Pyle Compact Mini Hum Eliminator Box - 2 Channel Passive Ground Loop Isolator, Noise Filter,AC Buzz Destroyer, Hum Killer w/ 1/4" TRS Phone,XLR Input/Output, Uses 1:1 Isolation Transformer

Goal: To play electric guitar through two 15 watt tubes amps with an ABY switch.Summary: It works! Nice and quiet, once I figured it out.Attempt1: Connect one guitar to the ABY switch, then onward to input channels 1 and 2 of the isolation transformers, and finally to two separate amps.Outcome 1: Muted volume and frequency response, topped with a heaping helping of AC noise. Unplayable at any gain setting.Attempt 2: Tried buffering through pedals between the guitar and ABY switch to feed both channels.Outcome 2: Even more AC noise, yikes!Attempt 3: Use only one channel of the isolation transformer, with the other channel connected directly from the ABY switch to the second amp.Outcome 3: Yes! Dead quiet, and the pedals add no noise when added to each channel, as long as there's no interconnection across channels. I can put pedals anywhere before the ABY or after, and it's all quiet.What's happening? The isolation transformer may be creating a serious ground loop when a common audio signal is connected to both channels. Under such conditions, my impression is that there may be two distinct ground loops formed on both the upstream and downstream sides of the transformers. Using only one channel fixes it. I haven't tried yet, but I suspect that using the other channel for an entirely different signal path, like a differnet guitar or mics running to a different amp or PA would work nicely. I will try to remember to update this once I try it.Bottom line: I opened this thing up to take a look, and it's well constructed, hand soldered, has wide pc board circuit tracings, and hot glue stabilizing the cable connectors. The little bitty transformers appear to be well-wound with permalloy cores and bobbins. There is no discernible change in tone using this rig, compared to plugging into the amps one at a time. Playing two amps together is awe-inspiring. This isolation transformer works well, if you are willing to experiment!

Was actually quite surprised with how well this works. In our church, we have a few live feeds set up throughout our building, 3 to be exact. to have greater control we route our audio and video separately. We were getting a loud hum/static noise to the live feeds set up in the building. We could isolate it to the in house feed because our livestream feed for online had no problems whatsoever. Connected this and the noise went away immediately.No tricks to it for us. Connected our audio board to the XLR input then connected our switcher (which is what we were using to send audio to the live feeds in the building) via XLR out and problem solved!

There can be many causes of hum / noise in a piece of equipment:* Bad equipment* RFI / EMI (radio frequency or electromagnetic interference)* Bad line power* Guitar-cord related ground loop (most common in guitar / microphone / amp situations)This item works dandy if you are experiencing a ground loop problem. There is a very easy way to test for this too: if you have a guitar amplifier that has unwanted hum / noise, simply unplug the guitar cord. If you're having a cord-related ground loop problem, the hum will vanish. Plug the cord back in, hum returns.That problem is exactly what this is for. Plug you guitar or microphone cord into the "in" jack, plug another into the "out" jack and to your amplifier, and this cleans it up well. An inexpensive and efficient solution.If your noise problem is caused by one of the other factors, that's not what this is designed to fix. You may need the more expensive Hum X or similar device to handle a socket-based ground loop or noise problem, or if it's a problem with electrical noise or RMI/EMI problems, you may need a pricey power conditioner.3-prong amplifiers: A way to test for socket-based ground loop issues is to use a prong adapter-- one of those orange or gray cheap things that converts a 3 prong plug into a 2 prong. This is for TESTING only as continued us can cause problems (there's a reason your amp has 3 prongs). Plug the amp into the adapter, plug the adapter into your electric socket, and if the hum vanishes a device like the Hum X will fix the problem. Avoid the temptation to just keep using the cheap prong adapter. It removes the grounding of the amp, and is a good way to burn out an amp or even cause a line fire. Of course if your amp only has 2 prongs in the first place, this doesn't apply at all.Bottom line: if the hum is caused by issues between the guitar and amplifier-- such is very easy to check by simply removing the guitar cord-- and this product will fix that. Note that if you have a serious issue with your guitar electronics or pickups, that may require repairing. But in my case this relatively inexpensive solution nearly zeroed my hum issues. Very pleased that it worked for me. If it doesn't work for you-- at least you'll have nice clean guitar line flow and you can look for other causes for hum.