-15 ™ Owner’s Manual
Hello from the Tone Farm Congratulations on your choice of the TransAtlantic TA-15 and Welcome to the MESA/ Boogie Family. The 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.
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_______________________________
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.
Instruction Manual 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.
Overview: (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.
The Modes: 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.
The Modes: (Continued) 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.
The Modes: (Continued) 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.
The Modes: (Continued) 15W: CLASS A CLASS A power has long been touted the Holy Grail of power wiring schemes for all out Tone and there is good 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.
FRONT PANEL: Controls & Features INPUT: This is the instrument INPUT jack. This jack feeds the preamp and since the TransAtlantic 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. INPUT FT SW FOOTSWITCH: This 1/4 inch mono jack is for connection of the Channel Select Footswitch.
FRONT PANEL: Controls & Features (Continued) 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 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.
A O O FRONT PANEL: Controls & Features (Continued) BASS: The BASS is probably the simplest control on the TA-15 and it simply dials in low frequencies to the mix in the preamp section. It is a less “volatile” Tone control than the TREBLE in that high settings will only cause an unbalanced sound, and not some other “stress” issue on the tubes or circuit.
FRONT PANEL: Controls & Features (Continued) CHANNEL SELECT: This 3 position mini toggle allows manual selection of the Channels when the Footswitch is not connected. Set it to the center FT-SW position to use the Channel Select Footswitch.
-15 ™ HI 1 TOP BST HI 2 ON POWER STANDBY ON INPUT FT SW 25W REAR PANEL: VOLUME TREBLE PULL BASS FT SW 15 CUT / MASTER 5W 25W 15 GAIN 5W TREBLE BASS MASTER REAR VIEW: TransAtlantic TA-15 120 V~ 60 Hz 1A FUSE 1.
SAMPLE SETTINGS Spanky Clean / Blues Vibe NORMAL -15 TWEED ™ HI 1 TOP BST HI 2 ON POWER STANDBY ON INPUT FT SW 25W VOLUME TREBLE BASS PULL 15 CUT / MASTER FT SW 5W CUT (knob pushed in) 25W 15 GAIN 5W TREBLE BASS MASTER 15W or 5W Clean Punch / Brit Crunch NORMAL -15 TWEED ™ HI 1 TOP BST HI 2 ON POWER STANDBY ON INPUT FT SW 25W VOLUME TREBLE BASS PULL 15 CUT / MASTER FT SW 5W 25W 15 GAIN 5W TREBLE BASS MASTER CUT (knob pushed in) Classic Brit Clean & Lead NORMAL
SAMPLE SETTINGS AC Solo / Vintage Clean NORMAL -15 TWEED ™ HI 1 TOP BST HI 2 ON POWER STANDBY ON INPUT FT SW 25W VOLUME TREBLE PULL BASS 15 CUT / MASTER CUT or (knob pushed in) FT SW 5W 25W 15 GAIN 5W TREBLE BASS MASTER Pull Master As Needed AC Grind / Saturated Brit NORMAL -15 TWEED ™ HI 1 TOP BST HI 2 ON POWER STANDBY ON INPUT FT SW 25W VOLUME TREBLE PULL BASS 15 CUT / MASTER CUT or (knob pushed in) FT SW 5W 25W 15 GAIN 5W TREBLE BASS MASTER Pull Master As Ne
USER SETTINGS NORMAL -15 TWEED ™ HI 1 TOP BST HI 2 ON POWER STANDBY ON INPUT FT SW 25W VOLUME TREBLE BASS PULL 15 CUT / MASTER FT SW 25W 15 5W 5W NORMAL TWEED GAIN TREBLE BASS -15 ™ HI 1 TOP BST MASTER HI 2 ON POWER STANDBY ON INPUT FT SW 25W VOLUME TREBLE BASS PULL 15 CUT / MASTER FT SW 25W 15 5W 5W NORMAL TWEED GAIN TREBLE BASS -15 ™ HI 1 TOP BST MASTER HI 2 ON POWER STANDBY ON INPUT FT SW 25W VOLUME TREBLE BASS PULL 15 CUT / MASTER FT SW 25W 15
USER SETTINGS NORMAL -15 TWEED ™ HI 1 TOP BST HI 2 ON POWER STANDBY ON INPUT FT SW 25W VOLUME TREBLE BASS PULL 15 CUT / MASTER 25W FT SW 15 5W 5W NORMAL TWEED GAIN TREBLE BASS -15 ™ HI 1 TOP BST MASTER HI 2 ON POWER STANDBY ON INPUT FT SW 25W VOLUME TREBLE BASS PULL 15 CUT / MASTER 25W FT SW 15 5W 5W NORMAL TWEED GAIN TREBLE BASS -15 ™ HI 1 TOP BST MASTER HI 2 ON POWER STANDBY ON INPUT FT SW 25W VOLUME TREBLE BASS PULL 15 CUT / MASTER 25W FT SW
TUBE NOISE & MICROPHONICS: You may occasionally experience some form of tube noise or microphonics. Certainly no cause for alarm, this quirky behavior comes with the territory and the Tone. Much like changing a light bulb, you don’t need a technician to cure these types of minor user serviceable annoyances and in fact, you’ll be amazed at how easy it is to cure tube problems...
DIAGNOSING PRE-AMP TUBE PROBLEMS: Because your amplifier is an all tube design, it is quite possible that you will at some point experience minor pre-amp tube noise. Rest assured - this is no cause for alarm and you can take care of the problem yourself in a matter of minutes by simply swapping tubes. Let us begin by saying; It is a “very good” idea to keep at least a couple of spare pre-amp tubes on hand at all times to insure uninterrupted performance.
BIAS ADJUSTMENT: (Part of a continuing series) An Article written by Randall Smith that we thought you might find interesting. CATHODE ( ) GRID ( , ) SCREEN GRID ( ) Here’s a question we often hear: “Why doesn’t Mesa put bias adjustments in their amplifiers?” BEAMCONFINING ELECTRODE ( ) .. ..... . ... . ... .. ... PLATE ( , ) Structure of a 6L6 / 5881 Beam Power Pentode. Well, there’s a short answer and a long answer to this question.
in amperes. Voltage is the degree of electric charge — like the “pressure” to use the old water analogy. Let me illustrate how different voltage and current are: When you scrape your feet across a carpeted floor in dry, wintery conditions, your body can become charged with 50,000 to 100,000 volts of static electricity. And when you reach for the door knob, a spark jumps and you feel it! The voltage is super high but the current (measured in micro-amps) is tiny - otherwise you would die from electrocution.
BIAS ADJUSTMENT: (Continued) Again, this has some merit .. but it’s still not as good as using tubes that are matched in the first place because compensating for the mis-match causes the push-pull circuit itself to become unbalanced. Two wrongs don’t really make a right. Some of the other recommended biasing, “methods” — such as — “.. tubes running red hot, increase the bias .. sounds harsh and runs too cool, turn it down ...” are guesswork at best.
SPEAKER IMPEDANCE MATCHING & HOOK-UP GUIDE: IMPEDANCE: Wiring up speakers to provide the most effective load and making sure that all of them are in phase will help in creating the best sound possible. This is not too difficult, as long as you understand a few things about loading and how to connect your speakers to provide an optimal resistive load. MESA/Boogie amplifiers can handle 4 and 8 ohms effectively.
SPEAKER IMPEDANCE MATCHING & HOOK-UP GUIDE: (Continued) PARALLEL: When wiring in parallel, the resistance of the speakers decreases. Two 8 ohm speakers wired in ( hooked-up ) Parallel results in a 4 ohm load. It’s easy to calculate the effect of a resistive load when all the speakers are all the same resistance. It is really not suggested to wire different resistive load values in Parallel ( 8 and 4, 16 and 8 etc.
WIRING SCHEMES...
6 WIRING SCHEMES...
WIRING SCHEMES...
WIRING SCHEMES...
ON TRIODES, PENTODES & IRISHMEN: With apologies to Friends and Relatives from the Emerald Isle - who will make their appearance soon enough - the humor which follows is dedicated to the memories of Spec McAuliff and Fae (Rafael) McNally, two of the True Greats. As their numerical references suggest, the terms Diode, Triode and Pentode indicate the number of elements within the vacuum tube i.e. two, three or five. All tubes also require a filament or heater which is not included in the count.
ON TRIODES, PENTODES & IRISHMEN: (Continued) Thus a diode tube - one with a cathode and an anode - is mostly used to rectify alternating current into direct current by passing it without restriction, but in one direction only. This also explains why closing time is strictly enforced at Irish pubs: During normal operation, the traffic flow is similarly unimpeded and uni-directional toward the bar and this process rectifies the work-day negativity.
PENTODES: (Continued) Thus the proper cocktail waitress - visible through the louvers - is scantily clad so as to be all the more effective at reinforcing the attractive influence of her bar and by being located in between the door and the bar, she serves as bait to lure customers past the door’s negative influence.
Removing the TransAtlantic Cover for Tube Replacement **** Before removing cover make sure the amplifier is powered off and the AC cord is unplugged. Remove the two screws from the left and right side of the amplifier. Caution: There are two wires connecting the chassis to the cover. Do not lift the cover straight up. Carefully rotate the cover forward maintaining close distance between the chassis and front of the cover.
TransAtlantic TA-15 Tube Replacement V4 V5 4 x 12AX7 2x EL 84 V3 V2 REAR OF CHASSIS V1 FRONT OF CHASSIS BEFORE CHANGING TUBES FLIP POWER SWITCH TO OFF V6 5 Watts = V6 15 Watts = V5, V6 25 Watts = V5, V6 Power Tubes To maintain warranty use Mesa/Boogie tubes when replacement is necessary 1317 Ross Street • Petaluma, California 94954 • (707) 778-6565 Preamp Tubes - Input Stage for Ch2 - 2nd Gain Stage for Ch2 V1A&B - Parallel Input Stages for Ch1 V2A V2B V3A&B - Tone Control Driver for Ch’
590792 TREBLE ALL FRONT PANEL KNOBS PT# 408620 VOLUME 590155 FRONT PANEL: TransAtlantic TA-15 INPUT FT SW JACK x 2 pt# 619112 120 V~ 60 Hz 1A 1.25 A SLO BLO A.C.
MESA BOOGIE The Spirit of Art in Technology Thank you for trusting MESA/Boogie to be your amplifier company and we wish you many years of toneful enjoyment from this handbuilt all tube instrument.
The Spirit of Art in Technology (707) 778-6565 FAX NO.
