It mitigates hum by component but not on all parts of the signal path. End line use and PA side use were poor.

this a great addition to anyone's equipment. all of the hum and noise has been removed, and now all is quiet. good stuff..

If you have two guitar amps and you want to use both at the same time, then this premium product is for you. It will turn both amps from buzzy/hum noise into quiet and back to normal. If you have one guitar amp and it's noisy and wish to eliminate hum, then get a noise suppressor pedal. The reason has to do with how this product functions and its intended purpose. It's a shame that the Morley Hum Eliminator doesn't have the rating it deserves, but I understand why folks would misinterpret its design function.

I have a lot of electronics and crossing wires under the rug in my office/jam space with multiple loops, so I needed something to alleviate the hum. This did the trick.

I've been using these for years. Excellent cutting out the hum in amps and PA systems, especially in older establishments that may have wiring issues.

First, about the bad reviews: You didn't a have ground loop-caused issues. That's why the Hum Eliminator didn't solve your problem. It only solves ground loop issues.

I have a lot of gear in my studio. I have a lot of things connected together. They all need power from the wall. Sometimes, the ground ("earth" if your a Brit) potential between two devices differs, creating a ground loop, and thus 60Hz hum. The greater the potential, the louder the hum.

I asked the interwebz to break this down in simple terms for me. Device A and device B are connected, and powered from the wall (even two different sockets, maybe even in two different rooms). Ground ("earth") does not normally carry any current, and shouldn't. It's meant to ground the devices to prevent electrical shock or electrocution. In theory, all devices should have a ground potential of 0 volts. Let's say device A has ground potential of 0V. But device B has ground potential of 0.1V because of the building's wiring conditions. Connect the devices with audio cables, now you have a ground loop. Device A (0 volts) → Audio cable ground → Device B (0.1 volts) → Electrical wiring → back to Device A (0 volts). A current flows through this loop due to the difference in potential. That current is heard as hum. The greater the difference, the louder the 60 cycle (Hz) hum.

The Hum Exterminator, by isolating ground paths using a specialized transformer, effectively breaks this loop. Thus, it stops current flow, eliminating the audible hum, all while maintaining proper electrical safety.

That's the explanation, and that is also why the negative reviews found it unsatisfactory. They didn't have a ground loop issue. They had some other issue. The Hum Eliminator is also a great diagnostic tool. If these reviewers had known better, they'd have appreciated that the Hum Eliminator "eliminated" (ha) ground loop as the cause, and could have started looking elsewhere (e.g., bad cables, etc.).

In my case, I've used it to great success. I always keep two extras on hand. If I need to use those, I order two more extras.

Here's a recent example of a success. Two new rack-mounted line level mixers. I noticed 60Hz hum. It was subtle, but still unacceptable. I tried powering them from a socket in the next room. Still got the hum. I stuck Hum Eliminators in-between, and the hum disappeared, confirming that it was indeed a ground loop issue. This is why I always keep extra Hum Eliminators on hand. In a perfect world, all electrical wiring would be perfect and contractors who build structures would do immaculate work. But that's not reality. Hum Eliminator makes it possible for me to continue working without stressing out about ground loop issues that are outside of my immediate control. Slap a Hum Eliminator between the equipment and the wall socket, and it almost always solves the problem. If it doesn't solve the problem, then I know I have a different issue! So, it's a great piece of gear either way.

I spent way too much time chasing a ground loop hum in my you-tube review recordings done in my personal studio until I bought one of these and used it for my computer plug in. It never happened in bass recordings for songwriters, only when I sued my logitech cam software for live videos. Recording gear = line 6 UX2 and Podfarm 2.

Bought 2 and they did not remove any hum, returned for a refund

I didn't return this... too lazy to go through all of that hassle for $, but I did try it on 7 of my different amps (Milkman, Two different Princetons, AC15, Vibroverb, Tremolux, Mesa Boogie) across 5 different places (my house, my practice space, my sister's house, my friend's house, a recording studio). It didn't do anything to stop noise in any outlet that I tried. Tried it with multiple single coil and humbucker (Murphy labs SG, etc.) guitars.

Bummer.

My rack preamp (Sansamp GED-2112) and bass amp (LM IV) did not like each other. Even with the amp's mute engaged, ground hum would come through the speaker when the preamp was powered on and connected (either thru the front, or in effects loop). Rubber rack isolation tabs did not solve the issue. De-racking the preamp and powering it from an entirely different outlet did not solve the issue. Isolating the line by running it through a JDI and lifting the ground slightly reduced the noise, but did not fully address the ground loop hum. Using a line isolator box behaved similarly -- it reduced ground hum, but did not eliminate it.

Running the GED-2112 into the Morely Hum Exterminator, plugged into the same Furman as my amp, immediately nuked the ground hum and relieved me of immense stress and annoyance toward my (no longer) misbehaving rack. This is a magical, if unsexy, piece of kit. Highly recommended.

This little guy does tone down hum to an extent, but doesn't quite EXTERMINATE. Useful enough to keep, but not quite as good as I'd hoped.

Haven't tried it much, but the hum I was having is gone. Will try it again soon.

I had spent a lot of time trying to troubleshoot my amp humming. I should have bought this first. Very easy to use - simply plug and play. It works!

The Hum Exterminator is great at resolving ground loop noise caused by cheap laptop power supplies. Here's a surefire way to know if it'll work in your setup. You know those cheap grey/orange 2-prong AC plug adapters you can buy at the hardware store? Plug into one of those (as a test only). If it solves your noise, the Hum Exterminator will do so better, safer, and without the risk of electric shock. Highly recommended.

I bought one of these knowing the next gig I had we sometimes have noise issues, and we did! Our sound engineer tried a few things and said "let's try this and see if it really works". It was like someone flicked a switch and turned off the noise!! I bought another the next week!

I really wanted to think this would clear up my hum woes. I read a lot of reviews and watched 5-6 videos showing how awesome it was. I just got it today, immediately plugged it into the wall and plugged my amp into it (ROCKET Amp 20 watt), used my decibel meter, took a measurement, then unplugged the amp and plugged into the wall and remeasured. Absolutely NO DIFFERENCE. Both read 37.5 db. I tried again. Same reading. tried a 3rd time. Yep, no difference. I boxed it up and emailed my sales Rep to send an RA#. Sorry Morley. My house is 2 years old with new wiring, so it's not the electricity. There's no way to screw this up. There are no directions in the box because you plug...it...in. That's it.

Fantastic product. This is not a sexy purchase like a new guitar, amp, or pedal. But I play through two amps in stereo, and it completely eliminates the ground loop hum without impacting my guitar guitar tone at all. So for under $, your more expensive gear sounds a lot better and is more enjoyable to play through.

I have heard good things about this. Probably the ground loops problem is undefeatable in my apartment. My landlord is highly trustworthy. The house my apartment is in is 120 years old, and taking into consideration my landlord's assurance that the wiring is up to date, I've concluded the Morley hum exterminator is capable of dealing with only so much. I've bought an amp from Sweetwater which can be battery powered, and it should arrive today. I expect that running an amp on batteries instead of electricity will solve my problem.

I tried just about everything to solve a ground hum in my subwoofer. First I purchased some power conditioners to see if that would help. It didn't stop the hum, but at least it made my system safer.

I finally narrowed down the source of the hum. It was the power supply for my second monitor. I did some research and found the Morely Hum Exterminator. I wasn't sure if it would work, considering I had tried all kinds of other things that failed to stop the hum. The Morley arrived and I plugged my second monitor into it and plugged it into my power conditioner. The hum stopped. Completely gone.

I am so happy with this purchase and can highly recommend this to anybody with stubborn ground hum in their system.

If you are using a tube amp and are planning on playing anywhere other than your bedroom, get this. Most local venues are wired by people who don't know what is needed for a band; therefore, you can get some shoddy wiring and hums. This has worked so far at knocking that our and cleaning up my sound.

I've had a pair of Passive Avantone Mix Cubes (purchased at Sweetwater, of course) running through a 1990's Alesis RA-100 power amp that have always had noticeable hummm when sitting idle. After trying different power sources and different cables, I purchased the HumX, installed it and problem solved! As always, a dual thumbs-up for my Rep, Adam Chesi.

I was ready to trash a headphone distribution unit due to loud 60 cycle hum but decided to try this Hum Eliminator first. Pugging it into the headphone distribution device's A/C power cord silenced the hum nearly completely allowing me to continue to use it. I also use one to reduce Hum in a set of monitor speakers at a live show venue with similar successful results.

If you are like me and suffer(ed) from a noisy amp due a poor outlet, SKIP THIS PURCHASE!

It was asking a lot of ANY product to tame the ugly chatter coming through my amp, and I bought this with healthy skepticism. However, it did nothing AT ALL to reduce this awful noise.

I elected instead to plug into a less-convenient outlet across the room with a power strip extension cord and that alone reduced the noise back to the typical 60-cycle hum. Just for laughs, I put the Morley into that outlet and connected it to my amp. EVEN THE SUBTLE HUM could not be appreciably reduced with this "eliminator."

Maybe it has some utility elsewhere but as a noise-reducer for an offending amp/wall outlet, it is worthless in my experiemce.

It just works to quiet stuff down

This is just a pretty straight forward review of a very affordable device that can make the difference between your rig being hum free or not because not all 110v Electrical systems in clubs, venues, and other concert spaces are dependable or the same. This is especially true in older facilities.

I always carry two of these with me; one for my set up, and a spare which I've used multiple times for other musicians I played with when they've encountered the same 60 cycle hum. From guitar players to keyboard player anyone that uses a standalone amp needs a Hum Exterminator. And it also turns out that sound engineers love them too.

I've had mine for well over five years and I performed several hundred gigs and they've always been dependable, reliable and they take care of the problem.

It does exactly what it is supposed to do, and works flawlessly!

My band rehearses at my house. My amp was constantly buzzing and humming. Who knows what appliances were adding to the electrical buzz coming through my amp. The Morley Hum Eliminator did just that. At first the price caught me a bit by surprise, but after considering it as essential as anything else I plug into, it's no brainer.

UNFORTUNATELY MY HUM WAS NOT ELIMINATED SO I BLAME SOMETHING ELSE. HOWEVER THE SERVICE THAT I RECEIVED FROM SWEETWATER WAS OUTSTANDING. I WILL DEFINATELY DO BUSINESS WITH YOU AGAIN

Cheap and easy solution to a vexing problem. I like to run two amps at the same time, with output to each amp coming from one or more stereo pedals. Whenever I would turn on even one of the amps, I had irritating buzz. Jiggling the AC plug at the wall outlet somewhat helped reduce the buzz, but it would always come back. After doing some research, I decide to give this little gadget a try. Plugged one of the amps into it, and instant bliss. No more buzz, just gentle hiss from both amps. I wasn't sure if I'd need more than one of these devices, but it turned out one is all I needed.

What a great lil tool to have in your arsenal to quieten or totally eliminate that annoying hum that finds it way in your set or recordings. This little gadget is well worth the price. I had a small practice amp that was really great to use became of it's size and weight that had an awesome sound all but that annoying him so I decided to take a chance on the simple little device at the advice of one one of the tech's at sweet water and was so glad I took his advise and purchased this tool, thank you sweetwater iam now officially hum free!

I had purchased a CD recorder that produced a hum. I was contemplating sending it back, but instead discussed the hum eliminator with my sales rep. It came today and I plugged the recorder into it. Before inserting any CD's I turned the volume on my receiver way up. NO HUM WHATSOEVER!! So glad that I can now keep the recorder and enjoy totally hum free recording and playback.
Thanks as always to Tim Holsinger and his team.

The only thing this eliminated was $ from my bank account. And naturally I couldn't use it in time to return it. Awesome!

I got this thing to eliminate a hum that I couldn't diagnose. One of the shows I produce has 4 hosts. Between them and the rest of my production team, there are a ridiculous amount of computers, cameras, cell phones, and a whole lot of lighting equipment. Anyway, it took some guess & check but I was able to figure it out by changing what I plugged in the outlet via the hum exterminator. It works!

It is great!!!

Got rid of that constant hum out of my amps! Can finally play above volume level 3!

Does what it is supposed to.

I was having an issue with buzzing when I would plug a pedal into my laptop to edit settings. I reached out to my Sales Engineer Tim and he suggested this product. It works beautifully, no more hum or buzzing when I connect to my computer!

If you play anywhere without proper wiring (which is about everywhere), then this is a needed tool for sound quality. Playing in a place with neon lights, I was getting a hum through my Fender Blues Jr, but this fixed it. Worth it to eliminate some annoyance.

Took most of the noise out but not all of it. Definitely an improvement though.

During rehearsal, I heard some hum and static coming out of my Fender modeling amp and thought 'what can I do to avoid as much hum as possible?' Some research turned up the Morley Hum Exterminator. I combined it with a Furman Power Conditioner and now feel I've got a reasonable amount of hum protection. I don't wait to plug it in - it's always connected. One less thing to think about.

I had high hopes for this but it didn't make a dent in my amp buzz.

Nothing fancy here but it did its job. No more unwanted noise.

I am pleased with, coupled with a power conditioner it has elimated background noise that has bothered me forever. It is now gone.

Trying to reduce hum from my 90s Fender Twin... can't find a combination of wall plugs/amps/effects where this makes any difference. Doesn't make anything worse, just doesn't reduce noise.

I had a ground potential issue between my theater amp and the subwoofer, so Inpllugged the power strip I to the Morley and the Morley I to the wall… VIOLA! Hum gone.

Since incorporating this little item into the signal path, I have not heard any hum, or any other transients. Very nice for the price.

Product works great!

Seems to work great.

This a must for your gigs. It eliminates any hum your might get through your speakers or amps.

These Hum exterminators are a must for your amps or sound equipment. They will eliminate any hum you might get when playing at different venues. Just good insurance for a clean sound.

I have AC hum in my phonograph circuit, comprising the turntable with a low output moving coil cartridge, external phono preamp, main preamp with a tube stage, and monoblock amplifiers. I bought two Morley hum exterminators and an isolation transformer to get rid of the hum. I honestly cannot tell the benefits of the hum eliminator over a simple 'cheater' plug that removes the ground pin of an equipment power cable from the household circuit. You also need to know just what systems are in the ground loop that causes the hum. If it's not a contributor then installing a hum eliminator on the equipment is of no use. I spent days on this swapping this or that hum elimination product around, and now have only one Morley hum eliminator in the circuit, more for lack of desire to dive back in and remove it than a documented necessity for keeping it there. In my scenario, the clear benefits of the hum eliminator are unclear. It is a very inexpensive thing and worth buying for experimentation purposes, but it's not a slam dunk solution by any means.

It's stopped the hum coming through my sound mixer. I will buy a spare one.

Apparently, 60 cycle hum was not the problem I was experiencing in my set up.

But I'll keep it in case of future difficulties.

So why buy this expensive piece of equipment when a simple three prong adapter will do the job? Because possible electrocution is not at all appealing. Three prong power adapters can help suppress some noise but are NOT an adequate ground. Sure they can reduce some amp noise and hiss, but they also are not actual ground, which while using pedals, microphones and other electrical equipment and circuits can be quite dangerous. Splurge on yourself, get this small, but useful, true ground power adaptor for piece of mind.

worked exactly as advertised and removed a nasty pa vox/acoustic guitar hum at an outdoor gig.

They work. Yay! Handy Item...

Eliminated the hum on 2 hifi pre-amps.

I love this product because it works really well. No regrets at all!

This unit did exactly what I needed it to do. I moved to a new apartment and when I plugged in my pedal board, the hum was unbearable. This drops it significantly and doesn't bother me anymore. The only reason I gave this 4 stars is because I also saw the Furman SS-6B 6-outlet Surge Suppressor Strip after I bought this and tried it. It did the exact same thing I needed for half the price and 6 outlets instead of one.

Took the noise floor down noticeably on a Marshall tube amp. This is a good device to have on hand.

This is the second hum eliminator That I own. We regularly play a club with a nasty 60 cycle issue existing on the electric plug I always use. Plugged this in first, then my amps, and no hums!!
Had the same situation in my studio with an old guitar amp. Plugged the amp into this units and total silence!! When you need a work-around for nasty buzzes and hums, this does the trick. Will it work for EVERY possible cause of a hum or buzz? I don't know. But it works great for my issues which are two different scenarios.