ENCORE AMPLIFIER
OWNERS MANUAL
Serial Number
TABLE OF CON
CONTENTS
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
Encore Amplifier. Your unit has
been individually handmade from
the finest parts and materials. The
Encore utilizes proprietary Cello
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.
If you have any questions,
contact your authorized Cello
Designer or call the factory. It is
our wish to assist you in every
way, now and in the future.
1
ENCORE TRUE DUAL MONO AMPLIFIER
Product Concept and Description
CONCEPT
Cello developed the Performance
Amplifier (PA) to obtain the most natural
sound and widest dynamic range from
the finest speaker systems. The Encore
True Dual Mono Amplifier (ETDMA)
offers similar sonic qualities for music
listeners who require the ultimate in
medium power amplification.
DESCRIPTION
The ETDMA consists of two separate
mono amplifiers, each in its own chassis,
held together by a common front plate,
top plate, and rear serial number plate.
Each chassis has its own line cord and, if
separated from the other chassis, operates
as a mono amplifier. Unlike some. "dual
mono" amplifiers on the market which are
really stereo amplifiers with separate
power supplies in a single chassis, the
ETDMA offers true mono amplifier
performance in the size of a stereo unit.
The ETDMA incorporates a number of
engineering advances which allow high
performance in a compact and efficient
design, without fan cooling, providing a
practical and appealing product for
inclusion in music systems of the
finest quality.
■
Power Rating. 50 Watts into 8 Ohms.
20-20KHz with no more than 0.3% .THD
■
Gain.
28.50 dB, unbalanced source,
34.50 dB, balanced source.
■
Input Sensitivity.
752 mV
■
Input Impedance.,
330 KOhms, + Audio
5 KOhms, -Audio.
■
Fuse Type.
3AB 2.5A SB, 100V-120V.
3AB 1.5A SB, 200V-240V.
■
Dimensions.
Front Plate is 4.75" high
by 19" wide by .25" deep. Chassis 3."
high by 17.25" wide by 12" deep.
AUDIO CIRCUITRY
The heart of the ETDMA is the actual
driver board from the PA, without the
heatsink tunnels, driver transistors and
output transistors required for the highest
voltage and current (power) levels. The
ETDMA sounds like the PA because it
utilizes the same circuit board, parts, and
associated circuitry for medium power
performance. A solid copper, nickel-plated
heatsink bracket, specially designed for this
product, takes heat out of the transistors
and evacuates it into the entire chassis
including the top and bottom plates.
Balanced inputs are provided using Fischer
3-pin connectors.
Whether driven from
balanced or unbalanced outputs, the
3-wire input system offers sonic advan-
tages not to be missed by critical listeners
(see Balanced Lines, a paper by Mark
Levinson and Tom Colangelo, available
from Cello, Ltd.). The output power of
the ETDMA is rated at 50W @ 8 Ohms.
Speakers can be driven which present
loads as low as 1 Ohm. The ETDMA
circuitry is exceptionally stable and can be
operated 24 hours a day in residential and
professional applications.
POWER SUPPLY
The ETDMA utilizes a dual choke system
similar to the PA supply, but scaled down
for reduced power requirements of the
audio circuitry.
Most power amplifiers use a capacitor
input system which includes a power
transformer, bridge, and filter capacitors.
They deliver DC operating voltages to
the audio circuitry. Larger and larger
transformers are used to charge bigger
and bigger capacitors, but the peak
demands of musical signals exceed the
energy storage of the capacitors. Some
companies use active, regulated power
supplies for improved sonic quality, but it
2
ENCORE TRUE DUAL MONO AMPLIFIER
Product Concept and Description, cont.
is not practical to use this approach for
higher power amplifiers. A great deal of
money is spent on taking up space and
creating heat, without addressing AC
mains problems which affect sonic
quality.
Cello's dual choke power supply
system utilizes the entire AC waveform,
not just the peaks (like the capacitor input
system) and is very efficient so that no
cost, space, or heat is wasted (as in the
active regulator system). The high
quality, custom-made transformers and
chokes provide energy storage far beyond
the impression of their physical size. The
advantages of the dual choke input
system are quite apparent on a listening
basis, providing controlled, powerful,
deep bass and other sonic refinements.
SONIC
QUALITY
The first reaction of most listeners is,
"Flow can such a sound come from such a
compact package?" In fact, when Cello
engineers first connected the prototype of
the ETDMA for Mark Levinson to audi-
tion, he got up and checked to make sure
that it really was the ETDMA playing and
not his PA set. After auditioning the
ETDMA, one can appreciate and under-
stand the significance of the PA technol-
ogy better, since it is now available in a
power range that corresponds to what the
largest number of listeners need for their
music systems. The speed and clarity of
the ETDMA is astonishing, with no
hardness in the higher frequencies. The
sound presentation has effortless qual-
ities associated with amplifiers having
higher power ratings, yet with the sonic
refinements and transparency associated
with all Cello products.
CONSTRUCT
ION
The ETDMA utilizes bar-and-plate chassis
construction so that individual panels can
be replaced if necessary. Stainless steel
hardware, gold contacts, and many
premium parts ensure as-new sonic
performance for decades of trouble
free operation.
Most audio products use the same
family of circuits and parts, metalwork
and hardware. If you inspect Cello
products on the inside and outside, you
will find very few parts common to other
audio products on the market. Cello
products cost more because they are built
with superior circuit designs, parts, and
manufacturing techniques for those who
want higher performance, reliability,
freedom from obsolescence, and complete,
long term satisfaction.
SUMMARY
The ETDMA is a compact power amplifier
offering state-of-the-art performance and
construction in the medium power class.
Balanced line inputs, dual choke supplies,
mono construction, copper heatsinks, and
advanced engineering are combined to
offer Cello quality in an attractive and
elegant package.
3
ENCORE TRUE DUAL MONO AMPLIFIER
Instructions
UNPACKING
The packing box for the Encore Amplifier
should arrive in good condition. Please
look for damage to the carton, although
this is most unlikely due to the strength of
the carton construction. Cut and open
packing carefully and save all foam pieces
and boxes for reuse in the event that the
unit must be shipped in the future.
Should the boxes become lost, please
contact the factory for replacement
cartons.
The carton should contain:
■
Encore Amplifier
■
2 A.C. cables
■ torx wrench
INSTALLATION
Be certain that the amplifiers are installed
so that they have proper ventilation.
Placing the units in small, close-fitting
enclosures is not recommended. Room air
temperature should not exceed 122
degrees F./50 degrees C.
SELECTION OF AUDIO CABLES
Any high quality RCA cables may be used.
For balanced line connections, we strongly
suggest using Cello Strings cable made to
factory specifications. Improperly
constructed cables cause problems. It
takes equipment and experience to make
high quality balanced line terminations.
Cello Strings are available in any desired
length, with a variety of connectors, for
different system requirements.
CONNECTION
(See connection identification diagram
on page A1.)
1)
Make sure the power switches located
on the rear panel of the amplifiers
are "OFF."
2)
Verify that the amplifiers are set to the
same A.C. mains voltage as the A.C.
mains in your home or studio. (A.C.
mains voltage is labeled on the rear
panel of the amplifier.)
3)
Connect the preamplifier outputs or
other driving equipment outputs to
the amplifier inputs located on the
rear panel.
4)
Connect speaker cables to speaker
outputs on the rear panel. Be sure to
keep the spade terminal from rotating
while turning the the screw. Tighten
until there is zero play, then apply an
additional 1/8th
turn to make the
connection snug.
CAUTION: Do not over-tighten, as
you will break the terminal strip.
5)
Install the A.C. cords into the I.E.C.
mains connectors located on the
rear panel.
6)
Connect the A.C. cords to the A.C.
outlets in your home or studio.
NOTE: Do not run A.C. cords, audio
signal or speaker cables under rugs or
sharp objects where they may be damaged.
OPERATION
CAUTION: Do not operate this device if
physical damage has occurred to unit, or
if the unit has been exposed to water or
other liquids, until proper repairs and/or
unit integrity tests have been effected by
authorized personnel.
1)
Be sure all electrical connections are
correct and secure. Triple check them.
2)
Turn peripheral units on first. Avoid
switching these units on and off while
amplifier is on.
3)
Set volume control on preamplifier to
minimum.
4)
Turn amplifier switches to "ON"
position.
5)
Begin source material (turntable, tuner,
CD, etc.) and raise preamplifier volume
control to desired listening level. Enjoy!
NOTE: To remove amplifier from
system, turn down volume then turn
amplifiers "OFF" and reverse steps for
connection.
BRIDGED OPERATION
(See connection identification diagram
on page A2.)
One pair of Encore Amplifier units may
be used as a mono amplifier in bridged
mode. This provides four times the
regular power.
CAUTION: Bridged operation should
only be carried out with the recommen-
dation of the speaker manufacturer.
A bridging kit (P/N: 75-3410-00) is
required to operate Encore Amplifiers in
bridged mode. The kit may be purchased
from your Cello System Designer or
ordered directly from the factory.
4
ENCORE TRUE DUAL MONO AMPLIFIER
Instructions, cont.
The following bridged operation
instructions are for connecting one pair
of amp units (one channel).
1)
With power "OFF" connect AC cord
as instructed in Encore Amplifier
manual.
2)
Connect input to one amplifier only.
We will call this amp unit "Amp 1."
The second amp unit will be called
"Amp 2."
3)
Connect the input jumper cable,
included in the bridging kit, from the
bridging connector of
"
Amp 1
"
to the
input of
"
Amp 2.
"
Both are labeled on
the rear panel of your Encore unit.
4)
Connect one speaker's positive (+) or
high lead (usually marked in red) to
the output terminal labeled "H"
(
High) of "Amp 1."
5)
Connect the same speaker's negative
(-) or low lead (usually marked in
black) to the output terminal labeled
"H" (High) of "Amp 2."
6)
Connect the output ground jumper
cable, included in the bridging kit,
from the output terminal labeled "L"
(Low) of "Amp 1" to the output
terminal labeled "L" of "Amp 2."
This channel is now ready for
operation.
To connect for stereo, simply repeat
the procedure in steps 1-6 on the second
set of amps.
CAUTION: Make certain preamplifier
volume is turned down before AC
power of bridged amplifiers is
switched "ON."
SERVICE
Do not attempt to modify the Encore
Amplifier. Should you have any ques-
tions or problems with your Encore,
please contact Cello's Customer Service
Department and allow us to assist
you.
If your Encore requires service, this
department will provide you with a
Return Authorization (R.A.) number and
instructions on how to return your unit
to the factory. All returns to the factory
require an assigned R.A. number.
Returns received without original
packing will be shipped out in Cello
cartons at owner's expense. Replace-
ment packing materials are available
by calling the Customer Service
Department.
CELLO LIMITED WARRANTY
Parts: Five years 100% coverage for
all parts.
Labor:
Five years 100% coverage for
all labor.
Shipping: One year 100% coverage for
all shipping and insurance charges pre-
paid to and from the factory from
anywhere in the world via reasonable
carrier. (Note: Special freight or rush
shipments will incur customer charge.)
After one year, units coming into the
factory must arrive with shipping
charges pre-paid. Return shipping
charges will be paid by the factory.
Warranty of Replacement Parts from
the
factory: The remainder of the
warranty period for the unit or one year
(
whichever is longer) shall be the
warranty applied to any replacement
part(s) issued.
Warranty of Repair
Work Performed:
Any specific repairs or modifications
effected by the factory or authorized
service facility shall be guaranteed for
100% parts and labor for the remainder
of the warranty period for the unit or
one year (whichever is longer).
Transferability:
All of the above war-
ranties are transferable to any succession
of subsequent owners. Please contact
your nearest Cello Designer or the
Customer Service Department at the
factory for details of subsequent owner
warranty registration.
Tampering: Any unauthorized modifi-
cations, repairs or tampering with any
Cello product will void its warranty.
Abuse/Misuse: Any indications of
obvious owner abuse, negligence or
i
mproper usage, as determined by the
factory, shall void the warranty.
MAINTENANCE
The finish of the Encore Amplifier is of
brushed and anodized aluminum.
Ammonia-based glass cleaner or alcohol
and a soft cloth work well to restore
the shine and remove finger prints. Be
sure that the unit is off and unplugged
before cleaning. Avoid getting excess
cleaning fluid inside the amplifier. Take
care when cleaning rear panel. Do not
rub so hard as to remove the silkscreen
lettering.
5
ENCORE TRUE DUAL MONO AMPLIFIER
Physical Specifications
ENCORE AMPLIFIER
ENGLISH
METRIC
Height (chassis)
MONO
3.0 in.
STEREO
3.0 in.
MONO
7.6 cm
STEREO
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.
6
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%
4 Ohms 20V output<0.3%
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.)
7
Cello, Ltd.
315 Peck Street, Bldg. 23
New Haven, CT 06513
203 865-1237 FAX 203 624-3679
/
