[fsimms]

really quite easy to hear. Just because I can't say why doesn't mean it doesn't happen.

I can say why.  I worked at NASA and used to look at signals on the grounds in equipment.   One Shuttle Simulator kept failing and I saw large currents on the grounds.   These were at radio frequencies and they were triggering some of the circuts.   I fixed the problem by adding a small wirewrap wire at a point that would make one ground loop into 2 smaller ones.   The simulator worked fine after that.    I had to use a differential probe on the oscilloscope to see the currents as they were hard to see.   

What does that have to do with power cords you might think.   With most of our equipment we get ground loops in the power cords to various pieces of equipment.    The ground loop is just a closed loop of copper that will ring like a bell at radio frequencies.   An example of the closed loop of copper is the wall socket ground pin of the power cord to the preamp.  This is then tied to the ground of the electronics inside and goes out on the outside connector of the RCA plug to the amp.   The amp then ties the RCA input plug to the ground of the electronics and then to the ground wire in the power cord back to the wall socket.  Inside the wall socket the ground wire is tied to the ground pin of the preamp's power cable.   This makes a closed copper loop.   This can ring like a bell at radio frequencies in the level of volts!   Of course you can't hear the radio frequencies, but they can leak into the electronics of the preamp and amp and modulate the transistors and other electronic components causing them to be working in the wrong range.  This can cause audible effects.   

What can a power cord do to fix that?  I use Virtual Dynamics power 3 cords that have magnets in the power cord.  This causes the ground oscillations to die out.   It is easy to hear the effect on all the equipment that I have tried them on.   The music becomes clearer.    Audio manufactures can fix this in their power supplies just as easy as a power cord manufacture can.

It is possible to use a good dual trace oscilloscope to see these currents with two identical probes.  If anybody is interested on how to configure the probes and scope then I will be happy to tell them.

Bob

[Russell Dawkins]

Not neccessarily, but they are made with a fair share of engineering.

And I felt this way before I published a hifi magazine.  Sorry, I'm not
a DIY guy.  Have had my bouts with it and even some fun but on my
best day, I can't make a better speaker than the stuff the majors throw
out in their dumpster.

If I don't get it, that's fine.

People are always much more proud of the stuff they've built themselves,
that's normal.  And that's also a cool aspect of the DIY part of this hobby.

The reverse smugness is always amusing.

Sorry, I'll stick to my job and let the speaker mfrs stick to theirs.

Amen! DIY for yourself is one thing, but there's nothing like doing it where the consumer votes on your results with their wallets to teach humility.

Another side of this is you won't often hear a recording engineer commenting negatively on some other engineer's work, because once you have gone through the process yourself you realize what an achievement it is merely to get something finished and out there at all, sounding halfway reasonable.

Having done both this and designed speakers, I have nothing but respect for anyone in the biz.
Nowadays I also tend to listen to the music, and not notice minor technical flaws in the process of delivery.

I still have to be picky when it comes to choosing monitoring equipment, though.

[cornelius]

Frank, I dug reading your DBT cable story with MIT.  I have had more experience listening for differences in amplifiers than cables.  I think there are big differences in the amps that I've owned over the years, but can't quite say the same about cables - or at least the differences are really really small...

How do I know that my perceptions on amp differences are not placebo?  Some guys can't hear differences in DBTs with amps - my conditions at home were never perfectly level-matched... I'm wondering if I'd hear differences in my gear in a DBT.  Frank, do you use blind tests when designing your products?

[saisunil]

Here is my personal experience:

About 5 years ago I had a convincing experience with Tube Research Labs Power Cord (they are no longer in the cable business.)

I gave the TRL PC to someone and when I plugged a zip cord into the amp - the "magic" in my system was gone. I was upset and could not understand what happened. The system Magic reappeared with the insertion of the TRL PC. So I notices the absence of the power cord more than its presence.

Notable - what a good power cord should do is to reduce the noise floor and not add any flavor.

this experience actually led me to the journey of getting all TRL system - source to speakers and everything in between.

I think, if you'r not going to mess around with getting a good Power Cord - you are better off getting a unit with captive cord.

Whatever makes you enjoy the music and make us happy ... that is indisputable

[avahifi]

OK please tell me in intelligible electrical engineering terms, what characteristics should a "good sounding" power have.  (No fake science please).  Are these characteristics expensive to do?  Like what makes a 10 foot long power cord worth $5000 or so?  Please tell me.  Explain WHY, not just "it sounds so wonderful to me".  What is the difference in construction of a "good" power cord that is not there in an ordinary one?  Made on Mars under a full moon does not count. 

Regards,

Frank Van Alstine

[miklorsmith]

The problem with this approach is, of course, you exclude all participants without an electrical engineering background - probably 98% of us.  I've never heard a power cable company claim extraplanetary construction nor lunar cycle benefits.

[jules]

OK please tell me in intelligible electrical engineering terms, what characteristics should a "good sounding" power have.  (No fake science please).  Are these characteristics expensive to do?  Like what makes a 10 foot long power cord worth $5000 or so?  Please tell me.  Explain WHY, not just "it sounds so wonderful to me".  What is the difference in construction of a "good" power cord that is not there in an ordinary one?  Made on Mars under a full moon does not count.

I think the parameters suggested exclude everybody ... mercifully 

jules

[boead]

OK please tell me in intelligible electrical engineering terms, what characteristics should a "good sounding" power have.  (No fake science please).  Are these characteristics expensive to do?  Like what makes a 10 foot long power cord worth $5000 or so?  Please tell me.  Explain WHY, not just "it sounds so wonderful to me".  What is the difference in construction of a "good" power cord that is not there in an ordinary one?  Made on Mars under a full moon does not count. 

Regards,

Frank Van Alstine

who is buying $5000 10 foot power cords? Anyone here spend $5000 on a power cord? Come on now, we don't bite - hard.


I have a 12 foot or so Kimber I paid $300 for. I have Virtual Dynamics cords (power 3) I paid under $200 for and some Harmonic Techs I paid under $250 for. List price vs. actual price you know. Never pay list or close to it. Totally worth it, to me. I've used sub $100 cords and cables that sound great too, better then what was supplied stock that's for sure.

[Brett Buck]

The claim that "It just can't happen" is where the dogma is. I don't see how the experience of hearing the difference for yourself can be considered dogma in the least. It's really amazing how many people are convinced of their opinions without having made the attempt to hear it for themselves.

   The laws of physics regarding electricity are not opinions, not dogma,  nor are they subject to your interpretation.

    Brett

[DavidS]

enjoying the science vs this is what I hear discussion here.  I think this is exactly what the article writer was poking at in his limited article space.  Wondering why both can't be right - if it sounds better for you it is better and Frank love the science and that you don't waffle on the engineering and values you put behind your gear.  Based upon 5 pages of comments and provided he doesn't aspire to be loved by all Mr. Schroeder should be pretty pleased with his article.

[rustneversleeps]

can say why.  I worked at NASA and used to look at signals on the grounds in equipment.   One Shuttle Simulator kept failing and I saw large currents on the grounds.   These were at radio frequencies and they were triggering some of the circuts. 

Hi fsimms,

We do the same thing to some of our facilities, I am not sure if your equipment are connected in a multipoints grounding configuration, it would help lower the RF interference that picked up by the equipment cabinets, or generated within the equipment itself. It maybe overkill for home use, but grounding is critical for other applications.

[rustneversleeps]

In my town, when driving, people are actually starting to put their breaks on when there is a green light, only because everyone drives thru the red light. This is mob mentality. If everyone would stop running the red light, we could all start driving thru the green light without putting our breaks on or stopping

Wayner,

You are wrong, in your town, people drive 55 mph on the left lane when it's sunny, warm, and nice out, but go 80 mph on the icy roads during a blizzard, in the middle of the winter. This is mob metality, trying to kill you.

[rustneversleeps]

OK please tell me in intelligible electrical engineering terms, what characteristics should a "good sounding" power have.  (No fake science please).  Are these characteristics expensive to do?  Like what makes a 10 foot long power cord worth $5000 or so?  Please tell me.  Explain WHY, not just "it sounds so wonderful to me".  What is the difference in construction of a "good" power cord that is not there in an ordinary one?  Made on Mars under a full moon does not count. 

Frank,

You asked the wrong question. You should have asked what make those cable elevator work, and why would elevating the speaker cable a few inches off the floor would make the sound much better? Assuming the floor is not a copper plate, and there's insulation on the cable.

[robinje]

I like the fact that AVA gear has "hard wired" power cords because it keeps me from being tempted to waste money blindly experimenting with pricey boutique aftermarket cables full of hype.  I've previously taken a ride on that expensive merry-go-round with no tangible positive results.  Besides, my AVA gear sounds just fine as is!  I do, however, have an aftermarket power cord on my CD player (used as a transport).  I bought this ~$15 Volex cable because it is shielded and I was not certain if the supplied cable was, and it's long enough to reach my AC outlet.  I can't hear any difference, so maybe I wasted $15.  Live and learn...   

[avahifi]

Darn it, if nobody herein can give me a rational reason to buy expensive AC power cords other than "I like it" then what are the factors affecting your decisions?

I really want to know what electrical characteristics would be really important in designing a better sounding power cord.  Power cord makers, please chime in too if you please.  Educate me a bit if possible.  How can one make an informed buying decision if there is no real information?

One other thought, how about their use for Christmas lights?  Any better results expected there? 

Regards,

Frank Van Alstine

P.S. I do understand that an especially shielded AC power cord might be important with digital switching amplifiers and preamplifiers as they tend to broadcast the RFI range switching frequencies like a radio station gone berserk.  There every last bit of shielding might be important to not load down associated equipment (from tweeters to phono cartridges and everything in between) with out of band garbage.

[mfsoa]

P.S. I do understand that an especially shielded AC power cord might be important with digital switching amplifiers and preamplifiers as they tend to broadcast the RFI range switching frequencies like a radio station gone berserk.  There every last bit of shielding might be important to not load down associated equipment (from tweeters to phono cartridges and everything in between) with out of band garbage.

Maybe that's what I heard, then. It's a far more plausible explaination than anything I could come up with.

I don't see why the presence or absence of a reason for hearing something has anything to do with what is actually heard. I can't fully explain how my system works, but I can still hear it. I guess someone who knows absolutely nothing about electricity wouldn't hear the sound at all   

If I puke, I don't question whether I puked or not just because I don't know the cause of it.

Certainly my wife, who heard the exact same difference in PC swap on the class D amp that I did, and described it in the exact same way as I would have (all the while not knowing that it was power cords that I was switching - so no plecebo effect, no buyers expectations etc.) could not explain

what electrical characteristics would be really important in designing a better sounding power cord

- It does not in any way change what sound was produced.

-Mike

[avahifi]

My P.S. above does deal with switching amps of course.  But can you please tell me what was different about the AC power cord you switched too.  Was there any info about better shielding (if so exactly what, and so on)?

Why is there so little curiosity in this business about trying to learn what is really going on instead of just claiming, "I like it".

Regards,

Frank Van Alstine

[miklorsmith]

Because it's a bottomless well of argument where every question answered leads to 6 more and a host of "smarter" science guys calling you a dumbass.  It also seriously slows the pace of experimentation if you have been relying on the ears.

[mfsoa]

For me, the "I like it" comes first, then the "What might be causing what I like?"

If I don't get an answer to the latter, it does not affect my response to the former.

-Mike

[stereocilia]

For me, the "I like it" comes first, then the "What might be causing what I like?"

If I don't get an answer to the latter, it does not affect my response to the former.

-Mike

Well said.  Personally, I have to be open to the idea that the sound does not actually change even if I perceive a change.   After all, our perception of sound is mitigated by more than just the sound itself.  I'm also open to the idea that the right measurement of the sound itself has not yet been devised, but from what I've gleaned from those in the know about electronics and physics, that's less likely.

BTW, If I were closer to NJ/PA I think it would be cool to hear the PC effect on a class D amp.