Ground Loop Isolation Transformers and Chokes, Hum Eliminator and Video Hum Bucker. Eliminates video tearing.



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The Easiest to use.
Simply place it on the end of your power cord.

For analog and digital cable TV and cable modems. Solves "Ground Loop" and "Hum Bar" problems

CATV Filters.
Eliminates ground loop
problems from cable TV.

Video Hum Bucker Premium eliminates interference and hum on video lines

The Best video quality
with BNC connectors.
Video Isolation choke

Fix 1 video signal with premium chokes, BNC, RCA or S-Video connectors

The Best price
with RCA connectors.
Video Isolation

Fix 3 or 5 video signals with premium chokes, using RCA or BNC connectors

Fix 3 or 5 video signals with RCA or BNC connectors.

Fix 1 video signal with transformers with BNC, RCA or S-Video connectors

The Best price with BNC or S-Video connectors.

To fix 1 or 2 audio signals with standard transformers & RCA connectors

Fix 1 or 2 audio signals with RCA connectors.

Fix 2 audio signals
with XLR connectors.
Audio Isolation choke.

To fix audio and video signals.

HUMplug-e
This is an elegant and simple Hum filter.

Simply plug your equipment through this, to cure it of Ground Loops. Filters out unwanted voltage and current in the ground line that cause ground loop hum while simultaneously maintaining a solid, safe ground. You no longer have to run your audio signal through any type of filtering which can result in loss of volume, tone or both. Some devices simply remove the ground, which is never safe! Simply place the Hum-plug on the end of the power cord of the equipment that has a Ground Loop and plug the Hum-plug into any standard 15 amp outlet. Ground Loop is gone and audio signal remains intact. Easy to use, easy to install and completely effective! The Hum-plug is the safest way to get rid of ground loop hum. Retail Price is 105.00

HUMplug-e will work with 3 prong plugs only.
HUMplug-e only affects the ground prong.

HUMplug-e will NOT work with 2 prong plugs.

HUMplug-e Ground loop Eliminator Filter 85.00

To fix one CATV signal.

VRD-1FFj
Cable TV RF Isolator. Digital Cable TV RF Ground Loop Isolator

For analog and digital cable TV and cable modems. Solves "Ground Loop" and "Hum Bar" problems. 2 MHz to 1300 MHz CATV isolator."F" connectors in and out, (digital cable compatible). analog, digital and cable modem compatible. High isolation reduces ground loops. 2 MHz to 1300 MHz bandwidth. Low VSWR prevents signal degradation. Low insertion loss for high S/N ratio. (Supersedes the model VR-1FF).**Note: This unit will NOT work with satellite systems**
Retail Price is $69.95
Click for Installation Instructions.
VRD-1FFj Cable TV ground loop eliminator 55.00

To fix one CATV signal.

CATVglip
Cable TV RF Ground Loop Isolator
Helps reduce 60 Hz hum introduced into your home entertainment system through your cable connection. This is a common problem when hooking up a powered subwoofer to your home theater system. This product is completely passive and will not affect your cable TV signal strength. Provides isolation to break ground loops in cable systems. Only 1.5" long and connects in-line between your TV and the cable TV line. Simple male to female "F" connector installation. Operating frequency: 1 GHz.
Weight: 0.1 lbs
Click for Installation Instructions.
CATVglip Cable TV ground loop eliminator 49.00

Video Hum Bucker Premium To fix one video signal with BNC connectors.

HB Premium The Video Hum Bucker Premium eliminates interference and hum on video lines. The Hum Bucker simply connects in series with the video line. Video Hum Bucker Premium. DC to 500 MHz pass band. For Color and Black & White. No Low Frequency or High Frequency Roll-Off.
Remote Truck & Telco. For Inter-truck Hookup. For security. For entertainment.	Between Buildings. On Long Runs. Studios & Transmitters. Incoming Telco Circuits.
HB Premium-n Video ground loop eliminator 229.00

Fix one video signal with BNC connectors

UHFHBn
Standard Video Hum Bucker
Ground Loop Isolation Transformer.
Eliminates video tearing on long coax runs caused by power ground loops. This system prevents video-signal distortion caused by video ground loops. A standard quality Hum Bucker is used for removing hum from most sources of video, it passes 20 Hz to 4 MHz.

UHFHB-n Video ground loop eliminator 143.00

Premium Video Humbucker Ground Loop Correctors

Fix 1 video signal with premium chokes with BNC connectors

BNC connectors Video Ground Loop Corrector For 75 Ohm Systems

VBH-1BBj
BNC connectors.
DC to 600 MHz Bandwidth.
Video Ground Loop Corrector For 75 Ohm Systems.
Premium Video Humbucker Ground Loop Corrector
Use for Single Channel Composite Video. The Video ground loop corrector reduces ground current induced video interference such as 'hum bars' by a factor of over 100, eliminating the visible effects of these types of interference. The high bandwidth and low VSWR prevents signal degradation of the picture quality due to high frequency roll-off and cable reflections. Provides 56 dB reduction in ground loops. Low Insertion Loss for High S/N Ratio. 56 dB of CMRR typical at 60 Hz minimizes ground loops. Greater than 1 Vrms 60 Hz common-mode level handling. VSWR under 1.1 at 100 MHz to prevent waveform distortion. Insertion loss of 0.05 dB maintains maximum S/N ratio.
VBH-1BBj BNC Ground Loop Corrector 154.00

Fix 1 video signal with premium chokes with RCA connectors.

Single channel baseband composite video isolator with RCA connectors

VBH-1RRj
RCA connectors.
DC to 600 MHz Bandwidth.
Video Ground Loop Corrector For 75 Ohm Systems.
Premium Video Humbucker Ground Loop Corrector
Use for Single Channel Composite Video. The Video ground loop corrector reduces ground current induced video interference such as 'hum bars' by a factor of over 100, eliminating the visible effects of these types of interference. The high bandwidth and low VSWR prevents signal degradation of the picture quality due to high frequency roll-off and cable reflections. Provides 56 dB reduction in ground loops. Low Insertion Loss for High S/N Ratio. 56 dB of CMRR typical at 60 Hz minimizes ground loops. Greater than 1 Vrms 60 Hz common-mode level handling. VSWR under 1.1 at 100 MHz to prevent waveform distortion. Insertion loss of 0.05 dB maintains maximum S/N ratio.
VBH-1RRj RCA Ground Loop Corrector 154.00.

Fix 3 or 5 video signals with premium chokes, using RCA or BNC connectors.

		VBH-3RRj for 3 Channel RGB or Y/Pr/Pb Component Video DC to 600 MHz Bandwidth.
		VBH-3BBj for 3 Channel BNC or Y/Pr/Pb Component Video DC to 600 MHz Bandwidth.
		VBH-5BBj for 5 Channel RGBVH Component Video DC to 900 MHz Bandwidth.

Video Ground Loop Corrector For 75 Ohm Systems.

56 dB of CMRR typical at 60 Hz minimizes ground loops. DC to 600 MHz to 900 MHz bandwidth for excellent picture quality. Greater than 1 Vrms 60 Hz common-mode level handling. VSWR under 1.1 at 100 MHz to prevent waveform distortion Insertion loss of 0.05 dB maintains maximum S/N ratio reduces ground current induced video interference such as,hum bars,by a factor of over 100, eliminating the visible effects of these types of interference. The high bandwidth and low VSWR prevent degradation of the picture quality due to high frequency roll-off and cable reflections. Provides 56 dB Reduction in Ground Loops. Low VSWR Prevents Signal Degradation. Low Insertion Loss for High S/N Ratio. Channels may be used independently.
VBH-3RRj 3 Channel RGB Ground Loop Corrector 460.00
VBH-5BBj 5 Channel RGBVH Ground Loop Corrector 766.00

Fix 1 video signal with transformers with BNC Video connectors.

VB-1BBj
Baseband Composite Video isolator with BNC connectors. Video Isolation Transformer for 75 ohm Systems. 10 MHz Bandwidth keeps pictures looking sharp. Low insertion loss maintains maximum signal level. Provides 120 dB of isolation at 60 Hz. Precise impedance matching: VSWR under 1.06 typical up to 6 MHz. Low insertion loss: 0.55 dB typical.
Very high ground isolation: 120 dB CMRR typical at 60 Hz. Wide bandwidth: -3 dB at 10 Hz and 10 MHz. High input to output withstand voltage: 350 V RMS min at 60 Hz. When inserted into standard 75 S video cabling, this transformer based isolator eliminates video "hum bars", as well as the often associated audio hum or buzz in multimedia entertainment systems, by breaking the so-called "ground loop". Mounting holes allow easy horizontal or vertical mounting to standard rack rails.
VB-1BBj BNC Ground Loop Corrector 95.00

Single channel baseband composite video isolator with RCA connectors

VB-1RRj
Single channel baseband composite video isolator with RCA connectors.
Video Isolation Transformer for 75 S Composite or component video system. Wide bandwidth: -3 dB at 10 Hz and 20 MHz. Low insertion loss: 0.72 dB typical. RCA connectors.
Very high ground isolation: 120 dB CMRR typical at 60 Hz. Wide bandwidth: -3 dB at 10 Hz and 10 MHz. High input to output withstand voltage: 350 V RMS min at 60 Hz. When inserted into standard 75 S video cabling, this transformer based isolator eliminates video "hum bars", as well as the often associated audio hum or buzz in multimedia entertainment systems, by breaking the so-called "ground loop". Mounting holes allow easy horizontal or vertical mounting to standard rack rails.
VB-1RRj RCA Ground Loop Corrector 95.00

S-Video connector, Video Isolator for Separate Video or Y/C Video Signals

S-VHS Video Isolator Transformer for Separate Video or Y/C Video Signals

VS-1SSj
S-Video connector, Video Isolator Transformer for Separate Video or Y/C Video Signals
Identical in function to the VB-1BBj, but utilizes separate transformers for Y (luminance) and C (Chroma) signals. Wide bandwidth: -3 dB at 10 Hz and 20 MHz. Precision impedance: typical VSWR under 1.22 up to 20 MHz. Low insertion loss: 0.72 dB typical. Standard female mini DIN in & out connectors
Very high ground isolation: 120 dB CMRR typical at 60 Hz. Wide bandwidth: -3 dB at 10 Hz and 10 MHz. High input to output withstand voltage: 350 V RMS min at 60 Hz. When inserted into standard 75 S video cabling, this transformer based isolator eliminates video "hum bars", as well as the often associated audio hum or buzz in multimedia entertainment systems, by breaking the so-called "ground loop". Mounting holes allow easy horizontal or vertical mounting to standard rack rails.
VS-1SSj S-Video Ground Loop Corrector 130.00

To fix 1 audio signal with RCA connectors.

CI-1RRj
Single Channel Audio Input Isolator.
Ideal for use with Sub-Woofers and Mono Amplifiers.
Premium Audio Isolators and Interfaces for
Professional and Home Theater Applications
Audio Ground Isolator Stops Hum and Buzz in an Unbalanced Interface. Ruler flat frequency response preserves "Audiophile Quality" signals. High quality gold plated connectors for long term reliability. Eliminates the inherent ground noise coupling mechanism. When used in an unbalanced audio consumer interface, this isolator not only eliminates hum and buzz but also enhances audio quality by reducing Spectral contamination due to ultrasonic and RF interference. To avoid excessive high frequency losses, no more than 3 feet of cable should be used on its output. High-grade Nickel-Iron-Molybdenum alloy cores for extremely low distortion. Faraday shielded windings for maximum RF interference rejection. Common-mode ground noise rejection of 95 dB at 60 Hz. Wide bandwidth: -3 dB at 0.25 Hz and 50 kHz. Handles signals up to 7 volts at 20 Hz or 11 volts at 30 Hz. Input impedance is 49 k Ohm when driving a typical 47 k Ohm input.
CI-1RRj Single Channel Audio Input Isolator 105.00

To fix Stereo Audio with RCA connectors.

CI-2RRj
Stereo Dual Audio Input Isolator.
Designed for use in Home Theater and Automotive applications.
Premium Audio Isolators and Interfaces for
Professional and Home Theater Applications
Audio Ground Isolator Stops Hum and Buzz in an Unbalanced Interface. Ruler flat frequency response preserves "Audiophile Quality" signals. High quality gold plated connectors for long term reliability. Eliminates the inherent ground noise coupling mechanism. When used in an unbalanced audio consumer interface, this isolator not only eliminates hum and buzz but also enhances audio quality by reducing Spectral contamination due to ultrasonic and RF interference. To avoid excessive high frequency losses, no more than 3 feet of cable should be used on its output. High-grade Nickel-Iron-Molybdenum alloy cores for extremely low distortion. Faraday shielded windings for maximum RF interference rejection. Common-mode ground noise rejection of 95 dB at 60 Hz. Wide bandwidth: -3 dB at 0.25 Hz and 50 kHz. Handles signals up to 7 volts at 20 Hz or 11 volts at 30 Hz. Input impedance is 49 k Ohm when driving a typical 47 k Ohm input.
CI-2RRj Stereo Dual Audio Input Isolator 162.00

To fix an audio subwoofer with RCA connectors.

SUB-1RRj
Single channel low frequency audio isolator (RCA).
Ideal for subwoofer applications. The specially designed transformer in this unit provides unparalleled low frequency response while providing over 100 dB of common mode isolation, to solve even the most difficult subwoofer installation problems. The zero dB insertion loss also prevents carefully calibrated system levels from being disturbed. Common-mode ground noise rejection of 105 dB at 60 Hz. Extended low frequency response: -1 dB at 0.4 Hz, -3 dB at 0.15 Hz. Extremely low distortion: 0.01% at 20 Hz and -10 d BV. 0 dB insertion loss with 600 Ohm source and 47 k Ohm load.
SUB-1RRj RCA Single channel low frequency isolator 105.00

To fix a Stereo Signal with XLR connectors & terminal strips.

help eliminate RF interference from radio and television stations

PI-2XXj
Stereo (two channel) audio ground isolator.

Solves RFI susceptibility.
Solves shield noise coupling problems.
Solves most transformerless input problems.
Solves Common Mode Rejection Ratio (CMRR) problems.
Solves other equipment problems with Integral ground option switches.

Use with any source, balanced or unbalanced. Use with any load, balanced or unbalanced.
Versions are available with a choice of XLR, RCA, 1/4" Phone Jack or BNC connectors.

"Audiophile Quality" Ruler flat frequency response that will please any Audiophile.
Eliminate R.F. Interference (RFI) that comes from radio and television stations.
Gold plated connectors for long-term reliability.
Gold plated contacts on Built-in customer operated DIP-switches.
DIP-switches solve most equipment problems and allow for flexibility in grounding configurations.
Unpluggable screw terminal strips make "Home" to "Road" changeovers easy.

Transformer isolation.
Convenient 7.0" W x 3.5" D x 1.6" H. dimensions allow rack tray or rail mounting.
Includes High-grade Nickel-Iron-Molybdenum transformers with Faraday shields.
This isolator has 90 dB of common mode isolation at 60 Hz.
Super-Wide bandwidth: 0.25 Hz to 50 kHz
Handles signals up to +19 dBu at 20 Hz or +23 dBu at 30 Hz
Input impedance's are 24 k Ohm when driving typical 20 k Ohm inputs.
To avoid excessive high frequency losses, no more than 3 feet of cable should be used on each output.
PI-2XXj XLR Stereo Audio Input Isolator 190.00

To fix a Stereo Signal with XLR connectors, Phone Jacks & terminal strips.

Stereo Direct Box "Line" to "Mic" level Convertor & Isolator

DB-2PXj
Stereo Dual Direct Box "Line" to "Mic" level Convertor & Isolator.

Solves musical instrument hookup problems.
Solves "hum and buzz" problems in musical instrument hookups
Solves high frequency loss with use of long cables.
Solves Common Mode Rejection Ratio (CMRR) problems. 100 dB at 60 Hz.
Solves RFI susceptibility.
Solves other equipment problems with Integral ground option switches.
Converts unbalanced line levels to balanced mic level output

Designed to provide over 100 dB of common mode isolation at 60 Hz
Designed to convert Line level +4 dBu signals to Microphone level -38 dBu signals.
Transformer isolation allows maximum interconnection flexibility, since both sources and loads may be either balanced or unbalanced.

When loaded by the 1 k Ohm input impedance typical of mic preamplifiers, this isolator has a 140 k Ohm input impedance, making it ideal for high impedance sources.
It can be used with or without an active buffer as a "direct box" for electric guitars or synthesizers.
30 dB magnetic shielding is standard.

Use with any source, balanced or unbalanced. Use with any load, balanced or unbalanced.
Versions are available with a choice of XLR, RCA, 1/4" Phone Jack or BNC connectors.

"Audiophile Quality" Ruler flat frequency response that will please any Audiophile.
Eliminate R.F. Interference (RFI) that comes from radio and television stations.
Gold plated connectors for long-term reliability.
Gold plated contacts on Built-in customer operated DIP-switches.
DIP-switches solve most equipment problems and allow for flexibility in grounding configurations.
Unpluggable screw terminal strips make "Home" to "Road" changeovers easy.

Transformer isolation.
Convenient 7.0" W x 3.5" D x 1.6" H. dimensions allow rack tray or rail mounting.
Includes High-grade Nickel-Iron-Molybdenum transformers with Faraday shields.
This isolator has 100 dB of common mode isolation at 60 Hz.
Wide bandwidth.

DB-2PXj XLR Stereo "Line" to "Mic" level Convertor & Isolator 190.00

To fix a Stereo Signal with XLR connectors, & terminal strips.

Provides Ground isolation and Level Conversion

PC-2XRj
Stereo "Pro" to "Consumer" Converter & Isolator.

Solves shield noise coupling problems.
Solves "hum and buzz" problems
Solves Common Mode Rejection Ratio (CMRR) problems. 90 dB at 60 Hz.
Solves RFI susceptibility.
Solves other equipment problems with Integral ground option switches.
Converts nominal +4 dBu to nominal -10 dBV signal levels.
High CMRR when driven by balanced or unbalanced sources
Wide bandwidth: -3 dB at 0.5 Hz and 145 kHz
Integral ground option switches solve other equipment problems

These units allow connection of balanced line level signals to consumer level unbalanced inputs while also providing isolation to eliminate ground loops.
Internal Faraday and magnetic shields reject RFI and hum pickup.
Output cables should be kept under 10 feet (3 meters) to preserve high frequency bandwidth.

Use with any source, balanced or unbalanced. Use with any load, balanced or unbalanced.
Versions are available with a choice of XLR, RCA, 1/4" Phone Jack or BNC connectors.

"Audiophile Quality" Ruler flat frequency response that will please any Audiophile.
Eliminate R.F. Interference (RFI) that comes from radio and television stations.
Gold plated connectors for long-term reliability.
Gold plated contacts on Built-in customer operated DIP-switches.
DIP-switches solve most equipment problems and allow for flexibility in grounding configurations.
Unpluggable screw terminal strips make "Home" to "Road" changeovers easy.

Transformer isolation.
Convenient 7.0" W x 3.5" D x 1.6" H. dimensions allow rack tray or rail mounting.
Includes High-grade Nickel-Iron-Molybdenum transformers with Faraday shields.
This isolator has 90 dB of common mode isolation at 60 Hz.
Wide bandwidth.

PC-2XRj XLR Stereo "Pro" to "Consumer" Converter &Isolator 190.00

Understanding and eliminating ground loop problems.
What does it look like? From light to dark horizontal lines or bars, slowly traveling through the picture, from the bottom to the top of your TV screen or monitor. This is sometimes called video hum. Severe cases can cause tearing of your picture.

This image illustrates a moderate video ground loop problem. Note the three gray horizontal bands. The bands move up and down through the picture.

light to dark horizontal lines or bars, slowly traveling through the picture, from the bottom to the top of your TV screen or monitor

This shows a moderate ground loop problem on an oscilloscope. Video & 60 Hz.		This shows a restored video signal after the Humbucker is installed.
Ground loop Interference looks like a wavy line superimposed on the normal video signal.

What does it sound like?
Audio hum, 60-cycle noise, 60 Hz hum, similar to the lowest note on a bass guitar or bass drum.

What causes the problem?
Relatively long audio or video transmission cables (usually from room to room or longer), with 120 VAC powered equipment at both ends of the cable that is connected to different circuit breakers. This is the typical scenario but any length cable hooked to any equipment can have this problem. The name given to this problem is a ground loop.

What is a ground loop?
A difference in the ground voltage between two electronic devices powered by 120 VAC and connected together with your audio or video transmission cable. This difference (common mode) voltage will drive a current through your cable and superimpose itself onto your audio or video signal showing up as hum or lines. This is an addition of voltages. A similar effect can occur when an AC magnetic field comes close to your cable. The AC field can induce a current directly into your cable and superimpose itself onto your audio or video signal showing up as hum or lines. This is related to the workings of a transformer.

How are ground loops corrected?
Simply disconnect one side of the coax cable and insert a Hum Bucker between the coax cable and the equipment. The Hum Bucker will block the current flow and restore the audio and/or video to normal.

The fix for standard equipment is a video Isolation transformer.
The standard Hum Bucker blocks the current's path with a Video Isolation transformer.
A standard quality Hum Bucker is used for removing hum from most sources of video.
It passes about 20 Hz to 4 MHz, and its hum isolation is greater than a choke.
The transformer is primarily used in CCTV: security, avionics, display, etc.
Both transformer and choke can pass camera control signals.

The fix for premium equipment is a video isolation choke.
The Premium Hum Bucker blocks the current's path with a video isolation choke.
A broadcast-quality Premium Hum Bucker is used for removing hum from the finest sources of video, it passes DC to hundreds of MHz. The choke provides protection against moderate levels of 60 Hz hum, and protection against very high levels of RF noise. The choke is primarily used in high quality applications like Broadcast TV & ENG (electronic news gathering) etc. because it passes the DC component of the signal.

Do not remove the middle prong of your 3-prong electrical plugs!
This is very hazardous and a violation of UL code.
This increases the shock hazard and will not fix the problem. It is difficult to predict where a ground loop will occur.
Ground loops are usually an "after the fact" problem where the end user blames the installer, the installer blames the manufacturer, and the manufacture blames the electricians. Often nobody knows how to fix it. A ground loop problem may occur at multiple points in your system. Each problem must be corrected individually. This type of Interference can affect cameras, video recorders, monitors; video effects generators, switchers, computers and much more.

Details about the conditions causing ground loops.
The 120 VAC power wiring in all buildings has losses in the copper wiring. You can see this in the fast speed of an electrical saw at the outlet and a slower speed at the end of a long extension cord. The losses show up as voltage differences. You can actually take a voltmeter with 30-foot leads and measure a voltage between the ground on the 120 VAC outlet in one room and the ground on the 120 VAC outlet in another room. The ground (of course) is the screw that you can see and touch, that holds the plastic plate onto the electrical conduit box. The voltage gets higher with multiple power panels and high amperage loads. The equipment that is plugged into these outlets carries the same ground voltage on their own chassis. When a video transmission cable is connected between the two chassis it now becomes a current carrying conductor. The voltage difference causes current to flow through the coax inducing a (common mode) voltage into the video. This is seen and heard as Hum and usually displays itself in the form of horizontal lines or a disturbance floating through the picture.

Another way to look at Ground Loop problems.
How to prevent audio hum and video bars.

What is a Ground Loop?
When you hear hum in audio or see bars in video, it's often caused by a ground loop effect between two or more pieces of gear, plugged into two or more 120 VAC outlets.

One half of a ground loop is formed by connecting two electronic components together with a cable, such as, a DVD player is connected to a TV, with audio and video cables.

The second half of this ground loop is formed by the 120 VAC plugs of the same electronic equipment and the unseen ground wiring in the house, such as, the TV's power cord is plugged into one outlet and the DVD player is plugged into a second outlet and the wires in the wall connect the two together.

This loop is from a DVD player, through audio and video cables, to the TV, through the TV's power cord to the house wiring, through the house wiring to the outlet that the DVD is plugged into, through the DVD players power cord and back to the DVD player where we started.

How to Fix Ground Loops
For complex systems you may need to repeat these steps starting with a different piece of equipment in various combinations to locate the problem:

1. Strip the system down to one central piece, such as a mixer, by disconnecting all interconnects and AC cords except for the mixer.

2. Add one piece of equipment at a time; hook up AC and interconnections (making sure all grounds are connected and in good condition) then listen for hum or look for noise.

3. You can turn on and off the power each time you switch equipment to avoid pops and shorted outputs.

4. Proceed until you find the offending piece(s) causing the problem.

5. Plug the The Ground Loop Isolation Transformer in all lines between the offending equipment and the rest of the system.

6. Another common path for ground loops is through a chassis into the rack and then into another chassis. Test this by removing the chassis from the rack.

7. What about cutting or lifting the AC ground?
Caution: Removing or disabling the AC ground can cause electrocution and:
· Can cause distortion due to floating signal references
· Can cause noise to be dumped into another piece of equipment.

8. What about cutting or lifting the signal ground?
Cutting the shield at one end of the interconnecting cable:
· Can distort the signal return.
· Can alter the cable's frequency response.
· Can defeat the shielding effect.

Ground Loop Isolation Transformers are the safer and better solution,
they break the ground loop and keep all AC power grounds intact.

More filter information.

Hum Eliminators can do more than just prevent AC hum from being picked up by your sound systems. Special units can be used as one of the most cost-effective ways to convert unbalanced signals to true balanced signals.
Ground Loops Hum Eliminators prevent ground loop antennae from forming and picking up AC hum. AC hum & noise can be caused by a loop antenna effect across signal lines between two or more pieces of gear, or by long unbalanced cables picking up noise. Loop antenna(e) are basically a type of radio antenna, which tend to pick up the 60 Hz (and harmonics) AC signal being broadcast by a building's electrical current. These loop antennae are closed circuits usually along the ground wires and hence are commonly called ground loops.
Balanced and Unbalanced Unbalanced signals are more susceptible to picking up electrical noise & RF Interference than balanced signals are. The longer the unbalanced cable, the greater the chance of a problem. Hum Eliminators are one of the most cost-effective ways to convert between unbalanced signals and true balanced signals.
MIXERS and RECORDING
Many mixers have unbalanced or "impedance balanced" monitor outputs. Use Hum Eliminators to get true balanced outputs for noise-free performance. When using more than one mixer (or submixing), there's a good chance of getting ground loops (and buzz). Use Hum Eliminators to prevent these ground loops. Eliminating hum is one of the biggest challenges facing studios. Many studios will run all of their line level gear through Hum Eliminators to help ensure noise-free recording.
KEYBOARDS, SAMPLERS and SYNTHS
Most keyboards, samplers, and synthesizers have unbalanced -10 dBV outputs. Use a Hum Eliminator to balance the signals if used with other -10 dBV equipment. To use a -10 dBV unbalanced device with a +4 dBu balanced device, use a Line Level Shifter.
LIVE SOUND and DJ MIXERS
A common problem with live performance is long unbalanced cables picking up hum along the way. Balanced signals are more immune to picking up noise. Use the Hum Eliminator to balance unbalanced signals. Mobile DJs or bands never know when setting up their system if they're going to get a hum or not. The electrical wiring changes from one building to another. What works fine at one gig might not work at the next. Its worth the low cost to keep a Hum Eliminator available as nobody can afford to lose a gig because of hum problems. Some DJs run everything in their rig through Hum Eliminators to play it safe. The main outs on most DJ mixers are -10 dBV unbalanced RCA. When using with a +4 dBu power amp, over 2/3 thirds of the amp's volume can be lost. Use a Line Level Shifter to fix it.
POWER AMPLIFIERS
Running multiple amplifiers can create ground loops between the amplifiers, which will pick up the dreaded hum and buzz. Run each amplifier's input line through a Hum Eliminator to prevent this problem.
GUITARS
Many guitar players use rack and pedal effects. They can get buzz from ground loops that these devices create. Use a Hum Eliminator to stop that buzz. When using two or more guitar amplifiers, ground loops can form between the amplifiers. Because of the tremendous amounts of gain in guitar amps, the buzz can get so bad that the amplifiers will actually squeal (especially with tube amplifiers). Simply run the feed to each amp through one channel of a Hum Eliminator.
COMPUTER SOUND CARDS
Most sound cards have unbalanced inputs and outputs. Balance these with the Hum Eliminator. Even balanced sound cards have tremendous susceptibility to ground loops because of the computer's power supply. If you hear a buzz, try a Hum Eliminator.
BROADCASTING VIDEO
Press Boxes have many feeds all going to different gear, which can create lots of ground loops and hum. Use a Hum Eliminator on these feeds to eliminate the problem. Using a Hum Eliminator on the audio feed of a video camera can help prevent video hum (rolling bars).

Note:
Never use Hum Eliminators between amplifiers and speakers, equipment may be damaged. Only use the Hum Eliminator on line level signals.
Another common path for ground loops is through a chassis into the rack and then into another chassis. Test this by removing the chassis from the rack. The Hum Eliminator will help but you should also try isolating the chassis from the rack with electrical tape and insulating the rack screws with nylon washers.
Most ground loop problems can be solved using the Hum Eliminator. Patience is a necessity when attempting to solve ground loops! Many popular mixers with TRS balanced line inputs do not have common mode rejection. They drop the inverted signal, creating unbalanced inputs! To get the benefits of balanced inputs, run your balanced line into the Hum Eliminator and run a mono 1/4" line from the Hum Eliminator outputs to the mixer's TRS inputs. This way you are running a balanced line all the way up to the Hum Eliminator and you will not lose common mode rejection.

Note
Some audio power amplifiers have a small amount of hum inherent to the internal electronics. You can sometimes test for this by turning off the receiver and leaving on the power amplifier (be sure not to do damage to your system).

A question to ask yourself, have there been any changes to your video system or your power system just before your picture or sound got worse?

A ground loop filter will not work if you have any other wires that start from the same source and connect to the same monitor, this would 'short out' the filter. Such as audio cables, computer cables, steel 2 x 4s, power extension cables etc.

A good test is to disconnect all cables from the TV except the power cord and the cable from your ground loop corrector. The picture may change confirming your system may have a second ground loop, or a broken filter.

Sometimes a Cable box to your plasma TV looks like a ground loop problem but it is not.
The problem can be the refresh rate of the plasma TV that is set wrong.

How to test your CATV system to determine if a CATV filter will help you.
Some times a bad CATV ground loop problem will insert hum into your system even when your TV is turned off, and you are only listening to a CD etc.
A good test is to disconnect your CATV cable from your TV system.
If this stops your hum it is a good bet the CATV filter will work for you.
If the hum persists then you could disconnect more cables one at a time, starting with the longest cable runs. The cables that are most likely to cause your problem are relatively long audio or video transmission cables (usually from room to room), with 120 VAC powered equipment at both ends of the cable.
If your problem clears up after unplug the powered equipment at the far end of the cable then the HUMplug-e may be a good choice.
If you find a problem with one or more cables you will find many choices of filters to use on this page.

Installation Instructions for the VRD-1FFj and the CATVglip.
Solves "Ground Loop" and "Hum Bar" problems.

For analog and digital cable TV and cable modems.
Two female "F" connectors, in and out. VRD-1FFj 2 MHz to 1300 MHz bandwidth.
Male "F" connector & female "F" connector. VRD-1FFj 40 MHz to 1000 MHz bandwidth.

Step 1. Remove your existing coax cable at the systems entry point. STOP ! READ STEP 2 NOW !

Step 2. Before going any further, you must inspect the condition of your existing coax cables center
conductor (the solid wire in the center of the F-connector). The end of the center conductor must be
smooth, straight, cleanly cut, and should not extend past the edge of the nut, trim if needed. If it is bent
over in any way, gently straighten it with a pair of thin-nosed pliers before proceeding. If the end has
any significant flare to it (because it was cut by a pair of dull wire cutters) it must be cleaned up before
you install the VRD-1FFj This flare will damage the gold-plated contacts inside the VRD-1FFj
female "F"connectors, causing a bad connection that can result in lost channels and poor
performance. This type of damage to the VRD-1FFj's connectors will not be covered by warranty.

Step 3. Once you have determined that the end of the center conductor on your existing coax cable is
clean and of the proper length, you can install the VRD-1FFj Hold the VRD-1FFj isolator in one hand,
and insert your coax cable into either end of the isolator (the VRD-1FFj is bi-directional). Now, turn the
nut on your existing coax cables connector until snug. Do not rotate the VRD-1FFj; you want to spin the nut only. Rotating the VRD-1FFj is what causes the aforementioned damage to the VRD-1FFj's
connectors by the flared-out end of the existing coax cables center conductor.

Step 4. Now, attach an additional coax cable (not provided) to the other end of the VRD-1FFj Use a
short (6" to 1' or so) cable if you can find one. As before, hold the VRD-1FFj still, and rotate the nut on
the short cables connector until snug.

Step 5. Finally, insert the other end of the short cable into your systems input, and tighten the nut snug.

Step 6. Turn on your system, and enjoy the hum-free signals you are now experiencing!

Troubleshooting

Question 1: My hum is gone, but now I'm no longer able to get certain channels. What's wrong?
This can occur occasionally. We have been investigating this problem for a while now, and have
discovered it is due to one of two reasons:

A. In most of these cases, the connectors of the VRD-1FFj have been damaged enough from a bad
coax end to cause a poor connection. The fix is to make sure your coax cables end is clean before you
install the VRD-1FFj

B. The other reason this occurs is due to reflections of the video signal occurring at points along
the feed between the cable company and your home. Video reflections can be caused by improper tuning of the cable company's repeater amplifiers, illegal wire taps into the cable system (such as in apartment buildings), or unused video outlets in your home. Unused outlets must have a 75-Ohm terminator attached to the F-connector to prevent reflections. Go to an electronics store (i.e.: Radio Shack), purchase these terminator(s), and install them on all unused video outlets first as a possible fix. If you still have missing channels, try moving the VRD-1FFj to the other end of the coax cable
run in the room it is in. We have found that changing the lengths of the cables that are before and after
the VRD-1FFj is enough to eliminate the reflections that are causing the dropped channels.

Model # UHFHB
Video Ground Loop Transformer
call now 707 584 7844
Video Hum Bucker Eliminates video tearing on long coax runs caused by power ground loops. See Product Specification sheet below.

This system prevents video-signal distortion caused by video ground loops.
Used in locations where runs of video cable are suspected to have ground loops.

Installation and operation of model UHFHB Video Ground Loop Isolation Transformer.
Introduction

Ground loops are a common cause of video distortion. Undesirable symptoms include "hum" which appears as one or more horizontal bars, horizontal tearing or pulling, and vertical rolling. The Ground Loop Isolation Transformer is a passive ground loop correction device for coaxial video systems, it differentially nullifies the AC current that can occur in the video cable shield as a result of differing voltage potentials at each end of the shield.
The difference in potential can arise from the bridging of two power distribution systems supplying the camera and monitor in which the level of electrical ground varies. The result is the production of an AC current in the cable shield.
Installation
1. Please use all of the following information to install your UHFHB Ground Loop Transformer. The unit must be installed in conformance with national, state, and local electrical codes. The UHFHB prevents video-signal distortion caused by video ground loops. It differentially nullifies the AC current that can occur in the video cable shield as a result of differing voltage potentials at each end of the shield.
WARNING: To prevent the risk of fire or electric shock, do not handle grounded objects and the ends of video cables simultaneously, do not expose this unit to rain or moisture. Product specifications are subject to change without notice.
2. The UHFHB should be installed where runs of video cable are known to have ground loops. See the above Figure for a typical system interconnection. See below for a picture and a dimensional drawing.
Make the following connections:
3. Place the UHFHB between the camera output and the first video component, such as a switcher, coaxial cable control transmitter, or monitor.
4. Connect the camera or receiver output to the BNC connector marked in on the ground loop transformer.
5. Attach another cable between the BNC connector labeled out on the unit and the first active video component in the system. The holes on the base of the unit can be used to mount the unit.

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Voice... 707.584.7844
Fax ..... 707.584.5733
6068 Dolores Drive Rohnert Park CA. 94928

Video Hum Bucker an Isolation Transformer

The Video Hum Bucker is a Ground Loop Isolation Transformer.
A standard quality Hum Bucker is used for removing hum from most sources of video, it passes about 20 Hz to 4 MHz.
The Video Hum Bucker prevents video-signal distortion caused by video ground loops. It differentially nullifies the AC current that can occur in the video cable shield, as a result of differing voltage potentials at either end of the cable. The Video Hum Bucker, or Ground Loop Transformer, or Isolation Transformer, has been specially designed for coaxial cable. The passive nature of the Hum Bucker does not affect two-way communications (control and video), but will not pass DC direct current.
The Video Isolation Transformer breaks the DC connection in a video transmission line thus removing the ground loop effect and stopping the hum.
There is no DC path through the Hum Bucker, and much larger potential differences can be handled.
When there is a hum problem and potential differences are over 20 volts, the Video Isolation Transformer is the most practical product to use.
The hum created by electromagnetically induced currents from power lines or distribution systems will also be removed.
The designs of the Video Hum Bucker, or Ground Loop Eliminator and Video Isolation Transformers are such that they can be put anywhere in the transmission system.
The Hum Bucker works most conveniently when it is at the end of the cable run, so you can see the picture on the monitor improve as you install it.

Video Hum Bucker Premium DC to 500 MHz pass band Call now 707 584 7844
Flat Response Bandwidths DC to 500 MHz For Color and Black & White No Low Frequency or High Frequency Roll-Off No Differential Gain Distortion No Differential Phase Distortion Passive Device-Failure Free Reversible Small Compact Package Low Price	IN FIELD: Between Remote Truck & Telco Between Remote Truck & Microwave For Inter-truck Hookup For VTR VCR Units For security For Monitoring Lines For entertainment	IN STUDIO: Between Buildings On Long Runs in Buildings Between Studios & Transmitters On Incoming Telco Circuits On Outgoing Telco Circuits
The Video Hum Bucker Premium eliminates Interference and hum on video lines. Hum usually displays itself in the form of horizontal lines or a disturbance floating through the picture. The Hum Bucker is a passive device that simply connects in series with the video line. Low insertion loss with wide passband makes the Hum Bucker ideal for applications in video production, distribution, CCTV, or anywhere ground loops and Interference affects picture quality. NTSC and PAL compatible.

All minimum and maximum specifications are guaranteed. Unless noted otherwise, all specifications apply at 25EC. Specifications subject to change without notice. All information herein is believed to be accurate and reliable, however no responsibility is assumed for its use nor for any infringements of patents which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Jensen Transformers, Inc.


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