Conrad-johnson design CT5 User manual

Conrad-Johnson Owner’s Manual:
CT5 Composite-Triode Preamplifier
conrad-johnson It just sounds right.

CT5 Owner’s Manual 1
Thank you for selecting the conrad-johnson CT5 composite-triode
line stage preamplifier as the control center for your audio system.
The CT5 is a reference quality preamplifier derived from our cur-
rent flagship, the ACT2. The CT5 is capable of remarkably faithful
recreation of the dynamics, textures, tonalities, and ambience of
live musical performances. We believe that you will experience the
excitement of discovery in hearing more from your favorite re-
cordings 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.
Although the CT5 has been designed to operate in an intuitively
apparent way, you will find useful information on its installation and
operation in this manual. Please take a few minutes to read the
manual to better understand the features and capabilities of your
CT5. Note that this unit is phase inverting. See the section entitled
“Getting The Most From Your CT5" for details on correct hookup in
your system.
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
CT5, and to provide any needed service both during, and after the
warranty period. Our goal is to heighten your enjoyment of re-
corded music.

CT5 Owner’s Manual 2
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 not covered 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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CT5 Owner’s Manual 3
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

CT5 Owner’s Manual 4
nstallation
The first step in preparing your CT5 preamplifier for use is to install
the vacuum-tubes. To do this, remove the top plate of the tube
guard by removing the three socket-head screws using the sup-
plied hex-head screwdriver. The CT5 uses two type 6N30P tubes.
After checking the pin orientation, insert one tube in each tube
socket (the two tubes are interchangeable). Next, fit two of the in-
cluded silicone rubber rings over each tube, spaced at roughly 1/3
and 2/3 distances. These rings will minimize the effects of air-
borne microphonics on the tubes. Finally, reinstall the tube guard.
Set Up
To maintain proper ventilation, mount the CT5 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 CT5s 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 CT5 will have the correct operating voltage and fre-
quency 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 CT5 to
minimize its susceptibility to radio frequency interferenceand 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. At the same time, however, our primary goal is
the accurate reproduction of recorded music in the normal home
environment, and we have elected not to compromise this objec-
tive by the application of heavy-handed RFI filters, or by using
grounding practices that reduce RFI at the expense of degraded
audio performance. We find that the approach we have taken has
worked extremely well, resulting in only rare instances of EMI prob-
lems which could be treated locally as needed, rather than com-
promising the performance of our product in the 99.9% of installa-
tions where EMI is not a problem.
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CT5 Owner’s Manual 5
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 pream-
plifier well away from the power amplifier, and power (ac mains)
cords should be dressed to remain at least 4" (100mm) away from
input/output cables.

CT5 Owner’s Manual 6
onnection
SOURCES (PH/AUX1, TUNER, CD, VIDEO, AUX2): These high
level inputs are electrically equivalent. The load they present to the
source varies with the volume control setting, but in no case will it
drop below 25 kOhms. Connect the corresponding source compo-
nents to these inputs.
EPL1: This set of line-level inputs and outputs provides for connec-
tion of an external signal processor (e.g. parametric equalizer, tone
controls) or a tape recorder. Connect the EPL OUT to the input of
your signal processor or tape recorder, and the EPL IN to the out-
put of your processor or tape recorder. Alternatively, the EPL IN
connection can be used as an additional line level input.
THEATER: This is an external processor loop designed to conven-
iently accommodate the addition of a surround-sound processor
(SSP) to a high-quality two-channel system without compromising
two-channel performance. Connect the front left and front right
channel outputs from your SSP to THEATER IN. You can also con-
nect the THEATER OUT to an input on your SSP, allowing you to
do signal processing on selected two channel sources. When
THEATER is selected, the level controls are set and locked to unity
gain. Level and balance control are then accomplished via your
surround sound processor.
MAIN OUT: Two pairs of main outputs are provided. Connect to
the input of your amplifier (or crossover in a bi-amplified system).
We recommend the use of an amplifier with an input impedance of
20k ohms or higher. Since the CT5 inverts phase, it may be neces-
sary to invert the speaker leads to maintain correct absolute phase.
See the section on “Getting the most out of your CT5" for an ex-
planation.
TRIGGER OUTPUT: When the CT5 is switched on, these termi-
nals provide a constant dc voltage that can be sensed by the “trig-
ger” circuits used to switch on some power amplifiers. If your am-
plifier employs such a trigger circuit, and you wish to switch it on
and off from the preamplifier, connect these outputs to the trigger
input on your amplifier. Observe the coded polarities (“+” and “-“).
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CT5 Owner’s Manual 7
ontrols
<power>: Press the switch labeled power to switch the preampli-
fier on. A time delay auto-muting circuit is incorporated into the
CT5 to suppress turn-on/turn-off transients. All outputs are
grounded via relays for approximately 45 seconds after the unit is
turned on in order to suppress warm-up transient noises. During
auto-muting, the mute indicator led will flash. All control functions
are disabled during the auto-muting cycle. The muting relay also
grounds the outputs immediately at turn-off or in the event of any
power line interruption.
When first connected to ac mains, or after an interruption of power,
the CT5 will turn on in a default mode (after auto-muting), with the
level set at 20, and the CD input selected. In subsequent sessions,
as long as the ac mains has not suffered a power outage, the unit
will turn on at the last used volume setting and input.
<mute>: Pressing the mute button will silence the preamplifier
main outputs, and set the level display to zero on both channels.
Pressing the mute button again will restore the previously selected
level setting.
<vol up>, <vol dn>: Level setting on the CT5 is achieved by using
a programmed microprocessor to select combinations from among
an array of high-quality precision resistors. This arrangement al-
lows 100 steps of approximately .7 dB per step. The steps are
numbered 0 through 99, with 0 being silence, and 99 being maxi-
mum volume.
The level setting can be changed by pressing the vol up and vol dn
buttons on the front panel. Each time a button is pressed, the level
will move up or down one step. If a button is pressed and held, the
level control will cycle through the steps at an accelerating rate.
With each step, a slight “click” will be heard from the opening and
closing relays inside the CT5. Balance can only be set using the
remote control.
<source>: Pressing the button labeled source will cause the unit
to step through the five source inputs (ph/aux, tuner, cd, video,
aux2). The selected input will be indicated by an illuminated led.
<epl/thtr>: Pressing the epl/thtr button will cause the unit to step
from source through epl1 and theater. When source is selected,
the input selected by the source selector will be passed directly to
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CT5 Owner’s Manual 8
the volume control. When the EPL1 or THEATER inputs are se-
lected, the selected source will first pass through the external
processor loop before being routed to the volume control. When
THEATER is selected, the level will be set and locked to unity gain.
Remote Control
All operations of the CT5 can be controlled by the wireless remote
unit.
MUTE: Pressing the mute button will cause the main outputs to
mute and the level display to be zero. Pressing it again will restore
the last level setting. Pressing and holding the mute button for
more than three seconds will switchthe CT5 into standby mode (all
tube circuitry switched off). Pressing the mute button when the unit
is in standby mode will switch it back on.
SELECTORS (PH/AUX, TUNER, CD, VIDEO, AUX2): You can di-
rectly access any of these inputs by pressing the associated button
on the remote.
EPLS (EPL1, EPL2): Pressing the EPL buttons inserts the associ-
ated processor in the signal path. Pressing the button again will re-
establish a direct connection to the selected source. Pressing the
EPL2 button selects the THEATER input, setting and locking the
level to unity gain.
LEVEL (+, -): Duplicates the function of the front panel <vol up>,
<vol dn> controls.
BALANCE: Allows attenuation of either channel independently of
the other. Pressing the right balance button will reduce the left
channel level setting by one step. Pressing and holding the right
balance button will cause the left channel to cycle down through its
level settings at an accelerating rate. Pressing the left balance but-
ton will attenuate the right channel in the same manner.

CT5 Owner’s Manual 9
acuum Tube Replacement
The CT5 circuit employs two twin-triode vacuum tubes, both
6N30Ps. The triode sections in each tube are connected in parallel
to create a higher current composite triode (each channel uses one
tube). The 6N30P offers low noise, low microphonics, and gain well
suited to use in a zero-feedback line-stage. 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 CT5.
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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CT5 Owner’s Manual 10
etting The Most From Your CT5
In a system of commensurate high quality components, the
conrad-johnson CT5 offers an unparalleled level of sophistication
and refinement in music reproduction. To get the bestperformance
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 CT5 is phase inverting. If your system has an odd number of
inversions, (for example, if the CT5 is the only phase inverting unit
in the chain) then you must add one phase inversion. This is con-
veniently 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 estab-
lish 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 (in-
cluding some “audiophile” recordings), so listen to several before
concluding your investigation of absolute phase.
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CT5 Owner’s Manual 11
The Importance Of Wires
Interconnect and speaker wires are an important element in your
stereo system. Interconnects are available which will permit a ref-
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 CT5 before listening: The sonic performance of the
CT5 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 CT5 do not hesitate to call Customer Service at (703) 698-
8581.

CT5 Owner’s Manual 12
pecifications
Gain: 20 dB
Maximum Output: 10V rms
Bandpass:2Hz to more than 100kHz
Hum and Noise:100 dB below 2.5V output
Distortion at 1.0 V output: less than .1% THD or IMD
Phase:inverts phase of all inputs at main out
Ouput Impedance:800 ohms
Mechanical
Dimensions: 15.5"D x 19"W x 5"H
Net Weight: 31 lb net
Fuses
The CT5 has two power transformers (one for the tube circuitry,
one for the control circuits), each of which is protected by a fuse.
These fuses (F1 and F2) are located on the main pc board at the
back of the chassis near the transformers. There is also an ac
mains fuse (F3) located in the ac mains inlet socket on the back of
the unit. A failure of any of these fuses is a symptom of a more se-
rious problem, and a competent service technician should be con-
sulted. In no event should a fuse be replaced with a value or type
different than that originally supplied. Correct fuse values are:
If configured for 100 or 120V:
F1 3AG type 1/2 amp, fast blow
F2 3AG type 3/4 amp, slow blow
F3 5 x 20mm T800 (800 ma slow blow)
If configured for 220 or 240V:
F1 3AG type 1/4 amp, fast blow
F2 3AG type 1/2 amp, slow blow
F3 5 x 20mm T400 (400 ma slow blow)
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