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  • Ebtech Hum X Voltage Hum Filter
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Ebtech Hum X Voltage Hum Filter

by Ebtech
| 12 answered questions

Price: $51.41 & FREE Shipping. Details
In Stock.
Ships from and sold by Amazon.com. Gift-wrap available.
  • Get rid of ground related hum/buzz right at the source
  • Not a ground lift - maintains equipment ground
  • Suitable for use on 120V 60Hz grounded USA-style power outlets
  • Not designed to get rid of cable related or guitar pickup related hum
  • Use 1 Hum X per piece of gear. Multiple hum issues may require more than one Hum X
19 new 1 used from $69.94

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  • Buy Used and Save: Buy a Used "Ebtech Hum X Voltage Hum Filter" and save 22% off the $90.00 list price. Buy with confidence as the condition of this item and its timely delivery are guaranteed under the "Amazon A-to-z Guarantee". See all Used offers.

Frequently Bought Together

Ebtech Hum X Voltage Hum Filter + PAC SNI-1/3.5 3.5-mm Ground Loop Noise Isolator Works with iPod/Zune/iRiver and Others
Price for both: $62.81

Buy the selected items together

Product Details

  • Product Dimensions: 4.8 x 1.9 x 3.5 inches ; 4.8 ounces
  • Shipping Weight: 4.8 ounces (View shipping rates and policies)
  • Shipping: This item is also available for shipping to select countries outside the U.S.
  • ASIN: B0002E4YI8
  • Item model number: Hum X
  • Average Customer Review: 4.2 out of 5 stars  See all reviews (183 customer reviews)
  • Amazon Best Sellers Rank: #1,378 in Musical Instruments (See Top 100 in Musical Instruments)
  • Date first available at Amazon.com: October 2, 2001

Product Description

Exterminate ground hum at the source! Filters unwanted low voltage from ground line that cause ground Hum while maintaining ground connection. Simply plug Hum X into the offending outlet and plug your equipment into Hum X. That’s it! Max current draw 6 amps (720 watts). LED indicator and two-year warranty. NOTE: Hum is caused for many different reasons, the Hum X is designed specifically for ground loop related hum problems. For other types of hum issues, you may need our Hum Eliminator. Hum X works only on three prong power cords and outlets. Not sure if Hum X is solution to your hum problem? Contact tech@ebtechaudio.com for help.

Customer Questions & Answers

Customer Reviews

Now I am planning to buy another one... This is a very good product!
Jair Ivan Ruiz Arosemena
Because of this, the best solution for solving unbalanced connection ground loops is using an audio line isolation transformer.
Norm Smith
I plugged my monitor into this and it got rid of all the hum and now my speakers sound perfect.

Most Helpful Customer Reviews

85 of 86 people found the following review helpful By Michael D. Normington on July 31, 2010
Length: 2:31 Mins
It worked perfectly for my application. I use my laptop for DJing. When I plug in my laptop to my mixer I got an awful hum. I noticed that when I unplugged the power supply to the laptop and let it run on battery power the hum went away. This led me to the assumption that I needed a ground loop isolator (Hum-X). I got the Hum-X, plugged my laptop's power supply into it and it ito the wall and the hum was eliminated. The product works as intended. There are some other reviews here that say it doesn't work. Fact is, it doesn't work if your problem isn't a ground loop. If you have a ground loop problem, this will fix it.
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72 of 74 people found the following review helpful By Norm Smith on November 6, 2011
Verified Purchase
When two or more devices are connected to a common ground through different paths, ground path noise, or a ground loop can occur. Thus, a system grounded at two different points, with a potential difference between the two grounds can cause unwanted noise voltage in the circuit paths. Currents flow through these multiple paths and develop voltages which can cause damage, noise or 50Hz/60Hz hum in audio or video equipment.

The HUM X is an electronic device that will remove up to 6 volts of ground loop voltage differential and has a maximum load current rating of 6 Amps or approximately 720 Watts. It is not an isolation transformer. The HUM X is a 'differential amplifier'.

A differential amplifier uses an operational amplifier (op-amp). Differential amplifiers amplify the difference between two voltages making this type of circuit a subtractor unlike a summing amplifier which adds or sums together the input voltages. Eliminating the effects of the circulating current created by the differential voltage between two equipment grounds is the goal. The situation here being the common line ground and the load ground.

Removing a line cord's ground connection is simply not safe. It's also contrary to electrical safety regulations (NEC - National Electrical Code®) and potentially very dangerous. Removing the ground connection can defeat the protective action of any line voltage spike protectors located inside your equipment. If the ground connection is cut any fault in the insulation inside equipment can leak potentially dangerous voltage to the equipment case (chassis) instead of burning a protective fuse or tripping a protective circuit breaker.
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67 of 72 people found the following review helpful By biggvsdiccvs on December 30, 2011
Verified Purchase
The description on Amazon claims that this thing "Filters unwanted low voltage from ground line that cause ground Hum" without bothering to explain what that is. The description on the package actually mentions ground loops specifically.

I thought that maybe it had chokes that might help with high-frequency interference in some devices. It did not make a difference in my case. As far as its ability to eliminate ground loops, I was very skeptical, since it does its magic "while maintaining ground connection" (which is a good thing). By the way, in my case an audio isolation transformer solved the problem, as I knew it would. I wanted to try something different and it didn't work. For consumer audio (250 mV line level) I would recommend JK Audio Pureformer, which costs just a few $$ more than this thing -- pretty inexpensive for a good audio transformer.

Before returning the "hum filter", I got curious and made some I-V measurements. Here's what I found (all measurements made between the respective terminals of the plug and the outlet of the mysterious device):

hot-hot - 5 milliohms
cold-cold - 2.5 milliohms (yes, I can do that)
ground-ground - looks like silicon diodes in inverse-parallel, so at low voltage the resistance is relatively high, and at about 0.6 V they begin to conduct.

Actually, at first I used an regular ohmmeter, and it looked like the ground had a high resistance, which would make it unsafe, so I used a sourcemeter and got the above (correct) results.

This is not a filter at all, and it's ridiculously overpriced.

The good thing is that the diodes can sink at least 3 amps, which is as high as my sourcemeter will go.
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10 of 13 people found the following review helpful By Harry_SF on December 21, 2007
I upgraded my amp recently and heard a nasty hum through my speakers. My a/v installer recommended using a 3-prong to 2-prong adapter and the hum was gone. However, I didn't feel comfortable with this solution, b/c I've read that this can cause equipment damage, etc., so did some research and found the Hum X. I wasn't sure at first, but the reviews swayed me. I received the Hum X two days ago, inserted it b/t my amp and power center and the speaker was dead silent, so much so that I checked my amp to make sure the power was on. Hum X works, and I feel good that I didn't have to lift the ground to get rid of the hum. This product is highly recommended!
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108 of 156 people found the following review helpful By G. Conner TOP 500 REVIEWER on April 4, 2010
Consumer audio is RIFE with advertising falsehoods, mythical hype, and outright lies. With the possible exception of connection-cables, nowhere is that more apparent than with NOISE REDUCTION.

For "consumer-level" computer audio, this MAY help reduce ground-loop noise.

It is an isolation transformer, so it is NOT in the audio signal-path and therefore CAN NOT have any effect on noise in the signal chain. Just look at it. You can see that it is intended to plug into a POWER outlet, then have a POWER cable plugged into it. That means it CAN NOT POSSIBLY eliminate or even affect problems in the signal path.

So, unless you enjoy wasting money and time, DO NOT BELIEVE the claims that this "balances audio lines." It can't.

Further, this thing is so small, it cannot possibly work well for any professional application like pro-audio or instrument amplifiers. For an isolation transformer to work in those high-voltage applications, it must be VERY HEAVY DUTY, PHYSICALLY MASSIVE and MUST BE SHIELDED BY A FARADY CAGE. That means it must have a heavy metal can inside another metal can. The transformer must be INSIDE the internal metal shield, and it must be a large, massive transformer.

So, if you are a DJ using a computer or iPod for your music library, this MAY have some noise-reduction benefit. ( no guarantees, and probably won't.)

However, if you are a musician with a noisy amp, a guitarist with unshielded single-coil pickups or cheezy-cheap effects (like any line-6, danelectro or electro-harmonix product) this will do NOTHING to reduce noise.
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