It’s no great mystery that musician’s buy tube amps for tones and a feel that can only be derived from the glass bottles we call tubes. Players obtain MESA/Boogie amps because they realize that the amps are so tonally versatile and so well built that they can last their entire career. Many players possess a great knowledge about the features of their Boogies but what I’ve found in my travels is that there is quite a lot of confusion about the main participant in the tonal foundation, the tubes.
With all of the hype put out by the various tube distributors, a question that I encounter quite frequently is; “Why should I buy Boogie tubes for my amp?” If you own a Boogie amp, the answer is very simple. MESA/Boogie only sells the tubes that meet the requirements of MESA/Boogie amps. It’s a simple enough answer but some players can be somewhat skeptical. In the event you need a more in-depth answer, consider the following.
I think most of us are aware that there are very few manufacturers of tubes left in the world (none of the tubes made for our industry are currently manufactured in the United States). There are several different distributors for tubes and they all get their tubes from one or a few of the manufacturers. So, distributors are generally buying from the same sources. For the most part, the differences in the tubes you buy from different distributors come down to what model tubes they buy from manufacturers, how or if they test their tubes and what warranty they offer. While distributors occasionally have a special feature built into the tube they want to market, on the whole, the tubes they get from the manufacturers are the same.
MESA/Boogie does not manufacture tubes. We get our tubes from those same sources that are available to other distributors. But here is where similarities end.What sets our tubes apart is OUR testing, the warranty we back the tubes up with and the prices we offer. While we buy from the same manufacturers that other distributors have access to; we are selective about which tubes we will use in our amps. If a tube is toneful, we might purchase a large quantity to test for reliability. If it proves reliable and great sounding, then we may consider using them. Yeah, we’re picky. High performance machines require high performance parts. Testing is more than an educated guess or a trip to a hardware store tube tester. Tubes destined for the Home of Tone can expect to be challenged by ROBOTUBE, high gain amps and humans with hammers (kind of sounds like a scene from Gladiator). Designed by MESA/Engineering and built exclusively for us by an aerospace firm, Robotube is a one of a kind machine and easily the most modern and powerful in the industry. It has the brains of a computer and the ears of a musician. Robotube runs a battery of seven exacting tests on each power tube and analyzes performance so thoroughly that it can even predict the tube’s lifetime. Precision data generated during the seven-part test procedure is combined in Robotube’s memory and later printed out for each tube. However, there are still some factors of a tube’s performance that only a human (with a hammer) can properly analyze. After passing tests for noise and microphonics, then comes the MESA hammer test. Here, each tube is tested for reliability under severe shock and vibration... enough to duplicate your amp falling over at full volume. Man & Machine together make the difference for Boogie.
What about preamp tubes? Why use Boogie preamp tubes in amplifiers?
Again, it comes down to testing. Each of our preamp tubes has been fired up and shock tested (yeah… the hammer again) at high voltages in an actual Boogie amplifier. The preamp tubes that we sell are what we determine to be the best sounding and performing for our amps. Oftentimes, our stipulations for parts may benefit the entire industry. It’s all about tone, gain qualities, noise, microphonics and how the tube responds to the hammer when gained out at super high voltages. There are many different types of 12AX7s that are currently available on the market but only a few that meet our strict specifications. This is why using non-Boogie preamp tubes can result in a lifeless sounding amp. The amp is only as good as its weakest link. Even one tube can make the difference.
Other than price, what is the difference between a 12AX7 and a SPAX7?
What makes the SPAX7 worth more than what a 12AX7 costs is that they are the cream of the crop of the 12AX7 supply. The SPAX7 is a 12AX7 that when tested has proven to be extremely stable and quiet at high gain settings. If you plug SPAX7s into sockets connected to gain stages, you should find less noise at higher gain settings and have less chance of microphonic occurrences. The band we wrap around the tubes also helps to insure these qualities.
If you fall in love with the tone you get from a Mark 5 loaded with our 6L6 STR-440 tubes, when it is necessary to change these tubes, we want you to be able to achieve that same tone you fell in love with from your next set of STR-440s. Many people believe that you have to have your amp biased each time you change your tubes. This is true if you don’t have access to a consistent supply of tubes and Boogie amps. Our amps are “fixed biased” or permanently set to the correct bias value (with the exception of the self-biasing circuits in a few amps) and we only sell the tubes that will produce the right amount of idle current for the bias value of our amps. With Boogie tubes the tolerance is so tight that you can swap tubes easily. So, as long as you use Boogie tubes in Boogie amps you never have to worry about re-biasing your amp.
Mesa/Boogie 12AX7 Tube
Mesa/Boogie SPAX7-A Tube
Can you put Boogie tubes in amps other than Boogies?
Anyone can benefit from the performance expected by our stringent tube testing. However, most other amp manufacturers have not set their amps so that you can simply swap tubes without a technician’s assurance that the amp is “biased” for the tubes. Can you put other distributors' tubes in Boogies? It is not recommended that you use anything but MESA/Boogie tubes in our amps and in the case of a new amp, you will void your warranty by using other distributors’ tubes.Keep in mind that MESA/Boogie is first and foremost an amp manufacturer and because our amps require high performance tubes, we make sure they are available. However, we only sell the tubes that meet our specifications. Those that don’t, get rejected. Many other distributors are interested in selling (unloading) their entire inventory of tubes. They’ll tell you that certain rated tubes have hotter output or distort better or whatever line seems to work that’ll convince you to plug in tubes that can have drastically different plate current values at idle. This requires a player to bias their amp each time they experiment with different tubes in order to get the optimum performance from their amp. It’s time consuming, expensive and potentially dangerous. Rather than deal with this headache, players can use our amps and tubes to bypass the hassle. We build the best amps using the best parts and the result is that we’ve become one of the best represented amp companies on today’s stages. If you go Boogie all the way, great tone is assured.
If Boogie doesn’t have some tubes that are hotter than others, then what does the color code on power tubes represent?
We’ve got seven color code ratings and they represent current draw. The reason for having these ratings is so that you can match up, as closely as possible, a pair of tubes for a push pull circuit. It’s a spec issue and not a tonal one. Now wait… You just said that Boogie tubes are consistent and now you are telling me that there can be seven different ratings or current draws for some tube types. What’s up? If you deal much with electronics, then you know that you are not always dealing with precise measurements. As long as you stay within certain tolerances, you are “in spec”. The tolerance that we will accept for our tubes is so tight that these different draws will deliver consistency in both performance and tone.
We match pairs of certain types of power tubes, within our specifications, so that you can have as precise as possible a draw in current between two tubes working together in a push pull circuit. For the optimum in performance from your amp, it is important to use matched pairs of power tubes in the amp. Amps having more than one pair of tubes don’t have to use the same rated tubes throughout. For example there are two pair of power tubes in a Mark V Head. The two tubes in the innermost tubes sockets work together in this amp as do the two tubes in the outermost tubes sockets (from left to right, tubes 1 and 4 are working together and tubes 2 and 3 are working together). When this amp shipped from the factory it may have shown up with four power tubes that were rated Gray in it. When I go to replace the tubes, I might load Red rated tubes in the middle two sockets and Blue Rated tubes in the outside sockets. Because of our tight tolerance, I can do this without having to worry about a change in performance or tone. Keep in mind that when replacing any of the color-coded power tubes; it is always best to swap tubes in pairs.
If you own a tube amp for any length of time, you may need to or want to change your tubes. Sometimes it is a necessity and sometimes it is an experiment (as in the case of Boogie owners who want to take advantage of our 6L6 to EL-34 bias select switch). Spare tubes are great items to have around. Should you wish to experiment with the various power tubes available for an amp like the Lone Star which will operate (and sound differently) with a variety of Boogie tubes (6L6 STR-440, 5881 STR-425, set to tweed plug in the 6V6 STR-417 or flip the bias select switch to EL-34 and load up our EL-34 STR-447 for a whole different vibe), having the alternate tubes handy will add to the tonal versatility that your amp can offer at a moments notice. Anyone who plays out has no business taking a tube amp (be it Boogie or not) on stage without spare tubes. It’s like driving a car without a spare tire. You might go years without a failure but you never know when a spare will come in handy. We play tube amps because they provide tones and a feel that you can’t get from solid state or modeling amps. However, as with your car, routine maintenance (changing out tubes every so often – depending on use) is recommended and the use of spares is occasionally necessary. In a Boogie amp, you can diagnose and troubleshoot tube issues quickly (I’ve got another two pages worth of information on this subject for anyone who is interested). We make it easy. If you can change a light bulb, you are qualified to swap tubes in a Boogie. So, if you own a tube amp, keep spare tubes (and fuses) handy. If you own a Boogie, you might even want to stock up on alternate tubes (when applicable).
If all of this weren’t enough to convince you to use Boogie tubes, we also provide a warranty for our tubes. Our tube warranty is six months (which is about three months longer than most of the other distributors who even offer a warranty). We realize that despite all of our testing that we are still dealing with tubes and tubes are occasionally quirky. Tubes fail for various reasons. They don’t always last as long as the specs tell you they should. If for no other reason, the fact that we offer what may be the best warranty in our industry would be reason enough to invest in tubes with our Hallmark on them.
The last point I would like to make is that Boogie tubes aren’t the most expensive on the market. Most all of us want high performance and low prices. Boogie tubes offer both.
OK… I realize that there is a lot of information to absorb here and I hope that I’ve cleared up any misconceptions about tubes. Many players may accept the quick and simple answer when asking about using Boogie tubes in their amps. If you need to get more in depth on the subject, you now have the scoop.
- Maury's Music would like to thank Randall Smith and Mesa/Boogie for taking the time to put this article together.
