Mesa Boogie TransAtlantic TA-15 User Manual
Owner’s Manual
Hello from the Tone Farm
Congratulations on your choice of the Tr a n s aT l a n T i c TA-15 and Welcome to the MESA/
Boogie Family. e instrument you have chosen redefines the micro amp genre by including
preamp and power options that seem near impossible for an amplifier with such a humble
footprint. However, don’t judge this dynamo by its size, but rather by the incredible Tone
it produces that will allow you to access new levels of inspiration and expression.
Two footswitchable Channels cross the Atlantic with seamless finesse and give you a passport to the best British and American preamp sounds in two straightforward groups of
four controls. e five preamp modes (2 in Ch.1 - 3 in Ch. 2) are selected with a simple
mini toggle located in the top position in each Channel. Along with this array of iconic
preamps the TA-15 offers three amazing power choices in each Channel, each of which allow you to perfectly tune the power to enhance each of the the preamp Modes. e result of
all this flexibility is a fully capable live performance amp that would fit in your lunchbox,
as well as a recording chameleon that can morph into virtually any classic you might need
in the studio.
Our 40 year commitment to excellence along with our solemn promise to musicians - to
treat each of them as we ourselves would wish to be treated - guarantees you an experience
that will make you feel truly justified in your choice. We’re confident your new amplifier
will have you smiling and inspired within minutes of plugging in for the first time. However, what’s really gratifying is that you will be finding new and inspiring sounds years
after the price of admission has faded from memory and the Tr a n s aT l a n T i c continues to
unveil its true worth.
It’s with our sincere thanks for trusting us with your TONE and our best wishes for all
your musical endeavors that we welcome you home. Should you ever need assistance or
guidance we’re here to help. You now have in your hands an instrument of limitless expression. Our hope is that it takes you and your playing to new and unimagined places
throughout your musical journey. From all of us here at MESA…Enjoy!
TABLE OF CONTENTS
OVERVIEW _______________________________________________________________________ 1-2
HELPFUL HINTS __________________________________________________________________ 2-3
FRONT PANEL CONTROLS & FEATURES
THE MODES: NORMAL, TOP BOOST ____________________________________________________3
THE MODES: TWEED, HI 1, HI 2 ______________________________________________________ 4-5
POWER MODES: MULTI-WATT POWER ________________________________________________ 5-6
INPUT _____________________________________________________________________________7
FOOTSWITCH_______________________________________________________________________7
VOLUME / GAIN ___________________________________________________________________ 7-8
TREBLE ___________________________________________________________________________8
BASS ______________________________________________________________________________9
CUT / PULL MASTER _________________________________________________________________9
CHANNEL SELECT _________________________________________________________________10
MASTER: CHANNEL 2 _______________________________________________________________10
POWER: OFF / ON & STANDBY _______________________________________________________10
REAR PANEL CONTROLS, SWITCHES & JACKS
FUSE _____________________________________________________________________________11
A.C. RECEPTACLE __________________________________________________________________11
SPEAKERS ________________________________________________________________________11
FACTORY SAMPLE SETTINGS & PERSONAL SETTINGS SHEETS _______________________ 12-15
TUBE MAINTENANCE & DIAGNOSIS ________________________________________________ 16-17
BIAS ADJUSTMENT: A feature article by Randall Smith _______________________________ 18-20
SPEAKER IMPEDANCE & POSSIBLE HOOK-UP SCHEMES - Amps to Speaker Cab ________ 21-26
TRIODES, PENTODES & IRISHMEN: A feature article on the workings of tubes ____________ 27-29
TUBE DESCRIPTION & TASK CHART __________________________________________________30
PARTS SHEET _____________________________________________________________________31
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.
Instruction Manual
CAUTION:
Unplug power
before replacing
fuse
120 V~
60 Hz
2 A
2 A
SLO
BLO
SPEAKERS
8 OHM
PATENTED
6,621,907
7,173,488
7,602,927
CAUTION: CHASSIS SURFACE MAY BE HOT!
4 OHM
TRANSATLANTIC
TA-15
HANDBUILT IN PETALUMA, CAALL T UBE AMPLIFIER
®
CAUTION!
WARNING!
TUBE GUIDE
4 x 12AX7
2 x EL 84
F
U
S
E
F
U
S
E
INPUT
FT SW
VOLUME TREBLE BASS GAIN TREBLE BASS MASTER
POWER
STANDBY
NORMAL
15 15
HI 1
TOP BST
25W
FT
SW
5W
TWEED
HI 2
25W
5W
ON
ON
MASTER
PULL
CUT /
™
-15
Overview:
While the TA-15 control layout is rather sparse (compared to some MESA’s), there is a lot more going on internally than might be
apparent at first glance. Make no mistake, this is not a low line offering, but rather a power experiment in the world of micro. In every
way the TA-15 stands proud alongside any of our larger multi channel offerings with the same components, build quality, versatility
and performance… an equal in every way except mass.
The two Channels offer Mode choices that roam the Atlantic with Channel 1 focusing on the British side of the Pond and Channel 2
incorporating both British and American sounds.
Channel 1 offers two Modes that pay tribute to the Vox heritage; a lower gain NORMAL Mode that delivers shimmering higher headroom
clean sounds and TOP BOOST, our take on one of the most iconic Brit sounds that excels at clipped rhythm and lead sounds.
Channel 2 packs three Modes and this Channel alone offers more stylistically divergent landscapes than many whole amps. TWEED
follows the Southern Cal vintage line to deliver gorgeous clean chording sounds that have more low end and breathy air than Channel
1’s NORMAL mode and yet, clips smooth and furry when pushed. From there HI 1 jumps back to the U.K. for a Brit style higher gain
Mode that, when set lower, romps on vintage crunch rhythm sounds with stripped urgency. It also delivers searing high gain solo
sounds that retain a crisp, definitive attack as the GAIN control is cranked. Finally, another crossing and you’re back in Petaluma,
CA for the smooth warmth of the high gain Boogie lead voice found in HI 2. This Mode adds low end girth and sweetens the attack
frequencies to produced a fatter, rounder tone that is great for single note work.
Add to all this preamp versatility our patented Multi-Watt™ Power and you have the ultimate tools to craft a sound that is all yours.
Multi-Watt allows you to match one of three perfect power response characteristics to each of the Modes and footswitch between
two iconic sounds.
The 5W position on the mini toggle in each Channel captures the old world magic of 5 watts running in Single-Ended Class A which
along with being ultimately clippable, emphasizes the even order 2nd harmonic and produces a truly precious blend of warmth and
lined-up, chiming harmonics at low playing volumes.
FRONT VIEW: Tr a n s aT l a n T i c TA-15
REAR VIEW: Tr a n s aT l a n T i c TA-15
PAGE 1
Ov e r v i e w : (Continued)
The 15 setting brings on a Push-Pull wiring scheme while remaining in Class A and pumps up the wattage for the perfect blend of
vintage sound, manageable power and sweet, smooth clip.
From there things take a leap forward in time and power to our Patented Dyna-Watt™ power in the upper 25W position. This incredibly dynamic power scheme switches the wiring style to Class AB and allows the headroom to increase dramatically – more than you
would ever expect from a 25 watt amp - by unleashing a burst of power at the instant of attack. Voltage is stored and released in a
time-specific burst in the power supply as you play, creating punch headroom and tight-tracking authority well beyond your expectations of a “little amp”.
All this control over both the preamp architecture and power section wiring styles combined with the simplicity of the Gain and Tone
Controls create a package that allows for instant gratification and long-term exploration. How you choose to enjoy the Tr a n s aT l a n T i c
TA-15 is your call, but we feel confident that no matter what type of stylistic arena you find yourself in, the tools are here for you to
craft your own signature version of these classic sounds.
HELPFUL HINTS:
Cut the cable tie that holds the AC Power Cord to the Rear Tube Cover and connect it to a Grounded AC wall socket.1.
Connect the Mono ¼” Footswitch Cable to the Front Panel ¼” jack labeled FOOTSWITCH using the supplied Mono Cable.2.
Set the amplifier (and at least one speaker cabinet) on the floor you will be standing (or sitting on) while playing to complete the 3.
coupling circle that occurs. This will make the amplifier sound better, as well as feel better to play, because the sympathetic loop
created by the transmission from your hands to the guitar to the amp to your guitar to your hands remains unbroken.
When powering up (especially from cold), always allow the power tubes time to warm up before hitting them with high voltage 4.
(STANDBY ON and playing). Turn POWER to ON, wait at least 30 seconds, then turn STANDBY to ON.
The center mini toggle labeled FT SW provides manual access to the Channels when the Footswitch is not connected. Left calls 5.
up Channel 1, right calls up Channel 2. To use the Footswitch to access the Channels, select the FT SW (center position)
and connect the Footswitch to the jack on the left bottom of the Faceplate labeled FT SW.
A good general rule to follow; As the GAIN goes up, the BASS should come down. This will help prevent low-end flub and tubbi-6.
ness and keep the attack tracking tighter. This is especially true in the TOP BOOST Mode of Channel 1 and the TWEED Mode
of Channel 2 when searching for pushed sounds that lie somewhere between clean and dirty.
The CUT control in Channel 1 has a PULL MASTER function that allows you to run with the traditional “no master” architecture or, 7.
pull the CUT control and use that pot as a MASTER volume control for more overdriven sounds at lower playing volumes. When
in the MASTER-Active mode, the CUT control is hard-wired to a medium setting that is balanced between open and compressed.
If you are using Channel 1 in the MASTER-Active mode all the time and find this CUT setting unusable (most people have been
very happy with this scheme), call and ask to speak to a Product Specialist. They may be able to assist you or a qualified tech
(not covered by warranty) in changing this hard-wired setting. You could also send the amp back to us (shipping both ways paid
by you) and we will change it toward the direction you need for a nominal charge.
You will experience more footswitching noise (pop) when switching between Channels when only one is set to the 5W power 8.
setting. This is due to the more radical voltage changes that occur when knocking the power section down to the 5W level from
one of the higher power modes. (Using both Channels in 5W will not create excess noise as the voltage doesn’t change). May
we suggest when configuring your Channels for live performance footswitching applications, try using the 15 and 25W power
modes whenever possible as the voltage swings are not as great. This will provide the quietest footswitching performance.
PAGE 2
HELPFUL HINTS: (Continued)
GAIN
NORMAL
15 15
HI 1
TOP BST
25W
FT
SW
5W
TWEED
HI 2
25W
5W
Now that you have an overview of the TA-15, let’s get more specific with the Modes and controls to learn how they can help you
achieve the sounds you are looking for.
Th e MO d e s :
CHANNEL 1:
NORMAL:
This mode takes its architecture from the TOP BOOST circuitry and removes gain, adds brightness and fills out
the bottom with a little more air and dimension. It works best for clean work and provides substantially more headroom than TOP
BOOST. NORMAL is the choice when you need more stripped urgent clean sounds that will tuck up nicely in a mix. It is probably
not the best choice for overdriven or clipped rhythm sounds as there is not quite enough gain to smooth out the jagged edges, and
because of the added brightness it can sound a bit toward the ragged and buzzy when pushed too hard with
weaker pickups.
TOP BOOST:
This Mode represents our tribute to the amazing legacy of the British darling VOX. The
TOP BOOST circuit has appeared in countless Boutique renderings of the last 20 years and is considered
one of the must have staples in classic Rock guitar. Out of respect we chose to refrain from treading on this
hallowed ground until such time as we could bring something worthwhile to the party… not to simply duplicate,
but rather enhance this iconic sound. Well, with the inclusion of our patented Multi-Watt™ Channel Assignable Power and several
other “trade secrets” we’ve unearthed over the last 40 years of amp design, the time has come to redefine a classic. Only you can be
the judge if we’ve added something beautiful to the original, but our comparisons and the comments of our brothers in tone around
the world… including our English ones, leave us feeling pleased with a job well done.
TOP BOOST is great for many things from urgent jangly cleans with a bit of attitude to full on saturated solo sounds, but probably
its greatest asset is seen when riding the edge of clip. It seems to transition almost seamlessly from clean to saturation for there
are many subtle graduations within this usually small realm that widen it to resemble an entire empire - instead of a narrow, hard to
fine-tune band.
The choices found in the Multi-Watt Power switch greatly expand this edge-of-clip area and adds color to the mix along with harmonic
and volume changes. For the most traditional response the 15W setting will provide the best blend of characteristics and the best balance of volume versus clippability. If you’ve ever played an AC 15 you will instantly fall into familiar territory where the subtle changes
in your picking can push things in and out of clip with amazing expression. The 15W Power Mode also works well with TOP BOOST
for using the guitar’s Volume control to take you from clean to varying degrees of saturation by rolling up and down without losing the
sweet harmonic top end spectrum.
The 5W Power Mode will provide a sweeter blend of upper harmonics and allow you to bring the onset of clip down to very low
volume levels. Watch the BASS control setting in 5W as the lower power is not capable of managing high levels of GAIN and BASS
together. If you intend to run the GAIN control high when in 5W don’t be surprised to see your BASS control below 10:00 – or even
off – to achieve tight tracking bottom end response. The (Dyna-Watt) 25W Power Mode will respond the opposite way and allow you
to run both GAIN and BASS higher than in either 5W or 15W Modes. This mode is probably better suited to when you are using TOP
BOOST for either really clean (GAIN 10:00 or below) or really heavy sounds (GAIN above 3:00) where you need the bottom end tight
and percussive. In these two regions the extra power and headroom along with the accentuation in the upper mids that comes with
this burst of attack-instant voltage release really focuses things and adds authority.
PAGE 3
Th e MO d e s : (Co n t i n u e d )
GAIN
NORMAL
15 15
HI 1
TOP BST
25W
FT
SW
5W
TWEED
HI 2
25W
5W
CHANNEL 2:
TWEED:
This is the lowest gain of the three Modes in Channel 2 and is aimed at clean and edge of clip sounds. It draws the
framework of its circuit architecture from the early tweed amps from Southern Cal and then gets a healthy dose of magic from the 40
years of little secrets we’ve discovered to arrive at a beyond vintage level of Tone and performance.
When using TWEED for clean work the 15W and 25W (Dyna-Watt) Power Modes provide the best blend of
sparkle, warmth and headroom – with the 25W being the obvious choice for live performance situations. To
explore the world of soft clip sounds in TWEED, set the GAIN high (3:00 – 5:30), the BASS low (8:00 – 10:30)
and ponder the differences in 5W and 15W until you find just the right response for your needs.
Just keep in mind that it is always a good idea when looking for overdriven sounds, especially in the TWEED
and NORMAL Modes, to reduce the BASS setting as you increase the GAIN control. This will avoid flubbiness and keep the attack
tight and focused.
HI 1:
We’re back across the water again for a high gain tribute to the other great British amp and HI 1 captures all the tight attack,
thumpy, tight bottom and midrange cut for which these amps are famous. HI 1 is the choice anytime you need attack and a higher,
quicker feeling bottom end response.
Many players prefer this circuit for crunch or overdriven rhythmic playing, citing its percussive nature tracks tighter in the hands and
is more defined in a mix. It also shines for use with shorter scale mahogany guitars that have a woodier, throatier top end and more
lower midrange as a dominant part of their character.
When looking for single note solo sounds in HI 1 it may be necessary to run the TREBLE a little lower than you would for high gain
chording, say somewhere in the 9:30 – 10:30 range to soften the attack and round out the notes a bit for a smoother more vocal
character. When dialing up lower gain sounds in HI 1, whether for chording or lead work, try setting the BASS rather high - 1:30 –
3:30 – to add air and girth to the sound. In general, you can apply the BASS a little more liberally in HI 1 than in some of the other
Modes as the increased upper midrange attack present here will keep things tighter longer and the frequency of BASS is a bit higher
than in HI 2, so it can follow the attack a little easier in the time domain.
As far as power matching, HI 1 is pretty friendly with all three choices, however 15W and 25W showcase the classic Brit response best
with 15W leaning toward smoother soloing and 25W excelling at tight percussive chording. The 5W position works good for lower to
medium gain soloing, but don’t expect it to be as tight or percussive for the rhythmic work as the two higher power Modes.
HI 2:
to Sonoma County, famous for wine and high gain guitar sounds. HI 2 is all about Boogie. Smooth, round attack, molten sustain and
lined up layers of harmonics. This Mode is all about soloing. While you are welcome to explore its virtues for chording, it is single
notes that most benefit from the deeper lows, slightly tucked mids and higher harmonic landscape found in this classic sound.
In the Tr a n s aT l a n T i c however, for continuity’s sake, we’ve leaned just a pinch in the direction of HI 1 – slightly higher mid frequencies,
a little more attack and a touch higher BASS than in other Boogie lead modes for two reasons. First, lower power amplifiers are simply
not capable of pushing (steering/controlling) sub-low frequencies like their high power counterparts. They choke and lose definition
when the BASS is too low and use all their available power trying to drag the low frequencies around. Second, guitarists – for the
most part - are extremely conservative when it comes to sounds. Since most of us grew up listening to the same references, we want
to hear easily identifiable classic sounds that fit into a category when we try an amp or guitar. We’ve seen over the years that players
tend to stumble when there is a sound or mode in an amp that strays very far outside the “basic vibe” or style they perceive to be its
“thang”. For this reason we found it instantly more digestible to more players when we keep things more closely related.
Grab your suitcase, as again we cross the Atlantic on our tour of the world’s most classic guitar sounds. This time we’re back
PAGE 4
Th e MO d e s : (Co n t i n u e d )
GAIN
NORMAL
15 15
HI 1
TOP BST
25W
FT
SW
5W
TWEED
HI 2
25W
5W
So in HI 2 you will find all the desirable qualities of your favorite Boogie high gain Mode, but find them fine tuned in a way that sits
beautifully alongside the British flavor of HI 1. Plenty of difference to be recognizable… but not so different that it sticks out and feels
out of place.
Power-wise HI 2 works well with all three choices. For bold authority and the greatest dynamic content, the 25W would be the choice.
If you want a more liquid feel and more upper harmonic content, 15W is your ticket. And for all out insanity at whisper volumes for
tracking there is always 5W with the greater potential to add power Tube overdrive. Don’t overlook the 5W setting for lower gain solo
sounds… especially in the studio. Some awesome lower gain Blues sounds are possible by setting the GAIN control low, say 10:00
– 11:00 and cranking the MASTER in the 5W Mode. You might have to reduce the BASS a bit to keep the attack focused, but it’s very
expressive with a different harmonic signature than getting all the gain from the preamp.
POWER MODES: MULTI-WATT™ POWER
While the Tr a n s aT l a n T i c TA-15 is a veritable treasure chest of preamp sounds with the five different circuits tucked away in its hold,
the Tone shaping choices don’t, by any means, stop there. We always say “it’s 50% front end and 50% power”.
The power section in any amp has a great deal to do with its response, character and feel. The TA-15 is just as
well endowed in the power play as it is in preamp choices.
Our patented Multi-Watt™ Power allows not only the choice of Class of Operation, but also a choice in Wiring
Configuration. You get three distinctly different power sections – each with its own character and feel to link - per
Channel - with the preamp sounds you have crafted. The 5W and 15 W are old school classic power sections
with their own signature voice and response and the TA-15 would be amazing with these two alone. But we
had another patented secret up our sleeve and along with these two vintage-minded gems we’ve included a 25W Dyna-Watt™ power
Mode.
Dyna-Watt™ has been appearing on lower power MESA amplifiers since 1986 when we released our STUDIO 22 combo. We’ve been
using it ever since to shock people with an instantaneous burst of headroom and power present at the attack of the notes. Dyna-Watt
stores and releases a burst of extra power and then sags in a time specific curve to deliver the boldness and punch of a big amp, with
the light weight and friendly clip-ability of a low power amp. This addition allows the Tr a n s aT l a n T i c to be much more than a cute little
desktop recording or practice amp, but rather a chameleon that can handle a diverse style of applications from low volume practicing
to studio ace to medium size performance amp depending on how you choose to interface cabinetry.
5W: CLASS A SINGLE ENDED
wiring configuration produce the most vintage clip characteristics with a super smooth transition into power overdrive and an emphasis on the even order 2nd harmonic. The 2nd is an octave above the note you are playing and is the sweetest, most musical of
all. Single-Ended wiring cancels out the harsher 3rd harmonic and allows the 2nd to put the angels touch on your tone. Low volume
clean playing is absolutely gorgeous in this Mode in NORMAL or TWEED and may well become your favorite for practicing as you
save your ears for the gigs.
The 5W setting is also great for overdriven sounds and when used with a degree of restraint on the GAIN control, can produce some
of the best recording sounds ever. Remember that the 5W Mode can’t drive the same amount of low end with control as the other
two Power Modes and if you try the same sounds that work with those without adjusting both GAIN and BASS, you may end up with
mush. The power section will inevitably be adding some additional overdrive and the BASS will not be able to stay tight. It’s a good
idea to craft tones with the power available in mind with the Mode you have chosen at all times. It is 50% responsible for the end
result and if you learn to use both preamp and power Modes in harmony, you will find the TA-15 to be one of the most expressive
and versatile amps anywhere.
This lowest output Mode is by no means the weakest. Its Class A biasing and Single-Ended
PAGE 5
Th e MO d e s : (Co n t i n u e d )
15W: CLASS A
reason. It produces an extremely smooth transition into clip, lush harmonics and an angelic quality to the sound. When pushed to clip, it
responds with soft transients and never sounds harsh ever at the extremes. The TA-15 puts this to good use by combining it with some of
the most classic preamp circuits to allow a collection of the most sought after vintage circuits to exist in one very portable instrument.
The 15W Mode is great for both clean and overdrive sounds with enough power to provide ample headroom but low enough sweet sounding
power to ride the edge of soft clip easily and controllably. This 15W Mode works great for players who prefer using the guitar’s Volume
control to step seamlessly in and out of the soft clip realm. This concept works well in both the two low gain preamp Modes NORMAL
and TWEED as well as the three higher gain choices. The most dynamically responsive however will be TWEED (and to some degree
NORMAL) as TWEED has just enough gain at the top of its range to assist in being the perfect zone between clean and drive.
The 15 W Mode is by far our favorite for the TOP BOOST preamp Mode and this combination holds true to the legendary circuit and
performance this Mode pays tribute to. This power choice sweetens the jangly harmonics and cutting high mids present in the preamp
and sounds open and bouncy as you roam between soft clip and all out overdrive. It is especially cool when the GAIN is cranked for
single note soloing as the harmonic content is lush and creates an easy to play feel. Just remember to dial back the BASS a bit to
keep things tracking well.
The same goes for using 15W in combination with HI 1 and 2. This combo produces a beautiful harmonic richness, but watch the
amount of BASS you dial in, for it can get “slow” real fast if your not careful. Remember that these lower power settings simply don’t
have the horsepower to lead a bass-heavy signal around with any confidence.
25W: DYNA-WATT™ POWER
1986 when we released our STUDIO 22 combo. This patented power harness delivers way more sonic impact that you would expect
from an amp of this power rating and it does so with shocking speed and clarity.
CLASS A power has long been touted the Holy Grail of power wiring schemes for all out Tone and there is good
As we mentioned earlier Dyna-Watt™ has been appearing on lower power MESA amplifiers since
It’s all about dynamics! By storing up extra energy, releasing it at the instant of attack and then allowing the power to sag at a specific
rate, a dynamic envelope is created that translates into a musical bounce. The strings come alive and everything has a bouncy, alive
feel. Along with this tactile benefit there is the increase in perceived headroom and, because this extra energy is available at the instant
of attack, Dyna-Watt can manage larger amounts of low end than that of your more commonly-wired 25W power section or the 5W
and 15W Power Modes.
For clean work 25W has the headroom and spank to get over other instruments in a mix (in a situation realistic to its obvious limitations).
It will stay the tightest at the upper limits of the TA-15’s powerband as well as having more bold midrange punch and attack.
When searching for high gain sounds – especially for heavy, tight rhythm parts - that can track well and stay percussive Dyna-Watt
is definitely the choice. This will allow you to dump in the maximum amount of GAIN and BASS and still have some dynamic control
over things. It also works well for low gain Bluesy solo sounds where you want to jab in and out dynamically, sparring with the vocal
to create an exciting interplay.
PAGE 6
INPUT:
FRONT PANEL: Controls & Features
INPUT
FT SW
INPUT
FT SW
VOLUME TREBLE BASS GAIN TREBLE BASS MASTER
POWER
STANDBY
NORMAL
15 15
HI 1
TOP BST
25W
FT
SW
5W
TWEED
HI 2
25W
5W
ON
ON
MASTER
PULL
CUT /
™
-15
GAIN
15
HI 1
TWEED
HI 2
25W
5W
This is the instrument INPUT jack. This jack feeds the preamp and since the Tr a n s aT l a n T i c is a high gain amplifier and
therefore very sensitive, always use a high quality shielded cable between the instrument and the amplifier. This will prevent unwanted
noise and microphonic cable sounds.
FOOTSWITCH:
This 1/4 inch stereo jack is for connection of the Channel Select Footswitch. When the FOOTSWITCH is con-
nected here with the provided mono cable, the Channels can be controlled remotely.
VOLUME / GAIN:
These are the main front end controls in the preamp, no matter what Channel or Mode you are in, and they
meter the amount of tube drive or saturation present in the signal. These controls are called by different names (VOLUME) in Channel
1 and (GAIN) in Channel 2, but they function in the same way and do essentially the same job…
control the gain in the preamp. Their location in the circuit moves around depending on which Mode
is called up, but their function remains the same - they determine the attack character, headroom
and ultimately – how clean or dirty a given sound will be. For simplicity, from here forward we will
use the word GAIN to speak of the front end control in both Channels - even though it is labeled
VOLUME in Channel 1.
The GAIN also brings in and out upper harmonic content, depending on where it is set. As a
general rule, the lower the setting – the more upper harmonics there are passing through. As you increase the GAIN, the natural tube
saturation and compression fills in the sound, making things darker and more “round”. This trait can be used to your advantage – and
in fact serves the practical applications well – as it means that lower gain clean sounds remain open and dynamic with abundant
harmonics, while higher gain lead sounds get more compressed, warmer and more vocal.
Because the TA-15 is essentially a low power instrument (even though it’s loud), using the GAIN control tastefully, with finesse and
always with the Power Mode choice in mind is critical to achieving the best overall Tone. Unlike a 100 watt amplifier, the TA-15 is
most always adding some amount of overdrive or soft-clip into the mix – that’s part of its attraction – so it’s crucial to take that into
account to keep your attack intact and preserve the dynamic content of your sound.
IMPORTANT ! Many of the TA-15’s best sounds are found with the GAIN control set in its middle range – somewhere in the 11:00
– 2:00 region. You’ll be pleased to discover all the nuance and expression found here – especially when you start to use the Power
Modes as part of your Tone Crafting regimen. You’ll quickly find so much shaping power across those three hours (11:00 – 2:00) on the
GAIN’s Tone Clock that you may seldom roam the higher regions as the balance between preamp and power is truly magical here.
If you do need to run the GAIN in its upper region for high gain heavy styles, then your best plan of action is to stick with the 25W
Power Mode - as this will keep the low end as tight as possible and track the dynamic passages with more accuracy. However, don’t
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expect the same type of response you would find with these heavier sounds as you would from a 100 watt amp. The TA-15 is indeed
FRONT PANEL: Controls & Features
(Continued)
POWER
STANDBY
NORMAL
15 15
HI 1
TOP BST
25W
FT
SW
5W
TWEED
HI 2
25W
5W
ON
ON
MASTER
PULL
CUT /
™
-15
mighty in its class… but those little EL84’s can’t handle massive amounts of both preamp gain and huge low end like an amp running
the larger octal-based 6L6 or EL34 type power tubes. Running the GAIN control high in the 15W and 5W Modes in perfectly fine to
do, it just won’t keep the attack very focused… especially as you increase the playing loudness.
NOTE - CHANNEL 1: In Channel 1 the VOLUME control is both the front end (GAIN) control and the playing loudness or “master”
control as well. We wanted to pay tribute to these sounds in the most reverent way and there was no master volume control on the
original amplifiers - so as you turn up the VOLUME control in CHANNEL 1 - you are adding (gain) saturation AND turning up the
playing volume. Purists have long identified with this “no master” scheme - citing its more urgent response, clarity and dynamic touch
sensitivity. We agree with these observations to some degree – for these types of circuits – but there is little doubt that the trade-off
for this stripped “no-master” approach is difficult to overlook when it comes to the flexibility department.
So we gave you a choice by including a cool new feature for this type of circuit. When you need the old-school response of the original
“no-master” scheme and the gain versus volume issues that inherently arise from this scenario are not a problem… crank it up and
Rock!
But for those times when you do need control over the gain and saturation independent of the playing volume… pull the CUT control
out and… problem solved, you now have a MASTER volume control! The CUT is preset to about 1/3 of the way on (rolling off just a
little top end) and the same pot now functions as a fully independent MASTER volume control.
Again…Pushed In, the CUT/PULL MASTER control functions as a CUT control (rolling off high frequencies as you increase the
control clockwise - almost like a reverse PRESENCE control). Pulled Out, the CUT/PULL MASTER control becomes an inde-
pendent MASTER volume.
This “mod” to the original “vintage” architecture greatly enhances the flexibility of both NORMAL and TOP BOOST Modes and allows
you to use them for many more sounds and footswitchable scenarios. It opens up the landscape for these sounds to be applied in
new ways and allows them to interface to the modern world of sounds and yet retain their expressive charm and harmonic identity.
TREBLE:
This control, while being the second most powerful control in the preamp, is very simple to operate… and when you’ve
dialed in a little too much, it’s easy to tell right away. The TREBLE controls how much of the high frequencies in
the preamp will be blended in to the signal. This is another control to use in the middle ranges to produce the best
balance of tone and noise. The TREBLE can bring in unwanted noise (hiss) when set to the extreme high end of
its range (3:00 – 5:30) so avoid setting the TREBLE this high whenever possible.
Like the GAIN, the best sounds are found with the TREBLE in it’s middle range where an equal blend of highs from
here are mixed in with the lows from the BASS (and GAIN). If you need things brighter in CHANNEL 1 - try leaving
the CUT control set low (9:00 – 7:00). The top end that comes from there comes later down the line in the signal
path - closer to the power section - and will produce less likelihood of noise and task the preamp tubes less.
Very high settings of the TREBLE control will increase the likelihood of microphonic tubes to start making noise and begin ringing or
feeding back. It just adds too much top end into the signal path early and this is then amplified again and again making any sensitive
tubes show their weaker side. This will be most critical in TOP BOOST in Channel 1 and both HI 1 and HI 2 in Channel 2 where the
higher gain present will put more scrutiny on the preamp tubes.
In the TOP BOOST Mode of Channel 1 and the HI 1 Mode of Channel 2 you may find that the TREBLE wants to be set a bit lower
than in some of the other modes and it is not uncommon to find it set below11:00 for many great sounds… especially solo tones.
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