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Furman SPR20i

20-amp power line conditioner, surge protector, and voltage regulator

3 Reviews

Item # 756SPR20I

Out of Stock

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825 Gardens Blvd

109 South Carlton

Expected: 1/30/2018 Reserve risk-free

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Our take on the Furman SPR20i

If you have a heavy-duty 20-amp circuit powering your audio/video system, Furman's SPR-20i prevents unstable AC power from holding back its performance. It also guards against harmful power spikes and surges, and filters out the noise riding along on your home's electrical wiring. Never heard of Furman? Most studio engineers have. The company's spent over 30 years meeting the extreme AC power demands of professional recording, film, and broadcast studios.

Furman SPR20i back panel

The SPR20i's outlets accept both 20-amp and standard 15-amp AC plugs. Its power cord must be plugged into a 20-amp receptacle.

Protection and power conditioning for 20-amp circuits

If you have a heavy-duty 20-amp circuit powering your audio/video system, Furman's SPR-20i prevents unstable AC power from holding back its performance. It also guards against harmful power spikes and surges, and filters out the noise riding along on your home's electrical wiring. Never heard of Furman? Most studio engineers have. The company's spent over 30 years meeting the extreme AC power demands of professional recording, film, and broadcast studios.

An oasis of stable power for your system

As heavier and heavier demands are placed on the nation's aging power grid, inconsistencies in the quantity and quality of every home's AC power will only get worse. These fluctuations may not affect your refrigerator or dishwasher, but they can cause problems for the delicate circuitry in audio/video equipment, shortening your gear's lifespan and degrading both picture and sound quality. The SPR20i maintains an unwavering 120 volts — you can check it on the front-panel display. And unlike most voltage regulators, this one is designed to work with heavy-duty 20-amp circuits.

See and hear the signal, not the noise

The SPR20i's wide-bandwidth filtering cuts way down on the AC "line noise" that can mask subtle ambient sounds and fine picture detail. Twelve AC outlets on the back panel are divided into three banks, to isolate your system's digital and video circuits from analog components and amplifiers. This helps prevent noise created by one component from affecting the power going to your other plugged-in equipment. These outlets will work with 20-amp or standard 15-amp AC plugs, and they've got hospital-grade connectors that grip your gear's plugs securely.

Product Highlights:

  • 12 AC outlets with 3 isolated banks (outlets are compatible with 15-amp and 20-amp AC plugs):
    • one "Audio" bank of 4 filtered outlets
    • one "Video" bank of 4 outlets with additional ultrasonic filtering for digital or video components
    • one "Audio/Video" bank of 4 filtered outlets
  • 7-ft. AC power cord with NEMA 5-20P plug (requires a 20-amp circuit and a 5-20R T slot receptacle)
  • AC outlets use hospital-grade connectors to grip plugs firmly
  • voltage regulation circuitry ensures that your equipment receives a consistent, optimal amount of power
  • Series Multi-Stage Protection surge suppression system can withstand multiple catastrophic voltage spikes
  • Extreme Voltage Shutdown circuitry monitors incoming AC and automatically cuts off power to connected equipment if overvoltage is detected
  • wide-bandwidth EMI/RFI noise filtering for clearer sound and picture
  • Ultrasonic Bi-filtering isolates digital and video circuits from analog components
  • three sets of coaxial RF connections for cable/satellite/TV antenna
  • RJ-11 phone line input and output
  • front-panel display lets you check input voltage or current, and output voltage
  • maximum current rating: 20 amps
  • 17"W x 4-1/8"H x 18-3/8"D
  • weight: 31 lbs.
  • warranty: 5 years
  • Our 60-day money-back guarantee

What's in the Box:

  • Voltage Regulator
  • 7' AC power cord with NEMA 5-20P plug (requires 5-20R T-slot receptacle)
  • 2 Piece power cord bracket
  • 2 Machine screws
  • 2 Rack mount brackets
  • 6 Rack mount machine screws (each with star lock washer attached)
  • Owner's guide (English/ French)
  • Warranty registration card

Furman SPR20i Reviews

Average Customer Review(s):

(3 Reviews)


Ray from san francisco, CA on 3/27/2016

Crutchfield Customer Review (What's this?)

I love the Furman20



The Furman VS The Monster

Macahan from Houston, Texas on 3/30/2014

Crutchfield Customer Review (What's this?)

Before I bought the Furman I was the previous owner of Monster products. I had the HTS-5100 which was connected to the AVS-2000. I had recently noticed that this combo was only keeping my system at 118.5 volts on average. I was beginning to suspect that the 5100 was the problem. Also at least once a day both systems acted as if a huge surge was coming in and as a result the display on the 5100 would dip down to 117 volts. I was also noticing that the picture from my 60inch Sony LCD was not as sharp as it used to be, it looked rather dull and lifeless. So I took a chance and bought the furman and am I glad I did. The first thing I noticed was that my tv now looked sharper and the colors a little more vivid. The Furman is also better built than the 5100 and it weighs about 11 pounds more. The 2000 and the 5100 do have a dimmer switch while the Furman does not even though the instruction manual says so. Furman actually confirmed that was a typo and will send you a corrected version of the manual upon request. It was for that reason I gave it only a four star rating. The blue display is very bright and if placed a few feet to either side of your tv it will be noticeable. A great purchase that I do not regret.

Pros: Pricey but worth it.

Cons: No dimmer switch for the bright blue display even though the manual says it has one.

Absolute necessity for quality hi-fi equipment

deepee from Wallace, ID on 8/17/2013

Crutchfield Customer Review (What's this?)

Converting to high-grade audio tube equipment using KT-120 or KT-88 output tubes last year, I was encountering some wild voltage swings from our utillity, especially voltage jumps to 123VAC. These were murder on the rectifiers, which at $55 a pop are not pleasant to replace. Research led to the discovery that in the best of circumstances, under the U.S. ANSI standard, voltage to your house's service entrance can swing through about 12 volts (+ or minus 5% of 120 VAC) with even greater permissible short-term deviations. Since putting the Furman on line to a dedicated 20-amp breaker last winter, I'm on the same rectifiers, my tubes are happy, and I have enjoyed improved audio quality as well. My Fluke meter verifies Furman's claim that the Furman keeps output voltage rock-steady at 120 VAC, plus or minus less than a volt. Why expose expensive audio equipment to the vagaries of unacceptable but perfectly legal over- and under-volt situations?

Pros: Does its job as advertised. Essential for tube gear.

Cons: Spendy. But so are $50 rectifiers, $100 output tubes and capacitors.


Hands-on research

Product Research

Controls and Indicators


Stable Power: The SPR-20i's exclusive Stable Power AC Voltage Regulation Technology maintains 120 volt AC output with higher and lower voltage inputs, allowing power amplifiers and powered subwoofers to perform at their full potential. Using the SPR-20i, your home theater is supplied with constant, virtually unwavering AC voltage. Fuman's zero-crossing solid state technology provides 60 amps peak current, avoiding the current limiting found in AC regulators that convert AC power into DC, then synthesize an AC output signal.

EMI and RFI Filtration: EMI and RFI noise entering your A/V system through the AC power line couples to the components and masks low level signals, compromising performance. This low level content is critical because it relays the harmonics and ambience in audio, and the depth and clarity in video. Furman's exclusive Linear Filtering Technology dramatically reduces noise, ensuring consistent peak operation regardless of load conditions or the time of day.

Series Multi-Stage Protection (SMP): SMP is maintenance-free surge suppression, offering AC protection without sacrificing itself in the event of a catastrophic surge. The SMP circuit senses voltages so high that operation is impossible and turns the power off before damage can occur; if the voltage exceeds 140 volts power is removed from all the outlets and the Extreme Voltage LED lights.

EVS: The Extreme Voltage Shutdown (EVS) circuitry constantly monitors the line voltage for unsafe over-voltage conditions. When an extreme voltage is recognized all 12 outlets are automatically disconnected to protect your equipment. Once the line voltage returns to normal the outlets are reconnected.

12 AC Outlets: The Furman SPR-20i features 12 rear-panel outlets in three sections; all the outlets are 3-prong NEMA 5-20R T-Slot receptacles and will accept either standard NEMA 5-15 or NEMA 5-20P plugs:

  • Video Bank: The video bank has four outlets. In addition to the linear filter, an ultrasonic filter specifically benefits video components (DVR, DVD player, projector, Plasma and LCD TVs, etc).
  • Audio/Video Bank: The audio/video bank has four outlets, EMI and RFI noise is removed by the linear filter.
  • Audio Bank: The audio bank has four outlets, EMI and RFI noise is removed by the linear filter.

Transient Voltage Surge Protection: The SPR-20i features transient voltage surge suppression for standard telephone lines, coaxial cable TV lines, and coaxial satellite lines. There is one pair of phone input/output jacks and three pair of coaxial input/output jacks. The coax jacks are bi-directional and pass both DC carrier signals and high bandwidth HD signals with an insertion loss of less than 0.1 dB. All the in-line surge suppressors feature Furman's exclusive Zero Ground Contamination technology; this aids in eliminating audio buzzing and the video hum bars that can result from typical in-line suppressors.

Rack Mount: Brackets are included to rack mount the SPR-20i.

Controls and Indicators

Front Panel:

  • Power: power switch; turns all outlets on/off
  • Display: the blue LED display illuminates when the power switch is on; you can switch between showing the line input voltage and the input current
  • Protection OK LED: illuminates to indicate that the wall outlet is properly grounded and Line/Neutral polarity is correct
  • Extreme Voltage LED: illuminates to indicate the incoming voltage is too high and all the outlets have been disconnected
  • Display Switch: toggle the display between showing the line input voltage and the input current


Rear Panel:

  • Video Outlets: four linear filtered and ultrasonic filtered outlets
  • Audio/Video Outlets: four linear filtered outlets
  • Audio Outlets: four linear filtered outlets
  • Phone Jacks: input and output for standard telephone line
  • Coaxial Jacks: 3 pair of threaded F-type coax input and output terminals

Power Input:

  • NEMA 5-20P: The included power cord has a NEMA 5-20P plug (three-prong with one of the blades turned 90°), so it requires a 20-amp NEMA 5-20R receptacle.


AC Power:

  • Current Capacity:
    • Input: 20 amps
    • Output: 20 amps RMS (19 amps continuous @ 113 volts AC)
  • Voltage Regulation: continuous 120 volt AC output (+/-1.0 volt) with input from 113 volts AC to 126 volts AC (the SPR-20i will regulate well beyond 113 to 126 volts, but not within +/-1.0 volt)
  • Linear Noise Attenuation: Transverse (Differential) mode (from 0.05 to 100 ohm line impedance)
    • 10 kHz - 100 kHz: >40 dB
    • 100 kHz - 1 GHz: >80 dB
  • Power Consumption: 12 watts for display and control circuits (plus actual load)
  • Over-voltage Shutoff Threshold: 140 volts AC (+/-3 volts)
  • Weight: 31 pounds


Connected Equipment: Furman Sound's Connected Equipment Warranty covers equipment that is damaged by a transient voltage while properly connected through the Furman SPR-20i to a properly wired AC power line with a protective ground in an indoor location. Furman's Connected Equipment Warranty is limited to the amount of the deductible on the Purchaser's personal property insurance policy, up to $500.00. The Connected Equipment Warranty is in effect for a period of five years.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Q & A

Customer Q&A

Crutchfield asked  
Why did you buy this?

Performance to price - need it for a Super high-end system [ Peter  Dec 11, 2017 ]
I choose the Furman SPR-20i because is a reliable voltage regulator. I choose Crutchfield to buy it because Crutchfield is a reliable and authorized Furman seller. Thank you! [ JOSE  Dec 20, 2016 ]