Ebtech Hum X Voltage Hum Filter

by Ebtech

Product Features

• Get rid of ground related hum/buzz right at the source
• Not a ground lift - maintains safe equipment ground
• Suitable for use on 120V 60Hz grounded USA-style power outlets

Product Details

• Product Dimensions: 4.8 x 1.9 x 3.5 inches
• Shipping Weight: 5.6 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: HE-2
• Average Customer Review: 4.4 out of 5 stars  See all reviews (74 customer reviews)
• Amazon Best Sellers Rank: #540 in Musical Instruments (See Top 100 in Musical Instruments)
  • #2 in Musical Instruments > Recording Equipment > Power Conditioners

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. LED indicator and two-year warranty.

Customer Reviews

Most Helpful Customer Reviews

36 of 37 people found the following review helpful:

5.0 out of 5 stars Works great for laptop to sound system hum, July 31, 2010

By 

Michael D. Normington (Chicago, IL) - See all my reviews
(REAL NAME)   

This review is from: Ebtech Hum X Voltage Hum Filter (Electronics)

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.

9 of 9 people found the following review helpful:

5.0 out of 5 stars A lightweight alternative to using a heavy isolation transformer, November 6, 2011

By 

N. Smith (South Florida) - See all my reviews
(REAL NAME)   

Amazon Verified Purchase

This review is from: Ebtech Hum X Voltage Hum Filter (Electronics)

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.

Never use a three-wire to two-wire line voltage adapter on any piece of audio gear where a human can possibly come into contact with it. If having done so eliminates the hum, utilizing the Ebtech HUM X should safely allow correction of the condition.

You may also alternatively reliably isolate your equipment completely from the power line using a more expensive and very heavy isolation transformer. By using an isolation transformer, the ground noise voltage will now appear between the transformer windings and not circuit input. The noise coupling is primarily a function of parasitic capacitance between the transformer windings and can be reduced by placing a shield between the windings.

* Tripp Lite IS250 250W Isolation Transformer 2 outlet 6ft Cord

* Tripp Lite IS1000 1000W Isolation Transformer 4 outlet 6ft Cord

Typical ground loop problems can also be solved using 'audio' isolation transformers inserted into the audio lines.

* Ground Loop Isolator - Auto

* ART DTI Hum Eliminator

* ART CleanBox II Passive Hum Eliminator

* Behringer HD400 2-Channel Hum Destroyer

Optical coupling can also be used to eliminate the potential for ground loops.

* Turtle Beach Audio Advantage Micro II USB Analog & Digital Audio Adapter

* Digital Coax & Optical Toslink to Analog Audio Converter

A noise gate can also be used to reduce hum. A noise gate doesn't let any sound through the gate unless the sound has a signal level which is higher than the set gate threshold value. If the problematic hum is very faint a noise gate can make it much less annoying. When you set the noise gate threshold so that the gate does not pass any signal when there is silence in the source music the hum is not added to the main mix. When the sound level rises above the noise gate's trigger setting the humming is difficult to notice due to masking by the louder musical passages.

* Behringer MDX1600 2-Channel Expander/Gate/Compressor/ Peak Limiter

* DBX 266XL Dual Compressor Gate

Some DI (Direct Input) boxes employ the use of ground loop eliminating impedance matching audio isolation transformers. Such boxes allow mixing unbalanced and balanced audio lines.

* Sidekick Passive Direct Box

* Ebtech Hum Eliminator

* Ebtech HE-2-XLR Hum Eliminator 2-Channel Box with XLR Jacks

One can also try to use a ground lift in situations where two grounded pieces of equipment with unbalanced connections experience ground loop related humming problems. Ground lifting in unbalanced connections works effectively only when both pieces of equipment are properly grounded to same point. In some cases the humming problem may become worse if a ground lift is used. Thus, this so-called "fix" should be employed with extreme caution and usually only as a temporary solution. If the related equipment is properly grounded, simply lifting the signal ground between equipment may cause enormous amounts of humming and potentially damage the input amplifier of the receiving equipment because of the flowing stray currents on the ungrounded equipment. A better method of employing a ground lift is to modify the cable to include an AC path between grounds, or a small capacitor. This will reduce the possibility of the ground lifted cable to pick up RF interference but can also cause frequency response variations depending on capacitor size and equipment source impedance. Because of this, the best solution for solving unbalanced connection ground loops is using an audio line isolation transformer.

* Behringer DI100 Ultra-DI Direct Box

* Pyle-Pro PDC22 Dual 1/4'' Instrument To Balanced & Unbalanced (1/4''/XLR) Direct Box

A professional sound engineer should possess a variety of such devices to remedy a broad range of encountered ground loop scenarios.

81 of 111 people found the following review helpful:

3.0 out of 5 stars Only works in certain apps, cannot "balance" audio lines, April 4, 2010

By 

G. Conner (USA) - See all my reviews
(TOP 1000 REVIEWER)    (REAL NAME)   

This review is from: Ebtech Hum X Voltage Hum Filter (Electronics)

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.

Guitarists working in an electronically-noisy home or night-club environment absolutely MUST use a shielded transformer like the trip-lite isolation models ( range $95 to $450) AND they should use noise-free pickups with adequate internal shielding, PLUS fully-grounded copper shielding inside the guitar cavity. If you are a performing musician with chip-controllers for stage lighting, that advice goes DOUBLE.

One of the other reviewers noted that his did not work and he wonders "why it costs so much?"
It costs so much because consumers are ignorant. Manufacturers and sales-people take advantage of that ignorance.

It is IMPOSSIBLE for any device this small to 'eliminate' hum from professional power-amps or instrument amplifiers.
And if you simply look at it, you can understand WHY it is IMPOSSIBLE for it to have ANY EFFECT on the signal path; ...because IT IS NOT IN THE SIGNAL PATH.

Here are the harsh realities concerning ground loops:
Almost EVERY HOME OR COMMERCIAL VENUE has several ground-loops. Why? Because few architects are audio-electronic experts. Electricians aren't audio experts either and they don't care. They only care about wiring to code, and then only because they are legally-obligated to prevent fires. Any home or business that was wired without professional audio consultants WILL HAVE GROUND LOOPS and some associated noise. EVERY home that underwent remodeling or rewiring of new appliances has ground loops. Absolutely every restaurant with commercial kitchen-appliances has ground-loops galore.

THE ONLY way to reduce 60 cycle hum and EMI in high-voltage professional audio is to use a professional isolation transformer with an internal Faraday cage. Professional musicians must also use balanced audio lines, high-quality cable (Mogami, NOT over-priced Monster) and they must use the shortest possible signal cables. Further, those audio cables should never be near power cables, and if they must cross power cables, they should cross at right-angles and be at least one-foot away from each other. Connect ALL audio equipment to a SINGLE ISOLATED GROUND through a HEAVY DUTY isolation transformer.

You may not have the forty years experience I have in professional audio and you may not have any interest in electrical engineering. So I offer this advice to save you time-trouble and money. I also would like to have some positive impact on the consumer-audio market by educating innocent but misinformed consumers.

No device this tiny can properly isolate a noisy ground.
No device attached to the power cable can magically fix problems in the audio chain. It is physically impossible.

This is not merely an "opinion." These are laws of physics, and as such, are immutable.