Meyer Sound VX-1 - Manual (Page 2)

VX-1
Stereo
Program
Equalizer
Operating Instructions
Meyer Sound Laboratories, Inc.
2832 San Pablo Avenue
Berkeley, CA 94702
Input Connections The VX-1 accommodates nominal input levels of +4 dBu
(XLR connectors) balanced, or -10 dBV (RCA connectors)
unbalanced, selected by a rear-panel recessed switch.
The +4 dBu XLR input circuitry employs Meyer Sound’s
exclusive ISO™ Input, affording exceptional immunity from
ground loops and common-mode noise. The circuit makes
use of custom transformers employing a high-inductance
nickel core and Faraday shield, achieving 500 volts of com-
mon-mode isolation. All three input connector pins float from
both circuit ground and chassis ground.
The ISO™ input circuit accommodates a wide variety of
input wiring configurations with no change in gain. Figure 1
illustrates output polarity for various balanced and unbal-
anced connections.
Source Output
Configuration
Wiring of ISO™ Input
Pin 1 Pin 2 Pin 3
VX-1 Output Polarity
Pin 1 Pin 2 Pin 3
Balanced n/c - +
n/c + -
GND - +
GND + -
Unbalanced n/c GND +
n/c + GND
GND - +
GND + -
Figure 1. ISO™ Input Polarity Table
Connect -10 dBV unbalanced signal sources to the
rear-panel RCA connectors. These inputs bypass the
ISO™ transformer stage, and the connector shells are
tied to circuit ground.
Upon making input connections, check to be sure that
the input selector switch is set correctly.
Output Connections Signal outputs from the VX-1 are active balanced, at nominal
+4 dBu operating level. The connectors may be wired bal- anced or unbalanced, with maximum output levels
before clipping of +25 dBu or +19 dBu, respectively.
AC Power Inlet and
Voltage Selector The VX-1 is equipped with an international standard IEC 320
Mains AC inlet that accepts a variety of power cord types to
accommodate mains outlets worldwide.
The VX-1 must have the correct power cord, voltage setting
and fuse for the AC power source in your area. To avoid
electrical shock and damage, use only the cord specified by
Meyer Sound, or an equivalent that satisfies the
requirements of the local safety testing agency.
To change the AC voltage setting, first disconnect
the AC cord. Using a small flat-blade screwdriver,
move the slide switches to the appropriate position as
indicated by the adjacent panel legend.
Primary protection for the VX-1 is provided by a 1 ¦
4
A SloBlo
fuse located in a receptacle adjacent to the AC inlet. Before
examining or replacing the fuse, first disconnect the AC
cord.
AC Fuse To replace the fuse, insert a flat-blade screwdriver in
the fuse cap and gently turn counterclockwise. The
fuse will spring from its socket. Replace only with a
fuse of the type and rating specified by Meyer Sound.
Figure 2. VX-1 Rear Panel Connections (one channel shown)
+4 dBu
Balanced
Output
XLR
RCA
Output A Output B +4 dBu
-10 dBV
Input A
1 / 4
AC Voltage Ranges
210 - 250
170 - 210
105 - 125
85 - 105
A
Slo Blo
85-105
105-125
210-250
170-210
AC Voltage
85-250V
50-60Hz
20W MAX
Input
Select
+4 dBu
-10 dBV
Input B
CAUTION: Set voltage before applying power.
PUSH PUSH
+4 dBu
Balanced
Input
-10 dBV
Unbalanced
Input Mains
AC Power
Cord