Page 1
OOGIE
B
M
ESA
Owner's Manual
Series 2
Page 2
Hello from the Tone Farm
...You, smart player and all around intuitive human, have put your trust in us to be
your amplifier company. This is something we do not take lightly. By purchasing and
choosing this unit to be a part of your musical voice, you have become part of the
MESA family...WELCOME! Our goal is to never let you down. Your reward is that
you are now the owner of a great amp, bred of fine all tube amp heritage...benefiting
from the many pioneering and patented MESA circuits that led to the refinement of
your new instrument. Feel confident, as we do, this amp will inspire many hours of
musical satisfaction and lasting enjoyment. It was built with you in mind, by players
who know the value of a fine musical instrument and the commitment it takes to
make great music. The same commitment to quality, value and support we make to
you...our new friend.
Page 3
Precautions
OVERVIEW 1/2
INSTANT GRATIFICATION
(2 DEMONSTRATION SETTINGS) 2
CHANNEL / MODE SELECT
CHANNEL 1: CLEAN & PUSHED 3
CHANNEL 2: RAW, VINTAGE & MODERN 3/4
CONTROLS
GAIN 4/5
TREBLE 5
MIDDLE 5/6
BASS 6
PRESENCE 6
REVERB (Rect-o-Verb Combo & Heads only) 6
MASTER 7
OUTPUT CONTROL 7
SOLO CONTROL 8
TOGGLE SWITCHES
STANDBY 8
POWER 8
REAR PANEL CONTROLS, SWITCHES & JACKS
SLAVE OUT 9
SPEAKERS 9
BIAS SELECT 9/10
FX LOOP: Send & Return 10
EXTERNAL SWITCHING 10
CHANNEL SELECT TOGGLE 11
FUSE 11
AC RECEPTACLE 11
FACTORY SAMPLE SETTINGS 12/13
PERSONAL SETTINGS SHEET 14/15
TUBE DESCRIPTION & TASK CHARTS 16
SPEAKER IMPEDANCE & POSSIBLE HOOK-UP SCHEMES: Amplifiers to Speaker Cabinets 17/22
DIAGNOSING POWER TUBE FAILURES & MAINTENANCE 23
DIAGNOSING PRE-AMP TUBE PROBLEMS 24
BIAS ADJUSTMENT: A feature article by Randall Smith 25/27
TRIODES, PENTODES & IRISHMEN: A feature article by Randall Smith 28/30
PART SHEET 31
TABLE OF CONTENTS
Series 2
Page 4
PRECAUTIONS & WARNINGS
Your MESA/Boogie Amplifier is a professional instrument. Please treat it with respect and operate it properly.
USE COMMON SENSE AND ALWAYS OBSERVE THESE PRECAUTIONS:
READ AND FOLLOW INSTRUCTIONS OF PROPER USAGE.
YOUR AMPLIFIER IS LOUD! EXPOSURE TO HIGH SOUND VOLUMES MAY CAUSE PERMANENT HEARING DAMAGE !
No user serviceable parts inside. Refer service to qualified personnel. Always unplug AC power before removing chassis.
EXPORT MODELS: Always insure that unit is wired for proper voltage. Make certain grounding conforms with local standards.
WARNING: EU: permission from the Supply Authority is needed before connection.
WARNING: Vacuum tube amplifiers generate heat. To insure proper ventilation always make
certain there is at least four inches (100mm) of space behind the rear of the amplifier cabinet.
Keep away from curtains or any flammable objects.
WARNING: Do not block any ventilation openings on the rear or top of the amplifier. Do not
impede ventilation by placing objects on top of the amplifier which extend past the rear edge of
its cabinet.
WARNING: Do not expose the amplifier to rain, moisture, dripping or splashing water. Do not
place objects filled with liquids on or nearby the amplifier.
WARNING: Always make certain proper load is connected before operating the amplifier.
Failure to do so could pose a shock hazard and may result in damage to the amplifier.
Do not expose amplifier to direct sunlight or extremely high temperatures.
Always insure that amplifier is properly grounded. Always unplug AC power cord before changing
fuse or any tubes. When replacing fuse, use only same type and rating.
Avoid direct contact with heated tubes.
Keep amplifier away from children.
Be sure to connect to an AC power supply that meets the power supply specifications listed on
the rear of the unit. Remove the power plug from the AC mains socket if the unit is to be stored
for an extended period of time. If there is any danger of lightning occurring nearby, remove the
power plug from the wall socket in advance.
To
avoid damaging your speakers and other playback equipment, turn off the power of all related
equipment before
making the connections.
Do not use excessive force in handling control buttons, switches and controls. Do not use
solvents such as benzene or paint thinner to clean the unit. Wipe off the exterior with soft cloth.
Page 5
Congratulations on your choice of the
SINGLE RECTIFIER 50 Series 2
amplifi er. You have purchased a handbuilt instrument of
the fi nest quality and craftsmanship. A unique blend of yesteryears’ black magic power section design combined with our race-shop
approach to fi nely tuned, high gain pre-amp circuitry leaves the
RECT-O 50
Series 2
standing alone...instantly a classic destined
for vintage status. With two channels housing fi ve defi nitive and distinctly different Modes, a complete array of amazing guitar sounds
can be obtained quickly and easily.
Series 2
Operating Instructions
FRONT PANEL HEAD VERSION: SOLO 50 HEAD SERIES 2
Instant Gratification Demo Settings
INPUT
CLEAN
PUSHED
MODERN
RA
W
POWER
ON
ON
STANDBY
GAIN
TREBLEMIDPRESENCE BASSMASTER
SOLO OUTPUT
CH2
CH1
REAR PANEL HEAD VERSION: SOLO 50 HEAD SERIES 2
10%
FX MIX
RETURN
SEND
WARNING:
Unplug power
before replacing
fuse or removing
bolts mounting
F
U
S
E
F
U
S
E
POWER FUSE
2.5 A
SLO
BLO
120 V~
50-60 Hz
2.5 A
FRONT PANEL COMBO VERSION: RECT-O-VERB 50 SERIES 2
INPUT
POWERSTANDBY
ON
ON
GAIN
MASTER
PRESENCEBASSTREBLE MID
OUTPUT
CLEAN
PUSHED
MODERN
RA
W
CH2
CH1
REAR PANEL COMBO VERSION: RECT-O-VERB 50 SERIES 2
CHANNEL SOLO REVERB
WARNING:
Unplug power
before replacing
fuse or removing
bolts mounting
F
U
S
E
F
U
S
E
POWER FUSE
2.5 A
SLO
BLO
120 V~
50-60 Hz
2.5 A
EXTERNAL SWITCHING
WARNING:
To reduce risk of fire or
electric
shock, replace fuse with
sam
e type and rating only. Do not
CAUTION:
To reduce risk of fire or electric
shock,
do not remove cover. No
user-serviceable parts
inside. Refer
V
I
N
T
A
G
E
V
I
N
T
A
G
E
SOLO
FUSE
CHANNEL 1
CHANNEL 2
SET TO CHANNEL 1
TO
USE FOOTSWITCH
FOOTSWITCH
SOCKET
BELOW
SEND RETURN FX MIX
PARALLEL EFFECTS LOOP
10%
90
%
ALL TUBE AMPLIFIER HANDMADE IN PETALUMA, CALIF USA
8 OHM
4 OHM
4 OHM
SPEAKERS
OUT
SLAVE
(USE WITH TWO 8 OHM SPKRS)
(COMBO) (TO EXT. PWR AMP)
SINGLE RECTIFIER SERIES 2 RECTOVERB
CAUTION
SWITCH MUST MATCH
TUBES IN USE
6L6
BIAS SWITCH
EL34
FUSE
CHANNEL
1
CHANNEL
2
SET TO CHANNEL 1
TO USE FOOTSWITCH
PATENTED 4,211,000 & OTHERS PENDING FOR SOLO, MUTE & LOOP CONFIGURATION
PAT
ENTED 4,211,000 & OTHERS PENDING FOR SOLO, MUTE & LOOP CONFIGURATION
FOOT
SWITCH
SOLO CHANNEL
EXT. SWITCHING
4 OHM
4 OHM
8 OHM
SPEAKERS
WARNING
:
To reduce risk of fire or
electric
shock, replace fuse with
same
type and rating only. Do not
CAUTION
:
To reduce risk of fire or electric
shock,
do not remove cover. No
user-serviceable
parts inside. Refer
FX LOOP
90
%
CAUTION
SWITCH MUST MATCH
TUBES IN USE
EL34
BIAS SWITCH
6L6
ALL TUBE AMPLIFIER HANDMADE IN PETALUMA, CALIF USA
SINGLE RECTIFIER SERIES 2 SOLO HEAD
OUT
SLA
VE
(TO EXT. PWR AMP)
REVERB
OVERVIEW:
Page 6
FRONT PANEL:
RECT-O-VERB Series 2
POWER UP:
First remove the protective covers from the tubes (plastic webbing) before connecting the A.C. cord
Connect your favorite guitar to the instrument INPUT jack. Flip the POWER switch to the ON position while
RECT-O 50’s
want to hear.
INSTANT GRATIFICATION: Demo Setting #2
INPUT
CLEAN
PUSHED
MODERN
RAW
POWER
ON
ON
STANDBY
GAIN
TREBLEMIDPRESENCE BASSMASTER
SOLO OUTPUT
CH2
CH1
V
I
N
T
A
G
E
WARNING:
Unplug power
before replacing
fuse or removing
bolts mounting
chassis.
F
U
S
E
F
U
S
E
POWER FUSE
2.5 A
SLO
BLO
120 V~
50-60 Hz
2.5 A
FUSE
CHANNEL
1
CHANNEL
2
SET TO CHANNEL 1
TO USE FOOTSWITC
H
FOOTSWITCH
SOCKET
BELOW
PATENTED 4,211,000 & OTHERS PENDING FOR SOLO, MUTE & LOOP CONFIGURATION
RECT-O-VERB COMBO Series 2
WARNING:
Unplug power
before replacing
fuse or removing
bolts mounting
chassis.
F
U
S
E
F
U
S
E
POWER FUSE
2.5 A
SLO
BLO
120 V~
50-60 Hz
2.5 A
FUSE
CHANNEL
1
CHANNEL
2
SET TO CHANNEL 1
TO USE FOOTSWITC
H
PATENTED 4,211,000 & OTHERS PENDING FOR SOLO, MUTE & LOOP CONFIGURATION
FOOT
SWITCH
SOLO 50 HEAD Series 2
INSTANT GRATIFICATION: Demo Setting #1
INPUT
CLEAN
PUSHED
MODERN
RAW
POWER
ON
ON
STANDBY
GAIN
TREBLEMIDPRESENCE BASSMASTER
SOLO OUTPUT
CH2
CH1
V
I
N
T
A
G
E
Page 7
This is the lowest gain circuit of the
RECT-OS’
fi ve modes and is optimized for producing balanced
This mode is a radical departure from the sweet shimmering blend of the CLEAN modes low gain character. Huge increases
RECT-O
RECT-OS’
coolest overdrive solo sounds.
This new
RECT-O
mode has the lowest gain of the three in the high gain lead channel. Its’ less saturated nature greatly en-
for certain
offers, as
This high gain mode is the famous liquid
RECT-O
voice and it can be found in its original state
RECT-OS’
magic 50 watt
modes musical and natural tube compression. Spend time learning the lower regions of the
is set in its lower range and RAW is set in its medium to higher range and yet each possesses a character that is
CHANNEL / MODE SELECT:
INPUT
HEAD VERSION
CLEAN
PUSHED
MODERN
RAW
HEAD VERSION
V
I
N
T
A
G
E
INPUT
Page 8
MODERN:
Aggressive. This is the word that best describes the menacing power of the
RECT-OS’
most rebellious of all modes.
This control adjusts the predominant gain stage in each channels’ circuit with the function and taper being optimized for
RECT-O 50
is really two separate multi-mode amplifi ers built onto one chassis, so
Control for each channel comes in a different place and adjusts a different point in
Control is the most powerful
RECT-O 50
Controls’ role in shaping the overall tone of the sound we will look at it in two
alone and
in conjunction with the tone controls.
enhances the saturation and replaces some of the upper harmonics with a richer, warmer quality and a fuller
RECT-OS’
best sounds...especially for soloing due to the crucial blend of an expressive attack combined with
saturates the signal and enhances low and low mid frequencies. While this region provides the maximum satu-
Control sparingly and only when maximum sustain is needed.
RECT-OS’
extreme gain potential, the highest regions of the
RECT-O 50
CHANNEL / MODE SELECT: (Continued)
CONTROLS:
HEAD VERSION
GAIN
INPUT
CLEAN
PUSHED
MODERN
RAW
V
I
N
T
A
G
E
GAIN:
Page 9
Basically, a simple rule applies...as the Gain is increased the Tone control string
Control in its middle region. Here the Tone control string is very active and provides
TREBLE:
As in most tube guitar amplifi ers, the
Control ( in both channels of your
RECT-O 50
RECT-O 50,
there is an optimum region of the
Control where ample top end is mixed in
Control above this median
RECT-O 50
Control
The
Control is responsible for the blend of midrange frequencies in the mix and though its effect is not as dramatic as
RECT-O 50
Control settings ( 7:00 - 11:00 ) where a scoop in
feel to the strings and therefore less apparent resistance to the pick. As the
Control settings ( 2:00 - 5:00 ) can introduce added gain and create enhanced
CONTROLS:
(Continued)
HEAD VERSION
TREBLE
GAIN
HEAD VERSION
MID
TREBLE
MID:
Page 10
Control is swept past 1:00, it quickly starts to add gain in these midrange frequencies adding cut and punch.
capable of taking both CLEAN and
Control a little more tricky to learn at fi rst,
BASS:
Last, but not least in the string of tone controls we come to the
. This control works similarly in both channels in that it
it mixes in changes
the TREBLE Control and the same scheme applies.
The
Control is a high frequency attentuator that is placed at the end of each channels pre-amp stage
Control settings darken and, in fact compress the signal
RECT-O
Control in its lower regions, where a balanced, vocal response is achieved.
RECT-O
and this can be great for sparkling clean sounds
is truly amazing in this most agro mode.
These self explanatory controls deliver the rich natural reverb sound. Although
available is not. In Channel 2 there is slightly less
available overall because of this channels’ very nature.
that it is easier to prevent the massive amount of Gain and signal strength present in either of
oscillations.
This channels aggressive nature lends itself more to musical styles where high settings of
are simply not traditional. Don’t worry...there is still plenty of
for drenched solo
Control a little
CONTROLS:
(Continued)
HEAD VERSION
MID
BASS
HEAD VERSION
PRESENCE
BASS
REVERB
MAST
ENCE
PRESENCE:
REVERB: RECT-O-VERB / COMBO & HEAD
Page 11
MASTER:
This control is the master feed from the end of the pre-amp to the driver stage and the Effects Loop. As you can
Control, enabling the two channels relative volumes to be matched regardless of
Control makes possible a wide range of sounds through
sounds at high volumes and conversely, high
sounds at low volumes
Control in its
ranges ( 9:00 - 2:00 ). Here, the channels will
Control creates the send to the Effects Loop, extreme settings will cause
This control determines the overall output volume level of the amplifi er. After the GAIN Controls have been set for the
Control
RECT-O 50
Control will serve as the master level control.
RECT-O
Control and therefore also controls the volume of the power section.
50
RECT-O
The OUTPUT Level will be the only active control on the Front Panel (the PRESENCE Control of Channel 1 will be active only
Channel 2’s MODERN mode - as part of its voicing - utilizes substantially less negative feedback in the power stage creating a
RECT-O
as a power amp. The more conventional power
CONTROLS:
(Continued)
HEAD VERSION
PRESENCE
MASTER
SOLO OUTPUT
HEAD VERSION
OUTPUT:
Page 12
SOLO:
This control can only be activated if the correct Footswitch is connected
to the Footswitch DIN jack.
is an
Perfect for set breaks... this toggle switch also serves an even more important purpose. In the Standby position the
switch is in the Standby position.
switch to the ON position. This prevents
This switch delivers the A.C. power to the
RECT-O 50.
Make sure the unit is grounded (all three terminals of the A.C.
RECT-O 50.
CONTROLS:
(Continued)
SOLO OUTPUT
HEAD VERSION
POWER
ON
ON
STANDBY
HEAD VERSION
POWER
ON
ON
STANDBY
HEAD VERSION
STANDBY:
POWER:
Page 13
SLAVE OUT:
This 1/4” jack provides a signal derived from the speaker jack. Perfect for using the
RECT-O 50
jack or a feedback loop will occur. Much like holding a microphone into the PA system’s cabinets...a
Sensitivity to speaker mismatching in regards to ohmage differences is low, hence no damage to the amplifi er will
RECT-O 50
Your
RECT-O 50
RECT-O 50 Series 2
REAR PANEL:
REAR VIEW - HEAD VERSION
10%
FX MIX
RETURN
SEND
WARNING:
Unplug power
before replacing
fuse or removing
bolts mounting
chassis.
F
U
S
E
F
U
S
E
POWER FUSE
2.5 A
SLO
BLO
120 V~
50-60 Hz
2.5 A
FUSE
CHANNEL
1
CHANNEL
2
SET TO CHANNEL 1
TO USE FOOTSWITC
H
PATENTED 4,211,000 & OTHERS PENDING FOR SOLO, MUTE & LOOP CONFIGURATION
FOOT
SWITCH
SOLO CHANNEL
EXT. SWITCHING
4 OHM
4 OHM
8 OHM
SPEAKERS
WARNING
:
To reduce risk of fire or
electric shock, replace fuse with
same type and rating only. Do not
expose this unit to rain or moisture.
CAUTION
:
To reduce risk of fire or electric
shock, do not remove cover. No userserviceable parts inside. Refer
servicing to qualified personnel.
FX LOOP
90
%
CAUTION
SWITCH MUST MATCH
TUBES IN USE
EL34
BIAS SWITCH
6L6
ALL TUBE AMPLIFIER HANDMADE IN PETALUMA, CALIF USA
SINGLE RECTIFIER SERIES 2 SOLO HEAD
OUT
SLAVE
(TO EXT. PWR AMP)
4 OHM
4 O
SPE
ALL TUBE AMPLIFIER HANDMADE IN PETA
SINGLE RECTIFIER SERIES 2
OUT
SLAVE
(TO EXT. PWR AMP)
HEAD VERSION
4 OHM
4 OHM
8 OHM
SPEAKERS
ALL TUBE AMPLIFIER HANDMADE IN PETALUMA, CALIF USA
SINGLE RECTIFIER SERIES 2 SOLO HEAD
OUT
SLAVE
(TO EXT. PWR AMP)
CAUTION
SWITCH MUST MATCH
TUBES IN USE
EL34
BIAS SWITCH
6L6
SPEAKERS:
BIAS SELECT:
Page 14
chording or soloing, to an all out high gain crunch or lead sound. Players that use mostly these
RECT-O 50
amplifi ers. If you need a variety
In our many tests and continued use of the currently available EL34 type power tubes on
RECT-O 50
Failure to
These two 1/4” jacks are the patch point for external signal processing effects. The
in the
RECT-O 50
RECT-O 50
for your processors, simply connect the Effects Loop
jack to your fi rst effects’ Input
jack. Connect your last effects Output jack to the Effects Loop
jack.
Control to blend in the desired amount of the processed signal with the original
Control at the lower end of the control. In this manner the least
interrupts the signal between the pre-amp
jack can double as a power amp input jack. You will also want to run the
Control at
as a Power In patch point. Connect your last effects’ Output jack to the Effects
jack. We
RECT-O 50’s
RECT-O 50
These jacks allow ( usually MIDI-programmed ) operation of your amplifi er’s functions from an external
10%
FX MIX
RETURN
SEND
WARNING
:
To reduce risk of fire or
electric shock, replace fuse with
same type and rating only. Do not
expose this unit to rain or moisture.
FX LOOP
90
%
SOLO CHANNEL
EXT. SWITCHING
CAUTION:
To reduce risk of fire or electric
shock, do not remove cover. No userserviceable parts inside. Refer
servicing to qualified personnel.
REAR PANEL: (Continued)
BIAS SELECT: (Continued)
EFFECTS LOOP: SEND, RETURN & MIX
EXTERNAL SWITCHING:
Page 15
This switch simply allows you to switch between the two channels (CHANNEL 1 and CHANNEL 2) without
This is the A.C.’s (Alternating Current) main fuse and provides protection from outside A .C. fl uctuations as well as power
blow, replace it with the same rating in a Slo-Blo type package. The domestic U.S. version
The total power consumption for the
RECT-O 50
MESA/Boogie
Pro Center.
CHANNEL 1
CHANNEL 2
SET TO CHANNEL 1
TO USE FOOTSWITCH
HEAD VERSION
WARNING:
Unplug power
before replacing
fuse or removing
bolts mounting
chassis.
F
U
S
E
F
U
S
E
POWER FUSE
2.5 A
SLO
BLO
120 V~
50-60 Hz
2.5 A
FUSE
PATENTED 4,211,000 & OTHERS PENDING FOR SOLO, MUTE & LOOP CONFIGURATION
WARNING:
Unplug power
before replacing
fuse or removing
bolts
mounting
chassis.
POWER FUSE
2.5 A
SLO
BLO
120 V~
50-60 Hz
2.5 A
HEAD VERSION
REAR PANEL: (Continued)
CHANNEL SELECT:
FUSE:
A.C. RECEPTACLE:
Page 16
FACTORY SAMPLE SETTINGS
HEAD VERSION SHOWN
MASTER
GAIN
TREBLEMIDPRESENCE BASS
SOLO
OUTPUT
MASTER
GAIN
TREBLE
MIDPRESENCE BASS
SOLO
OUTPUT
MASTER
GAIN
TREBLEMIDPRESENCE BASS
SOLO
OUTPUT
GAIN
TREBLEMIDPRESENCE BASS
SOLO
OUTPUT
MASTER
CH2
CH1
CH2
CH1
CH2
CH1
CH2
CH1
SAMPLE 1
Sparkling Clean
SAMPLE 2
Pushed Bluesy Rhythm / Solo: Both Channels
SAMPLE 3
Blues Lead: Both Channels
SAMPLE 4
High Gain Lead / Crunch: Both Channels
INPUT
CLEAN
PUSHED
MODER
N
RA
W
V
I
N
T
A
G
E
INPUT
CLEAN
PUSHED
MODER
N
RA
W
V
I
N
T
A
G
E
INPUT
CLEAN
PUSHED
MODER
N
RAW
V
I
N
T
A
G
E
INPUT
CLEAN
PUSHE
D
MODER
N
RA
W
V
I
N
T
A
G
E
FACTORY SAMPLE SETTINGS
HEAD VERSION SHOWN
Page 17
MASTER
GAIN
TREBLE
MID
PRESENCE
BASS
OUTPUT
MASTER
GAIN
TREBLE
MID
PRESENCE
BASS
OUTPUT
PRESENCEBASS
MID
TREBLE
GAIN
MASTER
CH2
CH1
CH2
CH1
BASS
GAIN
MASTER
PRESENCE
TREBLE
OUTPUT
CH2
CH1
MID
OUTPUT
CH2
CH1
FACTORY SAMPLE SETTINGS
COMBO VERSION SHOWN
SAMPLE 1
Sparkling Clean
SAMPLE 2
Pushed Bluesy Rhythm / Solo: Both Channels
SAMPLE 3
Blues Lead: Both Channels
SAMPLE 4
High Gain Lead / Crunch: Both Channels
INPUT
CLEAN
PUSHED
MODERN
RAW
V
I
N
T
A
G
E
INPUT
CLEAN
PUSHED
MODERN
RAW
V
I
N
T
A
G
E
INPUT
CLEAN
PUSHED
MODERN
RAW
V
I
N
T
A
G
E
INPUT
CLEAN
PUSHED
MODERN
RAW
V
I
N
T
A
G
E
Page 18
SOUND 1
SOUND 2
SOUND 3
SOUND 4
PERSONAL SETTINGS PAGE
HEAD VERSION SHOWN
MASTER
GAIN
TREBLEMIDPRESENCE BASS
INPUT
CLEAN
PUSHED
MODERN
RAW
SOLO
OUTPUT
CH2
CH1
V
I
N
T
A
G
E
MASTER
GAIN
TREBLE
MIDPRESENCE BASS
INPUT
CLEAN
PUSHED
MODERN
RAW
SOLO
OUTPUT
CH2
CH1
V
I
N
T
A
G
E
MASTER
GAIN
TREBLE
MIDPRESENCE BASS
INPUT
CLEAN
PUSHED
MODERN
RAW
SOLO
OUTPUT
CH2
CH1
V
I
N
T
A
G
E
MASTER
GAIN
TREBLE
MIDPRESENCE BASS
INPUT
CLEAN
PUSHED
MODERN
RAW
SOLO
OUTPUT
CH2
CH1
V
I
N
T
A
G
E
Page 19
SOUND 1
SOUND 2
SOUND 3
SOUND 4
PERSONAL SETTINGS PAGE
COMBO VERSION SHOWN
GAIN
MASTER
PRESENCEBASSTREBLE MID
CH2
CH1
INPUT
CLEAN
PUSHED
MODERN
RAW
OUTPUT
V
I
N
T
A
G
E
SOLO
GAIN
MASTER
PRESENCEBASSTREBLE MID
CH2
CH1
INPUT
CLEAN
PUSHED
MODERN
RAW
OUTPUT
V
I
N
T
A
G
E
SOLO
GAIN
MASTER
PRESENCEBASSTREBLE MID
CH2
CH1
INPUT
CLEAN
PUSHED
MODERN
RAW
OUTPUT
V
I
N
T
A
G
E
SOLO
GAIN
MASTER
PRESENCEBASSTREBLE MID
CH2
CH1
INPUT
CLEAN
PUSHED
MODERN
RAW
OUTPUT
V
I
N
T
A
G
E
SOLO
Page 20
RECT-O-VERB / SOLO 50
6L6
6L6
PARTIAL VIEW OF
LARGE TRANSFORMER
12AX7
REAR OF CHASSIS
(HEAD VERSION)
NOTE: POWER TUBES ARE HOT ! BEFORE CHANGING
TUBES TURN POWER SWITCH TO OFF AND LET COOL
OR USE A RAG FOR PROTECTION.
TUBE TASK CHART
Description of Tube Functions
V1A= Input Stage
V1B= 2nd Stage (Rh
ythm & Lead)
V2A=3rdStage Rhythm
V2B= 3rd Stage Lead
V3A= 4th Stage Lead
V3B= 5th Stage Lead
V5
V4
V3
V2
V1
A B A B A B A BA B
V4A= FX Send
V4B=FX Return
V5=A
V5=B
Phase Inverter
Page 21
SPEAKER IMPEDANCE MATCHING & HOOK-UP GUIDE:
Wiring up speakers to provide the most effective load and making sure that all of them are in phase will help in
MESA/Boogie
amplifi ers can handle 4 and 8 ohms effectively. Never run below 4 ohms in a tube amplifi er unless you are absolutely
MESA’S Bass 400+
). You can always have a higher resistance ( 16 ohms, for
When running a higher resistance ( for example: 8 ohm output into 16 ohm cabinet ), a slightly different feel and
When you wire ( hook-up ) speakers in Series, the speakers resistance ( as measured in ohms ) is additive - i.e. put-
Speaker A = 8 Ohms
Speaker B = 8 Ohms
SERIES:
Connect the Negative side of Speaker A
to the Positive side of Speaker B
POSITIVE =
NEGATIVE
=
B
L
A
C
K
S
H
A
D
O
W
B
L
A
C
K
S
H
A
D
O
W
IMPEDANCE:
MIS-MATCHING:
WHAT IS MY CABINETS IMPEDANCE:
SERIES:
Page 22
SPEAKER IMPEDANCE MATCHING & HOOK-UP GUIDE: (Continued)
When wiring in parallel, the resistance of the speakers decreases. Two 8 ohm speakers wired in ( hooked-up )
This is really just two sets of Series wired speakers connected in Parallel. This is
POSITIVE
Speaker
A
8 Ohms
Speaker
B
8 Ohms
NEGATIVE
Total Load = 4 Ohms
B
L
A
C
K
S
H
A
D
O
W
B
L
A
C
K
S
H
A
D
O
W
SPEAKER A
SPEAKER B
SPEAKER C
SPEAKER
D
NEGATIVE
All 4 Spkrs. are 8 Ohms
POSITIVE
B
L
A
C
K
S
H
A
D
O
W
B
L
A
C
K
S
H
A
D
O
W
B
L
A
C
K
S
H
A
D
O
W
B
L
A
C
K
S
H
A
D
O
W
PARALLEL:
COMBINATION OF SERIES & PARALLEL:
Page 23
1
2
5
4
4 Ohm Cabinet
3
8 OHM 4 OHM 4 OHM
Partial back view of
some Mesa amp
8 Ohm Cabinet
SAFE MISMATCH
WIRING SCHEMES...Amplifier to Speaker Cabinets
4 OHM 8 OHM 16 OHM
Partial back view of amplifier
16 Ohm Cabinet
4 OHM 8 OHM 16 OHM
Partial back view of amplifier
16 Ohm Cabinet
SAFE MISMATCH
8 OHM 4 OHM 4 OHM
Partial back view of amplifier
8 OHM 4 OHM 4 OHM
Partial back view of amplifier
8 Ohm Cabinet
4 Ohm Cabinet
8 Ohm Cabinet
Page 24
8 OHM 4 OHM 4 OHM
Partial back view of amplifier
8 Ohm Cabinet
8 Ohm Cabinet
6
8 Ohm Cabinet
16 Ohm Cabinet
8
4 OHM 4 OHM 8 OHM
Partial back view of amplifier
SAFE MISMATCH
8 OHM
Partial back view of amplifier
SERIES BOX
8 Ohm
4 Ohm
4 Ohm
4 Ohm Cabinet
4 Ohm Cabinet
4 OHM 4 OHM
8 OHM
Partial back view of amplifier
PARALLEL BOX
8 Ohm
16 Ohm
16 Ohm
16 Ohm Cabinet
16 Ohm Cabinet
9
4 OHM 4 OHM
7
WIRING SCHEMES...Amplifier to Speaker Cabinets
CORRECT MATCH
CORRECT
MATCH
CORRECT
MATCH
Page 25
4 OHM 4 OHM 8 OHM
Partial back view of amplifier
8 Ohm Cabinet
8 Ohm Cabinet
SERIES BOX
16 Ohm
8 Ohm
8 Ohm
8 Ohm Cabinet
10
SAFE MISMATCH
12
4 OHM 4 OHM
Partial back view of amplifier
16 Ohm Cabinet
16 Ohm Cabinet
11
8 OHM
8 Ohm Cabinet
16 Ohm Cabinet
16 Ohm Cabinet
4 OHM4 OHM8 OHM
Partial back view of amp
PARALLEL BOX
8 Ohm
16 Ohm
16 Ohm
WIRING SCHEMES...Amplifier to Speaker Cabinets
CORRECT MATCH
SAFE MISMATCH
Page 26
4 OHM 4 OHM 8 OHM
Partial back view of amplifier
8 Ohm Cabinet
8 Ohm Cabinet
SERIES BOX
16 Ohm
8 Ohm
8 Ohm
16 Ohm Cabinet
13
SAFE MISMATCH
WIRING SCHEMES...Amplifier to Speaker Cabinets
4 OHM4 OHM8 OHM
Partial back view of amplifier
16 Ohm Cabinet
16 Ohm Cabinet
PARALLEL BOX
8 Ohm
16 Ohm
16 Ohm
16 Ohm Cabinet
SAFE MISMATCH
14
Page 27
TUBE NOISE & MICROPHONICS:
You may occasionally experience some form of tube noise or microphonics. Certainly no cause
If they are hot and you
There are two main types of tube faults: shorts and noise. Both large and small tubes
Often caused by contamination within in a tube, the culprit can usually be identifi ed, and by lightly tapping on the glass,
Road King
on Standby, remove it from its socket and turn it back
Road King
briefl y with one power tube missing. You may notice a slight background hum,
DIAGNOSING POWER TUBE FAILURE:
TUBE NOISE:
Page 28
DIAGNOSING PRE-AMP TUBE PROBLEMS:
Because your amplifi er is an all tube design, it is quite possible that you will at some
Page 29
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
( )
( )
( )
,
( , )
( )
PLATE
Structure of a 6L6 / 5881
Beam Power Pentode.
BEAMCONFINING
ELECTRODE
SCREEN
GRID
GRID
CATHODE
BIAS ADJUSTMENT: (Part of a continuing series)
Mesa
put bias adjustments
MESA/Boogies
Boogies
don’t have bias adjusters are primarily in the business of selling tubes - not amps. They don’t want to throw away 30 percent
MESA
tolerance tubes.
— which is quicker) what you are doing is establishing the correct amount of idle CURRENT that fl ows through the power tubes.
Page 30
BIAS ADJUSTMENT: (Continued)
control grids.
Page 31
BIAS ADJUSTMENT: (Continued)
Again, this has some merit .. but it’s still not as good as using tubes that are matched in the fi rst
— come together to give the best sonic performance, consistently and reliably. Every part and voltage is important — yet no one
circuitry where there are two different bias voltages used for separate pairs of power tubes ...
MESA
tubes into one of our amps and you’re ready for tone. Guar-
MESA/Boogie
players you couldn’t estimate.
MESA/Boogie
Pro Center or from us directly. Nobody
Boogies
only please! Until then, Relax, Breathe and Nourish your soul!
MESA/Boogie Ltd.
Page 32
ON TRIODES, PENTODES & IRISHMEN:
Page 33
ON TRIODES, PENTODES & IRISHMEN: (Continued)
Thus a diode tube - one with a cathode and an anode - is mostly used to
This section is a continuing technical treatise on the workings of Irish Pubs but to make it easier for the layman to
Occasionally though, bar doors - even the louvered type - were found to be too effective, and too many customers
TRIODES:
PENTODES:
Page 34
PENTODES: (Continued)
Thus the proper cocktail waitress - visible through the louvers - is scantily clad so as to be all the more
Page 35
INPUT
CLEAN
PUSHED
MODERN
RAW
POWER
ON
ON
STANDBY
GAIN
TREBLEMID
PRESENCE
BASSMASTER
SOLO OUTPUT
CH 2
CH 1
FRONT VIEW HEAD VERSION:
BOTH SWITCHES
pt
#
600631
LIGHT RECEPTACLE
pt # 703850
LIGHT BULB
pt # 703047
POT #
590148
POT #
590148
POT #
590738
POT #
590737
POT #
590151
POT #
590148
POT #
590739
POT #
590378
POT #
590737
POT #
590148
POT #
590738
POT #
590792
POT #
590794
POT #
590739
RED LENS
pt # 703782
LENS
pt # 703300
JACK pt #
610120
SWITCH
pt # 607111
ALL CONTROL KNOBS
Pt # 408110
SWITCH
pt # 607313
CONTROLS
pt # 590151
1
REVERB
2
REAR P
ANEL HEAD VERSION:
10%
FX MI
X
RETURN
SEND
WARNING:
Unplug power
before
replacing
fuse
or removing
bolts mounting
chassis.
F
U
S
E
F
U
S
E
POWER FUSE
2.5 A
SLO
BLO
120 V~
50-60 Hz
2.5 A
WER FUSE
FUSE
CHANNEL 1
CHANNEL 2
SET TO CHANNEL 1
TO
USE FOOTSWITC
H
PATENTED 4,211,000 & OTHERS PENDING FOR SOLO, MUTE & LOOP CONFIGURATION
FOOT
SWITCH
SOLO CHANNEL
EXT. SWITCHING
4 OHM
4 OHM
8 OHM
SPEAKERS
WARNING:
To reduce risk of fire or
electric
shock,
replace fuse with
same
type and rating only. Do not
CAUTION:
To reduce risk of fire or electric
shock,
do not remove cover. No
user-serviceable
parts inside. Refer
FX LOOP
90
%
SWITCH MUST MATCH
TUBES IN USE
EL34
BIAS SWITCH
6L6
ALL TUBE AMPLIFIER HANDMADE IN PETALUMA, CALIF US
A
SINGLE RECTIFIER SERIES 2 SOLO HEAD
OUT
SLAVE
(TO EXT. PWR AMP)
FX MIX
CONTROL
pt # 592736
JACKS
pt # 619112
ALL 3 JACKS
pt # 61911
2
JACK
pt # 61911
2
FUSE HOLDER
DOMESTIC pt # 790347
EXPORT pt # 790346
SWITCH
pt # 600631
SWITCH
pt
#
602000
JACKS
pt# 619112
JA
CK
pt# 613600
V
I
NTA
G
E
Located on the Front Panel
NOTE: CHASSIS PA
RTS AND THEIR RESPECTIVE NUMBERS
ARE THE SAME FOR BO
TH THE HEAD & COMBO VERSIONS
OF THE RECT-O 50 SERIES 2 AMPLIFIERS
RECT-O-VERB
ONL
Y
AC RECEPTACLE
pt # 613713
Page 36
Page 37
Page 38
1317 Ross Street Petaluma, CA 94954
USA
Phone: (707) 778-6565 Fax: (707) 765-1503
The Spirit of Art in Technology
Loading...