LEVEL A/B

These two pots control the volume level of each side or channel of the 2:90. Since there's only one Standby Switch on this unit they may also be useful as channel muting controls. NOTE: If only one speaker is to be used on one channel and no speaker load on the other, always turn the unused channel’s Level Control to zero. To prevent oscillation (motorboating) turn the Presence Control of that channel all the way up.

PRESENCE A/B

These controls "open up" the 2:90 producing brightness and sparkle for clean sounds at higher settings or sizzle and edge when set high for distortion sounds. At lower Presence settings you can darken and compress lead sounds making them warmer and fatter. Turning the presence controls to zero "chokes the brights" completely, making the 2:90 great for jazz clean sounds or round vocal lead work.

POWER/STANDBY

These two toggles located next to the Presence controls deliver A.C. Mains voltage and D.C. filament voltage. When powering up cold - always turn the power on first - wait 30 seconds - then turn the Standby on. This procedure reduces shock on cold tubes and prolongs tube life. Remembering to use the Standby on set breaks also prolongs tube life. NOTE: Power tube life varies depending on many factors i.e. how much you play, how long you play, how you treat your equipment etc. We've found that most discerning pro's who use their gear five to seven nights a week start noticing some tone loss somewhere around 8 months to a year. Some people, however, use the same set of power tubes for years with no complaints. We recommend changing your power tubes once a year if you play a lot. This way you're ensured of smooth operation and optimum tone. Always use MESA power tubes of matching color codes whenever possible. These are matched correctly and hammer tested, and actually cost less than the so called matched competitors in most cases. Also, it keeps your 2:90's warranty intact.

MAIN FUSE

The recessed grey fuse cap located above the Pilot light holds the 290's main fuse. Should this fuse blow, replace it with SLO-BLO type of an appropriate rating. Domestic and Canada use 6 1/4 amp SLO-BLO. Disregard the 4 amp labeling - this is for units not wired for 117v operation.

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Mesa/Boogie 2:90 manual Level A/B, Presence A/B, Power/Standby, Main Fuse
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2:90 specifications

The Mesa/Boogie 2:90 power amplifier is a revered piece of equipment in the world of guitar amplification, known for its exceptional sound quality, robust construction, and versatile features. This powerhouse is designed with a distinct capability to enhance both studio recordings and live performances, making it a popular choice among professional musicians and tone enthusiasts alike.

One of the defining characteristics of the Mesa/Boogie 2:90 is its Class A/B power design, which affords a unique blend of power, warmth, and clarity. The amplifier delivers 90 watts per channel, providing ample headroom while maintaining exceptional tonal fidelity. This robust output allows it to handle high volume levels without sacrificing sound quality, making it ideal for both small venues and large stages.

The 2:90 features dual EL84 power tubes that impart a rich harmonic character, ensuring that players receive a full-bodied sound with impressive dynamic range. The use of these tubes is instrumental in producing the warm, vintage-like tones that musicians crave, while the overall design ensures that the amplifier reacts responsively to the guitarist’s playing style.

Another key feature of the Mesa/Boogie 2:90 is its dual-channel architecture, which allows for a wide range of tonal possibilities. Each channel can be tailored to different musical styles, offering controls for gain, treble, midrange, and bass, which provide users with the ability to sculpt their sound precisely. Additionally, the amp includes a “presence” knob that further enhances the high frequencies, adding clarity and sparkle to the tone.

The reliability of the amplifier is bolstered by its rugged construction. Built into a durable chassis, the 2:90 is designed to withstand the rigors of touring and frequent use. The internal cooling system ensures optimal performance, preventing overheating even under the most demanding conditions.

In conclusion, the Mesa/Boogie 2:90 power amplifier stands out as a versatile and powerful option for guitarists seeking top-notch sound quality and reliability. With its Class A/B design, dynamic tube-driven character, dual-channel flexibility, and rugged build, it remains an enduring favorite in the music industry. Whether in the studio or on stage, the 2:90 is capable of delivering a rich and dynamic audio experience that meets the demanding needs of today’s musicians.
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