by Doug Blackburn Review Summary – Two of the other three product lines are more specialized isolation products requiring 240VAC two-phase power. Many newer homes have 100-amp electrical panels, while 200-amp panels (or greater) are found in larger homes with more luxury equipment (outdoor lighting systems, swimming pools, large air conditioning units and electric furnaces), so Torus Power’s wall-mount isolation units could potentially be used for the whole house.
The remaining product line features “box style” units that will appeal to many, with their black chassis and simple silver faceplate and no rack ears. These will look right at home in a typical equipment rack for a home-audio or home-theater system. Thus, with all of its product lines, Torus Power has covered just about every consumer base.
Torus Power products are interesting in that there’s nothing inside the chassis except a huge isolation transformer, the wiring, the backside of the AC outlets, the surge suppression devices, and a few control components (voltage regulation will be introduced soon). There are no conventional filter networks anywhere. Torus Power took a unique approach by working with Plitron, a transformer manufacturer, to create an isolation transformer that doesn’t behave like a conventional toroidal transformer. Toroids, as commonly used and specified, do little to block high-frequency noise on the power line in either direction. The isolation toroids Torus Power uses have special design features that address higher frequencies, beginning at 2000Hz. This is a much lower frequency than you find for typical conventional Power Transformers that have filter networks using capacitors or capacitors and inductors.
According to provided specifications, noise reduction for the Torus Power units is just beginning at 2000Hz. At 20,000Hz there’s about 12dB of noise reduction. At 200,000Hz, noise is reduced by about 24dB. Near 500,000Hz, noise reduction peaks at 36-40dB. It then slowly diminishes as frequencies increase to 2MHz, where it levels off at about 20dB. Torus Power’s numbers are better than those for many capacitor-based Power Transformers below 100,000Hz. Above 100,000Hz, it’s not uncommon to find similar noise-reduction capabilities in other products. Of course, the capacitor-based products don’t isolate connected components from the power line as do the Torus Power products.
Unlike most other Power Transformers, there are no capacitors used as filters in the Torus Power products. This has the hypothetical benefit of eliminating dielectric (insulator) memory from smearing audio quality. Many have speculated that the relatively large amounts of dielectric in capacitors used in Power Transformers actually retains some memory of immediately preceding audio signals. Eliminating the capacitors, then, should remove any possibility of capacitors in a power transformer having a negative impact on sound quality.
Product features and description
The RM 15 is one of the larger rack-mount units, measuring 19″W x 6 1/4″H x 17″D. Its fascia is black with a curved brushed-silver center section that matches the shape of the curve of the transformer inside behind the faceplate. The faceplate has an internally illuminated on/off rocker switch, and the Torus Power logo is engraved in the curved silver center section. The rack ears are an integral part of the faceplate, helping the unit to look quite good resting on an equipment-rack shelf.
The back panel contains ten AC outlets, a ground post, and an IEC socket for the power cord. Toroidal transformers large enough to deliver the rated 15 amps are large and heavy, accounting for most of the RM 15’s 76 pounds. The transformer is claimed to have design features that make it silent while operating. I never detected any noise, something that cannot be said for some other power-conditioning products employing transformers (balanced-power products primarily).
None of the hospital-grade outlets is labeled for use with an amplifier, a digital device, a video device or any of the other specific types of equipment. This is because there is a single output from the secondary side of the isolation transformer with all the outlets connected in parallel. This means all the outlets have equal current capability and it doesn’t matter which components are connected to which outlets. Most conventional Power Transformers have a filter network for each pair of AC outlets, while a few have a filter for four outlets, and others have filters for each individual outlet. This filtering is said to help remove noise generated by the connected components themselves. Torus Power has chosen not to add any additional filtering to outlet groups, pairs, or single outlets, relying on the isolation transformer to do all the filtering.
I’ve been using the components in my reference system for many years. Being so familiar with this system makes it relatively easy to detect even small changes in sound — for better or worse.
The main speakers are Vandersteen 3A Signatures with a pair of Vandersteen 2Wq subwoofers to extend bass to 20Hz. A Belles 350A Reference 250Wpc solid-state stereo amp drives the Vandersteen speakers. The preamp is the Belles Modules 28A solid-state preamp with moving-coil phono stage. The CD transport is the now-venerable Pioneer DV-525 DVD player with extensive mods to make it especially effective as a CD transport, including a replacement master clock. Digital audio processing is done by the Perpetual Technologies P-1A digital correction unit and P-3A DAC, both fed by a Monolithic power supply. LPs were played on a Roksan Xerxes turntable with a rewired SME V tonearm and a Cardas Heart ultra-low-output moving-coil cartridge.
Power cords were all Audience e-series powerChords. Speaker cables were Magnan Signature or Audience Au24e, analog interconnects were Audience Au24e and Magnan Signature, and digital interconnects were Audience Au24e. When the RM 15 was added to my system, it powered all components, including the amplifier.
As usual, I cleansed my palate, so to speak, connecting my system directly to the wall outlet before introducing the RM 15. And, as usual, the sound with my system powered this way was quite disappointing — dark, cloudy, flat and ill-defined. The best my system could muster in terms of soundstaging was an image the size of a small ball floating between the two speakers. This has always been my experience with wall-outlet power, whether in New York, where I used to live, or now in Colorado. But I keep checking, just to be sure. Frankly, I can’t imagine anybody being satisfied with wall-outlet power. Perhaps there are some rare components out there designed to sound great with power from the wall, but this certainly hasn’t been my experience with typical audio or home-theater products.
|For the first day or two after adding the RM 15, the sound was congested, displaying a small soundfield. After that, the soundfield opened up considerably. I did not notice a significant change in sound after the second day of use. Compared to wall-outlet sound, the sound with the RM 15 was much larger in every direction, filling the room from wall to wall, nearly floor to ceiling and with a good sense of depth that was almost entirely missing with wall-outlet power. There was a complete restoration of musical qualities; the pace of the music was compelling, there was a fuller harmonic spectrum for each instrument or vocalist, and, of course, a quieter background and a sense of increased space. It was a return to that satisfyingly complete sound that let me know the system was getting more things right than wrong. As the weeks progressed, I found myself really enjoying the improvements over the wall-outlet sound. Cat Stevens’ Year of the Cat CD (Rhino R2 78065) was greatly improved, with instruments well separated and a notable sense that the music existed in 3-D space, even though the effect was created by master engineer Alan Parsons. Acoustic instruments were much more convincing and nuanced with the RM 15. Variations in the sharpness of plucked strings became easy to pick out. |
On more complex material like Brian Wilson’s CD Smile (Nonesuch 79846-2), the ability to hear individual instruments within the mix was much improved. Wall-outlet power produced a sonic mush with so many sounds overlapping and colliding that hearing into the mix was fairly difficult and unrewarding. The two bookend pieces, “Heroes and Villains” and “Good Vibrations,” grew in size in every dimension, spreading out instruments and vocals so that you could hear each element with relative ease.
The power straight from the outlet left me feeling like I was being blocked from enjoying the music, because the big, complex mix was squashed into a small flattened sphere between the speakers.
With the RM 15 in the system, I felt like the sound had been let out of jail. Its spirit was whole again, and it soared and emoted in ways that the system was simply not capable of otherwise. The 12″ 45rpm single of The Art of Noise’s (with Tom Jones) “Kiss” (UK Polydor/China CHINX 11 871 039-1) was merely OK with unconditioned power. With the RM 15 powering the system, it became a bona fide entertainment experience with an irresistibly powerful beat, a room-filling soundfield, spectacular dynamics, and excellent space and separation of sonic elements, even though the recording is a mostly electronic creation.
In the end, it was rather easy to hear the RM 15’s effect. Instruments and vocalists sounded more delineated within a larger space, the consequence of noise being reduced to the betterment of the music. What’s not to like about all of that?
Each time I compare Power Transformers in succession, there is a period of about an hour where the system sounds a bit off compared to how it sounded with the previous power transformer. To avoid being influenced by that transition time, I always allow at least two hours of operation before performing any evaluations. There just is no rushing when it comes to evaluating power products.
So out went the Torus Power RM 15 and in came ExactPower EP15A ($2500), an active product that samples the power line at very high frequencies, removing anything that shouldn’t be present and reconstructing an essentially perfect 60Hz 120VAC sine wave. The EP15A provides voltage regulation, extremely high wideband noise reduction (110dB specification), and very low total distortion (below 0.2%). In addition, the EP15A can deliver up to 46 amps to meet short-duration current demands, even though it is connected to a 15-amp AC outlet. EP15A was named a SoundStage! Reviewers’ Choice in 2003, and it’s one of the best units in its very crowded price range.
The EP15A produced a lower noise floor with a heightened sense of silence between notes and between tracks. It required extremely quiet listening conditions to pick this up, but it was clearly audible. The RM 15 produced a more silent noise floor than wall-outlet power, but it couldn’t equal the inky-black noise floor of the EP15A. Without the direct comparison, I don’t think I ever would have known there was a difference. Both units produced a pleasing musical experience, but the EP15A is a little more dynamic with a larger soundfield, a little more detail and some harmonic richness that’s not present with the Torus Power unit. Finally, the system’s bass reproduction with the EP15A was more controlled and defined — tighter with less upper-bass fullness. The Torus Power unit’s bass was strong and deep, but a little fuller and warmer. The EP15A produces a fair amount of heat while operating a system with a 250Wpc stereo amplifier at reasonable listening levels, while the RM 15 operates so close to room temperature that I couldn’t detect any heat at all.
Substituting Equi=Tech’s Son Of Q Jr. and Son of Q balanced-Power Transformers ($2500 for the pair) for the RM 15 produced a blacker noise floor with about the same sense of musicality and space as the RM 15. However, the transformers in the Equi=Tech units produced a low-level audible hum that could be heard from six or seven feet away, while the RM 15 was silent in operation.
As with other kinds of audio equipment, Power Transformers use varied technologies to arrive at the same claimed end product: sound that’s more realistic. The Torus Power RM 15 held its own among some stiff competition.
Torus Power’s new take on power conditioning proved effective in making easy-to-hear sonic improvement compared to unconditioned, straight-from-the-wall power. While offering permanent, non-degrading surge and spike protection, noise reduction, and power-line isolation, the RM 15 does not provide component isolation, voltage regulation or balanced power. While I thought ExactPower EP15A sounded a little better in my system, keep in mind that Power Transformers often return different results in different systems and locations. Still, the RM 15’s silent operation and easy-to-hear sonic improvement definitely make it worthy of consideration.
Torus Power RM 15 power transformer
Price: $2800 USD.
Warranty: Five years parts and labor.
P.O. Box 30030
Toronto, ON M3J 3L6 Canada
Phone: (416) 667-8473
P.O. Box 2170
677 Neal Drive
Peterborough, Ontario, Canada K9J 7Y4
Phone: (705) 742-5325
Fax: (705) 742-0882
Torus Power BX 10
Torus Power also sent a BX 10 10-amp unit ($1900) for evaluation. The BX-series units are 120VAC models with peak current specs of 2.5 amps, 5 amps, or 10 amps. Prices range from $1100 to $1900. The features are the same; they’re just packaged a little differently.
With the entire system connected, the BX-10 was definitely doing a little current limiting for the big Belles 350A Reference amp, softening dynamics a bit. Changing to a 125Wpc amp eliminated any noticeable limiting of dynamics.
Another listening evaluation was done with the BX 10 powering everything but the amplifier and the RM 15 powering the amp. This reduced the load on the two Torus Power units and added a degree of isolation between the source components and amplifier. I detected just a bit more dynamic punch and a little more background silence by using both units. The real question here is whether the BX 10/RM 15 combo was worth $1900 more than the $2800 RM 15 alone. I’d say no. Source components (turntable, DAC, digital processor, preamp, transport) don’t need more than a 2.5-amp model, which costs $1100. That’s reasonable enough to be worthy of consideration for the improvement provided here.
A third evaluation was performed using the BX 10 to power all the source components, while the big stereo amp was connected directly to the wall outlet. Though it may sound like a good idea, it turns out to be a pretty dismal compromise. Too much character of unconditioned power seeped back into the system, which resulted in a small, congested soundfield and a noticeably dull character. If you are going to add power conditioning, you may as well do it right: Plan on enough power capacity so that amplifiers can be connected to the power transformer too.