the amplifier. This allows you to completely eliminate crosstalk between
channels by having separate right and left channel amplifiers. NOTE: This is
only used with separate right and left channel amplifiers and is NOT the
setting for woofer use.

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Bass EQ Control
In vehicle sound systems they have a tendency to peak at about
100Hz to 120Hz and to roll off after that. This leaves a hole in the bass
response in the 40Hz to 50Hz range.
To compensate for this effect, ZAPCO has provided all Reference
Series amplifiers with a variable Bass equalization circuit. Each amplifier
has a “Bass Boost” control, which allows adjustment of the bass from 0dB to
as much as 18dB. This adjustment is made at a frequency of 44Hz.
Use the Bass EQ with caution. Too much equalization can easily
cause amplifier clipping and may even damage your speakers.
Bass Equalization Curves