zapco SEQ User Manual

Model SEQ

Preamp - Equalizer

A.R.P.A. OF AMERICA CORP.

MADE IN MODESTO, CA U.S.A.

Contents

Introduction 3

Features 3

Installation Instructions 4

Connecting the SEQ 5

Operation and Calibration 6

Input Gain Control 6

Mounting Method 7

SEQ Wiring Diagram-Method 1 9

SEQ Wiring Diagram-Method 2 10

Help - Technical Assistance 11

Manufacturing 12

2

Introduction

Congratulations! You have just chosen the premium in car audio
equipment. ZAPCO has well established its place as the technological
leader in the car audio industry. Because of this, you can rest assured
that you have the best car audio components in the world.

The ZAPCO SEQ Stereo preamp/equalizer provides multiple control
functions with 9 x 2 bands of graphic equalization (with separate controls
for each channel) in a compact, heavy-duty die cast package, utilizing
low noise, high slew rate amplifiers throughout.

Features

• 18 dB boost/cut range on eq bands.

• Custom slide pot taper for smooth gain change and better resolution.

• Master volume control using high-quality conductive plastic

potentiometers with superior L/R tracking and very low noise.

• Input and output LED overload indicators, accurate to within 1 dB of
clipping.

• On-off 22 dB cut switch with de-thumping circuitry.

• Variable-gain input preamplifier with 6 to 26 dB adjustable gain for

matching to low or high output level decks.

• Signal to noise >98 dB.

• Low impedance output drives long cables.

3

Installation Instructions

The cable supplied with your SEQ is comprised of seven wires. These
seven wires are terminated on one end in a connector designed to be
inserted into the back of the SEQ. The other wire ends have been left
unterminated.

The following are instructions on proper connection of the seven
unterminated wire ends and additional wiring to ensure proper system
grounding.

WIRES INSIDE SHIELDED CABLE:
Five wires are contained within the gray jacketed, shielded cable.

Signal inputs (to SEQ), outputs (from SEQ) & signal ground are all
contained within the shielded cable. Function & connection of these
wires are as follows unless otherwise indicated on a tag attached to the
cable:

Green - Right Channel Input

(to SEQ from right channel output of source unit)

White - Left Channel Input

(to SEQ from left channel output of source unit)

Red - Right Channel Output

(from SEQ to right channel input of amplifier)

Black - Left Channel Output

(from SEQ to left channel input of amplifier)

Bare - Signal Ground

(from shielded cable to case of source unit)*

WIRES EXTERNAL TO SHIELDED CABLE:
Two wires are external to the gray jacketed, shielded cable.

Power Input & Power Ground connections are external to the shielded
cable. Function & connection of these wires are as follows:

Red - Power Input to SEQ

(connect to constant, ‘unswitched’, 12V source - fused)**

Black - Power Ground

(connect to case of source unit)*

4

ADDITIONAL GROUND CONNECTIONS:
To ensure proper system grounding the following additional connections

must be made. RCA Shields & SEQ case must be connected to case of
source unit.

RCA Shields - Signal Ground from amplifier inputs (connect wire from

RCA Shields @ amplifier input to case of source unit)*

SEQ Case - Case Ground from SEQ

(connect wire from SEQ case to case of source unit)*

* Four separate wires should terminate under the same screw at the
case of the source unit.
**Preferably, this connection is made through a 1/4 amp, fast blow, fuse
directly to the car battery.

Connecting the SEQ

The SEQ has a special miniature circular 7 pin connector with gold
plated pins. The connector snaps into place like other high quality
connectors. To remove it, squeeze and then pull as shown:

Don’t turn - Don’t twist - Don’t use hand tools!

1. Squeeze finger grips to flex plastic coupling area. The locking tabs

will deflect outward and unlock.

2. Pull plug from receptacle.

5

Operation and Calibration

A. Input gain controls provide adjustable gain of 6dB to 26dB.
B. Input clipping detector flashes whenever input signal is within +/- 1dB

of clipping (super-bright LED).

C. Volume control: high-quality conductive plastic potentiometer.
D. Output clipping detector: indicates the onset of output clipping.
E. Equalizer boost/cut controls.

F. On/off/mute switch, full output in up position, off in center, mute

(-22dB) in down position, (instrumentation type toggle switch.)

G. “On”: indicator LED.

6

Input Gain Control

Calibration/Adjustment: The pre-amp circuit built into the SEQ is
capable of 26dB of gain. Separate left and right channel input gain and
adjustments are made via two access holes in the front cover.
Adjustment to the input gain may be necessary to match the source
(tape deck, tuner or CD) output level to the input sensitivity of the system
amplifiers. If this adjustment is set too low, the source may distort
before the system is able to achieve full power. If the input gain
adjustment is set too high, the internal circuitry of the SEQ and/or
system amplifiers may distort.

There are two clipping indicators, one for input stage clipping and one for
output clipping.

Insert a tape or compact disc recorded at high level into the source unit.
If the source unit has a balance control, ensure that it is set to center.
Set the SEQ filter controls flat (0dB). Using the small plastic screwdriver
included with the SEQ, adjust the input gain trim pots fully
counterclockwise. The trimpots are 20-turn pots. Turning each pot more
than 20 full turns counterclockwise will ensure that left & right channels
are matched before the gain adjustment procedure begins. If the source
has a volume control, set it from approximately 1/2 to 3/4 full output.
With the SEQ volume control rotated completely counterclockwise, begin
by turning one input gain pot clockwise (count the number of turns) until
the red input clip indicator flashes. Rotate the other input gain trimpot
the same number of turns as the first. Minor input gain adjustments may
be necessary to achieve left/right balance or for higher level tapes or
compact discs. Setting filter controls at a high boost position may also
cause the preamp output indicator to flash, requiring a reduction in input
gain.

7

Mounting Method

Bracket Method

Attach bracket to mounting surface placing no. 10 sheet metal or
machine screws through the bracket slots. Attach the bracket to the
equalizer using the enclosed 1/4” socket-head screws and nylon
shoulder washers. Once the equalizer is swiveled to the desired angle
(the SEQ may be mounted with the bracket either above or below it)
tighten the socket-head screws using a 3/16” allen wrench.

Warning: Using screws that are too long will seriously damage
components on the circuit board and will void the warranty!

Low Profile Mounting Method

Low profile mounting provides 1-5/8” maximum height above the
mounting surface. The SEQ has two holes in the back for low-profile
mounting. The connector sticks out of the back therefore, three holes
must be drilled, two for mounting screws (13/64” or 7/32”) and one for
the connector (at least 5/8” in diameter).

If the installer has access, one simple way of low profile mounting, is to
use 10-32 machine screws (included) threaded into the SEQ from the
rear. (Screws should not be extended into the SEQ further than 1”) (see
fig. 2). The mounting surface with the 13/64” or 7/32” holes will clear a
10-32 screw. Drill 5/8” or larger for the connector.

8

9

10

Technical Assistance

Should you experience a problem with your SEQ, please contact the
dealer that sold you this product. If your dealer is unable to solve your
problem, you may contact the factory service department directly.

Phone: [phone] Monday-Friday 8am-5pm Pacific time
Fax: [phone]

If you need to return this product for repair, please call the factory for a
return authorization number. We will ask you for information which will
include your name, return shipping address, daytime phone number,
model and serial number, and a detailed description of your problem. A
photocopy of your original purchase receipt is necessary to determine
warranty status and should also be included. Once we issue you a return
authorization number, please write it in a highly visible area on the
package. Zapco will not accept any packages that do not have a valid
return authorization number clearly marked on the outside of the
package.

Send all repairs to:
A.R.P.A. of America Corp.

Attn: Service Department
413 S. Riverside Drive, Suite D
Modesto, CA 95354

11

Manufacturing

This product is designed and manufactured in the USA. The following
operations are ENTIRELY performed in our Modesto, California plant.

1. PC Board insertion

The components are inserted into American made printed
circuit boards.

2. PC Soldering

The printed circuit board assembly is wave soldered.

3. Testing

The PC board is 100% tested to design specs.

4. Extrusion Machining

American made aluminum extrusion is cut and machined
to precise tolerances.

5. Assembly

The product is assembled.

6. Final Test

Every product is tested with the highest quality audio test
equipment to meet or exceed their published specifications.

7. Inspection and final packaging.

*Many companies claim that their products are built in the USA, but only
a few of the above steps are actually performed in America. Many of
these companies only do the final assembly, with steps 1 - 4 being done
outside the USA.

12

A.R.P.A. OF AMERICA CORP.

413 S. RIVERSIDE DRIVE, SUITE D

MODESTO, CA 95354

[phone]

FAX [phone]

SEQ

Rev. E

7/96