Triode Lab 2A3-EVO Integrated Amplifier

[Triode Lab 2A3 EVO Front view]

Detail, Detail, Detail!

[Italian version here]

Product name: 2A3-EVO Integrated Amplifier
Manufacturer: Triode Lab - Canada
Cost: $8000 US. for 3 input model (Currency conversion)

Reviewer: Roger McCuaig - TNT Canada
Reviewed: January, 2020


Triode Lab is based in Toronto and has been around since the 1990s. This is my first opportunity for an extended listening session of one of their products. A browse of their web site shows an impressive list of offerings that would make any triode lover salivate, including a new 211 based amp scheduled for 2020. All of their manufacturing is done in Canada with parts sourced from around the world. In 2017 Triode Lab moved to a direct sales model in an effort to control escalating costs while keeping the manufacturing in Canada. The unit that was delivered to me is the 2A3 EVO. The EVO is an integrated single ended triode (SET) amplifier with two line-level inputs (I would have liked 3). This is a new model that replaces the now discontinued 2A3-i which was offered from 2009 to 2019 and the unit under review carries a serial number ending in 0001.

About the 2A3 EVO

Triode Lab refers to this unit as their “Reference Integrated Amplifier”. What makes it a reference? The Evo is fitted with what Triode Lab considers to be their “best choice” components for this amp. Some examples are the Hashimoto (Japan) transformers, Mundorf (Germany) silver in oil coupling capacitors and the ALPS (Japan) volume pot. In the past these components were offered as upgrades. With a standardized component list it was then possible to redesign the circuit boards and component layout in order to reduce wire runs and minimize electrical crosstalk: the binding posts are beside the output transformers, the power transformer is right behind the 2A3 tubes and the power supply is at the back as far away as possible from the sensitive preamp stage at the front.

The tube inventory includes a 12AX7 preamp stage followed by a pair of 6SN7 drivers and, of course, the 2A3 direct heated triodes. The porcelain 2A3 sockets grab the tube with a determined SNAP, announcing that the big tube is solidly in its place. DC power is created with a rectifier tube. I was sent a metal cased 5T4 however the 5U4G and a few other models will do the job. There are a lot of NOS 12AX7 tubes still available so tube rolling in the preamp stage might lead to some interesting results. I was quite tempted to try my NOS Ei 12AX7 tubes that were made in pre-war Yugoslavia on Telefunken machinery. However, they presently reside in my Doge 8 and that would have required pulling a lot of components out of my system and removing umpteen screws to get at them so I decided not to do it.

All of Triode Lab’s designs have a no-frills industrial look which I personally think is quite fine. Clearly another strategy adopted in order to keep the price tag lower. Wife Acceptance Factor is not a consideration in this house as my new, dedicated music room seldom receives a visit from the wife. The unit under review is British Racing Green Metallic (a $500. upgrade) and the paint quality is excellent. The Triode Lab web site indicates 9 available colors, plus 6500 other custom colors including car paint. The transformers are housed in elegant looking satin black individual cases with rounded corners, each carrying a gold Hashimoto Transformer medallion on top. The satin black against British racing green is a very nice combination. There may be mixed opinions on whether putting the speaker binding posts on top instead of on the back is a good idea. I appreciate anything that reduces the need to get to the back of the unit. The power cable for this unit is quite massive and actually pretty sharp looking with a red, flat braid sleeve and black connectors; no skimping on quality anywhere on the EVO! Continuing on the theme, the two control knobs, input selector and volume, are on the top plate instead of on the front. A pleasing and functional layout.

[Triode Lab 2A3 EVO side view]

I was advised by Frank Ing at Triode Lab that the unit I received was new and had very few operating hours on it. He suggested that I should give it a few days of run time before starting any critical listening sessions. He encouraged me to "take your time". The unit arrived with the 2A3 tubes however the other tubes were still in transit from so I installed some spare tubes that I had on hand and started the burn-in process. Of course, I didn’t just walk away, I had to hear this new toy. (Whether or not an amplifier sounds better after 100 or 200 hours of run time is a question that has been hotly debated but will be left alone in this report) After an hour or two of listening to music fed from the Doge 7 tube DAC it was quite evident that the sound was too big, too airy, and the bass was clearly exaggerated and out of balance with the rest! This was way to pronounced to be simply a burn-in issue. It could be a problem with the tubes, or the amp or the setup. While pondering this, a wisp of memory stirred; didn’t I read some place that direct heated triodes were susceptible to over-driving problems? Fortunately, the Doge tube DAC has 2 modes of operation, DAC Mode and Preamp mode. The Doge 7 was running in DAC Mode at the time which means that the output was pinned at 2.7 volts. In Preamp Mode the output volume can be adjusted directly at the digital level in the DAC. Upon setting the DAC to Preamp Mode and the output to just under 2 volts (estimated), the EVO responded with a clean, balanced and natural sound. A follow up exchange of emails with Frank Ing confirmed that 2.7 volts is indeed too much for this amp. Something for potential buyers to keep in mind.

Critical Listening Time

The tubes arrived the day after the amp, so my tubes were replaced with the new ones and the break in period continued. About 100 hours of break in time was logged before any critical listening started. Triode Lab was nice enough to leave the unit with me for several weeks so by the end of the review period it certainly had a significant number of hours on it. The EVO had no problem driving the Coincident Total Victory II speakers (96 dB/Watt) to a comfortable listening level despite its diminutive rating of 4 Watts. Even when a bit louder than normal listening level was set, the volume knob setting was about 70% with the DAC running (note that this is in Preamp mode with the DAC output set to about 2 volts) and 80% for the turntable. Three sources were used for the listening tests; 1. The "Big Lenco" equipped with a Dynavector 507 MKII tonearm and a Zyx Universe cartridge, running through a Coincident Statement step up transformer and the Doge 8 MM phono stage; 2. Arcam CD72 player used as a transport; 3. A PC running JPLAY FEMTO. Both digital sources were sent to the Doge 7 Tube DAC.

The 2A3 is of course a direct heated triode. Whenever I hear the words “direct heated triode” (DHT), I automatically think 300B. It is interesting to note that the invention of the 2A3 in 1932 predates the 300B by 6 years. The 300B has become the most popular, possibly due to it’s more user friendly 8-Watt output. True to it's DHT roots, the 2A3 EVO possesses the warm voicing and the beautiful silky mid range that triode lovers can't do without. It also delivers extreme detail and superbly balanced and precise bass performance. The latter two traits are certainly not something that one can consider commonplace for single ended DHT amps, but are certainly possible to achieve for an experienced designer with a big enough budget.

The first revelation from the EVO, and somewhat of a surprise, was the dead silent background on the DAC input. Designing and building a SET amp with very low noise is considered to be extremely difficult, well Triode Lab has certainly passed with flying colours on that task. The MC phono channel with it's two additional gain stages before reaching the EVO input couldn't quite match this dead silent background of course. Frank Ing of Triode Lab describes the importance of a silent amp this way. "It's like looking at stars and galaxy. In cities or suburbs, you can still see a lot of stars with your eyes on a clear day. But you will be stunted (I presume he meant stunned), once you go into the country with no light pollution - even with your bare eyes, you will see a lot more. Same applies to tube amps (or generally HIFI), or photography, the darker - the better and more you will see/hear. Like our amps - the quality is as if you look at the sky on top of mountains." The darker the background, the more detail in the music and the EVO delivers huge detail. After listening to the EVO for a several weeks now, the amount of detail present still surprises me every time I play something.

Another salient characteristic of the EVO is the overall bass performance. One first notices the tight, accurate and ample sound. Everyone who enjoys listening to chamber music can relate to this; when the Cello starts a solo the sound fills the room; one can feel the air moving in the room. Not overpowering but omni-present. The EVO has the ability to make a cello sound like it's playing right beside me. After a few days and many different albums, I realized that the bass level always seemed to be just right, the perfect amount of bass on each piece of music. I don't have an explanation for this, but it's there!

The bass is deep, crisp and very well balanced, a beautiful rich midrange and clean and natural high end. The incredibly low sound floor allows it to dig out immense amounts of detail and precision in the music. Detail, detail, detail, it can't be said enough! It excels on jazz and chamber music where its attention to detail and its SET roots bring out the best in the music. It absolutely loves solo instruments and solo voices; Jamal, Gardot, Peyroux, … anything I tried was played with brio. Generally, the EVO produced a wide and deep soundstage with the front instruments tending to be slightly less forward that what I am used to with my Canary amps. It came just a touch shy of the dynamics I can get with my much bigger Canary amps. That being said, it may not be a fair comparison as the Canary amps are 6 times more powerful and are playing through a The Truth line stage, that is to say no active preamp components in the signal path. Running the power amp section of the EVO from The Truth would have been a very interesting test but unfortunately not possible. A review of a pair of Triode Lab monoblocks (flea) power amps is planned and I hope to run this with The Truth line stage. I am very anxious to hear that setup.

Some Specific Listening Notes

(All vinyl records unless otherwise indicated)

The 2004, Wynton Marsalis Quartet CD titled The Magic Hour is one of my customary evaluation recordings. The first track, Feeling of Jazz, begins with a deep bass solo, followed by a sudden crack of the drum. The powerful voice of Dianne Reeves blasts high notes as well as deep low notes and Wynton comes in with screeches from the trumpet. This is a perfect tool for evaluating dynamic range capability. Through the EVO, the detail was superb with the voice and instruments sounding as natural as I have ever heard them. The overall sound slightly favoured balance over dynamics. My 26-watt Canary mono-blocks give a more powerful interpretation of this track, featuring the dynamics of the music. That being said, the Canary amps flirt with the edge of their performance envelope for some of Miss Reeves’ full throttle high notes. The first thing that comes to mind, of course, is that in my system, the 4 watts of the EVO may not be able to match the 26 watts of the Canary mono-blocks when it comes to big peaks in the signal level.

On Cat Stevens - Tea for the Tillerman , the instruments in the background were quite clear even at low volume. Each instrument residing in its own space, defined and independent. Father and Son which is a simple song but at the same time complex music, sounded very good.

Andrew Hill - Point of Departure: This album features lots of solo instruments, sustained notes and long silences between notes and the EVO performs beautifully on this type of music.

On The Best of Kraftwerk the synthesizer sounds were delivered very well and the swings back and forth between channels exemplified the excellent capabilities of the EVO regarding sound stage.

Dire Straits - Brothers in Arms: Detail, detail, detail! Background instrument take on some prominence. Tight bass; just enough, just right.

The Best of the Doors: What becomes evident after a couple of minutes listening to Riders on the Storm is the pace. Not something that one immediately thinks about with Doors music but the beat and the flow of this track was very engaging.

Bill Bruford with Ralph Towner and Eddie Gomez (16/44.1 flac) - If Summer Had its Ghosts: They play together like they have been doing it forever. Every note is perfect, with overall cohesiveness and balanced sound, full soundstage. The EVO gave each player an equal part of the overall sound and a very defined place in the sound stage, the three instruments sounding equidistant from the listener. A perfect presentation for this album.

Tom Petty - Hard Promises: The track The Criminal Kind provided a striking example of the ability of the EVO to dig deep for detail. Near the end, the rhythm guitar lightly strums from A to A minor for several bars. Even though this is a rhythm instrument strumming in the background, the alternating C-sharp to C on the second string is quite distinct.

Some soft spots

There are two knobs on the unit, the input selector knob felt a slight bit wobbly, possibly a shipping issue. No attempt was made to figure out if it could tightened as it was deemed quite minor.

Having only two inputs may be an issue for some people. In my case, I typically connect two turntables and a DAC so I had to put aside one of the turntables for the test period.

Referring back to the DAC input level problem discussed above, it may be advisable for potential buyers to check with Frank Ing to ensure a proper match. Given Triode Lab's long history of customizing components it is quite likely that this can be dealt with.


The EVO does everything very well, whatever characteristics you care to list the EVO gets a high score. It excels in all of the desirable traits of an SET amplifier and adds to this a super low sound floor, massive amounts of detail and beautiful bass. Depth of sound-stage as well as dynamic range did not quite meet the performance level available with my push-pull 300B monoblocks. (possibly not a fair comparison) The 2A3 EVO may not have much (if any) competition as a Canadian made, 4 Watt, integrated SET amp at this performance level. The 2A3 EVO should be on the short list of anyone considering a low power SET integrated stereo amplifier.

Some of the music enjoyed while writing this review

  • Tom Petty: Hard Promises; vinyl, half speed mastered edition
  • The Vaselines: Enter The Vaselines; vinyl
  • Graham Parker: The Mona Lisa's Sister; vinyl
  • Supertramp: Breakfast in America; vinyl
  • The Orford String Quartet: Beethoven, String Quartet No.8; vinyl
  • Perlman, Zukerman, Eddy, Sanders: Trio Sonatas; 16/44.1 flac
  • King Crimson: The Young Person's Guide to King Crimson; vinyl

DISCLAIMER. TNT-Audio is a 100% independent magazine that neither accepts advertising from companies nor requires readers to register or pay for subscriptions. After publication of reviews, the authors do not retain samples other than on long-term loan for further evaluation or comparison with later-received gear. Hence, all contents are written free of any “editorial” or “advertising” influence, and all reviews in this publication, positive or negative, reflect the independent opinions of their respective authors. TNT-Audio will publish all manufacturer responses, subject to the reviewer's right to reply in turn.