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Mesa/Boogie - Blue Angel

Official product page (local backup made) - excerpts:

Progressive Linkage enables you to switch between or combine 2 6V6s & 4 EL84s for 15, 33, or 38 Watts of Pure Class A Power


Parallel FX Loop

Available as:

Fan Cooled Head (22 3/4")

1x12 Combo w/Celestion 90 Watt speaker and Slip Cover

2x10 Combo with Slip Cover

4x10 Combo with Slip Cover

"It seems to capture every articulation detail, every bit of pick or fingernail color. You can quite literally regulate the distortion level from note to note according to how hard you dig in." Joe Gore, Guitar Player September 1994

Some players say footswitching is for sissies. And with respect to this point of view, we introduce the Blue Angel. This dark beauty had its preamp's proverbial clock cleaned, making room for a power amp dedicated to just one thing: clipping naturally with unprecedented soul.

Five knobs...and the debut of Progressive Linkage™. SAY WHAT? No, not a carburetor-Progressive Linkage is a patented breakthrough concept in power amp design. This home-style barbeque grilles different cuts of tube for different power ranges and flavors-enabling you to choose between-or combine-them for the ultimate in pushed power expression. The Angel's tasty gumbo is fired by two 6V6's and four EL-84's. The bubbly, warm 6V6's throw down 15 juicy watts when used solo.

The flavor is Fullerton, circa 1960, sweet as the oranges that once grew in the pre-mall Southern California sun. Locking in the four EL-84's produces a brighter character-tighter and more aggressive, with a nice spread in the upper harmonics. This 33 watt configuration is royal jelly for the stinging blues.

Yet these two classic and undeniably favorite power tubes, great as they are, do have their drawbacks. When pushed too far into clip, 6V6's tend to get flubby and indistinct. EL84's, conversely, can be thin at times, lacking bass and warmth. Progressive Linkage changes all that, and ushers in a new era of touch sensitive power clip.

Combining these two occasionally ill-behaved power tubes by kicking into Simul LinkTM allows each tube's weakness to become a strength when used in tandem. The EL-84s add tightness and attack to the looser 6V6s. In return, the 6V6's better bass response warms up the EL-84s, giving them breathiness and a more resilient feel.

Date the Angel. Purists, your prayers are answered.

Download PDF manual or direct-download here (right-click, Save As)

Randall Smith's article about Progressive Linkage in the Blue Angel - excerpts:

Progressive Linkage satisfies a previously ignored need of guitarists. The first example of this technology is used in our new Blue Angel amplifier.

The 6V6 was widely used by Fender during the '50s and '60s for their low power models. These amplifiers were popular with "electric blues" guitarists who often found their amps underpowered, and simply turned them up! Of course the amp ran out of power and distorted heavily. But the distortion quickly became used as a further tool of musical expression when in the right hands.

Operating below the distortion threshold, the 6V6 sound is "skinny"-not objectionably thin, but bright nevertheless with bouncy, resilient dynamics. When overdriven, the low order second and third harmonics rise to predominance, obscuring the bright high frequencies and "fattening" the sound in a way which is a trademark of American blues. When severely overdriven, the distortion characteristic goes beyond what is desirable, producing an inarticulate low end which is bloated and tubby, obliterating most other frequencies with its woofiness.

Meanwhile in Europe--particularly in England-during the same period, the EL84 was the power tube of choice in small amplifiers. The sound of this tube is very different from that of the 6V6. The EL84 possesses a glassy brightness whose emphasis is in frequencies higher than the bright zone of the 6V6. The EL84's dynamic character seems less resilient and when driven into distortion, higher order harmonics prevail, and an aggressive, snarling bite ensues. Overdriven to extremes, it does not suffer from low end bloatiness but retains a more balanced spectrum with its aggressive midrange character dominating.

It is no wonder that when British guitarists began turning up their amps and "playing the blues," it sounded quite different from the Americans they were imitating. It's fair to say that the difference may have been less cultural and more technical--and largely owing to the differing tube types: American amplifiers used 6V6 or 6L6 types and the European units (which were sometimes identical to American circuits except for the power tubes) used EL84 and EL34 types. (The best example of this is the fact that the "plexi" Marshall circuit is identical to a 4x10 Fender Bassman.) Since both of these European tube types possess a more snarling, aggressive midrange distortion than 6V6 or 6L6 tubes, it is easy to see how "bad attitude" rock and roll styles such as heavy metal developed from blues-based music being played on amps fitted with European tubes and cranked up into heavy distortion.

With Progressive Linkage, the power amplifier is provided with a plurality of tube types and includes a switch to select different pairs of output tubes, either alternately or combined for simultaneous performance. The most useful, as well as logical, choice is an amplifier which combines 6V6s with EL84s for low to moderate power (as utilized in the Blue Angel) or one which uses 6L6s with EL34s for moderate to high power.

The single amplifier can produce the actual signature sounds of either of the two types of tubes making genuine British or American musical styles obtainable with true authenticity.

Another feature is the selectability of output power. For those who insist that only power amplifier distortion is acceptable (and preamp saturation is not) the problem of correct wattage is a major concern. Differing room size, acoustics, and the number and type of other instruments in the band dictate a certain power level which is appropriate. Dedicated players are often known to bring a small fleet of different powered amplifiers so that they have one that's right for the job.

Progressive Linkage largely solves this problem by offering three different and selectable levels of output power. The lowest is the single pair of 6V6s at around 15 watts. The next is the two pairs of EL84s operating alone to produce approximately 33 watts. And the last is the combined output oftwo 6V6s, plus four EL84s for a total capability of around 38 watts.

Another advantage of Progressive Linkage is the option of a third sonic characteristic achieved by using all tubes simultaneously. The tone produced is refined and highly desirable, as the likable tonal elements of each tube type seem to improve the weaknesses of the other. The 6V6s soften the brashness of the EL84s and add body to the lower regions. Simultaneously, the EL84s cause the combined sound to retain tightness and articulation while preventing objectionable low end woofiness from taking over.

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