I use hospital grade 10 gauge. Works fine. $300 power cords are about as heavy duty a snake oil as can be found.
Not always, if they wrote "this overpriced pretty piece of gear sounds no better than stuff at 1/10th the cost, just like all the overpriced stuff we review so you can just stop reading our reviews now"... kinda tends to cut down on the readership. In the end it's not about being right or wrong, it's about drawing people there so your advertising revenue pours in.
I've noticed in other genres, editors will even write deliberately controversial opinion/blog type articles they don't really buy into themselves, just to get people there to state "you're wrong" and have a lengthy argument between people so the site gets lots of ad impressions loaded. Anything that gets people commenting causes a snowball effect where more and more people stick around to read, and argue against something someone else wrote. The comments become more valuable than the reviewer's article itself.
Sounds kinda like this forum: perhaps the administrators should raise their advertising rates ?
On second thoughts, maybe cable war threads are just a fiendish ploy to increase revenue. 😉
The self-fulfilling prophecy
It it is expensive, it must sound better. Also known as auto-fructation. Lots of hoodah in this business.
It it is expensive, it must sound better. Also known as auto-fructation. Lots of hoodah in this business.
He,he,he I have I friend that told me that he needed a marshall power cord for his little Park G-10 otherwise it wouldn't work!
It took some explaining to convence him that it was just a standard power cable!!!!
jer 🙂
It took some explaining to convence him that it was just a standard power cable!!!!
jer 🙂
As long as the wire gauge is large enough to supply the main transformer, then different cords don't make any difference.
How do power leads make a difference to sound?
no power cord...no sound
get power cord...you get sound
end of story
no power cord...no sound
get power cord...you get sound
end of story
I've highlited the two relevant statements.
The fact that there are two paths the return current can take is indeed the reason distortion can ensue.
At lower frequencies, the signal loop becomes that created by the IC center conductor and the line cord safety ground. While that in itself does not create distortion, it creates an unshielded input. Stray, time varying magnetic field passing through that loop will induce a voltage signal within that loop, that loop being the low level signal path.
Remaining is....where are the sources of time varying magnetic field which would be associated with a line cord? Simply, the amplifier current draw from the wall. In fact, hot and neutral are in proximity to a portion of that ground loop by design.
That line current draw is an audio power level modulated current, made of haversines rich in odd harmonics. In addition, the power supply capacitor bank loop will couple actual hf audio signals through the bridge and transformer into the line cord. This line cord current spectra and modulation has been measured by others many times.
And, it does not occur when the music is silent. So the music one listens to is actually the confounder.
Cheers, John
Good point, John. Fancy low resistance power lead could make this worse, by increasing the loop current?
John,
We just gotta disagree! 🙂 At lower frequencies it may be that most of the current takes the path of least resistance but not all of it!
I really have fun with the folks who "know" electricity takes the path of least resistance.
When I started doing large scale sound systems the consultants required a copper ground buss bar in every equipment rack. All of the equipment would have signal ground connected to this. Even the two prong plug units! This was then connected to a special earth ground system often with it's own electrode via very thick copper cable. The idea was that this would guarantee a hum free system.
Care to guess how well it worked? Extra credit (difficult question) guess how they got around to getting rid of hum?
ES
This is a confusing statement. Are you pleading the case that eventually, one day, during a full moon which occurs on the Ides of march, we will disagree? Perhaps..history does not seem to side with that, however.
It is not the different path that's the problem. It's the fact that the different path allows flux intrusion. If there were no AC currents, the different path would not make a difference. A difference that makes no difference...is no difference..
One day I aspire to learn about this "electricity" thingy...
I'm confident that it worked exactly as designed.
Either bring in a coupla megajoules worth of lead acid batteries, or:
1. Shoot the consultants
2. Hire new ones.
3. Tell them to read 250.146(D) and IEEE-1050.
But lets face facts, shall we? Fixing stuff like that can be lucrative, no?
Cheers, John
John
The disagreement is that I think what you wrote can be misread that at LF all the current flows through the power cord and only at some unspecified HF returns to the coaxial shield.
Fixing stuff like that is not lucrative, they expect that since they specified perfection the error is mine and I have to meet a S/N spec. to get paid.
Their solution was to use ethernet compatible audio transmission systems and leave the grounding concerns to others. Of course on the last system I looked at designed this way the ethernet switches cost $300K and the amplifiers $200K! Oh yeah add another $100K for the audio to digits and back! First class audio transformers at every possible remote location for all possible sources would have been $3k!
One football field system I did required a balancing transformer on the send and receive side to keep the hum out!
As to flux intrusion DF96 in this country the actual earth is used a conductor. That means if you put two wires into the ground any distance apart there will be a voltage difference between them! So the AC power safety ground would be at a different voltage than the isolated audio ground. The current flow would be from the AC power cords in each piece of gear to the ground buss via the thick copper cable to the special electrode. Thick copper and lower resistance would lower the hum level implying that the design could approach no noise. Of course without the second path there would have been no deliberate current!
Recall this pic..
Where current goes depends on the impedance. Two paths, two breakpoints.
At low frequencies, the line cord ground conductance dominates.
At high frequencies, the line cord ground inductance decouples the safety ground.
cheers, jn
Attachments
John,
Here we are disagreeing again. Dominates is the key word. At LF the current ratio is due to the resistance ratio, on this we agree. I think the original statement could have been read to say ALL of the current goes through the power cord.
It is the meaning of "At lower frequencies, the signal loop becomes that created by the IC center conductor and the line cord safety ground" that we disagree on.
C'mon this is DIY it is against the unwritten rules to actually play nice and be agreeable! 🙂 (Or do we disagree on that? !!)
ES
Long power leads have inductance. This in series with capacitors forms an oscillator.
I have a test bed for class d amps and the testbed wouldnt work with 4 inch leads, the chip just kept resetting on anything more than min volume.
Also had a customer mount mosfets off the class d board on a heatsink which of course stopped the amp working.
I have a test bed for class d amps and the testbed wouldnt work with 4 inch leads, the chip just kept resetting on anything more than min volume.
Also had a customer mount mosfets off the class d board on a heatsink which of course stopped the amp working.
I wondered if it was something like that. People seem to have this funny idea that 'ground/earth' is some sort of zero volt ideal voltage source. They are surprised when two different grounds are, well, different! A hum loop is even worse, because two different paths to the same ground are different if there is any changing magnetic field passing through the loop (i.e. almost anywhere in most countries).simon7000 said:
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