True Manufacturing Company 8i User Manual
TRUE
systems
PRECISION 8i
8-CHANNEL PRECISION MICROPHONE PREAMPLIFIER with M/S decoding
and Direct Inputs
Version 1.2
OPERATION MANUAL
2
SAFETY and OPERATING PRECAUTIONS
Important Information:
This symbol indicates the presence of dangerous voltage within the product
enclosure that presents the risk of electric shock injury. When this symbol
appears next to an operation discussed in this manual, only qualified
technical personnel should perform that operation.
This symbol indicates important operating or maintenance instructions that
should be read carefully. Failure to observe these instructions could result in
damage to the product or other property.
WARNINGS:
To reduce the risk of electric shock injury, do not remove the top cover or rear
panel. Uninsulated dangerous voltage exists within the product’s enclosure.
Refer servicing to qualified personnel.
Do not defeat the earth ground connection in the AC power cable. Tips for eliminating
ground loops are discussed in the “TROUBLESHOOTING” section of this manual.
Do not operate this unit in the presence of rain, liquids or condensing moisture. Liquid
entering the product enclosure presents the risk of electric shock injury. Do not touch
the AC plug or enclosure with wet hands.
Do not defeat intended AC power connection polarization.
Do not use a damaged or excessively worn cord to connect this unit to AC power.
CAUTIONS:
Severe damage may be caused to your unit if the AC voltage setting is not correct
for the AC power available in your area. The voltage setting is visible on the AC inlet
module on the International Power Supply Module (PSU-P8i). See section on “AC
Mains Connection” for instructions on selecting the proper AC voltage setting. If you are
unsure about this, contact your dealer or TRUE Systems. Product failure caused by
improper voltage setting will not be covered under warranty.
Do not operate this unit in the presence of rain, liquids or condensing moisture. Liquid
entering the product enclosure is likely to cause performance degradation or failure.
Failures due to moisture entering the enclosure will not be covered under warranty.
Should liquid spill on the unit, immediately disconnect it from the AC power source and
return it to your dealer or TRUE Systems for servicing.
This product is designed to operate in an ambient temperature environment not to
exceed 50C (122F). Please ensure that this unit is mounted in such a way that vents
are not blocked and ambient temperature does not exceed 50C.
3
CERTIFICATIONS
Declaration of Conformity – CE
Sunrise Engineering and Design Inc. hereby declares the TRUE Systems
PRECISION 8i 8-channel microphone preamplifier to be in material conformity with the
following directives and related standards:
73/23/EEC – Low Voltage Directive
89/336/EEC – EMC Directive
EN60065:1998
EN55103-1: 1997
EN55103-2: 1997
Technical files are maintained at corporate headquarters of Sunrise Engineering and
Design Inc., 1634 S. Research Loop, Suite 110, Tucson, Arizona 85710, USA.
Owner’s Record
We recommend that you record the following information for reference in the event that
you need to contact TRUE Systems for technical support or repairs. Please return
your completed Warranty Card today.
Serial No._____________________ Purchase Date ______________________
Dealer _____________________________________________________________
Address ____________________________________________________________
Phone _______________________
PRECISION 8i
4
OPERATION MANUAL
CONTENTS
SAFETY and OPERATING PRECAUTIONS 2
CERTIFICATIONS 3
Owner’s Record 3
Table of Contents 4
INTRODUCTION 5
PRODUCT OVERVIEW 5
UP-AND-RUNNING IN A HURRY 6
INSTALLATION 7
Unpacking and Inspection 7
Mounting 8
Ventilation 8
OPERATION 8
Connections 8
AC Mains Connection 8
Output Cable Connection 10
Microphone Cable Connection 11
A Word About Cables 11
Front Panel Controls 12
More About M/S Decoding 14
DESIGN APPROACH 16
SPECIFICATIONS 16
TROUBLESHOOTING 17
REGISTRATION and WARRANTY 18
SERVICE and SUPPORT INFORMATION 19
PRECISION 8i
5
OPERATION MANUAL
INTRODUCTION
The PRECISION 8i is designed to provide the detailed, transparent sonic performance
necessary for the most critical direct tracking and live sound applications. It includes a
unique combination of functions that make it useful as a complete input system for
standalone or PC-based recording systems. And, the PRECISION 8i has special
features that provide the serious musician or recordist with useful tools to get the best
sound more quickly and easily.
We appreciate the confidence you have placed in TRUE Systems by purchasing this
product. Please feel free to contact us with questions or comments. And, we always
appreciate hearing about successful projects you have completed.
OVERVIEW
In addition to our acclaimed TRUE preamps, PRECISION 8i features two instrument
direct inputs (DI’s) that offer sonic performance previously thought to be available only
with dedicated, high-end DI’s. You’ll get incredible articulation and control for electric
bass, detail and smoothness for stringed instruments and keyboards
The 5-segment peak-hold level metering with selectable peak reference allows rapid
optimization of program levels between the PRECISION 8i and devices to which it is
interfaced. Dual output connections provide easy interconnection as well as the ability to
act as a mic splitter.
PRECISION 8i is ideal for location recording due to its compact, 1U rack size, 8channel format, useful level metering and easy interconnect. The integral M/S decoder
provides creative spatial image control and can be particularly useful in attaining an
exciting stereo image with minimum effort and microphone re-positioning. The M-S
microphone technique can be employed effectively in a wide variety of circumstances,
from classical ensemble, to drum kit overheads, to solo vocal or instrument – whenever
accurate capture of the performance and its acoustical space is desired. M-S micing
also eliminates the “hole-in-the-middle” effect.
In addition to the previously mentioned features, the PRECISION 8i includes:
Both 8-channel DB25 and individual TRS output connections - for easy connectivity.
Individual Polarity Reverse - to correct polarity inversions caused by mic position or
cable wiring variations.
Individual Phantom Power (48V) – available on the front panel.
PRECISION 8i
6
MID
SIDE
OPERATION MANUAL
UP-AND-RUNNING IN A HURRY
1. Read the “Safety and Operating Precautions”on page 2 of this manual.
2. Check the voltage selector on the International Power Supply Module (PSU-P8i) to
make sure it is set for the appropriate AC mains voltage in your area.
3. After making sure the main power switch is off, connect the AC power cord.
4. Connect output signal cables between PRECISION 8i and the analog line level
inputs of your recorder, mixer, signal processor, etc. Use either the individual 1/4”
TRS or DB25 eight-channel balanced output connectors. See the section
“Connections” for wiring details.
5. Connect mic cables to MIC 1 through MIC 8 as needed.
6. Connect the interface cable on the International Power Supply Module (PSU-P8i) to
the main PRECISION 8i unit.
7. Turn on the AC power.
8. Set PEAK REFERENCE selector to +26.
9. Set 48V and buttons as appropriate on each channel.
10. Depress the RESET button to clear Peak-Hold indicators.
11. Adjust Gain controls for adequate signal level as indicated on the PRECISION 8i
level indicators or on the level indicators of the device to which it is connected.
If you’re using the DI’s for electric instrument input:
1. Connect your instrument cables to Direct In 1 and Direct In 2 on the rear panel. The
Direct In jacks are located within the same connectors as MIC 7 and MIC 8. Simply
plug your 1/4” phone plug into the center portion of the desired connector. NOTE:
DO NOT use TRS plugs for these inputs as the DI will not function correctly.
2. Set buttons as appropriate.
3. Adjust DI-1 or DI-2 Gain controls for adequate signal level as indicated on the
PRECISION 8i level indicators or on the level indicators of the device to which it is
connected.
If you’re using the M/S Decoder:
1. Connect the cardioid or omni MID mic to MIC 1 input.
2. Connect the figure 8 SIDE mic to MIC 2 input. Face the SIDE mic toward the right
side of the sound field (perpendicular to the axis of the MID mic). See Figure 1.
3. Depress the MID-SIDE ON button. “Left” signal is routed to Channel 1 output. “Right”
signal is routed to Channel 2 output.
4. Adjust the Channel 1 gain control for adequate mono signal level.
5. Adjust the Channel 2 gain control to vary the image width as desired.
6. See the section “More About M-S Decoding” for more information.
Figure 1
M-S microphone orientation
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