6V6 Output Tube Taste Testing

Written by
Dave Hunter
Published on
January 21, 2021 3:06:44 PM PST January 21, 2021 3:06:44 PM PSTst, January 21, 2021 3:06:44 PM PST
A guitar amp’s output tubes contribute significantly to its voice and character, but many players and amp makers alike feel that lower-powered tubes make their presence known even more in the overall sound of any given amp. Lower-powered tubes tend to break up a little earlier, and therefore add more of their own personality to the overall sonic brew, especially at relatively lower volume levels where bigger, stronger output tubes will stay firm and clean.
Considered the traditional “smaller American tube” for its use in many 15 to 22-watt amps over the years, the 6V6 is also a favorite of many players seeking early and easy break up from their amp’s output stage, as experienced in the “tweed” era amps which so often carry them. As heard in these types of amps in particular, the 6V6 is beloved for its girthsome mids, relatively easy and dynamic compression, and a slightly gritty yet smooth texture that adds a lot of personality to overdriven tones in particular.
In other amp designs, however, a pair of 6V6s can also provide decent headroom and a firm, punchy tone with excellent clarity, along with a well-balanced tonality overall. As a smaller, lower-output tube, they aren’t known for producing a lot of firm, punchy low end, but can do pretty well in that regard when used in quads in more powerful amps of around 45 watts.
Any time the 6V6 is discussed, players’ thoughts are likely to go first to several Fender classics. The legendary tweed Deluxe and blackface Deluxe Reverb both use pairs of 6V6s for about 15 watts and 22 watts respectively, while the tweed Champ and Princeton used a single 6V6, and the brown, blackface and silverface Princeton Reverb generated around 12 watts from a pair. Several vintage Gibson amps also used these tubes, including the beloved GA-40 Les Paul amp and others in the GA range of the ’50s.  6V6s likewise appeared in models from Traynor, Ampeg, Silvertone/Danelectro, and others.
The lack of availability of robust and good-sounding new 6V6s led some manufacturers to abandon them in favor of EL84s for their small to medium-output amps in the late ’80s and ’90s, but the emergence of several viable candidates in more recent years has brought 6V6 designs back with a vengeance. In addition to several contemporary makers who use them in amps that were inspired by classics from the ’50s and ’60s, 6V6s have powered original designs from Dr Z, Bogner, Carr, TopHat, 65amps, Jim Kelley, and several others.
Let’s explore the sounds and personalities of three newly-manufactured makes of 6V6 output tubes, all of which are currently available from Mojotone: the Electro-Harmonix 6V6GT, Tung-Sol 6V6GT, and JJ 6V6 S.
In addition to my own “live” impressions gleaned from playing each set of matched 6V6s in the same amp over a prolonged period, I’ve recorded several sample clips for the purposes of easy and comparable A/B/C comparisons. Please note, too, that the notes below were taken without any previous reference to the manufacturers’ or sellers’ promotional info, but are provided as an objective impression of these tubes’ individual strengths.

Guitar, Amp & Settings
Four samples of each tube were recorded using a Gustavsson Fullerblaster T-style guitar with Wolfetone Telecaster pickup in the bridge position (in a traditional Tele bridge with brass saddles) and a Throbak humbucker in the neck position, into a custom tweed Deluxe-style amp in a 1x12 pine cabinet with Celestion G12-65 speaker.
  • Each of the three clips begins using the bridge pickup with guitar volume and tone controls up full, and the amp set to clean-on-the-edge-of-breakup.

  • The second segment in each clip maintains the same amp settings, but switches to the bridge and neck pickup together, with both guitar knobs still up full.

  • The third segment is on the neck humbucker only, with the amp’s volume control cranked up to about 7 out of 12 for some breakup.

  • The fourth segment is on the bridge pickup, with the same amp settings as in #3 above.

Electro-Harmonix 6V6GTPurportedly designed with reference to the great RCA 6V6GT and manufactured at New Sensor’s Xpo-Pul factory (aka Reflektor) in Saratov, Russia.

General Notes: The Electro-Harmonix 6V6GT was one of the first made to a quality able to withstand the high plate voltages on notoriously brutal amps like the Fender Deluxe Reverb, and thereby helped to bring the 6V6 back in fashion as a current-make tube. It has long been considered a rugged example, with special cathode coating and tri-alloy plate material, but more recently made E-H 6V6GTs also include support posts to minimize microphonic internal rattle. In addition to being durable, it maintains a reputation as a great-sounding all-around tube that packs a lot of classic characteristics, making it a top pick for many amp manufacturers today.
Clean-ish: Hit with the Tele bridge pickup and the amp set to the sweet spot between clean and crunchy, this E-H 6V6GT simply exudes classic American twang and rock ‘n’ roll tones. There’s just enough rawness in the brew to keep the sound rebellious, but it’s surprisingly musical and refined in some other ways—for a 6V6 in a tweed-style amp, at least—with impressive note definition and a really likeable balance throughout the range, and lots of chime and shimmer even when it’s breaking up a little. The guitar’s middle position delivers a rounder, plumbier voice that brings more richness and warmth into the brew, while remaining clear and just a tad funky.
Overdriven: The E-H pair delivers archetypal 6V6 breakup when pushed into overdrive by the Fullerblaster’s bridge pickup, where it exhibits that appealingly granular crunch that so many players love from this tube type. It also compresses very nicely, in a way that makes it very tactile and touch-sensitive to play, but without folding too badly or giving over to mush. There’s girthsome midrange character amid the overdrive too, but never to an extent that swamps the overall frequency spectrum, leaving the lows relatively tight for a smaller tube, and the highs clear and silky. On the neck humbucker, the E-H is obviously darker and thicker, but still avoids all-out muddiness, retaining impressive sweetness and articulation.
Good For: The Electro-Harmonix 6V6GT is a great choice for any amp from which you seek to attain classic non-master-volume, output-stage overdrive at lower to medium volume levels (aka “club levels”) without inducing all-out mud in your amp. It’s a well-balanced, musical, and appealing tube, and compares well with the classic 6V6s of the ’50s and ’60s in general character, for a modern tube.

Tung-Sol 6V6GTA Russian tube, manufactured at New Sensor’s Xpo-Pul factory (aka Reflektor) in Saratov, Russia.

General Notes: Made in the same Russian factory as the Electro-Harmonix 6V6GT, the Tung-Sol is almost identical in construction, although it does exhibit minor differences. The plates are the same, and this tube also contains the recent support rods, together making it a high-voltage 6V6 that’s also resistant to microphony. The fins atop the cathodes (just beneath the halo getter) are cut a little differently, though, and while much else might lead us to expect this to sound a lot like the E-H, it does have its own sonic character.
Clean-ish: Compared to the E-H above, the Tung-Sol 6V6GT is indeed extremely similar when hit by the Tele-style bridge pickup with the amp set to the sweet spot between clean and crunch, but overall it exhibits just a touch more elegance and richness amid the archetypal 6V6 sparkle and bite. The mild breakup when chords or single notes are hit hard leans a little more toward the creamy than the gritty, and there’s a certain subtle roundness to the overall voice, yet with good punch and clarity. With both pickups together, there’s still plenty of chime and sparkle, but also a thickness and girth that inspires rhythm playing.
Overdriven: Hit with the Fullerblaster’s bridge pickup in the cranked tweed-style amp, the ensuing overdrive tones follow logically from what we’re hearing above in the Tung-Sol’s cleaner performance. There’s definitely plenty of archetypally 6V6-like snarl and bite here, but the breakup tends to be smoother, with the crispy-crunchy edge of the distortion taking the back seat. As such, it’s a mildly “classier” breed of overdrive, perhaps. From the neck humbucker, this 6V6 delivers a thick, smooth, singing performance with plenty of warmth and depth.
Good For: The Tung-Sol 6V6GT is a great all-around tube, but is a particularly good choice when you’re seeking a little extra elegance and musicality from any amp. It does cleans and overdrive equally well, with great balance and clarity throughout, while leaning more toward the smooth rather than the gritty/crunchy of some other 6V6s.

JJ Electronics 6V6S An Eastern-European tube Manufactured by JJ Electronic in Cadca, Slovakia.

General Notes: This ruggedly built Slovakian-made 6V6 has a large glass envelope and a spiral filament to handle extremely high plate voltages (for this tube type). The plate structure itself is notably bulky and boxy. At a glance, you might even mistake the JJ 6V6 S for a smaller 6L6 variety—and it can even sub in for that tube in some amps. This is a 6V6 known for its ability to withstand punishing voltage levels, and many amp makers have turned to it when seeking a tube that will hold up in a stout, high-headroom output stage. Some players feel that it sounds and performs a little less like a classic 6V6 as a result.  
Clean-ish: When hit by the guitar’s bridge pickup in our amp’s so-called “semi-clean” setting, the JJ 6V6 S delivers notably less breakup than the other two tubes in this selection. It presents plenty of clarity and chime amid the cleans, along with a pronounced midrange hump, yet which still doesn’t overwhelm the firm lows and precise highs. As such, it’s less one for the gritty, gnarly rock ‘n’ roll twang, and more for the high-headroom cleans or pedal- or preamp-induced overdrive. The both-pickups selection at this setting induces a full, thick, chunky performance from the JJ.
Overdriven: Pushed to cranked-tweed levels with the Fullerblaster’s Tele bridge pickup injected, the JJ is meaty and thick, and pretty well balanced overall, but with a distinctive mids-forward character that makes for a lot of body. The leading edge of the overdrive is a little ragged and crispy rather than smooth, delivering some cutting power here, but there’s also a lot of headroom that will hold stout throughout the drive. Presented with the neck humbucker, the JJ is particularly full and muscular, with a good balance of clarity and breakup.
Good For: As with many other JJ tubes, this is a big-sounding 6V6 that makes an excellent choice when you’re seeking high headroom from a 6V6-loaded amp. It does sound very good all on its own, whether your amp’s set to clean or crunch, but it’s particularly suited to handling both punishing voltage levels in a stout output stage, and pedal- or high-gain-preamp-induced lead tones that push it hard from the amp’s front end.