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. Luckily, one of the great things about tube amps is that they can usually stand some abuse without causing any real harm ... at least not immediately.

But don’t these alterations imply that you are second-guessing the amp designer and that there’s a better set of operating conditions that the designer missed but the tube sellers have discovered?

Now some players may like the sound of their amp altered by tubes with extreme characteristics and with the bias set to help compensate. But often it is the mere novelty of change that they’re really responding to and when the amp goes back to the proper original way, we’ve seen them be far happier still!

Because every part in every one of our designs has been meticulously evaluated, compared and stressed over — no matter how seemingly insignificant it might be. And with every design we look for a “sweet spot” where all the parameters — including the bias — come together to give the best sonic performance, consistently and reliably. Every part and voltage is important — yet no one complains that these other parameters aren’t available for tinkering.

Consider our patented Simul-Classcircuitry where there are two different bias voltages used for separate pairs of power tubes ... and changing one voltage also changes the other. Great care goes into getting this just right and we think we’d be asking for trouble to have it adjustable for the world to play with ... unless you like paying to have your amp messed up. Sorry, I meant to say, “Uh, ... your amp needed biasing.”

If that doesn’t appeal to you, then merely plug a matched set of Mesa tubes into one of our amps and you’re ready for tone. Guaran- teed. You’d be amazed at the number of service calls we field every day that lead to a diagnosis of out-of-tolerance, non-spec tube problems. To think these would be prevented by including a bias adjustment is something of an insult to you and us. If you put the wrong size tires on your car, do you think changing the pressure will make them right?

Please, don’t think this is a blanket indictment of the other guys selling tubes — it isn’t. And their tubes aren’t all bad either. It just doesn’t make sense to pay more of your hard earned cash for tubes that were probably made in the same Russian or Chinese factory and which have the possibility of being outside the performance window we select for your amp. And it pains us to hear the hype and mystique built up around biasing when twenty-five years of evidence affirms our decision to make bias circuits that “never need adjustment”. How much money and trouble that has saved Mesa/Boogie players you couldn’t estimate.

Our rigorously tested and hand selected tubes are available at your nearest Mesa/Boogie Pro Center or from us directly. Nobody offers better price, quality or warranty than we do ... so why swerve?

Next time we’ll talk about our part in developing the great Sylvania STR 415 type 6L6 and how we’re on the verge of seeing something fairly close reappear on the market. Remember, we still have some of these super rugged mondo-bottles available for older amps — Boogies only please! Until then, Relax, Breathe and Nourish your soul!

Cheers!

Mesa/Boogie Ltd.

Randall Smith

Designer and President

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Mesa/Boogie MARK 1 owner manual Cheers Randall Smith Designer and President

MARK 1 specifications

The Mesa/Boogie MARK 1 is an iconic guitar amplifier that has significantly influenced the world of music since its introduction in the late 1960s. Designed by Randall Smith, the MARK 1 was one of the earliest examples of a high-gain, boutique-style amplifier, aimed at offering guitarists a versatile tool for achieving rich tones across various genres.

One of the standout features of the MARK 1 is its innovative preamp design, which utilizes multiple gain stages to produce a wide range of tonal options. This allows players to achieve everything from sparkling clean sounds to aggressive, saturated overdrive. The two-channel configuration—clean and lead—enables users to switch effortlessly between different sounds, making it a favorite among performers looking for adaptability in their rig.

The MARK 1 is also equipped with a powerful EQ section, featuring a 5-band graphic equalizer that grants further control over tonal shaping. This level of customization is rare in amplifiers of its time, allowing musicians to tailor their sound to perfection, whether in the studio or on stage. The “Fat” switch adds additional low-end response and gain, enhancing the amp's overall character and making it suitable for heavier genres.

Another hallmark of the MARK 1 is its compact design, which was revolutionary at the time. Weighing significantly less than traditional tube amplifiers, the MARK 1 was constructed with portability in mind, making it easy for gigging musicians to transport. This combination of power and portability made the MARK 1 a popular choice for artists across various genres, from rock to blues and jazz.

The MARK 1, like many of Mesa/Boogie’s offerings, is built with high-quality components, ensuring durability and reliability. The use of premium tubes in the power section contributes to its dynamic response and harmonic richness, vital for expressive playing.

Overall, the Mesa/Boogie MARK 1 is more than just an amplifier; it's a landmark in guitar amplification technology. With its versatility, compactness, and powerful tone-shaping capabilities, the MARK 1 paved the way for future amplifiers and continues to be revered by musicians around the world for its outstanding performance and timeless sound. Whether performing live or recording in the studio, the MARK 1 remains a trusted companion for guitarists seeking to explore the full spectrum of their musical expression.