zapco ST-2B User manual

1
ST-B SERIES
Owner’s Manual
Before o erating the unit, lease read this manual throughly and retain it for future reference.

MISSION STATEMENT
Committed to Excelle ce
ZAPCO is dedicated to the pursuit of audio fidelity. Our prime objectives are to
desi n 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.
Experie ce
(K owledge from doi g)
There is absolutely no substitute for experience; that is a simple fact of life.
Another simple fact is that ZAPCO has, for over forty years, been the leader in
definin quality standards for the car audio industry.
These years of experience have led to a thorou h understandin of the
challen es that are unique to the world of car audio. ZAPCO's relentless quest
for sonic purity consistently yields ima inative desi ns that utilize the most
innovative technolo ies. The resultin products set the criteria by which all
others in the industry are jud ed.

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Table of Co te ts
Before you start your installation ................................................................... 2
Plannin your power connections .................................................................. 3
Wire size ................................................................................................. 4
Mountin your ST-B amplifier ......................................................................... 5
Inputs and Controls ......................................................................................... 6
ST-2B Input Ends .....................................................................................6
ST-4B Input Ends ..................................................................................... 7
ST-1B Input Ends ..................................................................................... 8
Speaker Wirin of the ST-B Amplifiers ............................................................ 9
ST-2B Speaker Wirin ............................................................................. 9
ST-4B Speaker Wirin ............................................................................. 11
ST-1B Speaker Wirin ............................................................................. 13
Technical Specifications .................................................................................. 13
The ST-B Series. Great sou d for every day use.
ZAPCO has a reputation for sound reproduction and quality that is unsurpassed.
It is our dedication to sonic purity and our passion for performance that built
Zapco's reputation. With all the new amps comin into the market, not one
has been any threat to Zapco's standin as the premium amp and processor
line. Just check the audio competition scene and the audio forums.
But not everyone wants to compete. The question was this: could Zapco put
it's 40-years of audio experience to work to develop an amp for every-day
use? An amp that all can afford but that will stay true to the Zapco herita e for
sound and reliability? Absolutely! We can and we have! The new ST-B amps
are a testament to the fact that you can build a quality product with reat
sound in an amplifier for every day use.
With the Studio-B amplifiers Zapco brin s the sound quality and reliability that
built the Zapco le end to an amplifier that everyone can afford.

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Before you start your i stallatio
ZAPCO hi hly recommends that a fuse or circuit breaker be placed within 18"
of the battery. Althou h you will add a fuse or fuse block near the amplifier it
is still a possibility that a pinched power wire between the component fuse
and the battery could result in a short, or even a fire. The protection device
should be placed where it can be accessed easily and all wirin should be
routed safely and correctly accordin to the followin uidelines:
Do not run wirin close to hot or spinnin objects.
Always use wire rommets when routin wire throu h the firewall or any
other metal panels.
Make sure that the potential for pinched wirin is avoided by routin all wires
away from movin hin es and seats. This also includes brake, as and clutch
pedals, hood and trunk hin es, etc.
Continuous exposure to excessive sound pressure levels may cause permanent
hearin loss. ZAPCO stron ly advises that you use common sense when settin
volume levels. If you experience rin in in the ears, it could cause permanent
hearin dama e!
When connectin our amplifiers to pre-wired stock speakers, care must be
taken that there are no common connections between left and ri ht speaker
wires, i.e. two or more speakers usin the same round connection (very
common in pre-85 cars), as this will cause the amplifier to o into immediate
protection or may cause dama e to the amplifier. Output connections are not
common chassis round. Please follow the hookup instructions in this owner's
manual. Any questions should be directed to your local ZAPCO dealer.

3
Pla i g your power co ectio s
The power end plates of the Zapco ST-B amplifiers carry the power connecons
and the speaker connecons and vary somewhat by the number of channels.
For example, the power end of the ST-4B below has (of course) speaker
connecons for four channels. The ST-B amps all have on-board fuses and the
fuse ran as printed above the fuses. The main 12-volt power input, the
12-volt turn-on wire, and the main Ground connecon are common to both
models.
• The main power input must be connected the vehicle baery's posive
(+) terminal, and a main system fuse should be placed close to the baery
• The main round or ne ave connecon must be securely aached to
bare metal at the vehicle frame, or other heavy chassis component with
a direct connecon to the frame
Note: Seat bolts a d seat belt bolts are NOT good grou d poi ts
• The terminal between the main power and round is the +12 turn-on
input and can be connected to the head unit turn-on output wire.
If none is available it can be connected to an accessory (ACC) terminal.
You should avoid usin any i nition-on (IGN) wire, as they can be noisy
Tur -o trigger wire
+12 volt at Baery posive termi al Grou d to chassis

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Some words about Power a d Grou d
Note: The seco d most commo cause of u derperformi g amplifiers is i sufficie t power
curre t or a pour power co ectio . The most commo cause of u derperformi g amplifiers is
i sufficie t grou d curre t or a bad grou d co ectio .
12-volt current: Battery Power works only if it travels in a complete circuit from
the battery positive terminal to the battery ne ative terminal. Main power
input, of course, is attached to the battery positive terminal. Ground current is
returned to the battery throu h the chassis to the to the point where the battery
is rounded.
The current available for your amplifier to use to produce power will be
restricted by the smallest au e of wire in the circuit and by the weakest physical
connection in the circuit.
Wire Size
It's often surprisin how many people will obsess about si nal wire but routinely
provide the amplifier with only a fraction of the current it needs to do its job.
The most common wire au e used in car audio is 10- au e, and the most
common location for amplifiers is in the trunk.
Wire Sizi g Chart
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 -105amps 66422220
105-125 amps 44422000
125-150 amps 22220000
Let's look at a fairly small system. If you use a 50 watt/ch amp (25 amps)
for the hi hs and a 100 watt/ch amp (40 amps) for the woofers, you need at
least a 4- au e and maybe a 2-Gua e wire to provide 65 amps at the trunk.
Anythin less and your car won't o boom. It'll just o Blap!
Le gth of Ru

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Note: It takes lots of curre t to make lots of power!
Remember! An electrical circuit is just that... a complete circuit. For current to
travel, you must complete the circuit from the positive terminal to the ne ative
terminal (which is connected to the vehicle frame). So what ever Gau e wire
you use for power (B+) you must also use for round (B-).
Note: A 4-gauge power wire eeds 4-gauge grou d wire!
Use the Wire Sizin 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. A ain, always use the same au e wire for the main round
as you do for the main power. Always make your round as short as possible
and secure it to a clean solid surface, preferably the vehicle frame.
Mou ti g your ST-B amplifier
Mountin your Zapco amplifier is easy. Just keep in mind a few uidelines:
• The amplifier can be mounted in any direction, on wood, metal, or carpet
• The metal chassis of the amp can be rounded or left isolated
• The amplifier requires adequate ventilation. Creatin power creates heat,
and coolin requires air. Position the amplifier with sufficient surroundin
area for air supply and keep the end plates clear for future access
• Keep the amplifier out of the en ine compartment or other locations
that may cause excessive heat or moisture
• Do not mount the amplifier to a subwoofer box or other place that may
have excessive vibration
Setti g Gai s: Gain pots are not volume controls. Before you first turn on your
system, you should make sure all ain controls are set to minimum. Gain
controls should be used only if absolutely necessary. Turnin up ain controls
causes increased noise, makes distortion more likely and reduces the dynamic
ran e of your system. If you head unit does not have sufficient output, you will
et much better results by investin in a line driver to provide more si nal to
the amplifier.

ST-2B I put/Co trols E ds
The Input ends of the ST-2B amplifier is where you find the si nal input
connectors,the pass throu h outputs, the crossover controls. For Hi h Level
(speaker level) you also find the port for the input plu .
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1• Speaker level input plu for OEM hookup
2• RCA inputs from an after-market head unit
3• Pass throu h RCA output allows "daisy
chainin " amplifiers
4• Variable ain control (set to minimum
before initial turn-on)
5• Bass boost switch for 0, 6dB, or 12dB
6• Low Pass frequency selector for the bass
crossover
7• Crossover selector for low pass, full ran e,
or hi h pass
8• Hi h pass filter for the mids/hi hs
9• Green power-on LED and red protect LED
2 3
1 7
9
4
8
5
6

7
ST-4B I put/Co trols E ds
The ST-4B has similar functions as the ST-2B but the 4 channel layout puts the
controls in different positions.
3 4
25 9
7812
1
610
11 13
1• Speaker level input plu for OEM hookup
2• Front crossover function selector for full
ran e of hi h pass
3• Front Hi h Pass frequency control
4• Front Channels Variable ain control
(set to minimum before initial turn-on)
5• Front channels RCA inputs
6• Pass throu h RCA output (rear channels
can feed another amp)
7• Rear channels RCA inputs
8• Rear Channels Variable ain control
(set to minimum before initial turn-on)
9• Rear channels Bass Boost switch for 0, 6dB,
or 12dB
10• Rear Low Pass frequency control
11• Rear crossover function switch for hi h pass,
full ran e, or low pass
12• Rear Hi h Pass frequency control
13• Green power-on LED and red protect LED

8
ST-1B I put/Co trols E ds
The ST-1B has similar functions as the other ST-B amps but the 1 channel layout
puts the controls in different positions. Plus the ST-1B has a remote control port.
1• RCA inputs
2• RCA outputs
3• Variable ain control (set to minimum
before initial turn-on)
4• Crossover function selector for full ran e
of low pass
5• Low Pass frequency control
6• Sub Sonic filter
7• 0-180° Phase control
8• 0-12 dB Bass boost control
9• Remote control port
10• Power/protect LED
3
24 7
6 10
1
58
9

9
Speaker Wiri g of the ST-B Amplifiers
The Very Basics
• No speaker wires can be shorted to, or touchin either round or each other.
This will put the amp into protect and may dama e the amplifier
• When brid in the left and ri ht channels of any ST-B amplifier, you
use the left channel (Ch1) positive and the ri ht channel (Ch2) ne ative, as
indicated on the chassis by the speaker terminals
ST-2B Speaker Wiri g
2Ch Stereo Mode
A simple 2 speaker hookup for a ri ht and left stereo pair. Speakers can be 2Ω or 4Ω.
Si gle Cha el Mode
The ST-2B can be used in brid ed mono mode to drive a sin le speaker or a woofer.
NOTE that in brid ed mono mode the speaker load must be 4Ω minimum.
4Ω / 8Ω

3Ch Mode
It is possible to run the 2Ch amps in “3-Channel” mode by runnin a pair of
speakers for the mids and hi hs on left and ri ht channels, and at the same time
run a woofer brid ed between the L+ and R- terminals as shown. However, since
each channel will see 1/2 the impedance of the woofer you must use a woofer of no
less than 4Ω. The amplifier sees impedance by frequency, so you can have two 2Ω
loads but you must use a passive crossover on each speaker in the three channel
mode. With the crossovers in the line, the amplifier will always see a minimum load
of 2Ω on each channel at all frequencies.
• Main speakers can be 2Ω~4Ω. Woofer can be 4Ω~8Ω but cannot be less than
4Ω (as in any brid ed situation)
• The active amp crossovers are not used in this system
A 3-Way hookup requires a coil o the
woofer a d capacitors o the highs to
act as a crossover a d mai tai correct
impeda ce. Co sult the speaker ma ufacturer
for correct cap a d coil values.
2Ω Min
10
4Ω Min

All speakers 2Ω Min
11
ST-4B Speaker Wiri g
4Ch Mode
If usi g coaxial speakers, co sider usi g the HP filters at the lowest setti g to
keep deep bass from damagi g the speakers.
High Power 2Ch Mode
Similar to brid in a stereo amp to a mono woofer, you can use the 4-Ch amp in a
dual mono mode to create (in this case) a stereo amp with 190 watts RMS/ch.
As with any brid ed setup the speakers must be a minimum of 4Ω impedance.
If you are usin the active crossovers you should be sure that they are set to the
same frequency
High power stereo usi g dual mo o bridge hookups requires that the speakers
be a mi imu of 4 Ohms impeda ce each.
Brid ed 4Ω Min

2-way Active System
Usin the built-in active crossovers of the ST-4B, you can easily create an active
2-way system with mid/hi hs on the front channels and bass on the rear channels.
Below is an active system with a brid ed subwoofer on the rear channels.
5Ch System
The 5-speakers system requires a passive crossover between the front hi hs and
the mono woofer, with capacitors on the front hi hs positives and a coil on the
woofer positive. All amplifiers channels are full ran e.
Hi hs 2Ω Min
Mono Bass 4Ω Min
Hi hs 2Ω Min
Bass
4Ω Min
12
Hi hs 2Ω Min

13
ST-1B Speaker Wiri g
The ST-1B has two + and two - terminals so you can hook up one woofer or two.
One woofer can be 2Ω minimum. Two woofers must be 4Ω minimum each.
Tech ical Specificatio s
2Ω Min
ST-2B
Power @ 4Ω: 2 x 65 was
Power @ 2Ω: 2 x 90 was
Power @ 4Ω Brid ed: 180 was
THD @ Rated Power < 0.1%
Si nal to Noise Rao > 97dB
Channel separaon > 45dB
Freq. Response 20Hz-20KHz ±1dB
Input Sensivity .25v to 5v
Dim. in mm: 182(W) x 52(H) x 200(L)
Overall: 182(W) x 52(H) x 230(L)
ST-4B
Power @ 4Ω: 4 x 65 was
Power @ 2Ω: 4 x 90 was
Power @ 4Ω Brid ed: 2 x 180 was
THD @ Rated Power < 0.2%
Si nal to Noise Rao > 97dB
Channel separaon > 45dB
Freq. Response 20Hz-20KHz ±1dB
Input Sensivity .25v to 5v
Dim. in mm: 182(W) x 52(H) x 280(L)
Overall: 182(W) x 52(H) x 310(L)
ST-1B
Power @ 4Ω: 200 was
Power @ 2Ω: 300 was
THD @ Rated Power < 0.2%
Si nal to Noise Rao > 97dB
Input Sensivity .25v to 5v
Dim. in mm: 182(W) x 52(H) x 280(L)
Overall: 182(W) x 52(H) x 310(L)

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