Marchand Electronics MB201 User manual

© 2000 Marchand Electronics Inc. PO Box 473, Webster, NY, 14580 www.marchandelec.com [phone] FAX: [phone]
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Marchand Electronics Inc
PO Box 473, Webster, NY 14580
Tel:[phone] Fax:[phone]
[email protected] http://www.marchandelec.com
(c)1997,2000 Marchand Electronics Inc.
MB201 200 Watt MOSFET Power Amplifier
200W + 200W into 4 Ohm
125W + 125W into 8 Ohm
Features
The MB201 is a stereo MOSFET power amplifier for high quality audio reproduction. The construction is
all heavy-duty. The amplifier is housed in an aluminum chassis. Heatsinks on the side of the unit provide
the cooling. Inside is a toroidal power transformer and power supply with large storage capacitors. The
amplifier is designed for use with a 4 or 8 Ohm load, but it is stable with any output load.
The MB201 is also available in a mono configuration.
XLR Balanced inputs Balanced inputs for high noise immunity
RCA Standard line level inputs
Selector switch Switch between balanced and standard inputs
Phase switch Inverts the phase
Binding Posts Connection for the loudspeakers
Circuit breaker Protects the amplifier in case of overload
Thermal cutout Protects the amplifier in case it gets too hot
Power entry connector Standard line cord for 120V AC 1-phase operation.

© 2000 Marchand Electronics Inc. PO Box 473, Webster, NY, 14580 www.marchandelec.com [phone] FAX: [phone]
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Specifications.
Dimensions:
Frequency response: 6 Hz - 20KHz +/- 1 dB
Harmonic Distortion @ 1KHz, 10W 0.02% or better
Voltage gain 26 dB (20X)
Input impedance: 25 KOhm
Short circuit output current 15A
Output load 8 or 4 Ohm, stable with any load
Max power output 200W+200W into 4 Ohm, 125W+125W into 8 Ohm
Power requirement 120VAC, 6A breaker; 240 VAC available
Construction All metal cabinet, black with white legend
PR41 Preamplifier MB201 Power Amplifier
Inputs Left
Right
In in in in in in out In out
Full Range
Figure 1Typical Sound System
PR41 Preamplifier MB201Power Amplifier
Inputs Left
Right
MB201Power Amplifier
Left
Right
Electronic Crossover
XM6, XM9, XM16 or XM26
In in in in in in out
in out hi out lo in out
in out
High
Low
Figure 2Sound System with Electronic Crossover Network

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Figure 3: Inside view. Note the placement of the power amplifier modules; these are mounted onto the
heatsink on the side of the unit. The PS11 power supply board is mounted on the baseplate using 4 hex
standoffs. (Note: the picture shows a different power supply than the one provided with the kit). The
toroidal power transformer is mounted near the front of the unit on the baseplate.
Figure 4Rear view of the amplifier.

© 2000 Marchand Electronics Inc. PO Box 473, Webster, NY, 14580 www.marchandelec.com [phone] FAX: [phone]
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Figure 5Inside view of the rear panel.

© 2000 Marchand Electronics Inc. PO Box 473, Webster, NY, 14580 www.marchandelec.com [phone] FAX: [phone]
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Assembly Instructions for the MB201 Kit.
Parts list.
Qu. Description
2PM124 Kit, Power Amplifier+manual
1PS11 Kit, power supply+manual
1MB201 Cabinet
base cover
front panel rear panel
2heatsinks
1500VA power transformer,
45V+45V secondary
1Transformer bracket & hardware
1DPDT AC Power switch
2XLR connector,female
2RCA connector, red & black
4DPDT slide switch
2Dual binding post w. spacer
16 A circuit breaker
1Power entry connector
1Thermal cutout
1Resistor, 10K, 2W
5’ AWG22 hookup wire, red
5’ AWG22 hookup wire, orange
5’ AWG22 hookup wire, black
1’ AWG22 hookup wire, green
5’ AWG20 hookup wire, red
5’ AWG20 hookup wire, orange
5’ AWG20 hookup wire, black
1100 Ohm, 1W resistor
2solder lug
98/32 Hex head bolt
9#8 split lock washer
86/32 x 1/4” Machine Screw
41/2” Hex Treaded Standoff
26/32 x ½” Machine Screw
26/32 lock nut
64/40 x ½” Machine Screw
64/40 lock nut
82/56 x ½” Machine Screw
82/56 lock nut
1heatsink compound
Assembly instructions.
Before assembling the MB201 amplifier
complete the assembly of the two PM124 power
amplifier boards and the PS11 power supply
board.
Rear panel: Remove the rear panel from the
cabinet before starting this assembly. Mount the
following parts to the rear panel:
4 DPDT switches using 2/56 hardware.
2 XLR connectors using 4/40 hardware.
2 RCA connectors, one red, one black.
2 Pair of binding posts
Circuit breaker
Power entry module.
Use Figure 5as a guide when wiring up above
parts according to the wiring diagrams. The
wires going to the binding posts should be
twisted. The wires going to the inputs of the
PM124 modules should be twisted together in
two pairs of three. Leave plenty of wire length
for those wires going from the rear panel to
internal components. They will be trimmed to
length later.
After the assembly is completed the rear panel
can be bolted to the rear of the chassis using
6/32 machine screws and locknuts.
Thermal cutout: Mount the thermal cutout onto
the base plate of the cabinet using 6/32
hardware.
Power Switch: Install the power switch to the
front panel. Leave the front panel off for now.
Transformer: Install the toroidal power
transformer onto the baseplate of the cabinet
near the front. Use the mounting dish and the
two rubber washers. See Figure 6
Wiring note: Use the heavy gauge wire for the
AC wiring to and from the power transformer
and for the DC power supply wiring from the
PS25. Use the smaller gauge wire for all other
interconnect.
AC Wiring: Complete the AC wiring according
to the wiring diagram. Run the wires near the
edge of the chassis closest to the thermal
cutout. Use a length of green wire and a solder
lug to install the chassis grounding wire. The
solder lug should be placed under one of the
6/32 nuts that hold the rear panel.

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PS11 Power supply: Install the power supply
next to the power transformer using four hex
treaded standoffs.
PM124 power amplifier: Before installing the
power amplifier modules complete the wiring
between the modules and the rest of the amp.
After the wiring is complete install the modules
onto the heatsink as shown in Figure 3. Use
heat sink compound between the PM124
mounting bracket and the heatsink (this is
imporatnt!). Use the 8/32 bolts with hex head for
this. Use a lock washer with each bolt. Access to
the mounting bolts is difficult. Use a long hex-
wrench for this. It will be necessary to bend the
power resistors on the PM124 modules out of
the way during this step. After completion
realign these power resistors.
Chassis Gounding. Solder the 10K, 2W
resistor to the remaining solder lug. Solder a
length of black wire to the other end of the
resistor. Install solder lug under one of the 6/32
nuts of the rear panel. Connect the wire to one
of the GROUND connections (terminal marked
G of the two position terminal block) of the
PM124 amplifier board nearest the rear panel.
This will connect the chassis of the amplifier to
the DC ground of the power supply.
!!!! Assembly is now complete. !!!!
Initial power up.
The first time power is applied observe any
unusual events, like smoke, etc. Turn the power
off immediately if this happens and check for
correct construction. It is best to power up
initially using a variable power transformer
(variac) and observe operation at about half line
voltage.
The heatsinks will become warm during normal
operation. When the amplifier is powered up but
no power is delivered the heatsink should
become just slightly warm to the touch. If the
heatsinks become hot in this mode check (and
possibly lower!) the bias current of the PM124
amplifier modules.
Figure 6: Mounting of power transformer
Metal Plate
Nut
Rubber washer
Chassis bottom
Transformer
Bolt
Rubber washer

© 2000 Marchand Electronics Inc. PO Box 473, Webster, NY, 14580 www.marchandelec.com [phone] FAX: [phone]
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MB201 Power Amplifier
Power wiring
(c) 1999 Marchand Electronics Inc.
Thermal
cutout
Circuit
breaker Toroidal
Power
Transformer
PS25
red
orange
GND
red
yellow
blue
gray
black
black
DPDT
switch
w.
light
Rear
panel
Rear Panel
Power entry
Wire to
Case
N
L
Front
panel
Power
switch
PM24
GND
GND
V+
V-
V+
V-
PM24
GND
GND
V+
V-
black
AC
CT
CT
AC
red
orange
black
black
black
Red
Yellow
Blue
Gray
Cabinet
bottom
red
black
Use heavy gauge wire for all these connections
green

© 2000 Marchand Electronics Inc. PO Box 473, Webster, NY, 14580 www.marchandelec.com [phone] FAX: [phone]
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MB201 Power Amplifier
Signal Wiring
(c) 1999 Marchand Electronics Inc.
XLR
PM24
non
GND
inv
out
GND
XLR
12
3
RCA
-
+
RCA
RED
BLK
Left Channel
Binding
Posts
Slide
Switches
XLR
PM24
non
GND
inv
out
GND
XLR
12
3
RCA
-
+
RCA
RED
BLK
Right Channel
Binding
Posts
Slide
Switches
PhaseSource
Phase
red Speaker
Speaker
red
red
red
orange
orange
orange
orange black
black
red
black
red
red
red
red red
orange
orange
orange
orange
black
black
black
Use heavy gauge wire for the speaker wires only

© 2000 Marchand Electronics Inc. PO Box 473, Webster, NY, 14580 www.marchandelec.com [phone] FAX: [phone]
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XLR Y-cable
for bridging of MB201
(c) 1999 Marchand Electronics Inc.
XLR
12
3
blue
shield
white
XLR
12
3
XLR
12
3
Female
Male
Maleblue
shield
white
1: Shield
2: Signal +
3: Signal -
Figure 7: Y cable is used for bridging of amplifier.