The Torus Power AVR20 is based on a 20-amp Plitron power isolation transformer that includes automatic voltage regulation. It offers robust protection for a large system while opening up the performance dynamically by allowing incredible current draws during transient peaks.

It is easy to install, works flawlessly and should last a lifetime. If you have a good quality system, then consider this your next upgrade move. The AVR20 will take a good system and make it great!


Torus Power AVR20 Toroidal Isolation Power Transformer

  • Power Isolation Transformer
  • 20 Amp (2,400W) Capacity
  • Noise Reduction
  • Surge Suppression
  • Automatic Voltage Regulation
  • Web Interface
  • System Integration Features

I’m a professional engineer. Being an engineer means many things, one of which is that I believe most problems can be solved through the application of scientific principles. So I have some major reservations concerning manufacturers who make extravagant claims for their products when those products are based on pseudo-science or no science at all. There are tons of accessories and components in the high end that fall into this category.

20 Amp (2,400W):


10 Medical:

Grade Rear Panel Outlets



Front Panel:

Master Power Toggle

Front Panel Readout:

V In, V Out, Current Draw and IP Address


Voltage Regulation




90 – 130 VAC


120 VAC +/- 5 V

Output Impedance:

0.1 ohm

Input Type:

20 Amp IEC

Rear Panel Ethernet and:

RS 232 Jacks

95 lbs:



8” ( 203 mm) H x 19” (483 mm) W x 19” (483 mm) D


$4,999 USD


Torus Power


Torus Power, Power Transformer, Transformer, Reviews 2017

For example, power line conditioners are typically over-sold. The ones I have used offer spike protection and some sort of noise filtration. These are usually inexpensive and if you heed the manufacturers’ claims, they do what needs to be done. Then there are products that focus on regeneration of the power supply waveform. These are complex, expensive products where the engineers have gone to great lengths to clean up the power before sending it along to your system. The pay off for these systems is difficult for me to explain.

Torus Power AVR20 Toroidal Isolation Power Transformer - Front Black

On the other side of this argument, one can find products with designs that are based on solid science and engineering. These products may not always get the recognition they deserve. And in some cases, meeting the demands of physics requires the product to be heavy or intrinsically expensive. Perhaps the only real way to reach the level of performance you want is through a brute force approach.

So let’s take a look at the product under review here. The Torus Power AVR20 is a 20-amp power isolation transformer with automatic voltage regulation. This design results in a heavy copper-filled case that, despite that I said “brute force” above, is actually a very elegant and simple product that operates within the realm of analytical physics. I mean this thing does what is needed and it does it in the most straight forward and easily verifiable way possible. Its biggest downsides are that it’s heavy and it ain’t cheap.

Dr. Johnson reviewed a Torus Power isolation transformer in 2008. He did some bench testing that I did not. Find the review here.

Please read more about the AVR20 in my below review. Check out Torus Power’s website too. They have products ranging from small isolation transformers for a single component all the way up to wall or floor mounted products for massive, power-hungry systems!

Design and Setup

The Torus Power AVR 20 is a heavy and massive component. I guess the massive 20-amp Plitron power isolation transformer may be one small part of this! This power isolation transformer is the heart of this incredible product. In a nutshell, it is essentially a 1:1 power transformer that isolates your system from the outside power supply coming to your domicile. By their very nature, transformers such as these reduce noise (especially high frequency noise) and they also reduce the impedance your components see which allows for more instantaneous current delivery.

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Torus Power sources their transformers from Plitron, a company that has specialized in power transformers of all kinds for over 30 years. Why is this important? First of all, designing and winding toroidal transformers is in many ways an art as much as it is a science. An art that requires great precision. Another reason would be that poorly-executed transformers often put out a significant amount of mechanical hum, but Plitron has learned how to create very quiet-running transformers. I cannot hear or even feel the slightest vibration in the review unit that I have. Torus Power claims all their units meet the NC 10 acoustic noise standards which means they are suitable for use in the most demanding applications, including recording studios, television studios and sound mixing rooms.

There is a third trick up their sleeve as well. This is known as “Narrow Bandwidth Technology” or NBT for short. According to Torus Power, NBT balances all the electrical characteristics of the transformer so it acts as an enhanced low-pass filter. The filter starts attenuating noise at 2 kHz and then the distortion in the waveform drops by 12 dB/octave out to 500 kHz. This may be the largest inherent advantage of their technology. What this means in practice is that this unit squelches just about all the noise that enters the power grid on its way to your home or studio. Not only can this noise be a detriment to the life of your components, but it is also the source of audible and visible artifacts that can muddy the playback virtues of your system.

Torus Power AVR20 Toroidal Isolation Power Transformer - Rear Black

The Torus Power AVR 20 also presents a very low output impedance to your system. The AVR 20 has an output impedance of just 0.1 ohm. This speaks to its ability to deliver high instantaneous current. In fact, the AVR 20 can deliver peaks of up to 400A! My main power amp is an ATI AT 2007 which is a 200 wpc 7-channel class A/B amplifier. This amp has a 15A circuit breaker but can demand significantly higher current draws during short peaks in the musical waveform. The voltage to the amplifier will not sag under these demands so long as I have the AVR 20 in my system. This allows for greater headroom and keeps the soundstage from collapsing during peak demand levels.

Another core function of the AVR 20 is surge suppression. This is also an area where Torus Power breaks from the pack. Most power strips and power line conditioners provide surge suppression via Metal Oxide Varistors (MOVs). These are shunt-mode devices which clamp the over-voltage by shunting to ground. This effect raises the ground voltage which can cause audible/visual artifacts to appear. MOVs are also limited life components that need to be replaced after a few years. Furthermore, they are only effective on clamping sudden spikes and do not kick in when you have sustained over voltages which can be very damaging to your components.

The Torus Power AVR 20 uses Series Mode Surge Protection circuits which do not shunt voltage surges to ground. This system does not affect the ground voltage, it reduces long term over-voltages and has a long life expectancy. It meets IEEE standards of 6,000 V, 3,000 A and up to 1,000 repeats of this over-voltage condition. I think this will last a lifetime in my system.

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One may be excused for thinking that “AVR” in the component’s model designation stands for “Audio-Video R-something”. That in fact is not what it means. What it does mean is that the unit has what is known as Automatic Voltage Regulation. Remember when I said this product was based on a 1:1 transformer? Well that was a little white lie. This transformer actually has a number of different taps that switch in and out to keep the line voltage within an acceptable range so your system will run optimally. Like I said, sustained under- and over-voltages not only degrade system performance, but they also significantly shorten the life of the internal components of your equipment. The AVR 20 will automatically shut down whenever the mains voltage falls outside its correctable range. And this system is also silent in its operation.

Torus Power AVR20 Toroidal Isolation Power Transformer - Internal View

The last great feature set included with the AVR 20 is a “Smart Ethernet” control module. The AVR 20 has both Ethernet and RS 232 connections on the back panel. Torus Power describes their functionality thus, “All AVR and AVR2 models feature a built in web browser interface accessible on the local area network, via VPN, or through ihiji remote network management. Other useful features include password control, automatic e-mail notification of fault conditions, and delayed switch-on (5 seconds) when power is turned on, or restored. All Torus models equipped with the AVR feature also include RS232 control and are compatible with Crestron and Savant systems.”

The web interface allows some customization of the front panel read out in the AVR Setup. This allows timeout of the display after a specified period of no activity. This is nice because the readout and lighted mains toggle are both fairly bright and blue. This was not a concern for me as my EQ rack is largely out of sight. But for others, I wish there were a front panel toggle to turn off these lights. Torus Power folks tell me they are currently working on a new circuit breaker with a small, dim pinhole light for future generations of the AVR line.

Set up was about as simple as one can expect from a 100 pound power conditioner. I’m serious. The hardest part was wrestling this beast into my equipment cabinet. After that, the AVR 20 is simple plug and play. The unit has a hefty power cord with 20-amp jacks on both ends. The outputs are five dual hospital-grade outlets for a total of 10 available sockets. I surprisingly have 10 components that I powered through the AVR 20. Pretty much everything goes through it except my subwoofer and direct view display which are on a different circuit in the front of the room.

The biggest power drawing components I have are the multi-channel ATI power amp (12 – 15A) and my projector (3A). I thought these would be the products that would benefit the most from the AVR 20, but I now believe my Oppo BDP 105D Blu-ray player may also be showing signs of improved performance. That is because the unit cleans up a lot of noise in your power source.

In Use

So I live in a part of the world where allergens are a big problem. This causes me to have a stuffy head from time to time. It just so happens that my inner ears where feeling the pressure the day I put the Torus Power AVR 20 into the system. This meant I couldn’t tell you one single thing about the sound quality, at least at first. It would take a few days for my hearing to clear up.

Torus Power AVR20 Toroidal Isolation Power Transformer - Front Silver

This was actually not a major problem and in fact may have been beneficial in my attempts to evaluate the AVR 20. You see, products like the AVR 20 tend to provide only incremental improvements to the performance of a system. Most times, these changes are subtle and hard to ascertain for sure. This has been my experience in the past.

John Wick 2

John Wick 2

Since my ears were practically ringing, I was forced to concentrate on the image quality over the sound. What I saw was a major revelation. I didn’t have to strain or work real hard to see visible improvements in the image via my Blu-ray player and front projector.

The first thing that jumped out was a major increase in the detail of the image. This was a big wow, OMG type of moment! The difference was not at all subtle. And I know it was the AVR 20 because I didn’t see the same level of improvement over my direct view monitor which is on a different circuit.

Kong Skull Island

Kong Skull Island

It wasn’t just the detail in the image where I saw improvements. It was seen on every aspect of the image. The contrast was notably improved. I saw much less irritating ringing and surprisingly there appeared to be fewer compression artifacts as well.

The contrast was so much better that the picture appeared brighter on every scene. More brightness is always a good thing. Again, this was not subtle or hard to see. It was immediate and obvious. I did not have to strain to see these improvements. The improvements were very real. I couldn’t wait for my ears to clear up!

A few days later, my hearing did finally get back to normal. That’s when I learned that the improvements in sound quality would prove to be less obvious than what was experienced on the video end. I had to listen and pay attention so I could parse out what was going on. I didn’t have to strain, mind you, it just wasn’t as obvious as the video-related enhancements. (The several day delay in my hearing issues may have been a contributing factor in this observation.)

Prior to the Torus Power AVR20, the power line conditioners I have used have all been essentially surge suppression with some degree of noise reduction. Audio-wise, these products have generally reduced the noise floor. This has been the most apparent of improvements. I have also detected less overhang on transients with these products.

The AVR20 is the first isolation transformer I have used. It mirrored the same virtues I have heard with typical power conditioner products – lower noise floor and less overhang on transients. In the end, however, the Torus Power product went much farther than that.


John Coltrane“Coltrane”

The first thing I heard was that the sound had a fleshier weight to it. More gravitas, if you will. This enhancement was heard with music and movies alike. This effect created a much more robust foundation to the proceedings. The bass benefited further by sounding as if there was more power and punch on tap.

The Beatles

The Beatles “Sgt. Pepper’s”

I also heard an apparent decrease in harmonic distortion. This was heard through more detailed and refined textures in musical passages, particularly when a full orchestra was playing.

But it also allowed the treble to sparkle just a bit more. And the fleshier bass had more space between the notes.

The soundstage grew as well. This was in both the width and the height of the stage. And as I mentioned above, the soundstage seemed to retain this wider perspective even during high dynamic peaks. It wasn’t just a little bit bigger. It was huge, grandiose even. This brought me into a territory where I felt transported to the recording venues much more frequently and convincingly than ever before.

Speaking of dynamics, this may have been the biggest overall improvement I enjoyed when it came to the sound. Just as in my video-related observations, the audio also benefited from increased dynamics. Again, this was a universal enhancement – movies, music, TV, you name it. I think the increase in apparent headroom is the one feature of the Torus Power AVR20 that really took my system to the next level. Once the Torus Power was in and popping, my system was suddenly competitive with systems that cost twice as much. That’s what this incredible product can do for your system as well.

I have watched a lot of movies and listened to a ton of music with the Torus Power AVR20 in my system. The most sustaining observation and the one that summarizes all my observations is that my system is significantly more “immersive” than any time before. Ever.


Torus Power AVR20 Toroidal Isolation Power Transformer - Front Silver

THE TORUS POWER AVR20 provides high end power conditioning and isolation for your audio/video system. When installed in your system, you will enjoy improved dynamics, better resolution of details and a much more lifelike reproduction of the source material.

  • Power
  • Dynamics
  • Clarity
  • Resolution
  • Soundstage
Would Like To See
  • Front-panel dimmer for the readout
  • Less obtrusive light from the power toggle
  • WiFi

I will probably take some internet flack for what I am about to write. High end power cords are a total waste of your money. There is very little a straight wire can do to clean up or improve the junk coming out of the wall to any appreciable degree. And this is based on years of hands-on experience by yours truly.

But all that changes with the Torus Power AVR 20. This thing gives you clean power, low output impedance and a stable voltage supply. It can deliver serious transient response as well. This is the kind of power that gives you a platform to tweak your system’s power cords. It is the only way that I would continue the power cord upgrade journey. Try it for yourself and you will see.

The Torus Power AVR 20 will take any system up a notch or two. If you have a system that is good, great or even excellent, running your equipment through the AVR 20 will take your system to the next level. As an example, the street price of my system is around $30,000. This is not modest but in my view is at the point of diminishing returns. The AVR 20 let my system rise up and be competitive with systems costing as much as $75,000 – $100,000. This was an astonishing level of improvement for what is a relatively small investment. Add that the Torus Power AVR 20 provides on-going protection of your equipment and you have a most highly recommended component!

  • Your credibility as an Engineer is questioned when you write that cables are a waste of money. Every Cable acts as an antenna collecting EMI and RFI that pollutes your system. Basic engineering principle. Ah well you were going so nicely up until you said that. It must have been a brain slip. Take that out and you would have a nice breezy review full of personal anecdotes. As it is you shot yourself in the foot.
    Ok that said I hope you will reconsider and be more cautious next time.
    Moving on with the design of this product with its large toroidal transformer seems significantly different to other current designs such as those by well known brand Furman. A comparison to this brand might be used to highlight risks and benefits.

  • Anon

    My problem started when he called out the expense and effectiveness of regenerators, and then picked an isolation transformer that costs just as much.

    Furman and Audioquest build similar designs, with isolation transformers, voltage regulation, and surge protection.

    If I went with a big transformer design, I would also checkout balanced power, such as from Equitech or Core Power Technologies,

  • Jim Clements


    The power lines leading to your home pick up RFI and EMI interference as do the lines running through the walls of your home. So I must ask, what do your expensive power cables do to filter out this noise? They may not add as much noise as a stock cable but no straight wire can filter this noise. That’s my point. If you have any evidence that power cables can reduce this noise, then I would be delighted to read about it! Let me know. Thank you,


  • Jim
    Do you agree then that cables no matter where they are located, so long as they are connected to your system collect and transmit EMI RFI? I’m just reading what you’ve said. Moving onto this product review here let me ask some more questions of you. How does what you propose of this product or espouse get rid of RFI & rid of EMI already being conducted on interconnect signal conductors?
    How does what you propose or espouse get rid of RFI & rid of EMI already being conducted on power cord hot, neutral, ground?
    How does what you propose or espouse get rid of RFI & EMI collected out of airwaves inside of the HiFi or Video component generated by itself?
    Explain in detail please. Finally, just one more question here…who said “expensive cables remove noise”? I can only find your writing this, no one else? Looking forward to a long detailed and valuable discussion with you.

  • Jim Clements


    I am not sure what you are trying to accomplish here but this debate has been going on for a long time and it isn’t going to be resolved in the comments section of this review.

    My review describes the advantages of an isolation transformer. One of these advantages is that transformers are natively low pass filters. This means they choke much of the high frequency noise in the incoming power waveform. Once this noise is filtered, then experimenting with power cables starts to make sense to me. That was my point, taking raw, dirty power and running it through an expensive cable is in my opinion a pointless exercise.

    You obviously do not agree. I assume you have some expensive power cables and you are convinced they improve the sound. I think this is great and I hope you enjoy these experiments.

    And it is okay for us to agree to disagree on this. However, I do take offense that you said my credibility as an engineer is questioned due to my opinions on this issue. Really? I know tons of engineers who agree with my position. That unwarranted attack is out of line and I needed to respond to it. Thanks,


  • Anon

    Cables from Audioquest, Synergistic Research, and other manufacturers are D.C./dialectric biased. Cables from LessLoss, MIT Cables, Shunyata Research, and others include filters. As a reviewer, you should be aware of this.

  • Anon

    Cables from Audioquest, Synergistic Research, and other manufacturers are D.C./dialectric biased. Cables from LessLoss, MIT Cables, Shunyata Research, and others include filters. As a reviewer, you should be aware of this.

    Also, since you’re a man of science, view Shunyata Research’s video on how a power cable can make a difference, by searching for DTCD and ASCC Demonstration, on YouTube.