Mesa Baron Amplifier

by Marc Mickelson

Although it’s rarely bad to be the first publication to print a review of a significant new piece of high-end audio gear, it’s not all that bad to let others take their cracks at it before you either. The significance of being at the front of the line is obvious—and SoundStage! has been successful in this regard—but being last, or close to it, allows you the luxury of covering a product with the knowledge that its story—who makes it, what kind of technology is at work, whether it uses oxygen-free copper or high-purity silver wire—has been told again and again, so for the most part you can ignore the background information and concentrate on what’s really important, the product’s sound. There’s also something appealing about having the last word, maybe because it sticks in the mind longer (or we just think it does).

In any case, this review of the Mesa Baron is both new and old news. The stock Baron, which uses 5881 tubes, has been reviewed by just about every audio publication extant, and months ago too. But there’s a new Baron in charge, not so much a replacement for the stock unit, but instead a slight variation on it. This Baron uses the more audiophile-approved EL34 output tubes and has not been covered anywhere yet—until now.

Does anyone not know the story of the Baron and the company that manufactures it? In the smallest of nutshells, Mesa Engineering is perhaps the foremost maker of guitar amplifiers, and its president, Randall Smith, who is also the designer of the Baron, transferred his knowledge in the pro arena into the audiophile world. The Baron, Mesa’s first high-end product, was years in the making (an earlier version used 6550 and 5881 output tubes simultaneously), careful development being the cause for its slow birth. Since its introduction, the Baron has been joined in the Mesa high-end family by the Tigris integrated amplifier, with a preamplifier nearing completion.

Like the Tigris, the Baron allows for adjustment of its output parameters via a number of switches and knobs. Adjustment of operating mode—triode to pentode in one-third increments—negative feedback and grounding make using the Baron a blast, unless you lack the patience for such flexibility. The Baron delivers 150Wpc in full pentode mode, 120Wpc in 2/3 pentode, 85Wpc in 2/3 triode, and 60Wpc in full triode. The amp’s large front-panel meters make fine adjustment of tube bias and balance easy. They also lend a distinctive visual touch to the amplifier and allow you to track power output from your listening seat. Sets of very nice Tiff gold-plated binding posts (for 4- and 8-ohm loads) share the back panel with single-ended and pseudo-balanced inputs and two IEC receptacles. Two IECs? The Baron is a dual-mono amp, sharing not even an output transformer between its channels, and the two power-cord receptacles are part of this design criterion.

Barony

I used the Baron in two systems, although all listening impressions were derived while the Baron drove either my reference ProAc Response Four speakers or a pair of Nova Renditions (reviews of both in the works). These speakers proved to be good matches with the Baron, which, because of its rather high output impedance, may noticeably affect the tonal balance of speakers with an impedance curve that fluctuates more than 6 ohms across the frequency spectrum (speakers by Thiel come quickly to mind, although there are other makes and models to which this applies). Power, however, is not a problem with the Baron. It sounds more gutsy than its ratings might suggest.

In addition to the ProAc and Nova speakers, the review system included Lamm L1 and Joule Electra LA-100 Mk III linestages, Timbre TT-1 DAC, Wadia 20 transport, and JPS Labs interconnects and speaker cables. Also in the signal path were a Marigo Apparition Reference series 3A digital cable and Audio Magic Tubed Interconnect. I used power cords from Audio Magic, Audio Power Industries and JPS Labs along with a Marigo RMX Reference AC Distribution Center. As for other amplifiers, I’ve been lucky enough to have a number of high-quality contenders around for direct comparison, including Quicksilver M135 and Clayton M-70 monoblocks, three pairs of the big Lamm monoblocks (M1.1, M2.1, and ML1), and a Joule Electra VZN-80 Mk III stereo amp.

For the most part, the best combination of output mode and negative feedback depended on the speakers in use, although there were a couple of absolutes. I liked the ProAcs at 2/3 pentode power and the Renditions at 2/3 triode, both with no negative feedback, although experimentation was fun nonetheless. I wasn’t fond of full pentode mode because while it increased the overall power of the amplifier and punchiness in the bass, it also increased the system’s background hiss and turned the treble unbearably glassy. Full triode had the opposite effect, taking some of the life out of the sound, especially with any amount of negative feedback dialed in, but then the treble smoothed out, turning into the tonal equivalent of brown sugar, which is good on some things and not so good on others. I used this mode with acoustic music and had fine results. For the most part, however, I lived in the middle ground between the extremes, a lesson for life as well as audio.

It’s good to be the Baron

Keen-eyed readers may remember seeing a short piece I wrote on the Baron nearly two years ago. The amplifier that I heard then is not the same one that I received for review, which is to say that the model has undergone a few changes in the interim. Perhaps the most significant of these is the lowering of the amplifier’s voltage gain, which I found with the original model to be so high that only removing the (tube) preamp decreased the amount of background hiss to a reasonable level. While a currently produced Baron is still not a good match in this regard with, say, a CAT SL-1 Signature preamp (Mk I or II models), which has unusually high gain itself, the amplifier does now work more quietly with a greater number of active preamps and linestages. Both the Lamm L1 and Joule Electra LA-100 Mk III linestages worked well with the Baron, although the background hiss was still slightly higher than with other amplifiers. I’m sure Mesa’s soon-to-be-released preamp will be a splendid match with the Baron, but in the meantime you might want to look into using a solid-state preamp or even a passive linestage if you find the gain of the Baron to be too great. I also had a lot of fun running the Tigris integrated amp into the Baron and biamping with the two. More on this anon.

In terms of sound, the Baron—both the 5581 and EL34 versions—is decidedly not laid-back, but this doesn’t mean that it has an overtly bright or harsh tonal signature. It’s a tube amp all the way, but it does its work with insistence—projecting more than intellectualizing. While other tube amps sound polite with bloom and dynamics that cut through the sometimes-soporific ease, the Baron is all bloom and dynamics with a hearty helping of tube sweetness thrown in. It takes control and makes a strong argument for it being the right way to reproduce music.

The Baron provides plenty of energy at both extremes. Its bass is satisfying—forceful and weighty, though not of solid-state tautness—and its treble has the sort of extension and clarity that evades many tube amplifiers. Roy Hargrove’s trumpet on "Parker’s Mood," from the CD of the name (Verve 314 527 907-2), is very there, with characteristic bite, and the bass line has more growl than a tube amp should allow. And the dynamics! The Baron allows the jazz orchestra on "Powerhouse," from Don Byron’s wonderful Bug Music (Nonesuch 79438-2), to swell incrementally in power and volume, just as it would in real life. The Baron easily conquers any dynamic challenge—in fact, there are no dynamic challenges when you have the Baron in your system. It’s a tube muscle amp.

The Baron can throw an enormous and airy soundstage rivaling that of more expensive amps, including the Joule Electra VZN-80 Mk III (which is still the champ in this regard). The images that the Baron casts are solid, noticeably more so than those the Joule amp conjures, giving the entire presentation an impressive sense of space and the bodies within it. I really enjoy Shawn Colvin’s music and performances, and hearing her do "Poloroids" on the Columbia Records Radio Hour, Volume 1 sampler (Columbia CK66466) is a treat. The Baron floats Colvin’s voice dead center with crisp outlines and plenty of body. Same for Greg Brown on his newest Slant 6 Mind (Red House RHRCD98), which has a gritty, roughhewn quality, especially in comparison to Brown’s two previous CDs, Further In (Red House RHRCD88) and The Poet Game (Red House RHRCD68). All three are packed with acutely observed and intelligent songs—a good night’s worth of listening.

Rock takes on new life when played over a Baron-powered system. Everything from Rush’s Moving Pictures (Mercury 314 534 631-2) to The Presidents of the United States of America (Columbia CK67291) benefited from the Baron’s kick-ass way with lively, percussive music. One of the first recordings I pulled out immediately after I installed and dialed in the Baron was Marshall Crenshaw’s My Truck is My Home (Razor & Tie 2815), a collection of live performances that span a dozen or so years. The overall quality of the recorded material is uneven, although not as wildly as you might think given the amount of time over which the various tunes were set to tape. "You’re My Favorite Waste of Time" sounds especially good, although not in the traditional audiophile sense. Its loud and edgy guitar work sounds exceedingly real, and the slight reverb added to Crenshaw’s voice gives a clue to the overall effect the on-site engineer was trying to achieve. The Baron reproduces this track with power—a word I keep coming back to—and impact, both of which are usually reserved for those near the edge of the stage, not in the comfy listening seat.

If there’s a weakness in all this drive and spaciousness it’s that sometimes the Baron can be a bit too eager to please, taking a small-scale recording and turning it into something larger. The splendidly remastered version of Kind of Blue (Columbia/Legacy CK64935) takes on a bit too much scale in my opinion. The Baron also falls short of the very best amplifiers in the treble, its highs not being as utterly smooth as those of the various Lamm monoblocks I had on hand (and which cost multiple times the Baron’s price). But then the Baron has its own way of doing things, one that constantly made me wonder if the whole idea of reproduction wasn’t just passing me (and the other equipment) by. The last time I heard live music it sounded bigger and more expansive than anything reproduced through my audio system, and it also had the kind of immediate sheen that’s a sign of the real thing. The Baron’s presentation doesn’t lend itself to prettifying recordings—just as a fine musical instrument doesn’t ensure a great performance. The Baron will do that—make you reassess your audio beliefs.

Your options

I’ve always been a fan of EL34 output tubes. Amps that use them seem to have a tonal rightness that’s unmistakable, an ideal ratio of textural richness to overall resolution. EL34s are also one of the least-expensive output tubes—a fraction of the price of KT88s, for example—and good examples are readily available from a number of sources, so there’s no dishonor in foregoing the elitist route to save a lot of money.

Mesa will modify a stock Baron to use EL34s for $270, a procedure that will still allow you to use 5881s as well as KT88s, KT90s, and KT99As. Mesa knows its tubes, but in the case of the EL34s for the Baron, they decided to source them from tube guru Frank Morris at Gold Aero, who was the first person to experiment with the tubes in the Baron. And Morris didn’t skimp, choosing to use E34Ls, which are the premium EL34s produced by Tesla in Czechoslovakia. A matched and tested set of Tesla E34Ls for the Baron costs $480 and carries a generous one-year warranty.

Are the modification and extra cost justified? Yes, although the essential character of the Baron remains unchanged. With the E34Ls installed, the Baron is an even more likable bruiser, still able to kick out the jams, but the added measure of refinement that the new tubes bring is unmistakable and welcome. The E34L Baron has more body and is a bit sweeter, not enough to make me want to fidget with the mode or negative feedback, but just sweet enough to make me realize that the overall sound is more to my liking. In comparison, the 5581 Baron sounds a little dryer in the upper mids, although this can be offset with a bit of negative feedback. Its bass is also the smallest bit tighter, a good thing.

For a bit of sublime fun, I biamped with the Baron and its kissin’ cousin, the Tigris integrated amplifier, which has an adjustable set of pre-out jacks. Like the Baron, the Tigris is highly flexible, making the combination of the two a tweaker’s dream. I used the Tigris to drive the tweeters and midranges on my ProAc speakers, and the Baron (the 5881 model only, due to review logistics) to drive the bass. The best modes overall were 2/3 pentode for the Baron and 1/3 triode for the Tigris, both with no negative feedback.

I can’t say that the sound produced when the Baron/Tigris combination was pumping out the power was markedly better than the Baron driving the speakers alone. I liked the E34L Baron with the Lamm L1 linestage better than the 5881 Baron with the Tigris (which together cost less than the Lamm L1), but the combination did put an interesting wrinkle in the story. You could take the easy route and buy a Tigris and a stock Baron, or you could buy a Tigris and a moded Baron with sets of 5881s and E34Ls and adjust until you drop (in both cases you’d also get a headphone amp in the deal). The Tigris has three output modes, and the Baron has four. Both have user-selectable negative feedback, and you could make all adjustments independently for the bass and midrange/treble of your speakers. The possibilities are nearly endless, and I have to admit that I enjoyed exhausting them. I must have walked a half mile from my listening seat up to the equipment rack to make a change and then back again to hear what I had wrought. Not for the weak of patience, that’s for sure.

Endnotes

With the Baron, Mesa is blazing an original trail through the high-end landscape, offering a gregarious and flexible amplifier that now allows owners to use a number of different output tubes. If you’re looking for tube sweetness, the Baron can deliver, as it can a healthy amount of raw power. If you like changing your system’s perspective just for the fun of it, the Baron can oblige with everything from pentode overdrive to triode subtlety, with stops in between. It’s a big-hearted amp that never sounds power shy or subdued—unless you dial in these characteristics. To further perpetuate an audio bromide, the Baron embodies the best of solid state and tubes—power and finesse—and it can do its thing in varying degrees that should suit all but the most jaded audiophiles and reviewers.

If I were to begin this whole crazy audio ride over again with the knowledge I have now, I would be very tempted to buy a Baron and just drop out. No, it’s not the best amplifier I’ve heard overall, but it does so many things well and still maintains the sanity of its price—even with premium E34L tubes—that it’s hard to ignore. It shakes things up because in some ways it portrays music in a more vivid and exciting manner than any amp I’ve heard. If you’re in the market for a high-power amp, tube or solid-state, put the Baron on your list.

...Marc Mickelson
marc@soundstage.com

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