Several years ago I purchased an Emotiva CMX-2 DC Offset Elimination device with the goal of quieting my very loudly humming Tori Jr.  The amp’s transformers were so loud that I could hear them from 10 feet away.  There was also loud humming coming through the speakers.  I was fortunate to see both areas of humming significantly reduced with the Jr plugged into the CMX-2. Evidently we had a problem with DC on our AC lines, and there was no issue with the amp.

Shortly after buying the $139 Emotiva CMX-2, I sold the Torii Jr in order to take a different system direction.  The CMX-2 has been sitting on the sidelines for a couple of years now even though all of my tube pieces have been causing some hum through my speakers and have had varying levels of humming transformers.

Fast forward to a week ago…….I was reading an article about Vibex DC conditioning products and was so impressed with their claims that I decided to re-insert my CMX-2 DC Offset Eliminator and plug in the CSP3 and the ZROCK2… you know, just for kicks. The result was quite surprising and immediate, with nearly all humming gone, the system taking on a much blacker background, and a very noticeable higher level of resolution.

The Vibex folks were so convincing in their argument supporting DC conditioning that I decided to order two additional Emotiva CMX-2 units.  I went to the Emotiva website and was shocked and pleased to see that they had lowered the price to $82!  The two units arrived yesterday morning and I headed straight to the listening room to insert them.  Now, every piece in my system is receiving AC power via Emotiva CMX-2 DC Offset Eliminators.  

Soooooo…….how does the system sound with the Emotiva units in place?  The improvements are so remarkable that I’m close to saying that these three inexpensive devices have led to the most significant sound quality improvement I have ever heard with a change in equipment.  I am so very happy with the results of this little experiment that I just had to share.  

If you have humming in any part of your system, or even if you don’t have humming issues, I definitely recommend trying one or more Emotiva CMX-2 units.  With Emotiva’s complete satisfaction 30 day money back guarantee, why not give it a shot?  And if you have a large audio budget, why not go with one of the much pricier Vibex units and plug all of your equipment into it and be done with it?  I know this sounds crazy, but I’ve been in this audiophile game since 1971 and there is no mistaking what these little devices have done to the sound quality of my system.  Very, very, very impressive!  I’m done now.

Thanks Doug for sharing your experience.  Interesting for sure.... and no downsides for you? No dynamic loss, bass loss, textural loss, air.... etc?

Hey Will,

No, in fact, all of the things you mentioned have greatly improved.  My conclusion is that our incoming AC must have some serious DC content.  There seems to be no other explanation for this huge shift in sound quality.

My entire system seems to have taken a deep breath and gone into relaxed state where all struggles have disappeared. Resolution has jumped up many notches.  Bass detail, which was already quite good, is now off-the-charts good. Textural and timbral accuracy has taken a huge leap forward.  The sound stage, which was already very deep and wide, has increased in size and it is now saturated with air and warmth that I’ve never before experienced.  Front stage to back stage incremental layering has become far more clear.  Vocalists have taken on increased size and sound more real than ever.  Dynamics were previously very impressive, but now they are even better.  Cymbals, violins, snare drums, and other high frequency instruments are now presented with far more resolution and air, but also with greatly increased smoothness, warmth, effortlessness and ease.  These improvements remind me of what occurred when I replaced my OPPO 205 universal player with a Jay’s Audio CD transport and a Denafrips Pontus  DAC, but on a grander scale.  

Oh, I almost forgot to mention that the large toroidal transformers in my CD transport and two power amps no longer turn on with a loud roar.  When I hit the on switches now, all three pieces turn on silently, where before it was as if they were all stressing out and groaning over being asked to start making music.

And again, I can’t see any reasonable explanation for all of this outside of our AC being significantly compromised with harmful DC components.  With clean AC, every piece of equipment in the system seems to be thriving.  It feels like they’ve been healed from a horrible disease and are now free to live peaceful, happy, unhindered, productive lives.

I use the Emotiva CMX-2 as well with great results. However, when I received my Sarah I plugged it directly into the mains outlet. I am going to experiment this weekend and plug it into the CMX-2 instead to see if there is an improvement or reduction in sound quality. Thanks for reminding me.

Cool. Two tests.... I look forward to your results!

How would you characterize your power from the wall Ghostship?

From the Emotiva writeup it looks like the CMX-2 is a multipurpose AC filter:

"The CMX-2 delivers clean power, free of high-frequency line noise and potentially audible DC offsets to your audio components.....

......uses top grade common mode and differential mode L-C filtering to reduce or eliminate all types of high-frequency noise."

So guessing it will clean noise other than DC offset. Then the perpetual "condition or not" question becomes, is anything sonically taken with that... like finest detail and/or speed/or dynamics??? And obviously where our power starts matters... making creation of better power even more tricky to figure out. But with all this being questioned a long time, why wouldn't power conditioner designers keep working to try to resolve these issues, and maybe these folks have found it pretty well.

I have had a time with power over years, and heard downgrades with the improvements using a "Stock" Uberbuss, and PSAudio P5. But then I adapted to reduce those issues with cables and mods. I just find it tricky stuff here, but finally weigh it out to where the down sides are negligible, and enough less than the up to hang a while.... Then I find some opening up of speed and resolution elsewhere and try to improve on my power again to keep up. Right now the P5 is out of my loop, running a modified balanced transformer supply into my tuned-up Uber, and then a modified Brickwall... pretty stable and clean.

I wonder how the Emotiva might play into this.

Thanks for the follow up Doug. I think similar often happens for me, especially when I am focussed on trying to fix a certain aspect of the sound...then the parts of the sound that are little off become more present in mind and perception. Hum and buzz are killer for me, 60 and 120 hz particularly irritating... ending up with superman hum detection ears!

I run into this focus thing more often with tubes, though subtler in balance issues and solutions... but similar when I get really concentrated on trying to adjust a certain aspect of the sound with finesse, and in a fairly holistic way. Then when a tube choice seems to get me there, my first response is to want to order another pair for backup. The second thought though, is remembering that I already have lot of tubes, and that it takes me days to weeks sometimes to really hear all that is involved with a change that takes me from really good to a variation of really good.... especially across a broad range of recordings.

Ultimately I like this though. I keep learning a little better discernment of all the many balances that make our sound, individually and collectively, and this seems to make getting closer to "real" easier, while being fun to explore and learn along the way.

Doug,

Have you used a volt meter to measure the DC that may be on the AC line? You may be able to see a small amount. DC could come from some digital signal imposed on the AC line. This is done with cable TV and ISP services. There is also a technology that uses your home AC as a network line. Switching power supplies also operate with PWM technology. The DC noise can be all over the house, generated by even the LED lamps & wall warts in your home.
If you measure DC on your line, then also measure it after the DC filter.