Teresonic Reference 2a3

The Reference 2a3 integrated amplifier is a limited edition Single-Ended Triode (SET) design that does not use any capacitors in its audio circuitry. This produces a life-like analog sound. It's an all-tube design, which includes a rectifier tube, using New Old Stock (NOS) tubes such as 2a3, 6SN7, and 83 made by RCA mostly in 1940's and 1950's. The tubes are mounted in low-noise, gold plated, ceramic tube sockets, and the sockets are insulated from the chassis using vibration damping material to protect the tubes from any vibrations. Each amplifier is carefully handcrafted using proprietary topology and the world's finest parts.

"This 2A3 amp has a very open, relaxed, dynamic and detailed sound. It allows you to experience music in a deeply emotional way with a holographic soundstage. It brings you so close to the real thing you won't believe it. It is among the best High-power amplifiers I've ever heard, and it has the build quality to match." – Jack Roberts,, click here for review

Specifications include power of 2.5W per channel into 8 Ohms nominal impedance, bandwidth of 5Hz-70kHz ± 3dB, four sets of RCA inputs with 200mV sensitivity, and one XLR balanced input. Extremely low broom under 0.8mV and S/N ratio of 80dB makes it one of quietest amplifiers in the class. Power consumption is about 200W making this amplifier a true Green Audio device that you can enjoy for hours with low impact to the environment.

Reference-2a3-mWhile most of the industry is spending efforts on developing megawatt amplifiers that consume huge amounts of energy to drive ever more inefficient loudspeakers, we at Teresonic are taking a different approach. Our efforts are invested in creating ultra-high efficiency, ultra-high quality speakers capable of producing natural-sounding music with (very) low-power amplifiers. That's how the Reference 2a3 was born – as an example of all the beauty of natural music and efficiency.

Reference 2a3 wasn’t created as a commercial product to compete with many fine tube High-power amplifiers from Art Audio, Wavac, Audio Note, Carry Audio, First Watt, Manley Labs, Reimyo, as well as with fine DIY projects. It was designed as a reference standard among tube amplifiers, with Teresonic speakers and cables to demonstrate our commitment to the beauty of natural music. Reference 2a3 is a special order product for $14,980 – which is also subject to the availability of NOS tubes and other hard-to-find components. We will not cut corners and compromise with replacement parts, and we apologize in advance if we are not able to accept an order because of the availability of the necessary parts.

A dream system, consisting of a Teresonic Reference 2a3 amplifier, Ingenium loudspeakers with DX4 silver drivers and Clarison 10ft speaker cables, is offered at a special price of US$ 27,985. Such a system was demonstrated at the CES, T.H.E Show, and other events winning “the best sound of the show” prize every time. This is a very limited availability system, so please contact Teresonic before ordering. You can reach us by email at, or by phone, at 1.877.287.1649.

A System is more than the sum of its components

At the end of the day, it's about how your music sounds and that means how your entire system sounds when it is all put together. Matching system components can be a long and daunting task. Many audiophiles spend years trying to match system components. With one of the Teresonic speakers and fine amplifiers listed here, connected with Teresonic cables – a well matched, excellent sounding system is assured right out of the box. Of course, the listening room is critical and we pay a great deal of attention to that in Teresonic owner manuals. Also, feel free to contact us at, or by phone at 1.877.287.1649, with any questions about your system, its setup, or how to design the best listening space.

Which amplifier to chose?

Teresonic speakers have been tested with some of the finest amplifiers available. This isn't an exclusive list, and many other fine products can be found – especially among low power (1-30W) SET amplifiers and solid state amplifiers that match ultra-efficient Teresonic speakers.

Tubes vs. Solid State

Musicians, engineers and us, that is, audiophiles and music lovers, have long debated the question between the sound of tube amplifiers versus the sound of solid-state amplifiers. Although solid-state technology dominates today's world, vacuum tubes are becoming increasingly popular for high-fidelity audio applications. Actually, there are more manufacturers of high end tube stereo equipment now than at any point in history! Although we may have our preferences, the fact is there are excellent sounding tube and solid state amplifiers – so there are other questions to consider. Sign-up for our newsletter, and keep up with the latest developments in sound technology.

Simplicity leads to better sound

It's startling how much hassle, money, and time can be saved by introducing a little 'simplicity' into audio technology. It's much easier to match three system components instead of six or ten; reducing a system's complexity makes it is easier to troubleshoot, and it saves money that can be spent on better quality components or more recordings.
Take amplifiers for example: an integrated unit or pre-amp and power-amp separates? There are no technical reasons for separates to sound better than an integrated amplifier. It's quite the opposite. An integrated unit eliminates sixteen connectors and a pair of cables between two separates. That alone should improve sound in any system, not to mention the cost (cables, connectors, two power supplies, two chassis, etc.).

Low-power vs. High-power

Certainly there are quality products in each category, but low power amplifiers have some inherent advantages. Low power amplifiers contain fewer and smaller components, such as transformers, capacitors, resistors, etc. Accordingly, they cost less, weigh less, and take up less space. They almost always sound better, and since they consume significantly less energy they cost less to operate as well.
From an engineering point of view, it is clearly easier and less expensive to design and manufacture a high-quality 10W amplifier than an amplifier of equal quality that is a 100W or 500W monster. If every amplifier will sound better, and have fewer distortions, at lower volumes using fewer watts, why do we need 100's of Watts? Are our listening rooms so large, or speakers so terribly inefficient? What about the environmental impact of such power monsters?

Green Audio

High-end audio systems may consume over 2,000 Watts of power. If used for three hours a day, five days a week, it will consume 1,762 KWH. Does that sound like too much? If 100,000 people in US use such a system they consume almost 200,000 MWH – which in turn requires 13 million gallons of oil every year, just to support our audio pleasures?
Which part of the system is to blame? Amplifiers use most power. A 200-500W/channel amplifier can consume up to 2,000W of electric power, and multichannel applications make it worse. Hence low-power integrated amplifiers should be on every audiophile's list.

WAVAC EC-300B and MD-300B

The MD-300B distinguishes itself among SET amplifiers as it produces 10 beautiful SET watts per channel, and can be used as a stereo amplifier or as an integrated unit with three inputs and a passive volume control. It has no active preamplifier stage. Like all WAVAC Amps, it is transformer coupled with no caps in the signal path. WAVAC winds its own transformers with Oriented-Highbee-core material.


"With the Ingenium [and Wavac] you experience all the textures and harmonics of live music. They let you hear how the decay of instruments and acoustical environments sound. The music blooms and feels much more like real music. The whole listening experience becomes about the sounds and feelings of the music in a way that transcends an electronic listening experience."
- Jack Roberts

Jack Roberts reviews audio equipment for and his reference system includes Wavac amplifiers and Teresonic Ingenium speakers. The system was tested with Teresonic Integrum speakers as well. Both reviews are available at

Click here for the Integrum review.


Other components of Jack’s reference system include:
Source: Shindo 301 Vinyl Playback System
Preamp: Shindo Giscours preamp and Auditorium 23 Homage T1 step-up transformer
Amplifier: Wavac MD-300B and Wavac EC-300B. SET amp with Western Electric tubes
Power conditioner: Audience aR6-T with Au24 powerchord
Speakers: Teresonic Ingenium Silver with Lowther DX4 drivers with silver voice coils – According to Jack “These great speakers were the icing on the cake for completing my system. Along with the Wavac they allow me to have the sound of flesh and blood music and not the sound of reproduced music in my home.”

Cables: speaker cables are Teresonic Clarison – Jack says “Simply put, the best kept secret in audio.”

Sun Audio SV-2A3 Amplifier ($4,000)

“I’ve been captivated by a recent release by a young French pianist, Adam Laloum (CD, Mirare 131). He’s 25 years old, from Toulouse. Among my favorite Brahms piano works are the Three Intermezzi, Op.117, and I’ve rarely heard them played with such sensitivity and beauty as by Laloum. I was reminded of Arturo Benedetti Michelangeli, from an earlier era. Between the Magus speakers and the Sun Audio amplifier, Laloum was present in our living room in a way that ordinary hi-fi—conformity, commerce—could not recapture.” – Sam Tellig, Stereophile,

August 2012 Read more... and Sun Audio site

Pass Labs XA30.8 ($6,500)

"I listened to this amp for a little over two months with the Teresonic Ingeniums XR Silvers… I was shocked to discover that I had that feeling that makes your mind say, “Ah! that feels so right.” … when I put the Wavac back in it only took a few days until I really missed the XA30.8. I missed the Pass Labs’ power; I missed its scale; I missed its incredible harmonics, its overall tonal balance and just how wonderfully and emotionally involving my system is with it is powering the speakers. The XA30.8 does all these wonderful things with a way that seems effortless and thus very enjoyable to listen to for very long sessions.

The Pass Labs XA30.8 plays the textures, colors, tones and harmonics of music more realistically than any of the other amps I’ve mentioned. Its timbre realism with individual instruments and voices is just so satisfying. It allows my system to play music with such a enjoyable life-like flow. It has great PRaT and great fullness at the same time. This is something I have never heard an amplifier achieve to this extent. I can’t believe I’m saying all this about a transistor amp.

Jack Roberts, 2015


ASR Emitter I Exclusive Amplifier ($19,900)

"This is without a doubt the best solid state amplification device I have heard. It has incredible transparency! It has a magical see-through quality, different from my Wavac EC-300B. I expect one of the reasons for this is the incredibly low noise floor. For most of this review, I was using Teresonic’s top of the line Ingenium XR speakers that are over 100dB efficient. If there was noise there would have been no way to hide it; but there was none. This kind of low noise floor allows for great resolution of low-level detail, incredible spatial resolution, great micro-dynamics and real macro-dynamics that come through with a real since of ease. I honestly didn’t know my Teresonic could go so deep. Transients are so fast that the leading edge of instruments sounds alive. The authority of the low-end also give you plenty of weight combined with that leading edge. The Emitter One Exclusive does have an ever so slight dark tonal balance. I think this balances out the speed this amp has in a very musical way. Like I said, its ability to control the speakers gave me deeper bass than I had ever heard from the Teresonic speakers."

Jack Roberts, October 2012 - Read more… and ASR site

Peachtree Audio Decco Integrated Amp+DAC ($999)

Peachtree Audio Decco is a 65-watt-per-channel, hybrid integrated amplifier with a built- in non-up-sampling DAC. The DAC was designed by a well known DAC designer, Scott Nixon. The Teresonic Magus A55 and Peachtree Audio Deco combination offers a great sounding system for under $7,000.

Jack Roberts who reviewed such a system called it “…the best value in all of audiophile audio!” He continues, “It’s one of those things that’s hard to put in words, but the combo just sound simply wonderful whether I’m listening to music, watching TV or a great movie.” In conclusion he says, “…after living with these everyday for over a year, I want you to know that there is something very special about these speakers. The magic of Alnico combined with the superb cabinet designs of Teresonic has created a small monitor size speaker that is 98dB efficient. If that’s not remarkable enough, it reproduces sound that is alive, articulate, powerful, big, and just plain exciting to listen to.”
Read more…


Bob Carver ‘Black Magic’ VTA 20S Tube Amplifier ($2,500)

"This little amp uses one of my favorite tubes, the EL84; I love how seductive they sound. Two of my favorite amps over the years, the Beard P35 and the little Shindo Montille use the EL84. So it came as no surprise to me that this amp sounded very musical and very beautiful. Music flowed out of it into my Teresonic Ingenium XR, and filled my listening room with beautiful music. Turns out the EL84s have long been one of Bob’s favorite tubes as well. He used the M edition that allows the use of a higher plate voltage, which allows you to get a little more power out of them. Carver uses them in a push-pull configuration. I had to keep reminding myself that I was listening to a $2,490 amplifier. If I forgot that and begin to expect it to do everything my $29,000 Wavac EC300B did, then I could find some shortcomings; but you should get something for an extra $27,000, shouldn’t you?" - Jack Roberts, March 2013
Read more…

Art Audio Diavolo TW Ref Signature ($9,950)

“I used the Diavolo WE with my Teresonic Ingenium XR that use Lowthers DX4 silver drivers. The Diavolo did an exemplary job of driving these speakers. It played them with good transient speed, nice control of the bass, very good treble extension, and a midrange sound that can only be called lush, relaxed, and natural.

…On my system it played a truly believable, coherent, and dimensional soundstage. The depth and width perspectives were especially good without distracting the listener from the music. It was easy to delineate individual instruments and voices from each other. It sounds excellent with different types of music, and I think that important factor helps it rise above the performance of many SETs, especially those priced below $20,000…” - Jack Roberts, July 2013, Read more…


The Art Audio PX-25 is a zero-feedback design, automatic biasing stereo amplifier rated at 6wpc The PX25 tube is said to feature a midrange sound similar to 2A3 but with more extension at the frequency extremes, and of course more power. The slightly higher plate resistance, relative to a 300B, allowed Art Audio to design an output transformer with an extended bandwidth - beyond what is typical for 300B or 2A3 based amplifiers. This gorgeous, sweet sounding amplifier can be used as a power amplifier or an integrated unit when equipped with a volume control.

Vade Forrester reviews equipment for SoundStage and his reference system includes Art Audio PX-25 amplifier tested with Teresonic Ingenium speakers.

Vade says, “if you’re ready for some high-sensitivity speakers with reasonably wide frequency response, excellent soundstaging, dazzling dynamics, intrinsic coherency, and an arresting appearance, find a way to audition the Teresonic Ingeniums. And if you’re already a fan of Lowther-based speakers, you absolutely have to hear the Ingeniums. I’ve never heard Lowther drivers sound so complete.
There was a surprising amount of output from the enclosure at its 30Hz resonant frequency. I’m not used to hearing such deep bass from speakers with Lowther drivers, and I must say it’s a welcome development.
Click here for the full review.


Roksan Caspian M Series-1

Roksan is a British high-end audio company that became famous for making one of the first turntables to seriously contend with the Linn Sondek table. Caspian M Series-1 is the latest generation in the Caspian series and a very musical-sounding integrated amp. Caspian is a solid state amplifier but it's quite capable of being the centerpiece of an emotionally satisfying high-end system.
Caspian has great bandwidth, good dynamics, tight powerful bass, a very transparent midrange, plenty of power, a very good soundstage presentation, and best all, it doesn't sound much like a sand amp at all. Both the preamp stages and the amplifier stages are dual-mono designs, and the company separated the microprocessor and logic controls away from the amplification sections. It has a full-function remote control that could run an entire Roksan system, as well as five line inputs plus a tape input and output. The INPUT SELECTOR could also be accessed from the remote or the faceplate. The motorized VOLUME CONTROL with LED position indicator is easy to use and see.

Jack Roberts reviews audio equipment for and he reviewed Roksan amplifier and Teresonic Magus speakers.
The Teresonic Magus speakers are strikingly beautiful, stand-mounted, single driver monitors that utilize a Lowther-Voigt DX-55 driver in an oval, sculpted wooden enclosure. The matching stands are also very attractive and work well sonically. The finish of the 15-inch tall, multi-chambered, curved enclosure is furniture grade and liked by everyone that came in, and most people commented on their good looks. It amazes me that a speaker this small could be 98dB efficient, but upon use there was no doubt they were every bit that efficient.
One of the remarkable things about the Teresonic Magus' speakers was how wonderful they sounded with different amps and sources. I started by using them upstairs in a completely transistor and digital system. While the Magus are plenty good enough for downstairs; I want to tell you they produced the best sound I have ever heard from a Roksan integrated and the Oppo CD/DVD player.
The truth is I am glad I got to hear this combination before I finished the review of the Roksan Caspian M-Series-1 integrated amp. It was delightful to hear how wonderfully tuneful this combo can be. I wish I could afford or justify buying them for my upstairs system. They are incredible for music, TV, and movies. Their diction was incredible. Another thing this combination has in spades is P R a T. The combo is actually as good if not better than my reference system in regard to Pace, Rhythm, and Timing. The combo is as good as any Naim/Linn system I have ever heard.

Click here for the full review.

Contact Teresonic with any questions that you might have, at or 1.877.287.1649. Also, sign up for our newsletter to receive the latest information about product updates.


This design compared eight different tubes such as 6AQ5, 6V6, 6L6, 6973, 6DQ5/6GW6, 807, EL3 and E80L. The ratings are obviously subjective to author’s ear, but his bottom line is: “I think that most CD and solid state aficionados would initially prefer the 6973, and then over time be wooed to the EL3 or E80L. SET lovers are going to want the EL3.” Although, he claims that the 2a3 is still hard to beat by any tube at any price point.
Click here for the full article including schematics

Damon Coffman’s DIY low-power amp project
Damon is a violinist (“a hacker now, but a concert master decades ago”) and he wants the music he listens to, primarily classical and jazz, to sound like live performances. “A good 2A3 amp with vintage tubes does wonderful things to great music and has been my favorite amp for a long time.  My goal in this project was to find a (vintage) triode strapped pentode that could equal the magic.”

Multi-amp’s goal was to build an amp for less than $1000 that equals the quality of $8,000 commercial single ended amplifiers. If you are willing to make some compromises, primarily in the power output, he has found that you can build astonishingly good electronics for very little money. Then you can spend your savings where it counts the most—at the beginning and the end of the chain; the speakers and the phono cartridge. Multi-amp design is meant to show just how to do that.
Damon’s listening equipment includes an Immedia platter with a RPMII tone arm and Koetsu Urushi cartridge.  He uses the EAR 324 to drive the differential input on a Echo Audio Layla 24 and record the vinyl to disk at 96KHz/32bit recording.  His reference speakers are Teresonic Integrum with PM2A drivers. He says:
“Having played in the orchestra behind performers like Issac Stern and Pinchas Zukerman I know what their violins sound like in real life. The Integrums gave the most realistic reproduction I have heard from any speaker.”

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A System is more than the sum of its components. Which amplifier to chose? Tubes vs. Solid State. Simplicity leads to better sound. Low-power vs. High-power.