Furman IT-Reference 20i Symmetrical Power Conditioner
Published on May 26, 2010
Furman IT-Reference 20i Symmetrical Power Conditioner
Balanced power conditioner with four discrete duplex power banks as well as four high current outlets utilizing Power Factor technology with > 80 amps peak charge; linear AC filtering, surge suppression, telco (single in/out) and coaxial (three in/out jacks) surge suppression modules; > 40 dB of (rated) noise attenuation from 10 kHz – 100 kHz and > 80 dB from 100 kHz – 1 GHz; detachable line cords (one 20 amp and one 15 amp); rack ears; 83 pounds; 5.75” H x 17” W x 16.25” D; five-year warranty.
1690 Corporate Circle
Petaluma, CA 94954
Marantz CD5003 CD player, McIntosh MVP881BR blu-ray player, Bowers & Wilkins 804 Diamond speakers, Audioquest cables, Tascam US-122mkII soundcard/mixer, McIntosh MA6300 Integrated Amplifier, Monster Signature HTPS-7000II power conditioner (for comparison), PS Audio Power Plant Premier (for comparison), generic two-foot house fan, Denon AVR-5805 receiver, Dell Studio 1537 Laptop.
Setup and Tests
Although I planned to live with the Furman in my multi-room system for a time, I thought it would be fun to compare two other well-known conditioners and see how they handled a battery of tests. In addition to listening to musical tracks while the gear was plugged into the various conditioners, I also ran a dedicated feed out of the CD player and recorded it to my laptop via an external soundcard. Then, I burned a CD with the cuts to compare them directly. My tests were limited to audio performance alone.
Standard listening was done with the McIntosh gear while I utilized the Marantz disc player for recording purposes. One of tests I devised involved plugging a common house fan into the same outlet as the power conditioner (under test) and proceeded to turn the fan on and off and vary speeds while the recording took place. This allowed me to hear the distortion caused by an external device that might not be uncommon in a typical household (i.e. a microwave, HVAC system or any other high draw device). Also, I plugged in the Denon receiver that is rated to have up 13 amps current draw at maximum!
I used the standard power cords that came with all the equipment although the speaker cable and interconnect was “upgraded.”
The recordings I used specifically for the testing were:
1. Holly Cole, “Make It Go Away” from Dark Dear Heart
2. Pink Floyd, “Speak To Me” from Dark Side of the Moon
3. Excerpt from Saint-Saens: Fantaisie from Delos DE 3143
4. “The Rootwitch” by Michael Hedges
5. “Key Largo” sung by Sarah Vaughan
6. “This Is How You Remind Me” by Nickelback
7. Ry Cooder/V.M. Bhatt, “Ganges Delta Blues” from A Meeting by the River
8. Dead Can Dance, “Song of the Stars” from Spiritchaser
I kept each conditioner plugged in only while in use. When I did a “direct” comparison (to hear how the gear sounding from the wall) I used one outlet from the wall for the CD and the other for the amplifier.
I checked voltage from the filtered outlets (that corresponded to the digital connection on the Monster conditioner). The direct measurement was 118.5 – 119.3 volts. The Monster measured between 117.7 – 118.6 volts. The Furman measured 118.7 – 119.4 volts. The PS Audio maintained a constant voltage of 118.3.
I used the direct connection to the wall as a reference for cost purposes—i.e. why buy a multi-thousand dollar piece when the wall sounds just as good? Well, first of all, all these conditioners offer surge suppression and protection of some sort. They all offer at least 10 outlets from a single outlet in the wall. In addition, the PS Audio piece regulated voltage. The Furman offers the ability to source up to 20 amps of current while the others are rated for 15 amps. In my tests I used the 15 amp cord and nothing I used would have come close to using this much juice. It should be noted that Furman makes a reference product (15i) that sells for $1999 and is designed for 15 amp usage. My guess is that it would perform as well as the 20i used in my tests and would be the choice for most systems that don’t need the extra added current delivery of the 20i. The Monster retails for $1500 while the PS Audio currently retails for $1700 and was previously reviewed here: http://www.audaud.com/article.php?ArticleID=6519.
None of these units offer battery backup—something that is suggested for use with any device that has a hard drive (ex. DVR, music server, etc.) or has a lamp that needs to cool down when power is lost (ex. a rear projection television or front projector). A UPS (uninterruptible power supply) can prevent damage (or shortened life) to this equipment if power is lost.
The Monster piece also offers a connected equipment warranty (up to $750,000!), so if you don’t have a home owner’s insurance policy that covers electronics, you could replace damaged components due to electrical difficulties while connected to the Monster conditioner.
[Furman interior showing giant toroidal coil]
Listening – Part I
Selections seven and eight were used for the sighted listening with the AC conditioners. Comparisons were made from one to the next, back from one to another and directly from the wall to each conditioner.
The Fan. With all the connection options, the fan being switched on and off was audible through the speakers. This suggests that a dedicated electrical line be run for audio equipment to reduce (if not eliminate) the possibility of noise contamination from similar sources. It was also clearly audible when listening to the recordings made while the fan was in use.
On the day and time the testing was performed, the AC from the wall seemed perfectly acceptable and produced sound that was excellent from the equipment under use (valued at retail for more than $20,000). There were no extraneous noises, limiting, dynamic constriction or any other obvious anomalies that were detected. I was, however, limited to only being able to plug in two components.
From an audio performance standpoint I rated them: 1st PS Audio, 2nd Wall direct, close 3rd Furman and Monster 4th.
Monster HTPS-7000 II Signature. The Monster seemed to alter the sound in what most would describe as a “pleasant” manner. There was a bit of softening and mellowing. This would have been good if it only removed hash or grunge on the line, but it also took out some of the air and sense of space in the recording. Transients seemed a bit dulled. Also, the Monster seemed to affect some areas of the frequency range more than others. I can’t explain this other than to say that Furman suggests that it evenly filters across the entire range and perhaps Monster does not? If I had to put a percentage on the change I would say it was in the negative 5-7% range of change in my test. Casual listeners would notice nothing (or sense an improvement due to the softening), but under test with other devices the difference was noticeable. In one instance it seemed to improve the sound, but ultimately it altered the sound away from what I felt was correct.
Furman IT-Reference 20i. At times the Furman was indistinguishable from the wall. Tests between the direct connection and the other conditioners often sounded like a comparison between those conditioners and the Furman. That part is good—it didn’t do much to alter the sound. Although after repeated listening the Furman seemed to have a bit less air than the direct connection (and the PS Audio) and it did one of two things: Either it made the soundstage slightly more focused (correct) or narrowed the soundstage (incorrect). It was hard to tell which one was exactly happening and the difference was so small it almost isn’t worth noting. As a protective device (due to the large torroid), current sink (able to provide quick bursts of current on demand) and multiple outlets the Furman is a perfectly good piece of gear. It terms of a sonic difference it was somewhere in the negative 1-3% range.
PS Audio Power Plant Premier. I’ve already weighed in on this piece in my formal review, but let me just say here that the PS Audio was the only piece that I felt improved the sound. It retained the air and space in the recording but took out the edge at the same time while not altering the impact of the music. I’d say it was a 5-10% improvement with the equipment under test.
Listening – Part II
My attempts to hear differences from the recordings I had made were more difficult. I tried to use a couple of programs that analyze the difference between samples and subtract them, but they did not work as advertised with the samples I had made. I listened through headphones and couldn’t reliably judge which offered better sound. Track five sounded different in both the voice and the background noise (in the recording). To decide which recording was better was another matter. With speaker listening I was able to tell differences between tracks four and five. Another listener and I still preferred the PS Audio and direct connection the best. The Monster was definitely altering the sound in some fashion that didn’t seem accurate and occasionally the Furman appeared to reduce the sense of space and ability to hear differences in the recording environment.
Aside from the sound and product design there are many other differences between these three conditioners discussed below (in no particular order).
Weight and Solidity. The PS Audio Premier weighs 35 pounds, the Monster weighs 46 pounds and the Furman weighs 83 pounds! That weight alone might discourage some from getting the Furman (as it, along with other equipment, might exceed some cabinet weight limits). It terms of build quality the Furman was the most solid by a small margin in comparison to the PS Audio with the Monster trailing a bit behind. At this price point all the products appear to be well constructed. The outlets on the back of the Furman are all hospital grade and solid (12). The PS Audio uses their proprietary Powerport outlets (10) and the feel is solid as well. Monster has a few standard looking fused GFI outlets, a fused duplex and two duplex high current standard outlets in back (12 total). Size-wise the PS is only 4” high while the Monster and Furman are both about 5.75”.
Reliability. There is really nothing mechanical to the Furman except the circuit breaker power switch, so there isn’t much to go wrong. Looking inside is the same situation. The Monster has fuses on the back which can either blow over time or when you mistakenly connect high draw components to outlets that aren’t designed to handle the load. With the PS it is okay to connect high draw components to any of the outlets and just looking inside the Furman makes me think that it would work as well. If you happen to have multiple TVs, amplifiers or subwoofers, then the Monster may not be the best choice. The PS Audio failed once during my review although it was an easy fix. Since then it has worked 100%. PS Audio offers a three-year warranty, Monster offers five years and Furman’s is five years as well.
Power Connection. The Monster comes with a hard-wired 8’ cord (but I couldn’t tell you the gauge) and it looks pretty thick. Both the Furman and PS Audio have heavy duty cords that are replaceable (IEC) types. The Furman also comes with the 20 amp cord for outlets that are designed for its use.
Indicators, Programming and Features. The Furman has a power light and that’s it! There is no trigger option, outlet delay or anything along those lines. The PS offers an indicator with line voltage in and out and distortion in and out. The Monster indicates voltage out (which didn’t appear accurate according to my meter) and current draw among many other programmable options. Lights indicate a plethora of other things like correct ground, abnormal voltage, reversed wiring, switched outlets on, etc. Both the PS and the Monster offer delay and triggering options. Both the Furman and PS come with rack ears while Monster offers it as an option.
Every power conditioner I’ve tested in the past has used a unique approach to try to improve the quality of the AC coming out of the wall. Although tests often show reduced noise on the line, this may or may not have any impact on the sound of the system. The obvious reasons for using a conditioner are surge suppression and protection as well as multiplying the amount of available outlets. The reason to buy something much more expensive than a standard power strip is to prevent current limiting and negative effects in comparison to the direct connection to the wall. In the past I’ve heard reductions in quality using basic strips (especially with high power equipment like amplifiers). Also, on the video side, they can do little to eliminate noise problems whereas I’ve seen dedicated conditioners eliminate video noise and/or hum. In a properly set up system these conditions shouldn’t exist, but sometimes do.
As always, installing dedicated lines for audio/video gear can be the cheapest (electrical) improvement you can make to getting equipment sounding better without a conditioner. This is the first expenditure I would make before purchasing any power conditioner. In the testing above, sighting listening indicated differences in sound from the direct connection to the wall (although not always improvements). Had I not done this comparison test I would have been happy with any of these devices.
One of the advantages of the Furman is the ability to handle equipment with huge power demands. In my testing I wasn’t able to stress any of the conditioners in this aspect even with multiple amplifiers connected and running. Another plus is in its ruggedness. Of all the conditioners I used, I feel the Furman is the closest thing to a “set it up and forget it” type of product. As I mentioned earlier, the 15i at $1999 would be the sensible choice for almost all but the most elaborate systems. I wish I could say that the Furman dramatically improved the sound of my system, but it did not. In a different system the results might vary. What I can say is that it did almost nothing negative—which is saying a lot when it comes to products of this type.
— Brian Bloom