Conrad-Johnson TEA2 User manual

Conrad-Johnson Owner’s Manual:
TEA2 Phono Preamplifier
conrad-johnson It just sounds right.

TEA2 Owner’s Manual 1
Thank you for selecting the conrad-johnson TEA2 triode equaliza-
tion amplifier as the phono stage for your audio system. The TEA2
is capable of remarkably faithful recreation of the dynamics, tex-
tures, tonalities, and ambience of live musical performances. We
believe that you will experience the excitement of discovery in
hearing more from your favorite LPs than ever before.
At conrad-johnson, we expect our products to be a source of satis-
faction and of pride to their owners for many years to come. Ac-
cordingly, circuit designs, parts and materials for all conrad-
johnson products are selected with a view to maintaining optimal
performance over the years. Our reputation for producing among
the industry’s most reliable components is a natural consequence
of this engineering approach.
Please take a few minutes to read the manual to better understand
the features and capabilities of your TEA2. Note that the TEA2 is
available in two different versions –High Gain and Low Gain. See
the first section of this manual, “The TEA2 Family of Phono
Stages” for guidance in choosing the correct version for your appli-
cation.
In closing, we’d like to welcome you to the family of conrad-
johnson owners. We want you to enjoy your conrad-johnson prod-
uct to the fullest. To this end, our staff stands ready to answer any
questions you may have about the function and application of your
TEA2, and to provide any needed service both during, and after
the warranty period. Our goal is to heighten your enjoyment of re-
corded music.

TEA2 Owner’s Manual 2
he TEA2Family of Phono Stages
The TEA2 is available in High Gain and Low Gain versions. Both
versions share a common circuit approach featuring a zero loop
feedback circuit with passive RIAA equalization. Gain is provided
by two single ended triode stages in both versions. Both use a pair
of 12AX7s for the input stage (with the two triode sections con-
nected in parallel to minimize noise). The high gain version uses a
third 12AX7 for the second gain stage, while the low gain version
uses a 12AU7. Because these tubes are quite different, the two
versions also have different resistors associated with these tubes.
Choosing the Correct TEA2 for Your Application
With 55dB of gain, the TEA2HG high gain version is well suited to
cartridges with rated output of 1.0 mV (1000 micro Volts) or below.
It is not recommended for use with higher output cartridges, as
they may overload the circuits resulting in excessive distortion. For
cartridges with rated output above 1.0 mV, choose the low gain
TEA2LG (gain of 40 dB).
A TEA2 can be changed from HG to LG configuration and vice
versa at the factory. The change will entail replacing resistors and
the phono stage tubes. There will be a charge for parts, labor, and
return shipping for this service.
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TEA2 Owner’s Manual 3
imited Warranty For Conrad-Johnson Components
Conrad-Johnson Design, Inc. will provide service under warranty to
the original owner on products sold new in the United States for the
lesser period of three years from the date of purchase by the origi-
nal purchaser, or five years from the date of shipment to the au-
thorized conrad-johnson dealer. During the warranty period, con-
rad-johnson will repair defective units without charge for labor or
parts (with the exception of vacuum tubes and batteries).
Exclusions. The following are notcovered under this warranty:
a) Units which have been damaged by misuse, abuse, or acci-
dent.
b) Units which have been modified, altered, or improperly re-
paired by anyone not specifically authorized by conrad-johnson
design, inc.
c) Units not purchased from an authorized conrad-johnson
dealer in the United States for use in the United States.
d) Normal wear
e) Incidental or consequential damages are not covered under
this warranty. Some states do not allow the exclusion of inci-
dental or consequential damages, so this exclusion may not
apply to you.
Obtaining Warranty Service: To obtain warranty service, the unit
must be shipped, along with evidence of purchase, in factory pack-
ing to conrad-johnson design (or designated service center) with
freight and insurance prepaid by the owner. After repair, the unit
will be returned with freight and insurance prepaid by conrad-
johnson design to any destination in the United States.
All implied warranties, including merchantability and fitness for a
particular purpose are limited in duration to the duration of this ex-
press warranty. Some states do not allow limitations on the dura-
tion of implied warranties so the above limitations may not apply to
you.
This warranty gives you specific legal rights and you may also
have other rights which vary from state to state.
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TEA2 Owner’s Manual 4
Conrad-Johnson products purchased outside the United States are
covered by warranty terms of the importing distributor in the coun-
try in which the product was originally purchased, which may differ
from the terms set out herein. Importing distributors are not obli-
gated to provide warranty service for products originally purchased
outside their country. Conrad-Johnson will provide warranty service
for products outside the United States, but in these cases, the cus-
tomer must pay all shipping, handling and customs costs both to
and from our Service Department.
Questions about this warranty should be addressed to:
Service Department
conrad-johnson design, inc.
2733 Merrilee Drive
Fairfax, VA 22031
The conrad-johnson service department can also be reached by e-
mail at [email protected], by phone at 703-698-8581,
or by fax at 703-560-5360.
Service
If your conrad-johnson audio component requires service, repack it
using the original box and packing material and ship to the Service
Department address above. Boxes and packing materials can be
purchased through our service department if you no longer have
yours. Include with the unit a note describing the problem you are
having in as much detail as possible. It is especially important for
our technician to know if the problem is intermittent. If you want an
estimate of cost for out of warranty service, be sure to request it in
this note. Be aware that requesting an estimate will delay service
to your unit, as we will have to contact you for approval before
commencing service.
Registering The Warranty
Please return the enclosed card to the factory within 30 days of
purchase to register the warranty.

TEA2 Owner’s Manual 5
nstallation
Set Up
To maintain proper ventilation, mount the TEA2 horizontally on a
flat, hard surface, and take care that the ventilation holes in the
bottom are unobstructed. Allow at least two inches of clearance
above the unit and keep the cabinet or shelf open at the back.
All TEA2s sold in the United States are configured for operation on
a 60Hz ac power line producing between 108 and 126 volts. Export
versions of the TEA2 will have the correct operating voltage and
frequency clearly marked on the back panel of the unit, near the ac
power cord. In all cases, the actual line voltage should be within +
5/-10% of the nominal rated voltage.
Electromagnetic Interference (EMI)
Considerable care has been taken in the design of the TEA2 to
minimize its susceptibility to radio frequency interference and other
forms of EMI. Choice of materials, physical layout, grounding prac-
tice, and power supply design have all been specified with a view
to reducing the impact of electromagnetic fields on the perform-
ance of this unit. Our primary goal, however, is the accurate repro-
duction of recorded music in the normal home environment, and
we have elected not to compromise this objective by the applica-
tion of heavy-handed RFI filters. This approach has worked ex-
tremely well, resulting in few instances of EMI problems which can
be treated locally as needed, rather than compromising perform-
ance in the 99.9% of installations where EMI is not a problem.
Care in installation can often avoid EMI induced problems. The fol-
lowing practices should generally be observed in any application,
and will be especially important where EMI may be a problem.
Interconnect cables should be kept as short as possible (3 meters
or less), and shielded cable should be used (cable which has two
center conductors, and a separate external shield connected at
only one end).
Physical location and cable “dress” can be an important factor in
minimizing hum pickup. The installation should situate the TEA2
well away from the power amplifier, and power (ac mains) cords
should be dressed to remain at least 4" (100mm) away from in-
put/output cables.
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TEA2 Owner’s Manual 6
onnection and control
Connections
Input: Connect the cables from your tone-arm to these inputs.
Note that the input impedance can be adjusted from 100 Ohms to
47 kOhms via dual-inline switches mounted on the pc board.
OUTPUT: Connect to a line-level input of your preamplifier, inte-
grated amplifier, or receiver.
Controls
<power>: Move the toggle switch labeled power to the up position
to switch the phono preamplifier on. A time delay auto-muting cir-
cuit is incorporated into the TEA2 to suppress turn-on/turn-off tran-
sients. All outputs are grounded via relays for approximately 2
minutes after the unit is turned on in order to suppress warm-up
transient noises. The muting relay also grounds the outputs imme-
diately at turn-off or in the event of any power line interruption.
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TEA2 Owner’s Manual 7
Cartridge Loading
The TEA2 has provision for adjusting resistive loading on the input.
Loading is adjusted by the settings on a pair (one for each chan-
nel) of dual-inline (DIP) switchesmounted on the pc board near the
input connectors. Be sure to unplug the unit from the ac mains be-
fore removing cover to access these switches. The switches are
numbered from 1 to 4with switch 1 being the left-most (viewed
from the back). The TEA2 is delivered preset at the factory for an
input impedance of 47 kOhms.Loading can be adjusted as follows:
Cartridge Loading Settings on LOW GAIN Input
Resistive Load switch #
1 2 3 4
47 kOhms o o o o
9.6 kOhms x o o o
1.9 kOhms o x o o
500 Ohms o o x o
400 Ohms o x x o
200 Ohms o o o x
130 Ohms x x x x
x indicates switch in “on” position
o indicates switch in “off” position
note: the off position is indicated by an arrow on the body of the
switch array.
Be sure to use the same switch settings for both channels.

TEA2 Owner’s Manual 8
acuum Tube Replacement
The TEA2 circuit employs three twin-triode vacuum tubes –three
type 12AX7 (V1, V2 and V3) for the TEA2HG and two 12AX7s (V1
and V2) and one 12AU7 (V3) for the TEA2LG. The brands of tubes
we supply have been chosen by first selecting those brands which
are known to be most reliable, then by extensive auditioning of
these acceptable brands with the final choices being made solely
on the basis of sonic performance. We know of no vacuum tubes
available which will improve the sonic performance of your TEA2.
The tubes in your preamplifier have been tempered by a controlled
burn-in procedure that permits them to perform for a greatly ex-
tended period without sonic degradation, and then selected for
minimum residual noise. Replacement tubes are prepared and se-
lected in the same way. Therefore, we highly recommend that you
purchase replacement tube sets from conrad-johnson design.
We anticipate tube life to accommodate two to three years of op-
eration without degradation in normal use -if the preamplifier is
switched off when not in use. If the preamplifier is left on at all
times, tube life can be exhausted in a matter of a few months.
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TEA2 Owner’s Manual 9
etting The Most From Your TEA2
In a system of commensurate high quality components, the
conrad-johnson TEA2 offers an unparalleled level of sophistication
and refinement in music reproduction. To get the best performance
out of any audio system, there are a number of important details
that must be attended to.
Absolute Phase
Musical notes are heard through the ear’s response to waves of al-
ternating rise and fall of air pressure. Musical transients are almost
exclusively positive: that is, the initial effect is a rise in pressure.
The ear is capable of distinguishing these positive transients from
the musically unnatural alternative of a negative transient (an initial
fall in air pressure). In terms of your stereo system, these tran-
sients are created by your loudspeakers. If the speakers respond
to musical transients by first moving out, they are creating a rise in
pressure, and the system is said to be phase correct. If they re-
spond by moving in, they create a fall in pressure and the system
is said to be phase inverting. Each component in the stereo system
either preserves the phase of the incoming signal, and is said to be
phase correct, or inverts the phase and is said to be phase invert-
ing. It is unimportant whether an individual component is phase
correct or phase inverting, as long as the system as a whole is
phase correct. This will be the case if the number of phase inver-
sions is even (or zero).
The TEA2 is phase correct (non-inverting). If your system has an
odd number of inversions then you must add one phase inversion.
This is conveniently done by reversing the positive and negative
connections to your speakers (be sure to reverse both channels). If
you are not sure about the phase of every piece in your system,
you can establish correct absolute phase by careful listening.
When the system is in correct phase, transients will be noticeably
cleaner and more sharply defined. The effect is especially apparent
on plucked string sounds. A final warning -not all recordings are
phase correct (including some “audiophile” recordings), so listen to
several before concluding your investigation of absolute phase.
The Importance Of Wires
Interconnect and speaker wires are an important element in your
stereo system. Interconnects are available which will permit a ref-
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TEA2 Owner’s Manual 10
erence quality system to blossom and fulfill its promise of musical
reality. Others will strangle the system to the point where it be-
comes little better than average. To complicate matters, our ex-
perience suggests that the choice of interconnects will be system
dependent -those that are top ranked on one system may be a
poor choice for a different system. Consult your conrad-johnson
dealer for recommendations for your specific system.
Performance Tip
Warm up the TEA2 before listening: The sonic performance of the
TEA2 improves noticeably as the unit warms up. The midrange be-
comes more lucid, the highs smoother, and the soundstage ex-
pands. The warm up period can be expected to last about fifteen
minutes.
Questions: If you have questions about the installation or function
of your TEA2 do not hesitate to call Customer Service at (703)
698-8581.

TEA2 Owner’s Manual 11
pecifications
GainTEA2HG:55 dB
Gain TEA2LG:40 dB
OverloadTEA2HG: 50 mV
Overload TEA2LG: 175 mV
Hum and Noise TEA2HG:80 dB below10 mV input
Hum and Noise TEA2LG:80 dB below 10 mV input
Phase:phase correct
Output Impedance:below 200 ohms
Mechanical
Dimensions: 13.625"D x 19"W x 3.625"H
Net Weight: 14 lb net
Fuses
The TEA2 power transformer is protected by a fuse located in a
tray in the ac power inlet on the back of the chassis. To access the
fuse, first unplug the unit from the wall outlet, then remove the ac
power cord to reveal the pull out tray in the inlet. A failure of this
fuse is a symptom of a more serious problem, and a competent
service technician should be consulted. In no event should a fuse
be replaced with a value or type different than that originally sup-
plied. Correct fuse values are:
If configured for 100 or 120V:
F1 20 mm T400mA
If configured for 220 or 240V:
F1 20 mm T200mA
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