ENCORE AMPLIFIER OWNERS MANUAL - PDF

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					ENCORE AMPLIFIER
 OWNERS MANUAL

Serial Number
                               TABLE OF
                               CONTENTS CON

Introduction ..........................................................................................1
Product Concept and Description ........................................................2
Unpacking ............................................................................................ 4
Installation ............................................................................................4
Selection of Audio Cables.................................................................... 4
Connection........................................................................................... 4
Operation ..............................................................................................4
Bridged Operation ................................................................................4
Service...................................................................................................5
Warranty...............................................................................................5
Maintenance ......................................................................................... 5
Physical Specifications ......................................................................... 6
Electrical Specifications ........................................................................ 7
Connection Identification Diagram - Stereo and Mono .....................Al
Connection Identification Diagram - Bridged Mode.........................A2
                                        ENCORE TRUE DUAL MONO AMPLIFIER




 Introduction

Congratulations on choosing the           If you have any questions,
Encore Amplifier. Your unit has         contact your authorized Cello
been individually handmade from         Designer or call the factory. It is
the finest parts and materials. The     our wish to assist you in every
Encore utilizes proprietary Cello       way, now and in the future.
circuitry that represents true state-
of-the-art in audio electronics, and
is designed to perform to "as-new"
specifications for decades of musi-
cal enjoyment.
   We want your Encore Amplifier
to provide you with complete satis-
faction. Please read this manual
carefully and care for your Encore
so that it will retain its value,
beauty, and performance.




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ENCORE TRUE DUAL MONO AMPLIFIER




Product Concept and Description

CONCEPT                                      ■   Power Rating. 50 Watts into 8 Ohms.         3-pin connectors. Whether driven from
                                                 20-20KHz with no more than 0.3% .THD        balanced or unbalanced outputs, the
Cello developed the Performance
                                             ■   Gain. 28.50 dB, unbalanced source,          3-wire input system offers sonic advan-
Amplifier (PA) to obtain the most natural
                                                 34.50 dB, balanced source.                  tages not to be missed by critical listeners
sound and widest dynamic range from
                                                                                             (see Balanced Lines, a paper by Mark
the finest speaker systems. The Encore       ■ Input Sensitivity. 752 mV
                                                                                             Levinson and Tom Colangelo, available
True Dual Mono Amplifier (ETDMA)
                                             ■ Input Impedance.,                             from Cello, Ltd.). The output power of
offers similar sonic qualities for music
                                               330 KOhms, + Audio                            the ETDMA is rated at 50W @ 8 Ohms.
listeners who require the ultimate in
                                               5 KOhms, -Audio.                              Speakers can be driven which present
medium power amplification.
                                             ■ Fuse Type. 3AB 2.5A SB, 100V-120V.            loads as low as 1 Ohm. The ETDMA
                                               3AB 1.5A SB, 200V-240V.                       circuitry is exceptionally stable and can be
DESCRIPTION
                                             ■ Dimensions. Front Plate is 4.75" high         operated 24 hours a day in residential and
The ETDMA consists of two separate                                                           professional applications.
                                               by 19" wide by .25" deep. Chassis 3."
mono amplifiers, each in its own chassis,
                                               high by 17.25" wide by 12" deep.
held together by a common front plate,                                                       POWER SUPPLY
top plate, and rear serial number plate.
                                             AUDIO CIRCUITRY                                 The ETDMA utilizes a dual choke system
Each chassis has its own line cord and, if
                                                                                             similar to the PA supply, but scaled down
separated from the other chassis, operates   The heart of the ETDMA is the actual
                                                                                             for reduced power requirements of the
as a mono amplifier. Unlike some. "dual      driver board from the PA, without the
                                                                                             audio circuitry.
mono" amplifiers on the market which are     heatsink tunnels, driver transistors and
really stereo amplifiers with separate       output transistors required for the highest        Most power amplifiers use a capacitor
power supplies in a single chassis, the      voltage and current (power) levels. The         input system which includes a power
ETDMA offers true mono amplifier             ETDMA sounds like the PA because it             transformer, bridge, and filter capacitors.
performance in the size of a stereo unit.    utilizes the same circuit board, parts, and     They deliver DC operating voltages to
The ETDMA incorporates a number of           associated circuitry for medium power           the audio circuitry. Larger and larger
engineering advances which allow high        performance. A solid copper, nickel-plated      transformers are used to charge bigger
performance in a compact and efficient       heatsink bracket, specially designed for this   and bigger capacitors, but the peak
design, without fan cooling, providing a     product, takes heat out of the transistors      demands of musical signals exceed the
practical and appealing product for          and evacuates it into the entire chassis        energy storage of the capacitors. Some
inclusion in music systems of the            including the top and bottom plates.            companies use active, regulated power
finest quality.                              Balanced inputs are provided using Fischer      supplies for improved sonic quality, but it




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                                                                      ENCORE TRUE DUAL MONO AMPLIFIER




Product Concept and Description, cont.

is not practical to use this approach for      the ETDMA for Mark Levinson to audi-         performance for decades of trouble
higher power amplifiers. A great deal of       tion, he got up and checked to make sure     free operation.
money is spent on taking up space and          that it really was the ETDMA playing and        Most audio products use the same
creating heat, without addressing AC           not his PA set. After auditioning the        family of circuits and parts, metalwork
mains problems which affect sonic              ETDMA, one can appreciate and under-         and hardware. If you inspect Cello
quality. Cello's dual choke power supply       stand the significance of the PA technol-    products on the inside and outside, you
system utilizes the entire AC waveform,        ogy better, since it is now available in a   will find very few parts common to other
not just the peaks (like the capacitor input   power range that corresponds to what the     audio products on the market. Cello
system) and is very efficient so that no       largest number of listeners need for their   products cost more because they are built
cost, space, or heat is wasted (as in the      music systems. The speed and clarity of      with superior circuit designs, parts, and
active regulator system). The high             the ETDMA is astonishing, with no            manufacturing techniques for those who
quality, custom-made transformers and          hardness in the higher frequencies. The      want higher performance, reliability,
chokes provide energy storage far beyond       sound presentation has effortless qual-      freedom from obsolescence, and complete,
the impression of their physical size. The     ities associated with amplifiers having      long term satisfaction.
advantages of the dual choke input             higher power ratings, yet with the sonic
system are quite apparent on a listening       refinements and transparency associated      SUMMARY
basis, providing controlled, powerful,         with all Cello products.
deep bass and other sonic refinements.                                                      The ETDMA is a compact power amplifier
                                                                                            offering state-of-the-art performance and
                                               CONSTRUCT ION
                                                                                            construction in the medium power class.
SONIC QUALITY                                  The ETDMA utilizes bar-and-plate chassis     Balanced line inputs, dual choke supplies,
The first reaction of most listeners is,       construction so that individual panels can   mono construction, copper heatsinks, and
"Flow can such a sound come from such a        be replaced if necessary. Stainless steel    advanced engineering are combined to
compact package?" In fact, when Cello          hardware, gold contacts, and many            offer Cello quality in an attractive and
engineers first connected the prototype of     premium parts ensure as-new sonic            elegant package.




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ENCORE TRUE DUAL MONO AMPLIFIER




Instructions

UNPACKING                                      CONNECTION                                   if the unit has been exposed to water or
The packing box for the Encore Amplifier     (See connection identification diagram         other liquids, until proper repairs and/or
should arrive in good condition. Please      on page A1.)                                   unit integrity tests have been effected by
look for damage to the carton, although                                                     authorized personnel.
                                             1) Make sure the power switches located
this is most unlikely due to the strength of    on the rear panel of the amplifiers         1) Be sure all electrical connections are
the carton construction. Cut and open           are "OFF."                                      correct and secure. Triple check them.
packing carefully and save all foam pieces                                                  2) Turn peripheral units on first. Avoid
and boxes for reuse in the event that the    2) Verify that the amplifiers are set to the
                                                same A.C. mains voltage as the A.C.             switching these units on and off while
unit must be shipped in the future.                                                             amplifier is on.
                                                mains in your home or studio. (A.C.
Should the boxes become lost, please
                                                mains voltage is labeled on the rear        3) Set volume control on preamplifier to
contact the factory for replacement
                                                panel of the amplifier.)                        minimum.
cartons.
                                             3) Connect the preamplifier outputs or         4) Turn amplifier switches to "ON"
The carton should contain:
                                                other driving equipment outputs to              position.
   ■ Encore Amplifier                           the amplifier inputs located on the         5) Begin source material (turntable, tuner,
   ■ 2 A.C. cables                              rear panel.                                     CD, etc.) and raise preamplifier volume
   ■ torx wrench                             4) Connect speaker cables to speaker               control to desired listening level. Enjoy!
                                                outputs on the rear panel. Be sure to           NOTE: To remove amplifier from
INSTALLATION                                    keep the spade terminal from rotating       system, turn down volume then turn
Be certain that the amplifiers are installed    while turning the the screw. Tighten        amplifiers "OFF" and reverse steps for
so that they have proper ventilation.           until there is zero play, then apply an     connection.
Placing the units in small, close-fitting      additional 1/8th turn to make the
enclosures is not recommended. Room air         connection snug.                            BRIDGED OPERATION
temperature should not exceed 122               CAUTION: Do not over-tighten, as            (See connection identification diagram
degrees F./50 degrees C.                        you will break the terminal strip.          on page A2.)
                                             5) Install the A.C. cords into the I.E.C.      One pair of Encore Amplifier units may
SELECTION OF AUDIO CABLES                       mains connectors located on the             be used as a mono amplifier in bridged
Any high quality RCA cables may be used.        rear panel.                                 mode. This provides four times the
For balanced line connections, we strongly 6) Connect the A.C. cords to the A.C.            regular power.
suggest using Cello Strings cable made to       outlets in your home or studio.                CAUTION: Bridged operation should
factory specifications. Improperly              NOTE: Do not run A.C. cords, audio          only be carried out with the recommen-
constructed cables cause problems. It        signal or speaker cables under rugs or         dation of the speaker manufacturer.
takes equipment and experience to make       sharp objects where they may be damaged.
high quality balanced line terminations.                                                       A bridging kit (P/N: 75-3410-00) is
Cello Strings are available in any desired                                                  required to operate Encore Amplifiers in
length, with a variety of connectors, for    OPERATION                                      bridged mode. The kit may be purchased
different system requirements.               CAUTION: Do not operate this device if         from your Cello System Designer or
                                             physical damage has occurred to unit, or       ordered directly from the factory.




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                                                                   ENCORE TRUE DUAL MONO AMPLIFIER




Instructions, cont.

   The following bridged operation          SERVICE                                      (whichever is longer) shall be the
instructions are for connecting one pair                                                 warranty applied to any replacement
                                            Do not attempt to modify the Encore
of amp units (one channel).                                                              part(s) issued.
                                            Amplifier. Should you have any ques-
1) With power "OFF" connect AC cord         tions or problems with your Encore,          Warranty of Repair Work Performed:
   as instructed in Encore Amplifier        please contact Cello's Customer Service      Any specific repairs or modifications
   manual.                                  Department and allow us to assist you.       effected by the factory or authorized
2) Connect input to one amplifier only.         If your Encore requires service, this    service facility shall be guaranteed for
   We will call this amp unit "Amp 1."      department will provide you with a           100% parts and labor for the remainder
   The second amp unit will be called       Return Authorization (R.A.) number and       of the warranty period for the unit or
   "Amp 2."                                 instructions on how to return your unit      one year (whichever is longer).
3) Connect the input jumper cable,          to the factory. All returns to the factory   Transferability: All of the above war-
   included in the bridging kit, from the   require an assigned R.A. number.             ranties are transferable to any succession
   bridging connector of " Amp 1 " to the                                                of subsequent owners. Please contact
                                               Returns received without original
   input of "Amp 2." Both are labeled on                                                 your nearest Cello Designer or the
                                            packing will be shipped out in Cello
   the rear panel of your Encore unit.      cartons at owner's expense. Replace-         Customer Service Department at the
                                            ment packing materials are available         factory for details of subsequent owner
4) Connect one speaker's positive (+) or
                                            by calling the Customer Service              warranty registration.
   high lead (usually marked in red) to
   the output terminal labeled "H"          Department.                                  Tampering: Any unauthorized modifi-
   ( High) of "Amp 1."                                                                   cations, repairs or tampering with any
                                            CELLO LIMITED WARRANTY                       Cello product will void its warranty.
5) Connect the same speaker's negative
   (-) or low lead (usually marked in       Parts: Five years 100% coverage for          Abuse/Misuse: Any indications of
   black) to the output terminal labeled    all parts.                                   obvious owner abuse, negligence or
   "H" (High) of "Amp 2."                                                                i mproper usage, as determined by the
                                            Labor: Five years 100% coverage for
                                                                                         factory, shall void the warranty.
6) Connect the output ground jumper         all labor.
   cable, included in the bridging kit,     Shipping: One year 100% coverage for
   from the output terminal labeled "L"                                                  MAINTENANCE
                                            all shipping and insurance charges pre-
   (Low) of "Amp 1" to the output           paid to and from the factory from            The finish of the Encore Amplifier is of
   terminal labeled "L" of "Amp 2."         anywhere in the world via reasonable         brushed and anodized aluminum.
                                            carrier. (Note: Special freight or rush      Ammonia-based glass cleaner or alcohol
  This channel is now ready for
                                            shipments will incur customer charge.)       and a soft cloth work well to restore
operation.
                                                                                         the shine and remove finger prints. Be
   To connect for stereo, simply repeat        After one year, units coming into the     sure that the unit is off and unplugged
the procedure in steps 1-6 on the second    factory must arrive with shipping            before cleaning. Avoid getting excess
set of amps.                                charges pre-paid. Return shipping            cleaning fluid inside the amplifier. Take
   CAUTION: Make certain preamplifier       charges will be paid by the factory.         care when cleaning rear panel. Do not
volume is turned down before AC             Warranty of Replacement Parts from           rub so hard as to remove the silkscreen
power of bridged amplifiers is              the factory: The remainder of the            lettering.
switched "ON."                              warranty period for the unit or one year




                                                                                                                                      5
    ENCORE TRUE DUAL MONO AMPLIFIER




                                  Physical Specifications

                     ENCORE AMPLIFIER

                                                       ENGLISH                          METRIC
                                                   MONO           STEREO          MONO             STEREO
                     Height (chassis)              3.0 in.        3.0 in.         7.6 cm           7.6 cm
                     Height (max.)                 4.4 in.        4.9 in.         11.1 cm          12.4 cm
                     Width (chassis)               8.5 in.        17.0 in.        21.6 cm          43.2 cm
                     Width (max.)                  9.5 in.        19.0 in.       24.2 cm           48.3 cm
                     Depth (foothold)              10.5 in.       10.5 in.       26.7 cm           26.7 cm
                     Depth (chassis)               12.0 in.       12.0 in.       30.5 cm           30.5 cm
                     Depth (max.*)                13.3 in.        13.3 in.       33.7 cm           33.7 cm



                     Box dimensions:              22.0" x 19.0" x 10.5"
                                                  55.9 cm x 48.3 cm x 26.7 cm

                     Weight: Net                  28 lbs.        12.7 kg
                                Boxed             43 lbs.        19.5 kg

                      All weights are approximate and do not include exterior cabling.
                            * Measurement from the rear of terminal strip covers to front plate.
                      Does not account for space cabling.




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                                            ENCORE TRUE DUAL MONO AMPLIFIER




           Electrical Specifications

ENCORE AMPLIFIER

Power Output
        Single Amp                                   Rated
       I MP (Ohms)                                 Watts (RMS)
             8                                         50
             4                                         100

             Bridged Set
            I MP (Ohms)                            Watts (RMS)
                  8                                    200

I MD SMPTE
   60Hz & 7kHz
   20V ouput ................................................................. 3%

THD
  20Hz - 20kHz
  8 Ohms 20V output ...............................................<0.3%
      <0.3%
  4 Ohms 20V output

Frequency Response
   20kHz.................................................................. -0 .3d B
   100kHz.................................................................-6.0dB

Channel Separation
  L-R ..................................................................... Infinite
Signal to noise
   20V output
   1kHz ................................................................. <-100dB

Input Impedance
   Non-inverting............................................... 330kOhms
   Inverting ...........................................................5kOhms

Input Sensitivity
   20V output, 8 Ohms
   50W (RMS) .......................................................... 1.485V
Gain...................................................... 28.5dB unbalanced
                                                           34.5dB balanced

NOTE: All measurements are for one mono amp unless otherwise indicated.
(All specifications subject to change without notice.)




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         Cello, Ltd.
   315 Peck Street, Bldg. 23
    New Haven, CT 06513
203 865-1237 FAX 203 624-3679