Vacuum Tube Tone Guide

It's no secret here at Humbucker Music that we're big fans of tube amps.  On a day to day basis, we consider ourselves fortunate to be surrounded by such a great variety.  Honestly, at the moment there are so many great builders, it's really tough to narrow down all of the choices.  We get a lot questions about the range that we carry from customers just trying to find the one that will fit their particular needs best.  With so many amp purchases taking place online these days, most players don't have the opportunity to "play before they buy."  For this reason, we often only have the specs and components in order to draw conclusions about how a particular amp will sound. This is often made even tougher, as each builder brings a little something different to the table.  One aspect that may help a player envision how a particular amp will sound is the type of tubes it uses.  Though this isn't by any means an exact science, knowing the characteristics of different tubes may help to shed some light on what to expect from an amp in terms of tone.

In this article we profile some of the more popular tubes used in guitar amps, detailing what each brings to the table. Obviously, each application is going to be different, as is the approach that each builder takes. Our intent is to provide a basic idea of what each tube sounds like, hopefully helping you narrow the search down a bit.  Try to think of it as a basic vacuum tube guide.


The 6L6 is a very common power tube that can be found in many iconic amps, both in the British and American camps, although most players would consider it more on the American style of things in terms of sound .  This tube is both large in size and stout in its power output, with many higher powered tube amps employing them.  If you've ever heard the phrase "big bottle," more than likely what is being referred to is the 6L6.  It has been used in guitar amps dating back to the 50's and is at the heart of such iconic amps as the Fender Bassman and Twin Reverb, as well as many others.

From a sound standpoint, much of the strength of the 6L6 lays in its ability to produce large amounts of clean volume before beginning to overdrive.  This makes it a great choice for the player that is concerned about clean headroom.  Throughout the tonal spectrum, this tube is very balanced in the mids with a full bass response.  The clean tones are often described as "glassy" and "shimmering."  When pushed into overdrive, the tone is smooth and very linear.  6L6 driven amps make great platforms for pedals due to their clean headroom and even response.  In terms of power, this tube is a workhorse; each bottle is capable of generating 25 watts, although this is highly dependant upon how it runs in the circuit.

Some 6L6 driven amps that we would recommend:

Dr. Z EZG-50 Amplifier
Two-Rock Studio Pro 35 Head
Tone King Galaxy Amplifier


The 6V6 has quite a bit in common with the 6L6, in fact it's often been referred to as its "little brother."  This tube has been a mainstay in American-style guitar amps for the past 60 years. A few highly coveted classic designs driven by the 6V6 are the Tweed-era Fender Deluxe, as well as the Blackface-era Deluxe Reverbs.  Like the 6L6, the tone it produces is pretty balanced throughout the spectrum.  It differs from its big brother in power handling and headroom.  Rated at somewhere in the neighborhood of 12 watts per tube, the 6V6 tends to overdrive and compress at slightly lower volumes than the 6L6 in a comparable cuircut.

Fans of the 6V6 tend to gravitate towards this tube not only for its rich, warm clean tone, but also the warm, fat overdrive it produces when pushed. Many players comment on how musical the natural compression is as they increase the volume on their amps, and also how well this tube responds to changes in the volume on the guitar.  Being balanced in its frequency response as well as having a very linear overdrive, the  6V6 is a good choice for the player with a wide array of pedals, but also the purist whose rig is simply guitar-cable-amp.

Some 6V6 driven amps that we would recommend:

Tone King Metropolitan Amplifier
Swart AST Atomic Space Tone Amplifier
Dr. Z Remedy Amplifier


With the EL34, we move into what most would consider the "Brit" style of tubes. When we describe an amp as "British," it's important to keep in mind that it's much more a reflection of the style of the amp rather than where it is made. In general, British-style amps tend to have a bit more gain throughout the whole range of volume as well as a more present midrange.  Where American-style amps are often described as "warm" or "round," words such as "chimey" or "crunchy" are often used when speaking of Brit-style amps. Much of this has to do with the type of designs used, however, the type of power tubes also contributes to this characterization.

Many players often seek out the EL34 for its amazingly rich crunch when pushed into overdrive. This fact makes it a commonly used tube by brands such as Marshall and Hiwatt. This tube is also known for having a very complex midrange, which can vary anywhere from biting to warm, depending on how it's adjusted. Most circuits using this tube are going to have a bit more gain on tap than a 6L6/6V6 amp.  Although they will handle most pedals just fine, many players who play EL34 driven amps often opt to use the amp's natural overdrive as opposed to a pedal, as that is a definite strength of this particular valve. 

Some EL34 driven amps that we would recommend:

Orange Rockerverb 50 MKII Head
Mesa Boogie Stiletto Amplifier
Suhr Badger 30 Head


Like the EL34, the EL84 is more often found in British style amps than its "big bottle" counter-types.  It actually is the engine behind the legendary Vox AC30/AC15, and in more recent years has become very popular among many boutique amp builders. Its bright, chimey character when clean and prominent midrange growl when pushed make it a very versatile tube for a variety of applications. With a power output rating of about 7-8 watts per tube, the EL84 is often found in lower powered circuits and often in amps configured to run in Class A operation.  Although it is rated at less output than some of the other tubes we have mentioned, builders working in Class A operation are often able to produce amps that are anything but weak in terms of volume.

We find a variety of players enjoy the tone of the EL84 as it lends itself to a wide range of applications.  Of all the tubes that we have mentioned, the EL84 generally has the least amount of clean headroom, although this is highly dependent on the circuit it is used in.  Many players enjoy the natural compression and warmth that this tube exhibits when pushed.  Though often thought of as a bright sounding tube, the full mids and looser bass response definitely keep it from sounding thin.  Players that use pedals often find that EL84 driven amps are a great platform.  Those that prefer a completely clean tone to start with may find the tone a bit too rich for there liking.  For those players, you may want to look to one of the "big bottle" setups.

Some EL84 amps that we would recommend:

Dr. Z Maz 18 Jr. Amplifier
Suhr Badger 18 Head
Goodsell Super 17 Black Line

What About Preamp Tubes?

You may wonder why we didn't go into great detail about preamp tubes and honestly the reason is pretty simple.  Most guitar amps use some variant of a 12AX7 in the preamp section.  Though the preamp section of an amp is tremendously influential on the tone the amp produces, it's difficult to really draw many conclusions from the type of tubes being used.  Of course as with anything there are exceptions to the rule.  One preamp tube that we've seen popping up a lot lately is the EF86.  Though it's by no means the first time this tube has been used in the preamp section of a guitar amp, there does seem to be a resurgence as of late.  This is not at all surprising considering its performance.  Without getting too much into the technical differences between a 12AX7 variant and an EF86, what most players will notice right off the bat is how much gain the latter brings to the circuit.  This is not to be mistaken with distortion, what we're talking about is clean gain in a technical sense.  Many have described preamps containing this tube as lively, with a very immediate attack, making it very useful for both the purist and the player with a large pedal board.  After hearing some of these designs ourselves, it's not at all surprising that this tube has gained a pretty sizable following.

Some EF86 amps that we would recommend:

Dr. Z M12 Amplifier
Dr. Z Stangray Amplifier
Dr. Z Route 66 Amplifier