An electrical engineer on how power cables can impact sound quality


Sharing an fascinating discussion of how the design of power cables can impact sound quality of an audio system from an electrical engineer that does analog design for audio equipment.

The HiFi Podcast with Darren and Duncan / Radio Frequency: The 800MHz Gorilla

The discussion of how power cables can impact sound quality starts at 80 minutes into the podcast

From the Podcast:

"If you have an engineering degree and you’re hearing this and you’re shaking your head and you’re saying this is nonsense, my response to you is that you’re logical. Based on what you have learned, I completely understand your response, but unfortunately, the way that power cables operate is not the way that we were taught in electrical engineering necessarily."

"Power cables were always thought of as series devices. If we add this 2 meter power cable to 2 miles of powerline, why does this 2 meter power cable make a difference?"

An intro into the theory behind why power cables work from the podcast:

"The power cable is not necessarily a series element of a system. The parallel elements [of a power cable] and way they interact with RF in the room in a common mode sense to ground is incredibly important." [Meaning in parallel to ground]

My paraphrase of the rest of the discussion. They get into far more detail: The configuration and materials used in a power cable matter because they affect a cable’s capacitance which in turn changes the cable’s impedance. Most importantly, the change in impedance impacts electrical signal differently across the frequency spectrum.

Two ways to get more details on this:

  1. Listen to the podcast starting at 80 minutes into the podcast. The discussion of how a cable's design impacts its ability to shunt RF to ground starts right there.
  2. Send a question to the hosts of The Hi Fi Podcast. You can find their email on their website.

Credentials of the creators of The Hi Fi Podcast:

Darren:
Darren is the designer of many products for Boulder’s PS Audio brand, most recently known for Stereophile’s choice as the 2020 “Analog Component of the Year,” the PS Audio Stellar Phono preamplifier, and the incredibly well-reviewed new Stellar M1200 tube hybrid mono amplifiers.


With a career as an analog and digital circuit designer spanning two countries and several of the most well-known brands, Darren brings much experience to the table. He earned his EE and worked for both Bowers & Wilkins and Classe Audio before coming to Colorado, and also, before turning 30.

He is the designer of the PS Audio Stellar Phono phono preamp

Duncan:
Duncan has recorded 150+ bands, has published 450+ articles, columns and blogs and is an experienced DIYer when it comes to audio equipment and speakers. He met Darren when working as the Retail Sales Manager of Boulder’s PS Audio, and the two collaborated on an audiophile recording and concert series called “Invisible Audience,” not to mention the weekly hikes in the mountains. He is a mastering engineer, cable designer and musician, avid fly fisherman, bike polo enthusiast, husband and dad in his “free time.”


But what truly gives him a useful perspective for the podcast is his day job as a testing technician for the world’s largest online re-seller of high end audio, The Music Room. Over years in this role, he has listened to and evaluated thousands of the finest products from all over the industry and throughout high end audio’s extensive history.

calvinandhobbes

You can,  use a sensitive multimeter (4-1/2 digit) for an absolute value that can be converted to dB, or a good, sensitive audio measurement system like REW to listen to the speaker in a close-miked manner... usually at the tweeter since this is where the abundance of noise lives.

Thanks @piaudiol I just do not hear anything when the volume is up, but there is no content.

If I heard hissing abate when the thing was plugged in, I would be a believer, but maybe I am lucky as it cannot get darker than pitch black. Or maybe my hearing is bad or my background noise level is too high to hear it, or the power is good where I am at?

I have no experience like this description:

Even before I dropped the needle on the album, I noticed a slightly blacker background

Holmz - system noise is a lot like the Joni Mitchell lyrics " ...you don't know what you've got 'til it's gone..."

Until I recently retired I produced an electrical line filter oriented to the audio/video industry:  the UberBUSS, along with other power line devices.  It is a completely different approach to power filtration. Non-inductive with Power Factor Correction and parallel passive filters.  I had many customers tell me that they didn't have line noise, but wanted to try one anyway.  I offered a 30-day, 100% Money Back Guarantee.  My total returns were < 0.3%.  My skeptical customers all said "I had no idea what true background blackness (lack of noise) really meant.  That return percentage also included power cabling - you know: those things that don't make any difference.

For a skeptic's recent experience, watch Chris' Vinyl Attack video:

 

@piaudiol 
So I guess the inclusion of the video is implicitly meant to convey that your gear was not measurable as different, and could only be heard as different?

Uhm, no. Not what I said. Basically, BS walks, money (as in returns) talks.

With video, blacks are blacker, color saturation is visibly more even and image demarcation (image edges) are sharper. Eyes tell the truth that sometimes ears can’t hear.

In addition, using one of these on a TV with an IEC power inlet is (was) even better. Doesn’t matter, you can’t buy one and they NEVER show up on the used market.

BTW: Dave paid full price.

Positive Feedback Brutus Award 2013 by Dave Clark:

Pi Audio MPC/Mini++ AC Cord

www.piaudiogroup.com

Based on 14 ga cryogenically treated copper with Furutech plugs, Pi Audio MPC/Mini++ (14 ga cryogenically treated copper - 1.5 meter $499) does wonders on any Mac Mini. You get a boost in all the stuff you want without a boost in all the stuff you don’t want. What I mean is that compared to a stock cord, music takes on more drive and a dimensional palpable presence. Resolution is improved seven-fold; the music flows out into the room with a natural ease and liquidity, and you hear it all in a way that is never fatiguing or non-engaging. The music has that quality of there being less crap in the way… that is, one can simply hear more of the music. Same with the Aquila… something cool is going on here! I will say though, that if you want to use one, and the AQ Carbon Ethernet cables, then Dave Elledge has to be told ahead of time, as the two cable ends tend to fight over what limited real-estate exits on the rear of the Mac. Apple has the IEC and Ethernet connections very close together… so close that I was only able to use one or the other… but not both till Dave modified the IEC by trimming it down a bit. Even so, it is still a tight fit.

In the end, I have found the MPC/Mini++ to be a wonderful addition to the computer-based audio rig… so much so I bought the review sample. Give one a try, and you too will be smitten. I know I am and have purchased the review sample!

 

Although there is some RF coming in through the power line, most of the RF noise injected into our systems come from the nasty garbage we have in the room with our equipment.   Namely, all digital equipment, laptops, desktops, microwaves in the next room, CFL light bulbs, LED light bulbs, the list goes on.   Our digital stuff is tested to meet FCC Class B emissions but those emissions have nothing to do with audio, rather they are all concerned with the guy next door being able to watch TV via an antenna without interference while you play CDs or stream.   We can worry about RF on the power lines for sure, but let's also clean up our stereo listening room.