23
3.6.- HEAT EMISSION
Use the table below to predict the heat emission from your ampli-
fier, which can be useful to evaluate air conditioning requirements.
They are given in BTU (British Thermal Unit) and calories.
4. OPERATION
SWITCH ON/OFF
Switch your sound system on from back to front. Thus, switch on
the amplifiers last on your sound system. Switch sound sources
(CDs, turntables) first, then your mixer, then your processors and
crossovers and finally the amplifiers. If you have more than one
amplifier, switch them on sequentially, one at a time.
Follow the reverse order when switching off, and switch off the
amplifiers before any other element on your sound system.
CLIP
LED
The red LED light should never be on continuously. This will distort
the signal and may damage the speakers. In fact, severe clipping is
an easy way of burning a speaker's voice coil. At most, the
clip
light
could be lit occasionally.
Additionally, models E-2 and E-4 feature an automatic limiting
system that impedes prolonged saturation (
clip
), therefore
protecting the speakers from one of the most common failure types.
LEVEL CONTROLS
The INPUT LEVEL rotary potentiometer is used for changing the
input gain. Although related to output power, it is not a direct
representation of it. Thus, we can have maximum output power
with the gain at mid position. Similarly, we may
have the gain controls at maximum and not
have maximum output if our source signal is not
hot enough.
One way to use the volume controls is to set
them such that when the mixer's faders are at
their maximum level, we are just below clipping
level on the amplifier or clipping very
occasionally.
INPUTS - XLR and 1/4” PHONE (commonly referred to as "jack")
Both connectors are in parallel so any of them can be used to feed
signal to an amplifier channel. Although unbalanced signals can be
used, we recommend the use of balanced connections for the
greater immunity to interfering noise. XLR is normally preferred to
1/4” phone since it has a locking mechanism that avoids accidental
disconnection.
Since they are in parallel, they can be used to feed the signal to
another amplifier. For example, one could plug into channel A's XLR
connector, and use the 1/4” ("jack") connector of the same channel
to feed another amplifier with the same signal.
The graphs that follow show the recommended connection from
different connector types. The connectors on the left hand side plug
into the sound sources such as mixers, and the connectors on the
right plug into the amplifier's input connectors. Note that
unbalanced to balanced connections have two terminals joined
together (- and ground). When using balanced to balanced
connections, try lifting ground on the input connector if hum is
present in the system.
HIGH PERFORMANCE POWER AMPLIFIERS
MODEL
CARGA
Max. POWER
1/3 POWER
1/8 POWERA
IDLE
BTU/h
Kcal/h
BTU/h
Kcal/h
BTU/h
Kcal/h
BTU/h
Kcal/h
8 + 8 ohms
485
120
500
125
395
100
155
40
4 + 4 ohms
790
200
735
185
600
150
155
40
8 + 8 ohms
865
220
815
205
645
165
315
80
4 + 4 ohms
1440
365
1370
345
1060
265
315
80
8 + 8 ohms
810
205
355
90
140
35
235
60
4 + 4 ohms
1320
330
320
80
165
40
235
60
Bridge 8 ohms
1380
350
445
110
210
55
235
60
8 + 8 ohms
1280
325
565
145
230
60
315
80
4 + 4 ohms
1600
405
420
105
150
40
315
80
Bridge 8 ohms
1795
450
510
130
185
45
315
80
8 + 8 ohms
3740
940
1995
505
1130
285
315
80
4 + 4 ohms
5815
1465
2325
585
1305
330
315
80
Bridge 8 ohms
5710
1440
2215
560
1260
320
315
80
Fig.3.7
E - 2
E - 4
E - 8
E - 12
E - 20
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