The Making of the New Mesa Express 5:25 & 5:50

Guitarist Magazine pulls Mesa Founder, Designer & President, Randall Smith, away from his soldering iron to talk about the genesis of his latest new design, The Express Amps

Guitarist Magazine: Taking the Express as an example, what starts the ball rolling when you commence a new design and what are the key steps on the way to a finished product?

Randall Smith: One of the most enjoyable things we do at the shop is hang out and talk, especially Jim, Doug and I in the late afternoon.  These are creative bull sessions where we rap down ideas to make things better.  We’re constantly trying to improve everything, but especially the amps themselves since it all springs from them.  So, long before I’ve actually finished whichever product I’m currently designing, we’ve already churned up enthusiasm for “the next one” (and the one after that!)  In fact, one of the tougher decisions is deciding which one should be next!

Part of the process is picking the things we know work well and seeing where they can benefit another product, especially the weaker points of existing products.  Here’s a perfect example, it seems mundane but has had great and wide impact:  Our amp circuitry has traditionally required quite a number of separate power supplies to make everything work.  But by modifying the power transformer(s) and reconfiguring many of the sub-circuits, I was able to replace four separate low-voltage power supplies with one single one.  The bonus was that this opened up space on the board so I could add another preamp tube—and in the Express amps, that tube is dedicated to the Reverb circuitry.  Another example would be the power amp switchable between high-power push-pull and low-power single-ended configurations whose patent has just been approved.

An important part of the creative process is just fanaticizing what would make a really cool amp, and in the case of the Express, which sonic voicings do we want to include and where do we get them.  For me, amp design is evolutionary, so I tend to think of which circuits could be used or adapted to provide these various sounds in addition to which new ones need originating.  For the Express amps, the Blues and Crunch modes are both brand new whereas the Clean and Burn voicings are evolved from earlier designs.

Guitarist Magazine: We’ve often heard the phrase “black magic” mentioned when you talk about the way you lay out a printed circuit board, as you lay out each one by hand.  Without giving away any secrets, would you tell us a little about what that actually means and how much of an effect the PCB layout can have on the tone of an amp like the Express?

Randall Smith: Parts and trace location make a huge difference because there’s so much interaction going on in a guitar amp—and that’s presuming you already have a great circuit and the best parts to begin with!  I don’t want to bore you with “this part can’t be near that trace” kind of stuff… though that’s a lot of it.  And there are some “secrets” I’m going to hold onto because it’s taken a lot time and effort to discover them.  But I’m still learning and often have to do things over and over before we’re satisfied.  For me, discovery and innovation come from experimentation.  A while back I totally abandoned three months of work because the stray couplings were abysmal.  That amplifier never made it past the first prototype!  Remember, all our amps are developed on circuit boards from the very start because the board layout is such a vital, integral part of the design it can’t be treated as an afterthought.  Some of the criticism of PCB’s no doubt comes from guys who first built an amp point-to-point then tried to morph the same thing onto a circuit board.  All those interactions are going to be different, some better and many worse.  And when it doesn’t sound the same, they blame the circuit board—when the problem is really the layout on the board. 

It took me almost a year to produce the Express Line, and most of the time was spent designing the board.  But it’s worth the effort because a well-done circuit board provides both density and consistency that you can’t get any other way.  You couldn’t build an amp like the Road King using point-to-point.  And something like the Express would cost three times as much and suffer from scattered, inconsistent results in terms of delivering that magic.  It’s more difficult, and I think more important, to deliver consistency than to occasionally produce magic. What good is magic if you can’t produce it consistently.  Each player is only going to buy one amp… so what do you tell him, “Sorry, yours isn’t one of the magic ones.”?  No way.  I’ve got to sleuth out where that magic is coming from.  It may no longer be “magic” once I’ve understood it.  But the important thing is that the “magical performance” can then be built into each and every amp.

Andy Timmons fell so in love with Steve Mueller’s (Mesa Head of Sales) Lone Star #003 that he wouldn’t give it back.  He kept claiming it was the magic one that (in his experience with vintage and boutique amps) comes along now and then.  That #003 amp was one of the prototypes I had built myself so Steve kind of wanted it back.  But when we sent out number two hundred and something a couple of months later, Andy couldn’t tell which one was which.   The blind-fold test tells the real truth and that’s why we use it during our own development and production.  There’s no special process or selection for rock stars or regular guys.  Success comes only when they’re all equally good.

Guitarist Magazine: The Express has its own palette of sounds, yet we can hear hints of other famous Mesa amps in there too; what tonal ingredients went into cooking up the Express?

Randall Smith: Parts of the Express circuitry trace their lineage back to the Studio .22 of the early 1980’s.  Parts of it come from the Lone Star—whose own history goes back to the Mark I.  There are bits borrowed from the Stiletto, more bits from the F-Series and some of it is entirely new.  It’s interesting talking with a reviewer of your experience because you recognize and identify those elements.  And of course, without the great founders of Fender—the original tweed and black-face amps, none of this would have evolved.

Guitarist Magazine: That 5:25 Express is a real giant-killer, as many Boogies have been over the years.  What’s cooking behind those EL84’s in push-pull mode to get so much dynamic range, even when the amp’s practically flat out?

Randall Smith: Thanks, you like that, huh?  That’s “Dyna-Watt” one of our patented output circuits and in some ways it’s sort of the opposite of Class A.  In Class A the power tubes always draw the same amount of current from the power supply anywhere from idle to full throttle.  So there’s no power supply sag causing the voltages to bounce around as you play.  But Dyna-Watt heightens the power supply’s response to your playing, and that in turn increases the dynamic response of the audio.  It works kind of like a camera flash: it’s not a lot of light (or in this case audio power) but when it’s released in an explosive burst on the attack of the note it seems more powerful.  That heightened attack is then followed by a time-constant decay into a creamy power compression… that is until you stop playing for an instant then the supply recharges and is ready for another burst.  It’s very tactile and makes the guitar feel easier to play: punchier for clean stuff yet creamy when heavily overdriven.  And, most amazing, guitarists of all styles agreed on exactly the same duration for the timing and amount of that sag and recharge whether they played country, metal, blues, clean or what. 

Guitarist Magazine: The Express amps don’t just sound good, they look good too.  How much time and effort goes into the styling of an amp like the Express?

Randall Smith: Good question, especially about the time!  In one of those afternoon hang sessions we discussed how the cab should look and Jimmy (Jim Aschow, Mesa Executive VP & Cabinet Designer) knocked it out of the park the first time.  By the next day he had made some sample cabinets and we hardly changed anything after that.  What gave us the most trouble was the name, and then the logo.  We’ve used so many good names in the past, it’s getting hard to come up with new ones.  In fact that was one of the shortcomings we sought to overcome with the F-Series:  weak name!  That was going to be the Force Fifty or something but then people wanted more that just the 50 watter, so the name got abbreviated.  Sometimes the right name appears instantly.  But this time we were changing the name right up to the first run of chassis!  It was going to be the Subway Express and the Magnum Express—pretty decent names but they didn’t look right in the logo.  Too many letters.  Also, we wanted to bring some attention to that patented feature that allows these amps to switch down to 5 watts single ended.  That’s actually quite involved in these two amps because they first have to switch from Class AB to Class A in order to work single-ended.  Don’t mean to confuse your readers—I know you have a pretty good understanding of these electronics but it’s pretty deep stuff.  Anyway, there’s a lot of switching going on: plate, grid and cathode circuits all have to be re-configured for Class A before they’ll work single-ended.  Then there’s the patented part about maintaining flux balance so the same output transformer will work push-pull or single-ended.  Anyway, I’ve written fairly extensively about this technology on our web site so anyone who’s curious can dig into it there.

Guitarist Magazine: How easy is it for you to keep coming up with new ideas after all this time and where does the inspiration come from?

Randall Smith: It’s almost easier now because we’ve got so much more to work with… more ideas, more experience, and a lot more great circuits.  It’s still exciting for me to be designing new amplifiers with things I’ve just discovered and then seeing even more possibilities emerge as each new design unfolds.  And that adds more juice to those afternoon sessions hanging in the Tone Lounge.  But ninety-five percent of my time is spent locked in on doing the actual design and layout work, solving the problems and sweating the details.  In between the excitement and the fulfillment, it can be daunting and tedious. But if you’re going to make something good, you’ve got to do more than work at it, you’ve got to live it.  And if you’re going to live it, you better love it.  A short break always renews the excitement of seeing a bunch of ideas turn into a cool new amplifier.  That and all the great feedback we keep getting from players world-wide inspires all of us and keeps us grateful that we get to do this.  And that includes you too Nick.  Thanks again for your interest in Mesa/Boogie all these years.  Now go out and play!

See complete details on the Express product page