Coda 06X User manual

TECHNOLO G IES INC.
FET PHONO PREAMPLIFIER 06x
OPERATION MANUAL
SAFETY PRECAUTIONS 1
INTRODUCTION 2
INSTALLATION 3
DESIGN 7
TECHNICAL DATA 9
CARE & HANDLING 10
WARRANTY 11
WARRANTY REGISTRATION 12
06x FET PHONO PREAMPLIFIER
06x FET PHONO PREAMPLIFIER

WARNING 2
!
CAUTION
CAUTION
WARNING
WARNING !
SERVICING TO QUALIFIED SERVICE
CAUTION: TO PREVENT ELECTRIC SHOCK,
DO NOT REMOVE COVER. NO USER
SERVICEABLE PARTS INSIDE, REFER
PERSONNEL.
THIS SYMBOL IS INTENDED TO ALERT
YOU OF THE PRESENCE OF IMPORTANT
OPERATING AND MAINTENANCE
INSTRUCTIONS IN THE LITERATURE
ACCOMPANYING THE UNIT.
THIS SYMBOL IS TO ALERT YOU OF THE
PRESENCE OF UNINSULATED DANGER-
OUS VOLTAGE WITHIN THE UNIT'S
ENCLOSURE THAT MAY BE OF SUFFI-
CIENT MAGNITUDE TO CONSTITUTE A
RISK OF ELECTRIC SHOCK.
WARNING: TO PREVENT FIRE OR SHOCK HAZARD, DO NOT
EXPOSE THIS UNIT TO RAIN OR MOISTURE. TO
AVOID ELECTRICAL SHOCK, DO NOT OPEN THE
UNIT. REFER SERVICING TO QUALIFIED PERSONNEL.
Never install or remove the power cord from the chassis
unless it has been disconnected from the AC power source
first.
Never pull on the power cord when removing it from an AC
power source. Grasp it by the plug.
Do not leave the power cord connected to an AC power
source unless it is connected to the unit.
It is recommended that during extended periods of nonuse
the unit's power cord be unplugged from its AC power
source.
Route the AC power cord so that it will not be damaged or
walked on.
CAUTION -
-
-
-
-

INTRODUCTION 3
Thank you for selecting Coda Technologies and our precison line of of high definition,
high value audio components. The Phono Preamplifier 06x is a precision device,
designed in an effort to provide the listener with unmatched sound quality, design,
and construction which will provide you with many years of listening enjoyment.
In order to operate your preamplifier properly and to realize all of the capabilites of the
06x, we recommend that you read this entire manual carefully to insure maximum
benefit from your audio system.

INSTALLATION 4
The first section of the installation instructions for the 06x covers basic configuration of the
preamplifier. These brief steps will bring the 06x into operation. Make sure during installa-
tion that the preamplifier and all other components of your audio system are unpowered.
The diagram below shows the basic configuration, but we recommend you read the
whole manual in detail to ensure the best performance out of your Coda equipment.
UNBALANCED INPUT
BALANCED INPUT
THGIRTFEL RIGHTLEFT
PUSH
PUSH
!
FOR CONTINUED PROTECTION AGAINST
SHOCK OR FIRE HAZARD,DO NOT EXPOSE
THIS UNIT TO RAIN OR MOISTURE.
ACLINE INPUT
SEE SERIAL TAGFOR
POWER REQUIREMENTS
~
GROUND
BALANCED OUTPUT
THGIRTFEL
UNBALANCED OUTPUT
RIGHTLEFT
UNBALANCED
PREAMPLIFIER
BALANCED
PREAMPLIFIER
UNBALANCED
PHONOGRAPH
PHONOGRAPH
BALANCED

INSTALLATION 5
WARNING: NEVER OPERATE THIS UNIT WITH THE TOP COVER REMOVED. NEVER MAKE ANY
INTERNAL ADJUSTMENTS WHILE THIS UNIT IS CONNECTED TO AN AC POWER SOURCE.
1. Prior to installing the unit some configuration can be made internally, including input
selection and per-channel gain and loading. With the unit unplugged, remove the cover
using the supplied Allen key. There are six gain switches split into two sections and two
input selector switches. The input will be set from the factory to unbalanced and the gain
will be set to the default low/low settings. Refer to the diagram below to identify the two
gain sections and the settings for the input switches.
Cartridge Type Section 1 Section 2
High-output moving-magnet Low Low
Medium-output moving-coil Low High
Low-output moving-coil High High
I. Chassis
HIGH
LOW
UNBALANCED
BALANCED
HIGH
LOW
HIGH
LOW
HIGH
LOW
Section 1
Section 2
GAIN CONFIGURATION SWITCHES (MAIN BOARD, LEFT END, TOP-DOWN VIEW)

INSTALLATION 6
2. In order to set the input loading you must toggle the DIP switches which are located
on the main board of the preamplifier. Each one of these switches connects a resistor
or capacitor in parallel with the input and so adjusts the load value. The default values
are 47kΩand 50pF. Refer to the diagram below, which is repeated inside the unit, to
determine the values which need to be switched in for your cartridge. Replace the cover
after setting the switches.
3. The balanced outputs are equipped with switchable phase due to differences in USA/
European standards. The default setting is European but may be changed according to
the following diagram. These switches can also be used to select absolute phase.
4. Althoug the 06x is generally resistant to electromagnetic interference it is recom-
mended that the unit not be installed near any sources of strong electromagnetic fields.
5. Before installing the preamplifier make sure all of the power switches of any associated
components are switched off. If any of your other audio components do not have power
switches, make sure they are unplugged from their AC power source.
NOTE: THE LINE VOLTAGE OF THE PREAMPLIFIER 06X IS SWITCHABLE TO PERMIT USE IN DIF-
FERENT COUNTRIES. CONTACT CODA TECHNOLOGIES FOR INSTRUCTIONS ON CHANGING
THE OPERATING VOLTAGE.
XLR BOARD XLR BOARD
THGIRTFEL
BALANCED OUTPUT
THGIRTFEL
BALANCED OUTPUT
+
+
__
+
_
+
_
1
2
3
1
2
3
1
2
3
1
2
31
2
3
1
2
3
USAEuropean
4
DETAILED INSTALLATION
22 22
47 47
100 100
1000 1000
1000 PF 1000 PF
200 PF 200 PF
100 PF 100 PF
50 PF 50 PF
ON ON

DESIGN PHILOSOPHY 7
II. Source, Output and Power Connections
III. Front Panel
The input and output connections are marked on the rear lip of the top cover of the
preamplifier. Remember when connecting input and output cables to avoid inadvertently
swapping left / right channel connections. The connections are as follows:
After connecting the audio input and output cables and AC line input the preamplifier
will power on immediately; there is no power switch. The front-panel power LED will light to
indicate the power is on.
1. Ground Post
2. Unbalanced Input
3. Balanced Input
4. Unbalanced Output
5. Balanced Output
6. AC Line Input
There are no front-panel controls. All controls are inside and are to be selected prior to
operation (see pages 4 and 5). The only function of the front panel is a power indicator
LED, which backlights the window when the power is on.
CAUTION: IF A POWER INTERRUPTION OCCURS, TURN DOWN THE VOLUME OF YOUR
AUDIO SYSTEM BEFORE POWER RESUMES. SUDDEN POWER SURGE CAN CAUSE AN OUTPUT
LEVEL SPIKE WHICH COULD CAUSE DAMAGE TO YOUR AUDIO SYSTEM.
UNBALANCED INPUT
BALANCED INPUT
THGIRTFEL RIGHTLEFT
PUSH
PUSH
!
FOR CONTINUED PROTECTION AGAINST
SHOCK OR FIRE HAZARD,DO NOT EXPOSE
THIS UNIT TO RAIN OR MOISTURE.
AC LINE INPUT
SEE SERIAL TAG FOR
POWER REQUIREMENTS
~
GROUND
BALANCED OUTPUT
THGIRTFEL
UNBALANCED OUTPUT
RIGHTLEFT
1
345
62

DESIGN PHILOSOPHY 8
The circuitry utilized in your phono preamplifier is the result of an advanced and complete
design process combining innovation and proven fundamentals. This process avoids both
the limitations of total adherence to convention and the flaws resulting from inappropriate
application of clever circuit gimmicks. Our approach demands painstaking consideration
of ever facet of each design choice regardless of how small. Analytical, as well as subjec-
tive techniques are all applied in an open-minded fashion with “no compromise” musical
perfection as the goal. The resulting refinement of the product escapes simple explana-
tion. With this in mind we present here a few design highlights and concepts.
Primary voltage gain is accomplished with FETs. While careful design can yield good re-
sults from any device type, FETs consistently have the edge in voltage gain and interface
applications. This is borne out by superior sonic qualities observed in subjective testing. FETs
are inherently transconductance devices, meaning that an input voltage controls an out-
put current. In other words, it “senses” the audio signal without drawing substantial current
from the source to provide an output. This eliminates complex interactions with the source
allowing maximum performance from each system element and greatly reducing the
chance of cable characteristics altering the sound. The absence of input current in FETs
also allows high bias currents for linearity and speed without sacrificing DC parameters.
While excellent capacitors for coupling use exist, there can be no doubt that a signal
path free of coupling capacitors yields the best possible signal integrity. The DC stability
of the circuit eliminates the need for any questionable DC servo circuits or input or ouput
coupling capacitors. We make no AC compromises for DC performance, however. Our
key design choices provide not only inherent DC stability but also optimized AC pefor-
mance throughout the audio region and well beyond. These choices include the use of
top quality dual FETs in a differential configurations. Because the signal in these stages is
handled in a balanced manner, rejection of unwanted noise and modulation from ex-
ternal sources is extremely high. This rejection extends even to noise which may originate
within the circuit from support circuitry such as current sources. Stray RF signals are also
rejected well.
Since the necessary equalization requires the use of capacitors, we use only high grade
film-type capacitors. These and other equalization components were carefully chosen to
maintain response to within .2dB of RIAA standards. An additional subsonic rolloff at 14Hz
serves to reduce IM distortion. Noise is kept low by multiple parallelling of input devices,
careful selection of circuit impedences, and pre-screening of devices.
The class-A complimentary followers used to drive the preamp output are of such speed,
linearity and low output impedance that no feedback correction is required or used. The
advantage of this is that the circuit’s perfect stability and transient response are ppre-
served into a wide range of difficult and unpredictable loads. Variation in sound which
could occur through interactions with interconnect cables and other system elements are
thus avoided. A simple, very high performancei nverter provides a fully balanced output
on the phono preamplifier which allows the user to take advantage of the balanced
inputs on many preamplifiers. The most commonly acknowledged advantage of this is
rejection of stray noise pickup, but improvements in distortion and bandwidth may occur
also.
The requirements of a power supply for flawless audio reproduction are straightforward
but important. The supplies in the 06x take a very direct approach to high performance.
First, a top quality shielded toroid transformer with plenty of reserve current capability is
used. The shielding eliminates strong fields which could induce hum into sensitive circuitry.
About 25,000 uF of capacitance iwth very low ESR and inductance provides good pas-
sive filtering. A reference voltage is developed by delivering a constant current to zener

DESIGN PHILOSOPHY 9
diodes. The resulting voltage is heavily filtered and delivered to each stage through
independant class-A followers which completely decouples the stages. The resulting
non-reactive low impedance over an extremely wide bandwidth yields a perfect power
source for the individual circuits. The simplicity and absolute stability of the supplies
removes the chance of unpredictable interactions which may occur with the more elabo-
rate, high-feedback circuitry often used in similar equipment.
Most companies in the upper end of the audio industry use either sheet metal or formed
aluminum chassis. By contrast, the 06x has all structural parts made of machined extruded
aluminum. The advantage of this over an all-stamped chassis is that the machined
metal can be worked more precisely, allowing us to work on tighter tolerances and use
PC-mounted parts more easily. Moreover, such a design allows easier servicing either for
repair or for future upgrades. From the standpoint of appearance a machined surface
can be contoured in a far more pleasant manner giving the final product a more seam-
less appearance.
The amplifier’s chassis is made from heavy-gauge steel with a half-inch machined
aluminum faceplate. All exterior metal parts are anodized or powder coated for
durability.
Printed circuit boards are fiberglass epoxy with gold plating over a tin/nickel barrier.
The gold layer will not corrode, while the barrier layer prevents the gold from migrating
to the lower copper layer.
All resistors are precision metal film; 1% tolerance for 1/4-watt and 5% tolerance for
1-watt.
Capacitors have been eliminated wherever possible. No electrolytic capacitors are
used except in the power supply, where several high-capacitance electrolytics
provide outstanding filtering of the supply output.
All semiconductor devices are of very high grade. Voltage gain is accomplished with
an extremely high-quality, matched dual FET, chosen for it’s exceptionally low noise
characteristics.
All audio input and output connector contacts are gold-plated, and XLR receptacles
are manufactured by Neutrik of Switzerland. Wire is used as little as possible in the
signal path - only to connect the RCA jacks and speaker terminals to the circuit board
- and what is used is 141-strand silver-plated copper with silicone insulation.

TECHNICAL DATA 10
CIRCUIT SPECIFICATIONS
Frequency Response: +/- .2dB of RIAA with subsonic roll off @
14Hz
Distortion: < .01% from 20Hz to 20kHz @ 3V peak into
600Ωor higher shunted by 100pf or less.
Gain: unbalanced output - 37dB @ 1kHz
balanced output - 46dB @ 1kHz
Maximum Output: 12V peak
Noise: >87dB referenced to 1V output
Input Capacitance: 100pF to 1000pF
Input Impedance: 22Ωto 47kΩ
Output Impedance: 75Ωnon-reactive unbalanced
150Ωnon-reactive balanced
Crosstalk: 70dB @ 20kHz
DIMENSIONS
Height: 1.75” Faceplate, 2.35” Overall
Width: 19.0” Faceplate, 17.0” Overall
Depth: 9.75” Overall
Weight: 14 lbs. Shipping
POWER SUPPLY
Independantly regulated with shielded toroidal transformer and 25,000uF of capacitance.

CARE AND HANDLING 11
The interior of the preamplifier requires no special care. If exterior cleaning beyond simple
dusting is required, any dilute ammonia-based product is recommended. Do not use
any abrasive rags, cleaners or chemical solvents on the amplifier.
When handling the preamplifier, take care not to mar the faceplate. Aluminum is a
medium hardness metal and can be scratched by harder tool steels, and the grained
surface can be easily marred if the amplifier is set face-down on a hard surface. Do
not rest the preamplifier on it’s faceplate.
The preamplifier should not be left in direct sunlight or exposed to intense heat to avoid
damage to internal components or finish.
It is recommended that you do not throw away any shipping material. The box and
packing materials are ideal for moving, and if any service is required they will be
necessary for safe shipment.

WARRANTY 12
Warranty - Any failure of the Phono Preamplifier 06x, hereafter known as the product orI.
original product, to operate or to meet specifications, applicable at time of manufacture,
due to a manufacturing defect or component failure, will be corrected by Coda Tech-
nologies without charge for parts or labor, for a period of ten years from date of original
purchase. Coda Technologies will provide for surface transportation to and from the
factory for a period of one year from date of original purchase.
Procedure - If the product should require service under warranty contact Coda Tech-II.
nologies at the location on the back cover of this manual for shipping instructions. Prod-
ucts purchased outside of the United States will be covered by the warranty conditions
extended by the importing distributor which may differ from those given above.
Exclusion of Coverage - Coda Technologies is not obligated to service the product inIII.
certain conditions, as according to the following subsections.
The product has been damaged through:a.
operation not in accordance with the instructions in this manuali.
abuse, tampering, modification or accidentii.
serial number defacementiii.
The product has been transferred to a third party. This warranty is valid only for theb.
original purchaser of the product.
The product has been transported outside of the United States of Americac.
In these conditions any service will be made at Coda Technologies sole option.
Total Loss and Replacement - If the product is submitted for service due to a severeIV.
malfunction which has caused damage sufficient enough to make a repair attempt in-
feasible, the product will be replaced with another unit of equal or superior specifications.
Coda Technologies product line is frequently updated and changed, and the specific
model and version of the original product may be discontinued at any time without
notice. In this case no guarantees are made that the replacement unit will be visually
similar to the original product.
Subjective Differences - No guarantee is made that the product will perform to anyV.
specifications that cannot be measured and confirmed with precision audio analysis
equipment. Coda Technologies is only obligated to make repairs which will bring the
product into compliance with the specifications stated in this manual.
Unnecessary Service - In all conditions, if the product is submitted for service and foundVI.
to be operated without fault and within specifications, shipping charges will be billed to
the customer.
This warranty gives you specific legal rights. You may have other rights which vary
from state to state.
Disclaimer - Coda Technologies cannot be held responsible for any damage caused by
their products, including but not limited to:
Damage to speakers caused by failure of a Coda Technologies product to mute ora.
disable itself as expected or described in its manual.
Damage caused by connecting a load to a Coda Technologies product having anb.
improper impedance as described in the products manual.
Damage caused by defects in design, construction or component quality.c.

WARRANTY REGISTRATION 13
Fill in this registration sheet and fax or mail it to Coda Technologies to ensure
you are in our warranty system. This will facilitate warranty service should it
become necessary.
It is recommended that you retain a copy of this form for your own records.
Coda Technologies’ address and fax number are located on the back of
this manual.
Model Designation:
Serial Number:
Date of Purchase:
Notes:
Purchaser
Dealer:
Address:
City: Zip: State:
Phone:
Place of Purchase
Dealer:
Address:
City: Zip: State:
Phone:

SACRAMENTO, CA 95826 USA
TECHNOLOGIES INC.
7850 CUCAMONGA AVENUE #31
phone [phone] fax [phone]
on the web at CODA.CC
email us at [email protected]