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

From an electrical engineer, not an electrician, I can find a technical path on why it is true that power cables make a difference.  We as EEs need to comprehend the reactance of the cable - which is really a passive circuit.  There is reactance to ground, between the neutral and hot, . . . and to the outside world. Need to model the inductance and capacitances to all adjacent paths; this is a spice model that can be analyzed.  That mathematical model must include frequency domains that are beyond 60 Hz, and transient currents.  While I will never take the time to build that model and measure it, I do believe its a fact.  We must get beyond the adultescent thinking that power cables only carry power.  In the real world of audio, they are a component that do contribute to the end result.       

As someone that has a graduate degree in Electrical Engineering, there is no doubt cables can make a difference.. But for me it is always a price vs performance issue. If you have the means,  then go for them $10K power cables / power regenerators. It will improve your sound quality. But I would rather have $9,950 in the bank and spend $50 max for power cables.

Just a thought…

It’s not about the size of the cables. That’s the easy part. It’s about how closely the juice can meet the demand made by the dynamics of the music. Any deviation from the shapes and sizes of the music shows up in the sound we hear. A better cable will allow the juice to mimic the music better so they sounded better.

High end power cables are cool things that appeal to the audio nut. If you like them buy them. I strongly doubt they make any difference in sound; the nuance here is to avoid the really cheap stock ones. Audio Science Review is the most clearheaded opinion on things like this. The fact that many of the people who like fancy cables are tube enthusiasts says it all. 

I’m surprised there’s not a lot of experimenting with changing the amplifier’s housing. I used to run a pair of cheap JVC amps with their case tops removed so they would cool better and I could unplug the fans. That made a definite audible improvement because I couldn’t hear the fans anymore. This brings me to the idea of ultra highly modular amplifiers where more parts than just the power cord can be easily swapped. With tube amps you can roll tubes. I hear about people rolling op amps in some equipment. Quick change cases or covers with various material options and internal wiring harness options and whatever other options one might imagine could open a Pandora’s box of delicious decisions. It seems more likely to me that a permanently attached power cord that is soldered directly on to the power supply would eliminate potential issues from adding another plug. Might as wall solder right in to the wall too to get rid of that plug’s potential issues.