Equipment Review No. 2   December 2002

SMART Devices GC-120 AC Line Purifier
SRP: $1995

SMART Devices, Inc.
5945 Peachtree Corners East
Norcross, GA 30071-1337

Basic Description

Balanced AC power line purifier with 8 Hubbell hospital grade outlets; rated for 15A current continuously; metered reading of power; 20A circuit breaker; 19” W x 5.25” H x 12” D; 44 lbs; 3 year warranty.


Meridian 568 Preamplifier, Rotel RCD-950 CD player, Dish Network 4900 satellite receiver, Mark Levinson No. 29 power amplifier, Pentium 4 computer, Toshiba M-754 VCR, PS Audio P600 power regenerator (for comparison), Martin Logan SL3 speakers, Barco 808 projector, DeCorp/Audioquest cabling.

Setup & Explanation

I’ve been happily using the “Garbage Collector” in my system for many months, but have just got around to reviewing it. I have been in the process of changing all electrical wiring throughout my house, so this happened to be an excellent time for a review of this type of product. There isn’t much setup involved with the Smart purifier that needs any sort of lengthy description. Basically, I set it on the shelf and plugged everything that was close enough into it. There are two sections labeled Processing/Digital and Amplifiers/High Power. The digital outlets have an additional low pass filter to reduce interference from other components connected to the GC-120. You can see the power draw of the ancillary equipment by depressing a large blue button on the front of the unit.

A few companies are designing power conditioners with the understanding that balanced power helps reduce and eliminate outside electrical interference. The GC-120 is rated to work with power draw up to 1800 Watts. Sources of this interference (according to SMART) include: other equipment connected to the same source line, RF and EMI interference picked up in the AC like an antenna, transients and harmonics from SCR dimmers, triacs, fluorescent lamps, and household appliances, back EMF from solenoids and relays in washing machines, clothes dryers, air conditioners, etc., and DC components on the line from diodes used in lamps, coffee makers, hair dryers, switching supplies in computers, and other electrical devices.

The core of the SMART design (pun intended) is the large torroidal transformer. This is a custom made job with lots of construction choices made to help improve its performance in this product—Kapton insulator, quality shielding, mylar wraps, thick leads, and a special core manufacturing process. There is a shielded low-pass filter to reduce very high frequency energy before the transformer. This product does not use less expensive MOVs (metal oxide varistors) that, as SMART points out, fail with use eventually over time without warning. Instead, they use TransZorb transient surge suppressors that send overvoltage spikes or transients to ground. There is a GFI included in the GC-120. If there is a fault, the unit will shut off. When the fault is corrected, a push of a button will get the system up and running again. The Garbage Collector incorporates star grounding, high quality Hubbell AC outlets, and utilizes a dual circuit breaker. The front power switch that allows complete turn off of the purifier (and all that is connected to it) activates this breaker. Lastly, a 6 foot 14 gauge IEC power cord is included.

Listening I – In/Out Comparisons With Different Components

I should point out that results achieved with the SMART Devices Line Purifier will differ depending on many factors—some of which are mentioned in the Setup & Explanation. Even though I currently don’t have a dedicated outlet for my audio/video equipment, I do not have equipment in line with any sort of appliance like a refrigerator, lighting dimmer, fluorescent device, etc. I would expect an even larger improvement if that were the circumstance. I generally don’t have brownouts, although I did have the power go out during a storm while all the components were plugged into the SMART—there was no problem with any of them on turn-on. In the past, I seem to have noticed more difference with components that have poor power supplies or less regulation in the component itself. Lastly, as has been my previous experience, there is a more noticeable difference in comparisons directly with the wall outlet as opposed to other power conditioner devices.

I began with all the components plugged into the Line Purifier and started with the amplifier first. I used two different songs: “Ole” from John Coltrane’s Ole Coltrane and “Folks Who Live On The Hill” from Diana Krall’s Only Trust Your Heart. With the amplifier plugged into the SMART the audibility of the reverberation and space on the recordings increased. The voice sounded smoother and more natural, while the overall presentation improved in terms of effort and ease. The sound was more liquid. Plucking was more noticeable. With the amplifier plugged direct, the voice sounded more congested and there was more warmth (midrange). There was a change in the tonality and content of the recording hiss in the high frequencies ever so slightly. Bass plucking and dynamic contrast were improved with the amplifier back into the SMART. Either that or the lack of hash/coloration made this effect more discernible.

Next, I left the other components into the SMART and plugged the CD transport in and out. For this part of the testing I used “Destiny,” track 3 from Zero 7’s Simple Things and track 2, “Androgyny,” from Beautiful Garbage by Garbage. I was almost amazed at the difference between the in and the out comparisons. With the transport plugged into the SMART, the voice, crackling on the recording, and guitar plucking all changed in a positive fashion. There was just more there with SMART in the system. When I went directly into the wall, part of the high frequency content was removed, and at the same time there appeared to be more grain. With the second cut, having the SMART in produced a much tighter presentation that was smoother and easier to listen to. The sound was less edgy, more dimensional, and had better separation. When I went direct, the sound could best be described as rough around the edges. The voice was compressed with a slight amount of hash.

Lastly, I tried some classical music: Chopin’s Ballad No. 2, op. 38 on London 417 651-2, and an excerpt of Moussorgsky: Pictures at an Exhibition, Hut of Baba Yaga, Great Gate of Kiev from the Telarc Sampler Volume II, CD-80102. For this part of the testing I moved the preamplifier in and out of the SMART. With the preamplifier in the Line Purifier I noticed that the transitions between notes seemed more pronounced. The recording itself (Chopin) is slightly muffled, but tone and harmonics appeared to be improved. When the preamplifier was direct, the sound was less involving with some hardness in the midrange that made the recording sound as if it were too loud even though it was at the same volume as with the SMART. With the second recording, the sound was brighter, edgier, and not as clean direct into the wall. When I re-plugged into the Line Purifier the sound was more authoritative and not as edgy. The cymbals splashed but weren’t as harsh. The bass seemed better as well—it went deeper.

Listening II – Comparisons with the PS Audio P600

I am very fond of the improvement wrought by the PS Audio P600 power plant even considering its limited 600-Watt power rating. This unit is in the same price range as the SMART so I thought it would make a good comparison piece. Both devices have eight outlets and use balanced power. The PS Audio offers adjustments to line voltage, frequency, and types of waveform. The SMART draws less power from the AC line, has a much higher power capability, and is physically much smaller and lighter—although not light!

I began with track 9, “Year of the Cat,” off a Mobile Fidelity recording of Al Stewart’s Year of the Cat. The SMART had a greater sense of pace, piano sounded clangier, and the presentation was more upfront. The P600 sounded pillowy, relaxed, and had a lighter piano sound. Both had excellent vocals and instrumentation. Differences between these two pieces were smaller than the direct testing in Listening I.

I tried track 1, “Drummin’ Man” from Gene Krupa Compact Jazz. With the SMART, the voice was dryer sounding. There was a slight increase in treble. The P600 sounded softer and any edginess in the recording seemed to be gone.

For the last of the audio tests I used track 1, “Andante con moto” from Mendelssohn Symphony no. 3 in A minor, op. 56—Deutsche Grammophon 419 477-2. With the SMART, the sound was raw with nothing toned down. The sound with the P600 was sweeter, and not as boisterous and striking as with the SMART. Both provided a very impressive sound on this recording.


I have not had a great deal of luck seeing large difference in video performance with most of the power conditioners I’ve tried. Perhaps it is because the Barco projector I use does a better than average job of dealing with power conditions, or the fact that I can’t view two units side by side makes it difficult to note changes—especially dealing with projector warm up time.

I spent a while watching satellite TV (which runs through my computer to scale to 768P) to look for differences. With changing content, it was hard to see a big difference. At one point I thought I noticed improved black level, but when I went back I doubted seeing the difference. It is very possible that with a plasma television or another type of device these differences would be large.

In addition to satellite viewing I tried comparisons of scenes on two different DVDs: chapter 2 from The Others (which has tons of dark scenery mixed in with bright moments as well as motion), and chapter 4 from I Am Sam. This scene has some motion and lots of color as well as close-ups of the two main characters that is very sharp and delineated. I went back and forth a few times, but was hard pressed to see a difference. The source component (the computer) was plugged into the SMART at all times. Perhaps a conventional DVD player would have given results similar to the CD in and out testing. I didn’t see any degradation with the projector plugged into the SMART so I wouldn’t worry about plugging your video display in as well. I should also note that it would not be possible to do this test with the P600 and keep the other components plugged in—they draw more power than it is capable of handling.


I have no reservations about recommending the SMART Devices Line Purifier a.k.a. the Garbage Collector. It always worked flawlessly, never made any strange sounds, was well built, and demonstratively improved the sound of my system when the components were plugged into it. Eight outlets should be enough for most people, and it is small enough to fit into a normal rack. It is only limited by its 15A power rating. Unless you have a mega-amplifier that works best on a 20A circuit, my guess is that any component you own will work effectively with the SMART. Be smart and check it out! (I couldn’t resist.)

-- Brian Bloom

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