Conrad-Johnson ACT2 User manual

Conrad-Johnson Owner’s Manual:
ACT2 Advanced Composite-Triode Preamplifier
conrad-johnson It just sounds right.

ACT2 Owner’s Manual 1
Thank you for selecting the conrad-johnson ACT2 advanced
composite-triode line stage preamplifier as the control center for
your audio system. The ACT2 is conrad-johnson’s latest reference
preamplifier, replacing the legendary ART. The ACT2 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 recordings than ever before.
At conrad-johnson, we expect our products to be a source of
satisfaction and of pride to their owners for many years to come.
Accordingly, 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 ACT2 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
ACT2. Note that this unit is phase inverting. See the section
entitled “Getting The Most From Your ACT2" 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
product to the fullest. To this end, our staff stands ready to answer
any questions you may have about the function and application of
your ACT2, and to provide any needed service both during, and
after the warranty period. Our goal is to heighten your enjoyment of
recorded music.

ACT2 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
original purchaser, or five years from the date of shipment to the
authorized conrad-johnson dealer. During the warranty period,
conrad-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
accident.
b) Units which have been modified, altered, or improperly
repaired 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
incidental 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
packing 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
express warranty. Some states do not allow limitations on the
duration 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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ACT2 Owner’s Manual 3
Conrad-Johnson products purchased outside the United States are
covered by warranty terms of the importing distributor in the
country in which the product was originally purchased, which may
differ from the terms set out herein. Importing distributors are not
obligated 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 customer 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
obtained from our service department for a nominal charge, 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
contactyou 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

ACT2 Owner’s Manual 4
nstallation
The first step in preparing your ACT2 preamplifier for use is to
install the vacuum-tubes. To do this, remove the top plate of the
tube guard by removing the four socket screws using the supplied
hex-head screwdriver. The ACT2 uses four type 6N30P tubes.
After checking the pin orientation, insert one tube in each tube
socket. Next, fit two of the included 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.
The next step is to remove the transit screws. To minimize
microphonics, the critical audio circuits in the ACT2 are on a sub-
chassis that is mounted to the main chassis with flexible isolation
mounts. To prevent damage during shipping, this assembly is
secured by four screws through the bottom of the chassis. These
transit screws can be readily identified as the four silver screws on
white nylon washers. Before installing your ACT2, remove these
screws to release the suspension. Save the screws to re-use if it
becomes necessary to ship your ACT2.
Set Up
To maintain proper ventilation, mount the ACT2 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 ACT2s 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 ACT2 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 ACT2 to
minimize its susceptibility to radio frequency interference and other
forms of EMI. Choice of materials, physical layout, grounding
practice, and power supply design have all been specified with a
view to reducing the impact of electromagnetic fields on the
performance of this unit. At the same time, however, our primary
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ACT2 Owner’s Manual 5
goal is the accurate reproduction of recorded music in the normal
home environment, and we have elected not to compromise this
objective 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
problems which could be treated locally as needed, rather than
compromising the performance of our product in the 99.9% of
installations where EMI is not a problem.
Care in installation can often avoid EMI induced problems. The
following 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
preamplifier 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.

ACT2 Owner’s Manual 6
onnection
SOURCES (AUX/PH, 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 12 kOhms. Connect the corresponding source
components to these inputs.
EPL1: A set of line-level inputs and outputs provided for
connection of external signal processors (e.g. parametric equalizer,
tone controls). These can also be used for the connection of a tape
recorder. In this case, connect the EPL OUT to the recording input
of your tape recorder, and the EPL IN to the output of your tape
recorder. The EPL IN connection can also be used as an additional
line level input.
EPL2: This is an external processor loop designed to conveniently
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 the EPL2 input. You can also connect
the EPL2 OUT to an input on your SSP, allowing you to do matrix
processing on selected two channel sources. When EPL2 is
selected, the level controls are set to unity gain. Level and balance
control is 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 ACT2 inverts phase, it may be
necessary to invert the speaker leads to maintain correct absolute
phase. See the section on “Getting the most out of your ACT2" for
an explanation.
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ACT2 Owner’s Manual 7
ontrols
<power>: Press the switch labeled power to switch the
preamplifier on. A time delay auto-muting circuit is incorporated
into the ACT2 to eliminate transients generated by the warm-up,
and cool down cycles of the vacuum-tubes. All outputs are
grounded via relays for approximately 90 seconds after the unit is
turned on in order to suppress warm-up transient noises. During
this auto-muting period, 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 the ACT2 is turned off
(by pressing the power switch again), the standby led will be
illuminated.
When first connected to ac mains, or after an interruption of power,
the ACT2 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 ACT2 is achieved by
using a programmed microprocessor to select combinations from
among an array of high-quality precision resistors. This
arrangement allows 100 steps of approximately .7 dB per step. The
steps are numbered 0 through 99, with 0 being silence, and 99
being maximum 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 ACT2. 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.
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ACT2 Owner’s Manual 8
<epl/thtr>: Pressing the epl/thtr button will cause the unit to step
from source through epl1 and epl2(theater). When source is
selected, the input selected by the source selector will be passed
directly to the volume control. When the EPL1 or EPL2(theater)
inputs are selected, the selected source will first pass through the
external processor loop before being routed to the volume control.
When EPL2(theater) is selected, the level will be set and locked to
unity gain.
Remote Control
All operations of the ACT2 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 switch the ACT2 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
directly access any of these inputs by pressing the associated
button on the remote.
EPLS (EPL1, EPL2): Pressing the EPL buttons inserts the
associated 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 EPL2 input, setting the level
to unity gain.
LEVEL (+, -): Duplicates the function of the front panel <volu 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
button will attenuate the right channel in the same manner.

ACT2 Owner’s Manual 9
acuum Tube Replacement
The ACT2 circuit employs four vacuum tubes (V1 -V4), all
6N30Ps. 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
ACT2. The tubes in your preamplifier have been tempered by a
controlled burn-in procedure that permits them to perform for a
greatly extended period without sonic degradation, and then
selected for minimum residual noise. Replacement tubes are
prepared and selected 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
operation 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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ACT2 Owner’s Manual 10
etting The Most From Your ACT2
In a system of commensurate high quality components, the
conrad-johnson ACT2 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
alternating 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 transients 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 respond 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 inverting. 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 inversions is even (or zero).
The ACT2 is phase inverting. If your system has an odd number of
inversions, (for example, if the ACT2 is the only phase inverting
unit in the chain) 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.
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ACT2 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
reference quality system to blossom and fulfill its promise of
musical reality. Others will strangle the system to the point where it
becomes little better than average. To complicate matters, our
experience 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 ACT2 before listening: The sonic performance of the
ACT2 improves noticeably as the unit warms up. The midrange
becomes more lucid, the highs smoother, and the soundstage
expands. The warm up period can be expected to last about fifteen
minutes.
Questions: If you have questions about the installation or function
of your ACT2 do not hesitate to call Customer Service at (703)
698-8581.

ACT2 Owner’s Manual 12
pecifications
Gain: 20.5 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:500 ohms
Mechanical
Dimensions: 15.75"D x 19"W x 5.375"H
Net Weight: 30 lbs total.
Fuses
The ACT2 has two power transformers (one for the tube circuitry,
one for the control circuits), each of which is protected by a fuse. A
failure of either of these fuses is a symptom of a more serious
problem, and a competent service technician should be consulted.
In no event should these fuses be replaced with a value or type
different than that originally supplied. The fuses are located on the
input/output pc board at the back of the chassis. F1, the fuse for
the tube circuit transformer is located nearest the back panel. F2,
for the control circuitry, is located nearest the front panel. The
correct fuse values are:
If configured for 100 or 120V:
F1 1 amp, slow blow
F2 1/2 amp, slow blow
If configured for 220 or 240V:
F1 1/2 amp, slow blow
F2 1/4 amp, slow blow
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