Lexicon RV-8, Service Manual

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RV-8 Service Manual
RV-8 ANALOG BOARD THEORY
The analog board of the RV-8 encompasses all of the analog audio inputs and outputs, level controls and
A/D and D/A converters. This board is located below the RV-8 Video Board.
There are three separate signal paths: Main, Zone2 and Zone3. Each of the eight analog stereo inputs,
the tuner, the phono, or any of eight digital inputs can be routed to any of the three paths. The schematics
refer to Main, Rec, and Zone. Rec is named for Zone2 and Zone is named for Zone3 on the back panel.
Main Audio Paths
One of the eight analog stereo inputs, the tuner, or the phono can be routed to the main path and to the
A/D convertor(s). In addition, one of the eight digital inputs can be routed from the main board. The A/D
digitizes the analog signal (if selected) and passes it to the DSP on the main board. Digital signals from
the main board pass directly to the DSP.
(Refer to the Main Audio Paths 2-Channel Input block diagram
below) . The DSP creates eight different output signals from the 2-channel input. D/A converter IC's
convert each of the eight signals from the DSP to analog and then send them to their respective RCA
connectors. The outputs are also sent to the seven channels of amplification, with channels 6 and 7
having the ability to be redirected. A direct analog path is provided which passes a 2-channel analog input
signal directly to the Left and Right Front outputs via the level controls, bypassing the DSP and
converters
.
Main Audio Paths 2-Channel Input
to / from
Main Bd
Front
L/R
Level
A/D
8:1
Anlg
MUX
DAC
Front L/R
Rear L/R
Side L/R
Center/Sub
Front L/R Direct Analog Path
data
data
1
2
3
4
5
6
7
8
DAC
DAC
DAC
Phono
Preamp
Mic
Preamp
sw
sw
sw
Side
Level
A/D data
data
data
data
Mic1/2
Phono
+
Main Mux
sw
6/7 Mux
Amp
Front L/R Mux
Ctr/Sub Mux
Side L/R Mux
sw
sw
sw
sw
main clks
sw
Phono
75u
sw
Headphone
Rear Mux
Tuner
Module
sw Mic1/2
1,2
3
4,5
6,7
Tuner
sw
to
Amps
HDP pres
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
In addition, a 5.1-channel source can be selected for the Main audio path. There are two possible
methods of getting a 5.1 source into the box. Refer to the Main Audio Paths 5.1-Channel Input block
diagram on the next page)
6-4