Radial Engineering space heater, Руководство пользователя

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True to the Music
Radial Engineering Ltd. Space Heater™ User Guide
4
UNDERSTANDING THE SIGNAL FLOW
FROM INPUT DB25
INPUT
DRIVE
“HEAT” SWITCH
TUBE ON
HIGH
IMPEDANCE
BUFFER
HIGH
PASS
FILTER
GAIN
150V
75V
35V
LOOP
JACKS
SEND RECEIVE
BYPASS
RELAY
OUTPUT
BUSS ON
TO OUTPUT DSUB
ODD CHANNELS TO LEFT OUT
EVEN CHANNELS TO RIGHT OUT
BUSS ODD
VIRTUAL
EARTH
MIXER
CHANNEL
PAIR ON
LINK
OUTPUT
UNBAL
TO BAL
CONVERTER
HEADPHONE
AMPLIFIER
BUSS OUT ODD
HEADPHONES
LINK
INPUT
TO EVEN BUSS
CHANNEL:
MASTER SECTION:
HOW 12AX7 TUBES WORKS
The 12AX7 is a dual-triode tube, which essentially means that it has
two tubes in one. This allows it to be wired in a 2-channel/stereo
con
fi guration, which means that the Space Heater requires only four
tubes to cover eight channels.
VOLTAGE AND DISTORTION
Tubes produce a rich, even order harmonic distortion that is warm
and pleasing to the ears. Unlike solid-state circuits that go from no
distortion to 100%, tubes distort in a more gradual fashion. Tubes
work best when provided optimal voltage, as they will have plenty
of headroom before distorting. Starving the tube with a lower
voltage causes the tube to prematurely distort. The Space Heater’s
adjustable B+ voltage (HEAT) allows you to choose how you want
to drive the circuit.
1 2 3
4
9
Grid
Cathode
Filament 1
(CH 1)
Filament 2
(CH 2)
Plate
EXPLAINING THE SIGNAL FLOW:
The routing of the Space Heater is quite complex, so it is important
to study this block diagram to understand how audio is passed. First,
signal enters the Space Heater at the channel input
(1)
. Next, the
on switch
(2)
either turns on the circuit or bypasses it completely,
routing the signal directly to the output without processing. The
Drive control
(3)
sets the level of signal entering the tube
(4)
, which
also has its own On switch
(5)
to bypass the 12AX7 as well as a
Heat switch
(6)
to modify the voltage applied. A fi xed-frequency high
pass fi lter
(7)
is next in line, before the signal passes through the
output Level control
(8)
. Finally the signal passes through an output
transformer
(9)
followed by balanced insert points
(10)
.
When the Bus switch
(11)
is engaged, signal is passed to the
master section. The Link input
(12)
and output allows the user to
patch another Space Heater in and out of the virtual earth mixer
(13)
, combining the stereo outputs of multiple units. The built-in
headphone ampli fi er
(14)
takes its signal directly from the mixer
output and is always on with a dedicated volume control. The master
bus output can be turned on and off
(15)
and is equipped with its
own volume control.
1
11
12
13
14
15
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3
4
5
7
6
8
9
10