Mesa/Boogie Three Channel Dual & Triple Rectifier Solo... User manual

Mu l t i -Wa t t
DUAL & TRIPLE
Owner’s Manual

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.

READ AND FOLLOW INSTRUCTIONS OF PROPER USAGE.
IMPORTANT SAFETY INSTRUCTIONS
Read these instructions.
Keep these instructions.
Heed all warnings.
Follow all instructions.
Do not use this apparatus near water.
Clean only with dry cloth.
Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with one wider than the other. A grounding type plug
has two blades and a third grounding prong. The wide blade or the third prong are provided for your safety. If the provided plug does not fit into your outlet,
consult an electrician for replacement of the obsolete outlet.
Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and the point where they exit from the apparatus.
Only use attachments/accessories specified by the manufacturer.
Unplug this apparatus during lightning storms or when unused for long periods of time.
Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as power-supply cord or plug
is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally,
or has been dropped.
To insure proper ventilation always make sure there is at minimum four inches (101.6mm) of space behind the rear of the apparatus. The ventilation should not
be impeded by covering the ventilation openings with items, such as newspapers, tablecloths, curtains, etc. Do not impede ventilation by placing objects on top
of the apparatus which extend past the rear edge of its cabinet.
No naked flame sources, such as lighted candles, should be placed on the apparatus.
The apparatus shall not be exposed to dripping or splashing and no objects filled with liquids, such as vases, shall be placed on the apparatus.
WARNING: To reduce the risk of fire or electric shock, do not expose this apparatus to rain or moisture.
The AC plug is the mains disconnect. The plug should remain accessible after installation.
WARNING: EU: permission from the Supply Authority is needed before connection.
WARNING: Always make sure 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 the amplifier is properly grounded. Always unplug AC power cord before changing fuse, tubes or removing chassis. Use only same type and
rating when replacing fuse.
Avoid direct contact with heated tubes. Keep amplifier away from children.
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 when handling buttons, switches and controls. Do not use solvents such as benzene or paint thinner to clean the unit.
Always connect to an AC power supply that meets the power supply specifications listed on the rear of the unit. Export models: always insure unit is wired for
proper voltage. Make certain grounding conforms with local standards.
YOUR AMPLIFIER IS LOUD! EXPOSURE TO HIGH SOUND VOLUMES MAY CAUSE PERMANENT HEARING DAMAGE!
Your Mesa/Boogie Amplifier is a professional instrument. Please treat it with respect and operate it properly.

Multi-Watt
Dual & Triple Rectifier
TABLE OF CONTENTS
Overview______________________________________________________________________________1-2
FRONT PANEL CONTROLS
Getting Started & Helpful Hints ___________________________________________________________2-3
Instant Gratification (3 sample settings) _____________________________________________________ 4
CHANNEL MODES
Channel 1 (Clean / Pushed) _______________________________________________________________ 4
Channel 2 & 3 (Raw, Modern & Vintage) ____________________________________________________5-6
Multi-Watt™ Power ______________________________________________________________________ 6
THE CONTROLS
Gain,Treble and Master__________________________________________________________________6-8
Mid, Presence and Bass _________________________________________________________________8-9
Output and Solo_______________________________________________________________________9-10
Standby and Power _____________________________________________________________________ 11
REAR PANEL CONTROLS, SWITCHES & JACKS
Slave Control __________________________________________________________________________ 12
Speakers______________________________________________________________________________ 12
FX Loop ____________________________________________________________________________12-13
External Switching Jacks ________________________________________________________________ 14
Bias Switch _________________________________________________________________________14-15
Rectifier Select_________________________________________________________________________ 15
Power - Spongy & Bold __________________________________________________________________ 16
Fuse _________________________________________________________________________________ 16
Factory Sample Settings (All 3 Channels) ________________________________________________17-19
Personal Setting Sheets _______________________________________________________________20-22
Tube Description & Task Charts _________________________________________________________23-24
Tube Noise & Microphonics ______________________________________________________________ 25
Diagnosing Pre-Amp Tube Problems_______________________________________________________ 26
Bias Adjustment: A feature article by Randall Smith________________________________________27-29
Speaker Impedance & Possible Hook-Up Schemes - Amplifier to Speaker Cabs_________________30-35
Triodes, Pentodes & Irishmen: A feature article by Randall Smith _____________________________36-38
Parts Sheet____________________________________________________________________________ 39

PAGE 1
Overview:
Congratulations on your choice of the new Three Channel Dual or Triple Rectifier Head as your amplifier!
Their two channel relatives launched a sound back in 1990 that would come to define a musical style and now, 20 years later, are
synonymous with high gain guitar. The “Recto” - as it is affectionately known - has found its place in history as a rock ‘n roll icon and
seems to be growing in popularity every week. The long and ever growing list of recording credits and inspired owners endorsing the
beyond gain performance of these all tube machines of mayhem is testimony to their tone, versatility and reliability. The time proven
magic created by combining our patented Switchable Dual Rectifier power section with two different tube preamps of unsurpassed
gain, focus and expression created an instrument of devastating power.
That combination is exponentially more powerful with the Multi-Watt Dual & Triple Rectifiers. There are virtually no limits or compro-
mises as you can footswitch between three discreet channels - each sound dedicated and fully evolved! One channel is dedicated to
rhythm sounds lets you choose between two modes...CLEAN with its many colors of normal gain staging - and a boosted, re-voiced
PUSHED circuit that reveals an urgent, more aggressive gain range that is perfect for crunch rhythm or medium gain soloing.
The two Gain Channels feature a comprehensive revamping that retains the original two essential Recto modes VINTAGE & MOD-
ERN in all their blistering glory, but also adds an amazing mode called RAW. The RAW mode’s super sensitive personality roams
effortlessly through virtually all ranges of gain...from almost-clean to a fast tracking crunch, allowing you to harness the Recto spirit
for any style of music. With these two gain channels you may footswitch between any two of six solo modes! And if this performance
minded power isn’t enough to get you through a gig, we have the Recto with the SOLO Control found on some of our other models.
This valuable feature is an additional volume control wired in parallel to the OUTPUT Control allowing you to footswitch to a preset
amount of volume boost during live performance. And finally, to top it off, the series EFFECTS LOOP has also been updated to include
a footswitchable option to the already complete array of programmable choices.
To further enhance the performance of each preamp Channel we’ve included our patented Multi-Watt™Power feature. You now have
the choice of either two or four power tubes – producing either 50 or 100 watts of power – in each of the Three footswitchable Chan-
nels. This choice is selected at the mini toggle located below the Front Panel Mode switch enabling you to tune the power response
to best match the preamp style you are dedicating a given Channel to and increase the expressive factor many fold.
In addition to the wattage choices, to further tune your power the patented Switchable Rectifiers are now Channel Specific giving you
the choice of Tube Tracking or Solid State Rectifiers per Channel on a mini toggle on the Rear Panel. Tube Tracking brings on line
the proper amount of tube rectification – one for 50 watts, both for 100 watts and all three when 150 watts is selected on the TRIPLE
RECTIFIER - and produces a looser, saggier response with enhanced harmonics. DIODE tightens the response and produces the
Multi-Watt
Dual & Triple Rectifier
Operating Instructions
100W HEAD
CH
2
CH
3
CH
1
100 WATT
CLEAN
PUSHED
50 WATT
100 WATT
50 WATT
100 WATT
50 WATT
R A W
MODERN
R A W
MODERN
V
I
N
T
A
G
E
V
I
N
T
A
G
E
SEND LEVEL
BIAS
SELECT
DIODE
CH 1EL-346L6 CH 2 CH 3
TUBE TRACKING
RECTIFIER
SELECT
MAIN
POWER
PATENTED 4,211,893; 5,091,700; 5,168,438; 6,621,907; 6,724,897; 7,193,458; 7,602,927
LOOP
ON
CH 1
CH 2 CH 3
FTSW
100 WATT HEAD
DUAL RECTIFIER
BEST TO USE TUBE TRACKING WITH EL-34s
TUNER OUT
120 V~
60 Hz
4A
4 A
SLO
BLO
SPONGY BOLD
FRONT VIEW: DUAL or TRIPLE RECTIFIER Head
REAR VIEW: DUAL or TRIPLE RECTIFIER Head

PAGE 2
highest power, keeping the sound tight and percussive and the feel immediate and accurate. To finish off the power choices, the
patented BOLD/SPONGY Power switch creates a built-in Variac that enables you to switch the incoming AC line voltage down to ap-
proximately 95 volts for additional sag and a “browner” vibe that also loosens up the feel and raises the upper harmonics.
There is a TUNER OUT jack now located on the Rear Panel next to the EXTERNAL SWITCHING jacks that is active at all times. A
silent tuning feature is incorporated into the TUNER button on the Footswitch that mutes the signal when you press TUNER.
These eight modes housed in three simple to use channels, along with the Multi-Watt™ power and other improvements, open new
doors for the Recto to be considered by any player wanting great clean sounds and a myriad of solo possibilities. While they still
remain the hardest grinding heads out there, this versatility is sure to land the Multi-Watt™ Recto in some surprising new musical
environments.
GETTING STARTED:
Before we get to some basic sample settings, let’s get the Recto plugged in and ready to play.
1.) Connect the Footswitch DIN Cable to the DIN jack located near the center of the Rear Panel.
2.) Connect your speaker cabinet to the correct impedance Speaker Output jack located on the Rear Panel. (MESA cabinet imped-
ances are printed on the jack plate of all cabinets.) MESA 4x12 cabinets are 8 Ohm.
3.) Connect the included A.C. power cable to the A.C. receptacle located on the Rear Panel and plug the amplifier into a grounded
A.C. outlet.
4.) Flip the POWER switch to the ON (up) position and wait at least 30 seconds for the power tube filaments to warm up with the
STANDBY switch in the Standby (OFF/down) position. This cold start procedure prolongs tube life substantially if it is followed each
time your amplifier is powered up.
5.) Turn the OUTPUT Control off or to a very low setting before flipping the STANDBY switch to the ON (up) position.This will
prevent accidental settings that are too loud for the room or your ears. These amplifiers are capable of extremely loud volumes
and should be used with care to avoid damage to your hearing. Starting each power up with the OUTPUT Control zeroed will
help to eliminate painful and/or embarrassing situations.
6.) Flip the STANDBY switch to the ON (up) position and enter the world of Rectosis.
Before we move on to some sample settings that will help you to better understand the nature of the beast, here are some tips that
may save you some time and answer some questions.
FRONT PANEL: CO N T R O L s & FE A T u R E s

PAGE 3
HELPFUL HINTS:
1.) The Rear Panel CHANNEL SELECT rotary switch must be set to FOOTSWITCH for the Footswitch to select either channels or
features.
2.) The OUTPUT Control works only when the FX LOOP is activated. Switch out of the Loop Bypass position on the Loop Assign
Rotary Control to any of the other 5 positions.
3.) The SOLO Control is activated when the Footswitch is connected to the FOOTSWITCH jack on the Rear Panel and the FX LOOP
is activated. When the footswitch is not connected the SOLO Control will have no effect on the volume level.
4.) When the FX LOOP is activated it is normal to hear the volume drop a bit. Use the SEND Level Control on the Rear Panel even
if no processor is patched in to bring the volume level back up to approximately unity gain.
5.) The SOLO Control can be set for a volume level above that of the OUTPUT Control setting. It will not allow a setting below that
of the OUTPUT.
6.) The GAIN and TREBLE are the most powerful controls in all three channels.They should be used with taste and you will find that
the best sounds are found with these two controls set somewhere in their middle regions. Avoid setting the TREBLE above 2:00 when
the GAIN is maxed as the possibilities for noise and squealing from microphonic preamp tubes increases dramatically.
7.) You will notice a volume increase when switching from the CLEAN to PUSHED in Channel 1 and from VINTAGE to MODERN in
Channels 2 and 3. When switching from one mode to another always check your Channel MASTER setting to avoid sudden
volume jumps and possible hearing damage. It’s not a bad idea to get in the habit of zero-ing out the MASTER before reconfiguring
a channel.
8.) Choosing the proper Rectifier mode with the RECTIFIER SELECT switch (located on the Rear Panel) that best suits the sound
style you are trying to achieve in each channel can greatly enhance the performance. TUBE TRACKING produces a more elastic
feel and softer clipping characteristics which is especially great for single note soloing. SILICON DIODES produce more power
and headroom and can also track better for extreme gain settings while staying tighter in the bottom end.
9.) The PRESENCE Control determines a lot about the voicing of gain sounds. Set lower it will fatten and compress single note
sounds and lend a liquid feeling to the strings in Channel 2 and 3 and the PUSHED sound in Channel 1. Above 12:00 it starts adding
cut and tightness in all channels.
10.) When using PUSHED with the GAIN Control maxed (5:30), do not run the TREBLE Control above (2:30). Settings above (2:30)
can create possible oscillation in certain preamp tubes in the V1 position. This can be avoided altogether by setting the TREBLE
Control sensibly when the GAIN Control is maxed. Use the PRESENCE Control for additional brightness.
Hopefully these tips have helped you in getting ready to enjoy a walk on the wild side. By now you should be familiar with much of
the Rectos’ features so let’s check out the sound (like you haven’t yet) with an example of some popular sounds in three of the 8
modes.

PAGE 4
INSTANT GRATIFICATION:
Here are some examples of the most popular sounds in the three channels.There are additional
sample sounds presented later in this manual, but the possibilities are endless and we encourage you to find your own sounds through
experimentation.
Now that you have scratched the surface of tonal options it’s time to look at each individual control to see how they interact and what
role they play in helping you arrive at your sound quickly and easily.
CHANNEL MODES:
Each of the Rectos’ three channels contain a choice of modes - two in Channel 1 and three in Channels 2 and 3, so that each channel
may be configured for an array of sounds.These mode select mini toggles radically alter the voicing of the channel and many internal
changes occur as you switch through the modes. How you choose to use these different modes is up to you, but we think you will
agree that this scheme provides some of the most versatile footswitching available anywhere.
CHANNEL 1: CLEAN / PUSHED:
CLEAN : This is the lowest gain circuit of the Rectos’ eight modes and is optimized
for producing balanced pristine clean sounds. For the best understanding of how to achieve a great sound in this mode, please refer
back to the GAIN Control section of this manual. However, a great place to start is 12:30 or so on the GAIN Control with more sparkle
available below this and more warmth apparent above...from there adjust according to your guitars individual
response.
Because of its more traditional architecture this mode also works extremely well for vintage style drive sounds.
By turning the gain all the way up, a beautiful old school solo sound is possible...especially with neck single
coil pick-ups. The TREBLE and MIDDLE Controls can also add gain and sustain to this sound (reduce Pres-
ence to blend highs), but you will probably want to run the BASS Control below 10:30 to avoid flubbiness and
preserve a focused attack.
PUSHED: This mode is a radical departure from the sweet shimmering blend of the CLEAN modes low gain character. Huge increases
in gain early on in the first stages of the pre-amp produce one of the biggest differences between modes in the entire amplifier and
transforms what you thought to be a tame and gentle clean channel into a raging crunch machine.This incredible amount of gain also
creates one of the most expressive solo modes in your Recto. Because there are less stages of gain for the signal to travel through
and the tone control network is tuned for the brighter nature of clean sounds, this mode responds quicker to your pick attack and has
a more urgent, snappy feel. Don’t overlook this mode for some of the Rectos’ coolest overdrive solo sounds.
NOTE: When using PUSHED with the GAIN Control maxed (5:30), do not run the TREBLE Control above (2:30). Settings above
(2:30) can create possible oscillation in certain preamp tubes in the V1 position.This can be avoided altogether by setting the TREBLE
Control sensibly when the GAIN Control is maxed. Use the PRESENCE Control for additional brightness.
CHANNEL 1: Sample Setting #1
INPUT
GAIN
MASTERPRESENCE
TREBLE
MIDBASS
CHANNEL 2: Sample Setting #1
GAIN
MASTERPRESENCE
TREBLE
MIDBASS
CHANNEL 3: Sample Setting #1
GAIN
MASTERPRESENCE
TREBLE
MIDBASS
CH
1
CLEAN
PUSHED
100 WATT
50 WATT
RAW
MODERN
V
I
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T
A
G
E
100 WATT
50 WATT
CH
2
RAW
MODERN
V
I
N
T
A
G
E
100 WATT
50 WATT
CH
3
100W HEAD
CH
2
CH
3
CH
1
100 WATT
CLEAN
PUSHED
50 WATT
100 WATT
50 WATT
100 WATT
50 WATT
RAW
MODERN
RAW
MODERN
V
I
N
T
A
G
E
V
I
N
T
A
G
E

PAGE 5
RAW:
This mode is the lowest gain of the three in the two high gain
lead channels. Its less saturated nature greatly enhances the already versa-
tile bevy of sounds the two original lead channels offered.The range of gain
available covers an extremely wide spectrum and it can be set to double as
a formidable alternate clean mode, a low gain purring blues sound and be-
yond, all the way up to a grinding crunch or searing solo sound.The TREBLE
can be set relatively high (2:00) to add a little more gain and shred when
using RAW for certain crunch rhythm sounds.
VINTAGE:
This high gain mode is the famous liquid Recto voice. Its lush harmonic content and fat creamy feel has found
its way onto so many recordings, it is now a staple for anyone headed to the studio for an album project. Combining this super juicy,
expressive preamp with the Rectos’ black magic, tube-rectified power section creates colors in gain that most players find truly addic-
tive. Single note solo work is effortless as the strings become easy to play with VINTAGE modes musical and natural tube compres-
sion. Spend time learning the lower regions of the VINTAGE mode as the overlap between RAW and VINTAGE is a place where many
beautiful sounds lie. These two modes are similar enough when VINTAGE is set in its lower range and RAW is set in its medium to
higher range and yet, each posses a character that is unique and identifiable. Remember that you can swap channels to achieve
different voicings of the VINTAGE sound and no matter which you settle upon, you will likely find your trademark lead sound lurking
somewhere in this sea of liquid gain.
MODERN:
Aggressive.This is the word that best describes the menacing power of the Rectos’ most rebellious of all modes.
A take no prisoners, crushing assault of top end cut and lightning fast response creates a sound of unparalleled aggression that has
set a new standard for hard core sounds. The added tightness of the low end response combined with the radically more present top
end keeps the MODERN mode tracking accurately even at extreme gain settings.
MULTI-WATT™ POWER: Each Channel contains our patented MULTI-WATT power switch that allows you to choose either 50
or 100 watts (50 or 150 watts on TRIPLE RECTIFIER) of power enabling you to match the power output and feel to each of the three
foot switchable preamp sounds. The 50 WATT position (switch down) brings two of the four (outside pair – far left and far right) tubes
on line for a clippable 50 watts of power. The 100 WATT setting (150 WATT on TRIPLE RECTIFIER)
brings on line all the 6L6 power tubes for the full power and headroom. This setting is preferred for
pristine clean sounds and tight-tracking high gain sounds.
CHANNEL 2 + 3 RAW / VINTAGE / MODERN
GAIN
MASTERPRESENCE
TREBLE
MIDBASS
RAW
MODERN
V
I
N
T
A
G
E
100 WATT
50 WATT
CH
2
GAIN
MASTERPRESENCE
TREBLE
MIDBASS
RAW
MODERN
V
I
N
T
A
G
E
100 WATT
50 WATT
CH
2
CHANNEL MODES: (Continued)

PAGE 6
CONTROLS:
GAIN:
This control adjusts the predominant gain stage in each channels’ circuit with the function and taper being optimized for
each individual channel. Remember that your Recto is really three separate multi-mode amplifiers built onto one chassis, so though
each channel looks identical, the GAIN Control for each channel comes
in a different place and adjusts a different point in that channels circuit.
In most guitar amplifiers, and especially in all-tube circuits, the GAIN
Control is the most powerful control in the preamp. It shapes the overall
style and character of the sound and is responsible for whether the sound
is clean, overdriven or anywhere in between. In your Recto, the GAIN
Control is even more powerful. It not only determines the amount of drive,
but also acts as an integral part of the tone control string as well.
To simplify the GAIN Controls’ role in shaping the overall tone of the
sound we will look at it in two ways - 1; alone and 2; in conjunction with
the tone controls.
1) By itself the GAIN Control has basically three tonal regions -
Low (7:00 - 11:00) provides the cleanest, least saturated sounds and in this region the sound will be brighter and contain more upper
harmonics lending a three dimensional character to the sound.
Middle (11:15 - 2:00) enhances the saturation and replaces some of the upper harmonics with a richer, warmer quality and a fuller
bottom end response. Not yet fully saturated, this region is the easiest place to get a great sound in all three channels. This region
contains many of the Recto’ best sounds...especially for soloing due to the crucial blend of an expressive attack combined with ample
sustain.
High (2:15 - 5:00) saturates the signal and enhances low and low mid frequencies.While this region provides the maximum saturation
and therefor sustain, it also compresses and softens the attack characteristics. For this reason we suggest using this higher region
of the GAIN Control sparingly and only when maximum sustain is needed.
NOTE: Due to the Rectos’ extreme gain potential, the highest regions of the GAIN Control may possibly push the pre-amp tubes past
what they can handle, producing microphonic squealing. While we screen and test the tubes your amplifier was shipped with and the
tubes in your amp passed our rigourous test, we can’t predict how the tubes will respond over time exposed to extreme gain settings.
Your tubes are warranted for a period of 6 months under normal use, but you can save yourself the present and future inconvenience
of having to deal with annoying microphonic tube problems by simply using a little common sense...Don’t turn the Gain all the
way up!
If you must for a specific part or at very low volumes, back down the TREBLE and PRESENCE Controls.Your Recto was designed to
provide amazing gain and tone at less than extreme settings removing the need for you to crank everything all the way up. If you are
not able to achieve the sound you want at sensible settings on any or all of the controls, your problem may lie elsewhere in the signal
chain, i.e. pick-ups, cabinetry, processing etc. Keep in mind you can always call on one of our product specialist Monday through
Thursday and seek some advice should you find yourself struggling to get the sound you want.
2.) GAIN - In conjunction with the Tone Controls - Basically, a simple rule applies...as the Gain is increased the Tone control string
has less and less effect on the signal until at 5:00 the signal is so saturated that you are getting mostly Gain and very little Tone. Again,
this is the reason we suggest using the GAIN Control in its middle region. Here the Tone control string is very active and provides
maximum shaping power - allowing you to dial virtually any sound you desire.
INPUT
GAIN
TREBLE
REGIONAL TITLES ARE THE SAME FOR ALL
3 GAIN CONTROLS
Brightest
Most Balanced
Warmer & Saturated
CH
1
CLEAN
PUSHED
100 WATT
50 WATT

PAGE 7
TREBLE :
As in most tube guitar amplifiers, the TREBLE Control (in all three channels of your Recto ) is the most power-
ful of the rotary controls and is next in line only to the GAIN Control as a shaping tool. Because it is first in the signal path of the tone
controls - and from here the Middle and Bass receive their signal - it is by far the
dominant tone control. For this reason the setting of the TREBLE Control is very
important for equal representation of the three frequency regions to appear at
their respective controls. Like most of the controls on your Recto, there is an
optimum region of the TREBLE Control where ample top end is mixed in and yet
enough signal is still passed on to the MIDDLE and BASS Controls.
As you might surmise, here is the sweet spot. There are definitely great sounds
above and below this middle region (11:00 - 1:30), but the balance between the
TREBLE Control and the other two tone controls is compromised.
The one place you may want to throw caution to the wind and set the TREBLE
Control above this median zone presents itself in Channel 1 of your new Recto. In
both modes (Clean & Pushed), the TREBLE Control can be used to dump extra
gain into the mix. This is especially effective in the PUSHED mode for crunch
sounds.When doing so use the PRESENCE Control to roll off some of the more
than ample top end for a more compressed feel and fatter voice. As you might surmise, the BASS Controls’ effectiveness will be
reduced, so you may have to run a much higher setting than you are used to seeing to achieve a balance.This said, keep in mind that
the TREBLE Control in Channel 1 Pushed should not be set much above 2:30 to avoid unwanted microphonic tube problems.
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
see each Channel is fitted with its own MASTER Control, enabling the three channels relative volumes to be matched regardless of
their extremely different sound styles and gain signatures.The
MASTER Control makes possible a wide range of sounds
through its ability to use very low Gain sounds at high volumes
and conversely, high Gain sounds at low volumes and every-
where between.
Again, we suggest using the MASTER Control in its sensible
ranges (9:00 - 2:00). Here, the channels will be easier to match
with each other and the Effects Loop will see more reasonable
signal levels.
NOTE: Because the MASTER Control creates the send to
the Effects Loop, extreme settings will cause a large signal to
be sent to the Loop for that Channel. Not only may this cause
possible overloading of the processors Input stage, but will
make balancing the three channels’ Effect Send level difficult.
The Controls: (Continued)
INPUT
GAIN
TREBLE
REGIONAL TITLES ARE THE SAME FOR ALL 3 TREBLE CONTROLS
SWEET SPOT
CH
1
CLEAN
PUSHED
100 WATT
50 WATT
MASTER
INPUT
GAIN
TREBLE
REGIONAL SETTINGS ARE THE SAME FOR ALL 3 MASTER CONTROLS
MOST SENSIBLE RANGE
EASIEST TO BALANCE CHANNELS
REASONABLE FX LOOP SIGNAL LEVELS
CH
1
CLEAN
PUSHED
100 WATT
50 WATT

PAGE 8
MID :
The MID Control is responsible for the blend of midrange frequencies in the mix and though its effect is not as dra-
matic as that of the TREBLE Control, it plays an integral part in achieving any sound in your Recto. It is capable of changing the feel
dramatically as it blends in a group of frequencies that
tend to soften or stiffen the way a sound feels to play.
Most players tend to lean in the direction of lower MIDDLE
Control settings (7:00 - 11:00) where a scoop in this region
produces girth ( by letting the Bass become a little more
dominant ) and a lack of punch lends a more compressed,
even feel to the strings and therefore less apparent resis-
tance to the pick. As the MIDDLE Control is increased,
(11:30 - 1:30) the sound is rounded-out and filled-in with a
focused mid attack appearing rather quickly. As you would
guess, the feel starts to change - becoming more resistant.
Above this region the MIDDLE Control could be used to
compensate for either weaker pick-ups or for times when a
specific deficiency is produced by either an extremely high
setting of other tone controls, or a physical anomaly in the
room. While these MIDDLE Control settings (2:00 - 5:00)
can introduce added gain and create enhanced focus, the trade-off will be a stiffer, more forward, less compressed feel.
Channel 1 utilizes a different MIDDLE Control than that of the Channels 2 and 3 with a custom-designed taper and value. In its
low range (below 12:00) it functions as a normal midrange control with a taper suited to blending fine increments of these frequencies.
Most players lean toward a fairly radical scoop (7:00 - 10:30) for clean playing, preferring to let Treble and Bass remain dominant, thus
producing the signature sparkle and breath essential for a pristine clean sound.
As Channel 1’s MIDDLE Control is swept past 1:00, it quickly starts to add gain in these midrange frequencies adding cut and punch.
As the top end of the control is reached, (3:00 - 5:00) it becomes an additional gain control capable of taking both CLEAN and
PUSHED modes to extremes. Experiment with this cranked region in conjunction with conservative settings of the other tone controls
to balance both sound and feel. While this added flexibility may make Channel 1’s MIDDLE Control a little more tricky to learn at first,
it will become quite valuable as you start to realize the power of this super versatile channel.
PRESENCE :
The PRESENCE Control is a high frequency attentuator that is placed at the end of each channels pre-amp
stage and affects frequencies higher than those of the TREBLE Control. It acts independently of the other rotary tone controls and is
crucial in voicing the Channel. It is a powerful global tone control. Lower PRESENCE Control settings darken and, in fact compress
the signal which works well to fatten single note solo sounds, giving them girth and focus.
Some of the best lead sounds in your Recto will find the PRESENCE Control in its lower regions,
where a balanced, vocal response is achieved.
Higher settings unleash the mighty roar of your Recto and this can be great for sparkling clean
sounds in Channel 1 and more aggressive crunch rhythm sounds in the high gain modes.
HELPS ADD PUNCH TO WEAKER PICK-UPS
SCOOPED AND EASY TO PLAY
INPUT
GAIN
TREBLE
REGIONAL TITLES ARE THE SAME FOR ALL 3 MID CONTROLS
MID
CH
1
CLEAN
PUSHED
100 WATT
50 WATT
The Controls: (Continued)
PRESENCE
REGIONAL TITLES ARE THE SAME FOR ALL 3
PRESENCE CONTROLS
MAS
MID
SCOOPED AND EASY TO PLAY
MOST BALANCED VOCAL QUALITY

PAGE 9
BASS:
Last, but not least in the string of tone controls we come to the BASS . This control works similarly in all three chan-
nels in that it determines the amount of low frequencies present in a sound. However, the actual frequencies and style of lows it
mixes in changes from channel to channel. Like the MIDDLE Control, it falls in
line signal-wise after the TREBLE Control and the same scheme applies. When
the TREBLE Control is set high, the effectiveness of the BASS and MIDDLE
Controls is reduced. If the TREBLE Control is set low these two controls become
dominant.
For the most balanced sound and a balance of power between the three rotary
tone controls, try to use the TREBLE Control in its middle ranges. This scenario
produces nearly equal representation of all the frequencies on the tone controls
and provides a great neutral starting point for further tweaking.
OUTPUT CONTROL:
This control determines the overall output volume level of the amplifier. After the GAIN Controls
have been set for the desired sound style and the two channels levels have been balanced with the channel MASTER Controls, the
OUTPUT Control allows you to change the playing level by adjusting a single control. The OUTPUT
Control is also wired as the Effects Loop Return Level Control. Should you ever use your Recto as
a power amp alone by inserting a signal into the RETURN jack, the OUTPUT Control will serve as
the master level control.
NOTE: When using the EFFECTS RETURN as an input - to use the Recto as a power amp - the
SOLO Control can be used to attain a footswitchable boost if the Footswitch is connected. It is wired
in parallel to the OUTPUT Control and therefore also controls the volume of the power section.
NOTE: The Effects Loop RETURN jack can serve as a power amp input so that you may use the Recto as a power amp for either
stereo reproduction or to incorporate additional pre-amps. Here are a few things to remember that will help you when interfacing to
the Recto for use as a power amp only;
1.) Connect “Dummy” plug or loose cable to SEND jack. (This prevents any possible loading that could result in diminished RETURN
sensitivity.)
2.) The OUTPUT Level will be the only active control on the Front Panel (the PRESENCE Control of Channel 1 will be active only
when that channel is engaged - see #3)
3.) The SOLO Control may be used to footswitch to a pre-determined amount of boost when the footswitch is connected.
4.) Channel 2 & 3’s MODERN mode - as part of its voicing - utilizes substantially less negative feedback in the power stage creating
a scenario of greatly increased power sensitivity. This internal revoicing produces amazing results in the lead sounds and requires a
sophisticated network of elements to switch to prevent the increased power sensitivity from blowing you out of the room as you toggle
between Channel 2 & 3’s RAW & MODERN modes.
The Controls: (Continued)
BASS
VARIABLE ACCORDING
TO TREBLE & MID CONTROL
IN
CH1
CLEAN
PUSHED
GAIN
TREBLE
REGIONAL TITLES ARE THE SAME FOR ALL 3 BASS CONTROLS
MASTER
MID
HEAD
SOLO OUTPUT
PRESENCE
BASS

PAGE 10
Therefore, we recommend selecting Channel 1 when you wish to use the Recto as a power amp. The more conventional power
sensitivity of this channel will be the most compatible with external sources. Also, using Channel 1 in a power-only application means
that the PRESENCE Control will be active which allows you to tailor the power voicing to your specific tastes. If you do need the extra
sensitivity that Channel 2 & 3’s MODERN mode produces for a source that is unusually weak, it is there if you need it.The PRESENCE
Control will not have any effect on the sound as it switches with the mode change to an earlier stage in the pre-amp.
SOLO CONTROL:
This control can only be activated if the correct Footswitch is connected to the Footswitch DIN
jack. SOLO is an additional final output level control wired in parallel with the OUTPUT Control. It is capable of a setting above that
of the OUTPUT Control and can not be set below. The amount of apparent boost also depends on
that of the OUTPUT Control - in that if the amplifier is at either the extreme low or extreme high
levels of the OUTPUT, its effectiveness is minimized. It has been optimized for live performance
volume levels.
If the power section is either not a part of the sound (super quiet), or producing all its rated wattage
(super loud), there is very little signal for the SOLO control to work with. By using the Footswitch and selecting SOLO, a pre-settable
boost in overall levels is possible on the fly...giving you some control over your levels when it’s time to step out. Engineers may give
you a bit of a frown the first time you use it...but isn’t it time you heard yourself. It might even prevent them from punishing you with
the dreaded monitor or sidefill version of your tone.
STANDBY:
Perfect for set breaks...this toggle switch also serves an even more important purpose. In the Standby position
the tubes are at idle so that during power up they may warm up before being put to use. Before power is switched on make sure the
STANDBY switch is in the Standby position.
Wait at least 30 seconds and then flip the STANDBY switch to the ON position.This prevents tube problems
and increases their toneful life substantially.
POWER ON:
This switch delivers the A.C. power to the Recto. Make sure the unit is grounded (all three terminals of the
A.C. power cord must be connected whenever possible to avoid injury to the user as well as to the unit) and that the proper voltage
is present.
Follow the cold start procedure described in the ON/ STANDBY section above when powering up your new
Recto.
The Controls: (Continued)
HEAD
SOLO OUTPUT
PRESENCE
BASS
POWER
ON ON
STANDBY
POWER
ON ON
STANDBY
POWER
ON ON
STANDBY

PAGE 11
REST AREA

PAGE 12
SLAVE CONTROL:
This 1/4” jack and control provide a signal derived from the speaker jack. Perfect for using either Recto,
(Dual or Triple Heads) as a master pre-amp, and additional power amps for more power when needed. Some players use the SLAVE
to derive an FX Send Signal and go to other amps for their wet sound.
NOTE: Once a signal is taken from the SLAVE, it can not be inserted back into the FX Loop Return jack or a
feedback loop will occur. Much like holding a microphone into the PA system’s cabinets...a loud high pitched squeal
will be the result.
SPEAKERS:
Two 4 Ohm, Two 8 Ohm and one 16 Ohm jack are provided for speaker interfacing. Both the Dual and
Triple Rectifier Heads are not very sensitive to speaker mismatches and will not be damaged by them, except that very low ohmage
loads will cause the power tubes to wear faster. A single twelve-inch 8 Ohm speaker should generally be connected to the 8 Ohm
output. When using two 8 Ohm speakers, connect them both to the 4 Ohm outputs provided (because the total load is 4 Ohms in that
case.) Check out the information further back in this manual regarding speaker imped-
ance and possible speaker hook-up schemes.
4x12 cabinets may be 4, 8 or 16 Ohms. If you are not sure of the impedance of your
cabinet, you may need to remove the Rear Panel in order to verify the impedance rating
of the individual speaker or speakers. MESA/Boogie 4x12 and 4x10 cabinets come
standard wired to 8 Ohms, and are wired in series-parallel. Some Non-MESA 4x12
cabinets are wired 16 Ohms using four 16 Ohm speakers. By wiring all four speakers
in parallel, you can reduce the cabinet to an impedance load of 4 Ohms (assuming the speakers are 16 Ohms each.) No matter how
unusual your speaker setup, it is always possible to get good performance.
FX LOOP: The Effects Loop of your Recto is probably one of the most comprehensive loops in any amplifier. It is wired in series
to the dry signal and is comprised of five elements, four on the Rear Panel and one on the Front Panel.Together they provide virtually
seamless interfacing of processors of almost any style while preserving the integrity of this high tuned
gain machine. These elements are as follows;
1.) An ASSIGN rotary control that allows you to have any combination of LOOP ON status or com-
pletely remove it from the signal path altogether.
NOTE: LOOP BYPASS defeats the Front Panel OUTPUT and SOLO Controls as they are part of
the FX RETURN circuit. This tube stage and associated circuitry are omitted when you select LOOP
BYPASS. The Channel MASTER Controls become the final output controls in this case.
2.) A SEND LEVEL Control that allows matching of levels between the output of your Recto and your processor’s input.
SEND LEVEL
BIAS
SELECT
DIODE
CH 1EL-346L6 CH 2 CH 3
TUBE TRACKING
RECTIFIER
SELECT
MAIN
POWER
PATENTED 4,211,893; 5,091,700; 5,168,438; 6,621,907; 6,724,897; 7,193,458; 7,602,927
LOOP
ON
CH 1
CH 2 CH 3
FTSW
100 WATT HEAD
DUAL RECTIFIER
BEST TO USE TUBE TRACKING WITH EL-34s
TUNER OUT
120 V~
60 Hz
4A
4 A
SLO
BLO
SPONGY BOLD
SEND LEVEL
BIAS
SELECT
DIODE
CH 1EL-346L6 CH 2 CH 3
TUBE TRACKING
RECTIFIER
SELECT
MAIN
POWER
PATENTED 4,211,893; 5,091,700; 5,168,438; 6,621,907; 6,724,897; 7,193,458; 7,602,927
LOOP
ON
CH 1
CH 2 CH 3
FTSW
100 WATT HEAD
DUAL RECTIFIER
BEST TO USE TUBE TRACKING WITH EL-34s
TUNER OUT
120 V~
60 Hz
4A
4 A
SLO
BLO
SPONGY BOLD
LEVEL
SLAVE
OUT
(TO PWR AMP)
SPEAKERS
DUAL RECTIFIER 100W HEAD
ALL TUBE AMPLIFIER HANDBUILT IN PETALUMA, CALIFORNIA
16 OHM 8 OHM 4 OHM 4 OHM8 OHM
LEVEL
SLAVE
OUT
®
REAR PANEL:

PAGE 13
FX LOOP: (Continued)
3.) A SEND jack that captures the preamp signal and pads it down to accommodate outboard signal processors input stage.
4.) A RETURN jack that accepts the signal from a processors output and boosts the level back up to unity gain (or beyond) to be
mixed back into the original signal.
5.) An OUTPUT Control (Front Panel) that is the effects return stage level control which also doubles as an overall control for the
whole amplifier. This scheme allows the channels levels to be matched to each other and/or fine tuned for a sound and an effects
level. Once this is achieved the level of the whole amplifier can be raised or lowered with one control.
PATCHING EFFECTS:
Try this method of interfacing outboard processors for the best results;
1.) Connect your processors Input to the SEND jack.
2.) Connect the output of your processor to the RETURN jack.
NOTE: The shortest possible length of high quality shielded cable should be used to connect the processor to the loop jacks. Longer
lengths and/or poor cable quality can roll off top end or reduce punch and attack characteristics.
3.) Set the three channels for your desired applications and sounds.
NOTE: Keep in mind that cleaner sounds, although they appear to be the same volume as saturated sounds, send a more dynamic
signal to your processor and therefore will probably register as a hotter signal on the processors’ input indicator.This is not a problem,
but it will be of interest when setting up the sounds and channels. Set the channel MASTERS so that each sound is the right volume
to balance with the other channels and don’t worry about the processors’ input indicator unless clipping occurs.
4.) Select the LOOP ON position on the ASSIGN rotary control.
5.) Fine tune the send level with the SEND level control so that the processors’ input stage is not clipping in any channel and sending
adequate level.The NORMAL region marked on the sweep between (11:00 and 2:00) should provide a good match for most effects.
Don’t worry if the level seems like it dropped...you still have the return stage control.
6.) Set the desired mix of dry to wet signal with the processor’s mix control.
7.) Bring the amplifier up to the desired playing volume with the Front Panel OUTPUT Control.
NOTE: Remember that the OUTPUT and SOLO Controls are only active when the FX LOOP is engaged.
NOTE: The FX LOOP RETURN jack can be used as an input to the power amp of your Recto making it possible to use it for amplifying
signals derived from other preamps or effects in a stereo set-up. When connecting to this jack as a power amp input only the OUTPUT and
SOLO Controls and Channel 2 & 3 mode select switches will be active. For the most balanced response in power use Channel 2 or 3 in the
RAW or VINTAGE modes.This will configure the power section with the proper amount of negative feedback which will in turn make the Rectos’
power stage respond with a more traditional input sensitivity.
The PRESENCE Control will work in this scenario and you can use it to tailor the top end harmonics to your needs.The MODERN mode can be
selected to achieve a substantially higher input sensitivity, but you will have to be careful as this will make the OUTPUT Control extremely more
powerful and the amp will be LOUD. Also the PRESENCE Control will have no effect on the sound in the Modern mode in this scenario.
REAR PANEL: (Continued)

PAGE 14
TUNER OUT: This Output jack will enable you to feed a tuner with a clean padded signal derived from the first gain stage. A
silent tune feature is engaged when you select TUNER on the Footswitch that mutes the signal to the speakers to allow you to tune
the instrument without disturbing the band and audience.
EXTERNAL SWITCHING JACKS:
These jacks allow (usually MIDI-programmed) operation of your amplifier’s functions
from an external switching source. In either case, the switching is accomplished by connecting (“shorting”) the jack’s “Tip” to its “Ring”
(or ground.)
BIAS SWITCH:
Your Dual or Triple Rectifier Head was designed with versatility in mind.So to add to the already awesome
array of on-board features...we felt it essential that both of these Rectifier Heads be able to adapt their power output sections to use
the other classic pentode power tubes, the British style EL 34.These tubes are largely responsible for the signature
sound of many immediately identifiable and wonderful sounding amps created in Great Britain and used on some
of the best recordings to date.The nature of their sound is usually brighter in the extremely high frequencies...some
players find this almost thin at first.
However, aficionados of the EL34 sound know that nothing has the lushness of harmonics or spread like a power
amp using EL34’s. In truth EL34’s do focus in on a region of upper harmonics that 6L6’s reproduce, but not really
enhance, in the same way the EL34’s do.
This characteristic is sometimes preferred for sounds that range from a soft clip that would be used for chording or soloing, to an all
out high gain crunch or lead sound. Players that use mostly these types of sounds may prefer the EL34 clip to the 6L6’s that come
standard in both the Dual and Triple Rectifier Heads. If you need a variety of sounds and rely on a clean chording sound much
of the time, you will likely prefer the stock compliment of 6L6’s that both of these are fitted with. We feel the 6L6 is a more balanced
sounding tube that produces plenty of harmonic lushness, while at the same time delivering the rich lows that are crucial to both a
warm clean sound and huge, tight high gain crunch sound.
We recommend the 6L6 for reliability: In our many tests and continued use of the currently available EL34 type power tubes on
the market today, we regret to say that they do not appear to be as rugged in construction as the available 6L6.This is another reason
why your Dual or Triple Rectifier Head was shipped with 6L6 power tubes. If you plan to use the EL34’s we suggest that you keep
a full set of tubes and extra fuses with you during all performances in the event of a tube failure occurring when using the currently
available EL34’s.
REAR PANEL: (Continued)
SEND LEVEL
BIAS
SELECT
DIODE
CH 1EL-346L6 CH 2 CH 3
TUBE TRACKING
RECTIFIER
SELECT
MAIN
POWER
PATENTED 4,211,893; 5,091,700; 5,168,438; 6,621,907; 6,724,897; 7,193,458; 7,602,927
LOOP
ON
CH 1
CH 2 CH 3
FTSW
100 WATT HEAD
DUAL RECTIFIER
BEST TO USE TUBE TRACKING WITH EL-34s
TUNER OUT
120 V~
60 Hz
4A
4 A
SLO
BLO
SPONGY BOLD
SEND LEVEL
BIAS
SELECT
DIODE
CH 1EL-346L6 CH 2 CH 3
TUBE TRACKING
RECTIFIER
SELECT
MAIN
POWER
PATENTED 4,211,893; 5,091,700; 5,168,438; 6,621,907; 6,724,897; 7,193,458; 7,602,927
LOOP
ON
CH 1
CH 2 CH 3
FTSW
100 WATT HEAD
DUAL RECTIFIER
BEST TO USE TUBE TRACKING WITH EL-34s
TUNER OUT
120 V~
60 Hz
4A
4 A
SLO
BLO
SPONGY BOLD
SEND LEVEL
BIAS
SELECT
DIODE
CH 1EL-346L6 CH 2 CH 3
TUBE TRACKING
RECTIFIER
SELECT
MAIN
POWER
PATENTED 4,211,893; 5,091,700; 5,168,438; 6,621,907; 6,724,897; 7,193,458; 7,602,927
LOOP
ON
CH 1
CH 2 CH 3
FTSW
100 WATT HEAD
DUAL RECTIFIER
BEST TO USE TUBE TRACKING WITH EL-34s
TUNER OUT
120 V~
60 Hz
4A
4 A
SLO
BLO
SPONGY BOLD

PAGE 15
BIAS SWITCH: (Continued)
MAKE SURE THAT THE BIAS SWITCH IS SET CORRECTLY TO MATCH THE TUBE TYPE THAT
YOU ARE USING. Failure to do this will result in tube failure that could possibly burn resistors in the Bias supply. Although
this is a fairly simple repair for an authorized technician, it is easily avoidable. ALWAYS CHECK THE BIAS SWITCH setting if
you experiment with alternate tube types and you will enjoy uninterrupted performances from your amplifier.
TUBE TRACKING / DIODE: This patented switchable feature allows you to select between two different types of rectifiers for
different sounds and feel. It first appeared on the Dual Rectifier Head and is, in fact, part of the magic behind the whole Dual Rectifier
series of amplifiers. It has since found its way into some of our other products as well, such as the Maverick,
Heartbreaker and the Blue Angel.
The Dual and Triple feature Channel Specific RECTIFIER SELECT switches that allow you to match the Recti-
fier style to the power output and preamp selections you have made to further enhance the performance of
the footswitchable sounds. The two choices each have their sonic benefits and stylistic leanings. They create
nuance and flavor that will put the Channels in iconic territory right away. By setting the Channels with differ-
ent Rectifier choices - when appropriate - you will also increase their differences and showcase the amplifiers
incredible versatility.
DIODE: (Hi Power) calls up the silicone diode rectifiers which offer more punch, a tighter attack with added brightness and substan-
tially more headroom. This would be the preferred position for loud clean playing or tight rhythmic playing with a high front end GAIN
setting. When you want the low end to track tight.
TUBE TRACKING: (Normal) This position takes a power section walk down memory lane, paying tribute to those vintage gems of
yesteryear. In those early days of amplification, the only rectifiers available were tubes. Unbeknownst to their creators, these sweet
sounding amplifiers would someday become relics as the demand for higher volumes and more power per package led to the abandon-
ment of the tube rectifier in favor of the five cent silicone diode’s greater efficiency. With this decision went much of the sweetness and
soul, and by the late 60’s, most amps were bold, loud, and efficient, and unfortunately...sometimes lacking some of that earlier soul.
We wanted the Dual Rectifier series to capture that... “thing” that you... “can’t quite put your finger on...but you know it when it’s got
it.” Soul, Personality and Feel. The VACUUM TUBE position gives you a sweetness of sound and a liquid feel that simply cannot be
duplicated in any other way. This position shines for single note lead work in Channels 2 and 3 and delivers a warm, breathing sound
in the RAW and VINTAGE modes that was previously unavailable in all but the best vintage amps.
This switch calls up the proper amount of tube rectification (number of tubes) for a given output power setting determined by the Front
Panel POWER SELECT switch found in each of the three Channels. In the 50 WATT setting one 5U4 is brought on line producing
the saggiest, most clippable power mode. In the 100 WATT selection, two 5U4 are activated ( all three 5U4 are activated in the 150
WATT mode of the TRIPLE RECTIFIER) and a higher output “vintage inspired” power voice is revealed. This setting is great for sweet,
bouncy clean work, thick hazy crunch rhythm and soulful liquid lead sounds.
REAR PANEL: (Continued)
SEND LEVEL
BIAS
SELECT
DIODE
CH 1EL-346L6 CH 2 CH 3
TUBE TRACKING
RECTIFIER
SELECT
MAIN
POWER
PATENTED 4,211,893; 5,091,700; 5,168,438; 6,621,907; 6,724,897; 7,193,458; 7,602,927
LOOP
ON
CH 1
CH 2 CH 3
FTSW
100 WATT HEAD
DUAL RECTIFIER
BEST TO USE TUBE TRACKING WITH EL-34s
TUNER OUT
120 V~
60 Hz
4A
4 A
SLO
BLO
SPONGY BOLD

PAGE 16
POWER: SPONGY & BOLD
The two different power selections of both the Dual and Triple Rectifier Heads are
equally important when looking for a particular sound. “SPONGY” works like a built in Variac, reducing all the internal voltages for a
true vintage feeling and that extraordinary “brown sound.” Power is reduced somewhat too, making it easier to achieve
an overdriven power sound, especially when the RECTIFIER SELECT switch is in the VACUUM TUBE position.
Using either Rectifier Head in this power setting will also extend tube life and overall reliability, while still producing
enough to work many of your gigs...and all of your recording needs!
With either the Dual or Triple Rectifier’s POWER SELECT switch in the BOLD position, maximum power,
clean headroom and volume are obtained.
FUSE:
This is the A.C.’s (Alternating Current) main fuse and provides protection from outside A .C. fluctuations as well as power
tube failure damage. Should the Fuse blow, replace it with the same rating in a Slo-Blo type package. The domestic U.S. version
requires a 4 amp Slo-Blo fuse. A power tube short or failure is often the cause of a blown fuse...Follow the
cold start procedure mentioned in the switch section and watch the power tubes as you flip the STANDBY
to the ON position. If a power tube is going bad or is arcing you will see it! Flip the STANDBY switch to
Standby immediately and replace the faulty power tube and the fuse if necessary.
If you see nothing abnormal as you lift the STANDBY switch, it is possible that a power tube shorted tempo-
rarily and blew the Fuse. If this is the case it may work again normally. To be safe, you might want to replace
just the adjacent tube or all power tubes in the “shotgun” troubleshooting tradition and save the replaced
set as spares. Spare fuses are a must for the fabled cord bag along with your spare tubes. Always carry both for they could be worth
their weight in gold someday.
REAR PANEL: (Continued)
SEND LEVEL
BIAS
SELECT
DIODE
CH 1EL-346L6 CH 2 CH 3
TUBE TRACKING
RECTIFIER
SELECT
MAIN
POWER
PATENTED 4,211,893; 5,091,700; 5,168,438; 6,621,907; 6,724,897; 7,193,458; 7,602,927
LOOP
ON
CH 1
CH 2 CH 3
FTSW
100 WATT HEAD
DUAL RECTIFIER
BEST TO USE TUBE TRACKING WITH EL-34s
TUNER OUT
120 V~
60 Hz
4A
4 A
SLO
BLO
SPONGY BOLD
SEND LEVEL
BIAS
SELECT
DIODE
CH 1EL-346L6 CH 2 CH 3
TUBE TRACKING
RECTIFIER
SELECT
MAIN
POWER
PATENTED 4,211,893; 5,091,700; 5,168,438; 6,621,907; 6,724,897; 7,193,458; 7,602,927
LOOP
ON
CH 1
CH 2 CH 3
FTSW
100 WATT HEAD
DUAL RECTIFIER
BEST TO USE TUBE TRACKING WITH EL-34s
TUNER OUT
120 V~
60 Hz
4A
4 A
SLO
BLO
SPONGY BOLD