Conrad-Johnson MF2100 User manual

Conrad-Johnson Owner’s Manual:
MF2100, MF2200, MF2300 Amplifiers
conrad-johnson It just sounds right.

Thank you for selecting one of the MF2000 series amplifiers (the
MF2100, MF2200, and MF2300) to power your audio system. These
amplifiers draw on two decades of research at conrad-johnson into the
reproduction of recorded music. The result is a power amplifier with a
remarkable ability to recreate the the dynamics, textures, tonalities, and
ambience of live musical performances. With your new MF2000 series
amplifier,webelievethatyouwillexperiencetheexcitementofdiscovery
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 se-
lected with a view to maintaining optimal performance over the years.
Our reputation for producing among the industry’s most reliable compo-
nents is a natural consequence of this engineering approach.
Although operation of these amplifiers is quite straightforward, please
take a few minutes to read this manual for useful information on instal-
lation and operation.
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 MF2000 series
amplifier, and to provide any needed service both during, and after the
warranty period. Our goal is to heighten your enjoyment of recorded
music.
MF2000 Series Owner’s Manual 1

Limited 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
periodofthreeyears fromthedateof purchasebytheoriginal 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
insuranceprepaidbytheowner.Afterrepair,theunit willbereturnedwith
freight and insurance prepaid by conrad-johnson design to any destina-
tion in the United States.
Allimpliedwarranties,including merchantabilityandfitnessfor aparticu-
lar 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.
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
MF2000 Series Owner’s Manual 2

United States, but 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 Service Department can also be reached 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 ob-
tainedfrom our service departmentfor a nominalcharge if you nolonger
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 your approval before commencing service.
Registering The Warranty
Please return the enclosed card to the factory within 30 days of pur-
chase to register the warranty.
MF2000 Series Owner’s Manual 3

Installation
As is the case with any high-power amplifier, the MF2000 series ampli-
fiers dissipate a significant amount of heat. Provision must be made for
adequate ventilation. Mount the unit on a flat, hard surface, taking care
that the ventilation holes in the bottom are unobstructed. Maintain at
least four inches of clearance above the unit, and at least three inches
on the sides. The cabinet or shelf should be open at both front and back.
For more restricted installations, cooling fans are essential.
All MF2000 series amplifiers sold in the United States are configured for
operation on a 60Hz ac power line producing between 108 and 126
volts. Export versions of these amplifiers 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 MF2000 series
to minimize 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 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 in-
stances 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.
Careininstallationcanoften avoidEMIinducedproblems.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).
MF2000 Series Owner’s Manual 4

Physical location and cable "dress" can be an important factor in mini-
mizing 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.
Connection
INPUT: Connect the preamplifier to your amplifier at the RCA type
connectors located on the back of the amplifier.
OUTPUT: Five way binding posts are provided for connection of your
loudspeakers, with correct spacing to accept a standard "double ba-
nana" plug. They will also accept spade lugs, bare wire, or pin connec-
tors. The two channels should be connected in correct "relative phase".
This means that when the same signal is applied to both channels, the
right and left channels speaker diaphragms will move synchronously -
in and out together.
Terminals on speakers are usually coded - one designated "C",
"ground", "-" or black, the other designated "+" or red. "In phase"
connection of the speakers can normally be achieved by taking care to
connect the wire from the "+" amplifier terminal to the red or "+" coded
terminal on each speaker, and connecting the "-" terminal to the black
or "-" coded terminal on each speaker.
In phase connection of the speakers can be readily ascertained by ear.
Listen to a recording of a solo vocalist (use a mono recording if avail-
able). With the speakers in phase the voice should be clearly focused
between the two speakers. With the speakers connected out of phase,
thevoicewillbediffused,withnoidentifiablesource.Relativephasemay
be reversed by switching the "+" and "-" leads at one speaker only.
MF2000 Series Owner’s Manual 5

Getting The Most From Your Amplifier
In a system of commensurate high quality components, these conrad-
johnson amplifiers offer a high 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 which must be attended
to.
Absolute Phase
Musical notes are heard through the ear’s response to waves of alter-
nating rise and fall of air pressure. Musical transients are almost exclu-
sively positive: that is, the initial effect is a rise in pressure. The ear is
capable of distinguishing these positive transients from the musically
unnaturalalternative ofa negativetransient (aninitial fallin 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 MF2000 amplifiers are phase correct. 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
moresharplydefined.Theeffect isespeciallyapparentonplucked 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.
MF2000 Series Owner’s Manual 6

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 spe-
cific system.
Questions: If you have questions about the installation or function of
your amplifier do not hesitate to call Customer Service at (703) 698-
8581.
MF2000 Series Owner’s Manual 7

Specifications:
Power: 240 watts per channel RMS (MF2300), 200 watts per channel
RMS (MF2200) and 100 watts per channel RMS (MF2100) both chan-
nels driven into 8 ohms from 20Hz to 20KHz at no more than 1% total
harmonic distortion or intermodulation distortion.
Sensitivity: MF2200 & MF2300 2.0 V to rated power.
MF2100 1.6 V
Phase: Phase correct (non-inverting)
Frequency response: 20Hz to 20KHz +0, -.25dB
Hum and noise: 98dB below full power output.
Input impedance: 100K ohms.
Dimensions: MF2300 16.875D x 19W x 6.75H inches
MF2200 16.875D x 19W x 5.20H inches
MF2100 13.875D x 19W x 4.31H inches
Weight: MF2300 57 lbs., MF2200 47 lbs., MF2100 28 lbs.
Fuses: There are 5 fuses in the MF2000 Series Amplifiers. One is the
ac power line (mains) fuse. It is located in a fuse holder near the power
cable. The other four fuses are in the main DC power supplies. On the
MF2200 and MF2300, these are located in fuse holders near the output
jacks, labeled B+ and B-. On the MF2100, these DC power supply fuses
are inside the chassis on the printed circuit board.Never replace a fuse
with a value or type different from that originally supplied by the
factory. Correct values and types are listed below. In the event of a fuse
blowing repeatedly, contact your dealer or the conrad-johnson service
department.
100/120 V mains (220/240 V mains) B+/B-
MF2100 5 amp, slo-blo (3 amp, slo-blo) 4 amp fast-blo
MF2200 10 amp, slo-blo (7 amp, slo-blo) 5 amp fast-blo
MF2300 10 amp, slo-blo (7 amp, slo-blo) 6 amp fast-blo
MF2000 Series Owner’s Manual 8