Review: iFi Audio Groundhog

Ground Gate

If you’ve been playing this game as long as I have, then you’ve probably been buzzed at least once in your life – and I’m not talking about alcoholic euphoria either [Well, I’m out. -Dave]. No sir, I’m talking about that audible buzz you get the first time you plug some new component into your system.

Very recently, I got my “buzz” on when Audeze sent me a pair of LCD-i4’s for review. Here’s what happened: after unpacking these beauties from their unmarked box, I hastily hooked them onto my ears, checked to make sure the Pro iCAN was set to low gain, and then turned everything on. So far, so good. I played a little Power Trip on low volume (technically, an oxymoron in itself) just to get the party started and to verify the i4’s weren’t DOA. Unfortunately, the hooks were a little loose and I could feel them slowly slipping off. But when I went to adjust them, my fingers obviously had to touch the i4 to do so, and I got a nice loud and pronounced buzzing sound that scared the bejesus out of me as a result. Suffice it to say, it was a Kodak moment.

I had a ground issue, or at least I was pretty sure I did. But just to play it safe, I quickly fired off an email to the good folks at Audeze to ask if anyone else had experienced something similar with the i4. The good news: they had. The bad news: it was almost always due to a customer having a bad or missing ground. Audeze then asked me to plug the i4 into my phone just to be sure, and just like that, the buzz sound vanished. Crap.

Buzz Lightyear

So how does this happen? And what the heck is ground to begin with? And even more importantly, how does one suddenly have a problem with it outside of falling out of an airplane? But in order to even talk about ground, we first need to talk about voltage.

Despite being conveyed as a singular value, voltage is actually a measurement of electrical potential between two points. In other words, it’s a relative metric. So in order to calculate voltage at a single point in a circuit it has to be in reference to some other point. And what do you think that reference point is called? You guessed it, ground. Give that man a soldering iron! This is typically called a floating ground since it isn’t actually connected to the ground in the literal sense but still acts as a 0V reference point.

Technically speaking though, ground can also refer to well, the actual ground or Earth. For example, your AC wall outlet accepts three prongs: one for positive, the other for negative, and the third for ground. And as the above video explains, the ground prong in this case is literally connected to the Earth via a grounding rod. This is mainly for safety reasons as the ground wire not only acts as a 0V reference line, but also acts as a sink so any excess electrons over the wire can freely travel to the ground (Earth), preventing a fire or an unscheduled electrocution from occurring in case of a fault.

But here’s the thing: what if you have two devices connected to each other with different ground points? The RCA cable between them will also be grounded on both ends (ground is typically found on the shield of the cable), so current (the audio signal) can now flow freely to either ground points in the circuit causing what is commonly referred to as a ground loop. This loop then injects noise into the signal and suddenly you have a buzz [Finally! – Dave]. Or even worse, what if one of the components in your chain isn’t grounded at all? How can you add back ground to a circuit you can’t modify or don’t want to? [Hey, didn’t the reader just win a soldering iron? Get to work! -Dave] Finally, sometimes the ground connection in your RCA cable, or your USB one, or the ground out of the mains from your AC power supply can also play a role in leaking noise into the audio path and cause unwanted distortion and audible artifacts. To infinity and beyond.

Groundhog Day

iFi Audio has a fantastic little guide on how to diagnose the most common ground issues an audiophile will face. Their solution: the Groundhog. So what is it?

As you can see from the video, the Groundhog is a bunch of accessory cables that can put back a missing ground in a circuit. All you have to do is find the component in question, find an input that is compatible with one of these cables provided in the kit, and then connect the other end to an IEC power cord (three prong). For the more technically inclined, the Groundhog cable effectively grounds the negative DC output of a component’s power supply using the ground wire in your standard 3-prong AC outlet.

What I did was work my way backward through the audio chain. Starting with the i4, it was connected to the Pro iCAN so I found a free RCA output port and stuck the corresponding Groundhog cable in. Presto, problem solved. It was really that easy. Something I thought would take hours to debug was fixed in literally seconds. Woot.

Final Thoughts

The Groundhog is no silver bullet. For example, if your problem is with having too many grounds causing a nasty loop, the Groundhog isn’t what you want. Same is true if your issue is noise coming from EMI/RF leaking into the audio path (a simple ferrite choke is what you want in that case, but that’s a story for another day). Also, at $49 dollars, the Groundhog isn’t exactly cheap given you are most likely only going to need one cable out of the bunch. An alternative would be to go the DIY route or find a similar one off cable that may do the trick as well.

However, if you suspect you have a missing ground, the Groundhog could definitely be the order the day. It’s simple to use, highly effective, versatile, geared for audiophiles, and can save you hours of debugging trying to track down some nasty hum. And that my friends is a beautiful thing. Oh, and one more thing: I’m also told that if you plug a Groundhog into your system and you see its shadow, you are going to have a very metal winter. Something like that.