The AM Forum

...technology to significantly advance the audio performance AC wiring. It uses six close tolerance 16AWG, 99.99999% oxygen free copper conductors, each covered by an 85 micron layer of extruded silver, suspended in a dual micro mono-filament matrix and enclosed in the TSC shield. The result is a new level of power transmission efficiency coupled to superb mechanical damping and rejection of external RFI/EM interference. The separate, solid-core conductors eliminate strand interaction, hot spots and other artifacts that can degrade performance, while the extreme precision with which the TSC tubes are manufactured and arranged ensures complete consistency in performance. Let Odin feed your system and get ready for improved noise floor and resolution, increased transparency, dynamic range and freedom from grain, more believable sound staging, more natural life and musical dynamics, a breathtaking range of tonal colours. Suddenly the music will step away from the system producing it, taking on a life of its own, becoming a real performance – all because the power on which your system depends is cleaner and arriving quicker.

http://www.highendcable.co.uk/Nordost%20ODIN%20Power%20Cords.htm

"There's one born every minute"

"A fool & his money are soon parted"

"You can fool some of the people all of the time"

"4 of our special 811A's will easily put out over 500 Watts in linear service"

Ka-ching$$$$ ;)

73DG

BWAAAAAAAA HAAAAAAAAAAAAAAAA HAAAAAAAAAAAAAAAAAAHAAAAAAAAAAA!!!!

Effing priceless! 

DaveL

Never figured I'd see financing available -- or needed -- on a 1.25 meter power cord before. You never know, it might just be worth it to see/hear the "music step away from the system producing it". Can't remember ever experiencing that before.

We going to beat this to death again. Some like to heckle and poke fun at the entrepreneurs. Some of these entrepreneurs probably can laugh at the hecklers all the way to the bank. Of course, there are probably very few here that have gone to a hamfest and bought something and dragged it home, that was dumb and outrageous.

No, the "entrepreneurs" are laughing all the way to the bank.  I would market something just as outrageous and profitable myself if I were just a little more ambitious, and believe me, I have thought up a few good ones.  We are poking fun at the damned ignorant fool who falls for such crap with good money.

But OTOH, what if the bloke has a wife and kids at home who lack basic necessities because he blew the family income on such a ridiculous scam?  Dr. Brinkley would be proud.

I was wondering why we didn't hear you on the air tonight Don. Mystery solved!  ;D

I was on 3875 for a while this evening.  Were you listening on 3705? QRN level has subsided.

I noticed the white noise signal that apparently comes from Europe was very loud on 3870, also on 3865. Last year I don't remember hearing them this high up the band.  Also several dittily stations between 3850 and 3895. One was right on 3878. 160 was quiet too, but no signals heard on the band.

The signal on 3865 kHz has been there for at least several years. It's not there all the time but most of the time the past few years. Another one shows up around 3855 kHz and another around 3815 kHz had been there for many years. These are clearly emanating from Europe.

Every so often there are a few diddlies on 3878 and 3880 audible about 0530 Athens time.  There's a really loud fweeper at about 3730 (1 second tone modulated carrier), and between 3800-3850 there are a mess of diddlies and junk.

I haven't heard a trace of a carrier on 3875 lately, and CHU on 3330 has been VERY weak, only audible with the sync detector.  And no longer can I copy WWV on 5 MHz, but Radio Havana on 5025 comes in fairly well, albiet with a ton of multipath fading in the early AM here.  Condx, they are a changin'.

Was on 3.875 recently and heard the diddlies there. This was followed by the story of Tron trying to confuse it off the air.

There's also something on 3.705 that comes in some night, a low carrier with occasional weird sounds. It's constant, so not a weak AMer trying to break in.

Was on 3.785 earlier last night with 'MPY and the gang Don, then around 10:30 or so when Jeff 'NBC was on. There were a couple PW stations discussing ESSB that he was hearing and I wasn't, so I moved down to 3.705 and worked there for a while. Some annoying static crashes, but overall better than a few weeks back.

It's been a few years, but don't the lower bands get crappy as the high bands improve during the cycle? Or maybe it just seemed so since so many folks migrated up?

Todd,

We heard you break-in on 3875.  We turn it over to you a few times but you were gone.  Must of been just a drive-by.

Fred

I had some QRM locally but it was mainly the fact that I could hear you and Jeff great, as usual, and at least two other stations that were weak carriers overall. Could hear one guy talking about ESSB and nothing from the other. I'll be dropping in regularly to make sure you're behaving with your new found 813 power, though. 13 spares? That's all?? ;D

One last night was right on 3870.  I had never heard them that high before.  Hope this is not a harbinger of things to come. I believe it was coming from Europe too.  Much stronger (s/n ratio) on the NE beverage than on the dipole.

Condx change when the sunspots increase.  Less skip zone and close-in signals become more stable, but DX signals don't seem to come in quite so well, as ionospheric absorption increases. 40m becomes more useful for domestic QSOs at night. 160m DXers say DX signals weaken.  All told, 75m conditions should show improvement.

I think there are some on the 3900 range too. Similar sounding sigs on 160 meter but I can only hear those a few times a year.

Yep, those power cord are expensive but you could hang yourself with one! The cord would break on cheap consumer types.  

Don, 75 and 160 have been el-sucko from here all autumn except for one or two days.

I can't hear *anyone* Q5, even on the Bev, from W1, W2, W3 and W4-lands. It's like a curtain has been drawn across the Mississippi for me. Brent, Steve, Tim and the other E. Coast tall ships haven been at my noise level or worse for at least three weeks now.

Taking the opportunity to re-tube and tune receivers, even dial lights and all, will be looking fer you and others this weekend.

These 75M band conditions really stink!

Come to think of it Bill, I haven't heard you in a long time. Figured it was just a case of summer static, but it sounds like you're not hearing much from the right side of the country.

Had the receiver on earlier while working on a rig, just went back out and 75-80 seems to be in good shape with a lot of activity and a lot less noise. Been a long day here, gonna go shower off then go back out for a while.

I did a quick scan last night from 3900 down to 3700. Heard the following commercial stations.

3895: RTTY
3865: Noise-like digital
3855: Noise-like digital
3837: Digital but more pulse-like
3823: Noise-like digital
3783: RTTY
3756: Digital but more pulse-like
3746: Noise-like digital

I often hear a strong carrier along with the one on 3855.  Not sure if it is the same station. In Europe, the amateur band ends at 3800 kc/s, so these are all probably legitimate stations.

Unfortunately, this is true.

I listened some more.

There are also digi/noise stations on 3842 and 3918. DRM is on 3965 and analog AM on 3985 (many have already heard these two).

The RTTY on 3895 is actually three RTTY stations - 3892, 93 and 94 approximately.

They have obviously been using those power cables.

I like how Don hijacked his own thread.... ..


klc

OMG!

I'd  love to know how they get the power cord to clean up that pesky rectifier distortion. LOL!

I enjoy getting a laugh out of these finds Don.

Forget about the price.
Forget about the claims.
Forget about the "purity" of the metals.
Forget about that stuff.

Ok, don't forget about it, put is aside for a minute.

If you change the way the AC power cord is made - and I do not mean to just change the gauge - in a really clean low distortion hi-fi system, with a person with "normal" hearing acuity, and maybe a discerning ear (you figure out what that is), one can often hear somewhat rather startling changes in the timbre and "shape" of the stereo soundfield!

For example taking a decent DAC and changing the power cable often results in a rather confounding change in what is heard. It's not imagination or wishful thinking.

One way that "we" (friends in the hobby and myself) have experimented with this is to use coax for the wire. There are different schemes for using the braid and the center conductors. Of course we can easily see how coax might be different than the usual zip cord, and different than the spiral twist three wire standard AC power cords.

The discussion about how this may work revolves usually around RFI, radiated noise (from the internal PS of the unit) and things like that. Also there apparently is some energy reflected through the transformer from the switching transients and current pulses (from the charging caps).

I think it would be instructive to get into a lab with a good Faraday shield and hyper clean mains and see if the cause can be isolated between external RFI and internal re-radiation (which ends up on the ground side).

In any event, it seems like an awful lot of very insignificant stuff can and does cause repeatable and audible differences in very well designed and executed audio equipment to a greater and lesser degree.

I can give an analogy that might help to explain how this is possible:

Take a dead flat black velour square placed on a table. sprinkle a whole lot of salt on it. Easy to see, but hard to notice a single bit of salt. Now clean it off, put just a few bits of white salt. Easy to notice. That's what happens, you clean up the sound and little bits are easy to notice.

Some companies hawk wares that are based on this reality and to some extent prey  on those who have large amounts of discretionary income to blow, mostly for looks and prestige or so it seems - but none-the-less more often than not for some sonic change or perceived benefit.

I know this doesn't sit well with most of you reading this, but even so that's what's goin' on.

                   _-_-bear

But please explain how that 6' power cord can make any difference whatsoever, when the vast majority of the length of the power circuit path is supplied via standard, fully oxygenated, big-box store, consumer grade, unshielded copper house wiring, running from the entrance panel to the mains outlet where the "high end" power cord is plugged in.

Furthermore, the entrance panel is supplied by ordinary cu or al wire, often over-loaded, running from the nearest pole transformer to the electric meter. And the 11 kv to the pole transformer is supplied by miles of crappy, multi-spliced aluminium wire, with flaky corroded clamped connections, generating line noise all the way from the substation to the pole pig.

Don,

I empathize with what you said. You are not the first one to say that. I too say that!

The problem is that no one knows precisely what the heck is going on. No one. Or if they do, they are not saying. It's not a case of believing something into being - it is clearly audible when it works.

The best case to be made may be not in terms of what is on the power line coming in but to see the power line as a bi-directional line. In which case the power cord might be seen in a similar fashion to the function of a choke in series with a B+ line.

So, you may ask, why not put a choke there?
Indeed, why not.

The so called "Corcom" units, the RFI scrubbing input modules are frequently used, but even in that case changing the power cord seems to change what is heard in the speakers. NOT IN EVERY CASE.

Some people have suggested that the AC power cord acts like some sort of "tuning" stub...

One would think that after one uses soft recovery rectifiers, run through multiple stages of filtering that this could not possibly make any difference whatsoever? Yeah, but it does.

Fact is that people can and do hear differences in the sound when different types of regulators are used, and with various topologies of filtering. It may have something to do with what resides on the ground side, I do not know that answer.

Oddly enough many people hear and report that active series voltage regulation is inferior to shunt regulation following series regulation, and both are inferior to your basic C-L-C-L, etc... and definitely the LC or CL following any regulation is better than not... we're talking insanely small amounts of noise after that sort of regulation!!

With all of this, it helps to keep in mind that you are actually listening to the power supply - the amplification (if it is an amplifier) is only adjusting the level of the power supply rail to the load. (yes, there is common mode rejection, but that is imperfect and under dynamic conditions much more difficult to quantify).

                    _-_-bear

PS. as I have said before, if this is of any interest, or you want to consider building or modifying any audio gear, there are excellent discussions on these ideas and circuit design, engineering and theory on http://www.diyaudio.com (http://www.diyaudio.com) DiyAudio.com. Take a look! :D

How often do the people who work at the power plant bathe?

If that be the case, would not the best sound, free of crap from power lines, come from a big set of batteries, making the necessary DC without the use of inverters or connected to a charger?

Quiet, pure DC.  What every amplifier loves most... :)

But the plates of the battery hinder the patina of the sound field, reduce width and mute transients. Maybe some oxygen-free stiffening capacitors could help. Of course, the battery would need to be charged with a low distortion charger. Otherwise, some of the electrons would not be phase-aligned and any benefits of the battery would be lost.

The magnetic field of the earth also has an effect. Most tests do not account for this so most claims of improved sound are invalid.

Isn't religion supposed to be off limits to this BB?

Can you imagine how different the audiophile industry would be if it were govt regulated like other industries such as brokerage firms, banks, drugs, meats, construction and others?  FDA, OSHA, SEC, CFTC, etc.

Bubba would have a lot more company  ...  ;D

T

W7FTO -yes. Been done.

Especially with preamps.
Power amps, has been done.

Turns out however, batteries are NOT free of noise! :D

Long discussions have taken place on this topic and what to do about it.
Turns out that there are some combinations of regulator circuits that are measured with less noise...

Ah well... camels through the eye of the needle...

                  _-_-bear

Even if all of that snake oil and hogwash did actually work ::) at what point do you hit "the point of diminishing return??

I still think that the sole purpose for coming up with some of that szht is simply to relieve the audio enthusiast of a bloated wallet.

c'mon what in the hell are "audio grade" knobs going to give you for several hundred bux a piece? ? ? ?   ::)  ::)

I had a chat with someone in the "high-end" amplifier business at Dayton this year, and he chuckled as he pointed out that the customer base for his $80,000 tube-type amplifiers largely includes the likes of NBA and NFL stars.


We need to make a clear distinction between audio enthusiasts and audiophiles, as opposed to audiophools.

Hey, Bear,
               Since you are our resident expert on all things audiophool, here is one for you to ponder..................

Does the oxygen free copper wire make for better antenners? ? ? ? ? ?  ;D  ;D

Sounds like this could become an entrepeneurial opportunity to me  ;)  ;)

Slab,

Obviously not... antennas are pretty much first order devices, at least in terms of what the purpose/result is. Not much subtlety, either you hear the signal or you don't, either the other station hears you or doesn't.

Audio and hearing is a different game. Vision is a different game. Some folks obsess about the quality of a picture on a video screen, the color too.

Photographers used to be into grain and grain structure of emulsions, etc...

Race car drivers deal with getting their tires just right. The suspension tuning.

Tennis players with string type, tension and racquet brand and model...

etc.

Definitely there is a point of diminishing returns. Definitely. However, in audio as you get rid of distortions and what I'll call "confounding information" and/or manage to reconstruct the soundfield closer to what we could call a "naturally" occurring one  (the so-called original performance, or as if it was happening in the room), small things suddenly are obvious and seem to jump out. Sort of like if you cleared off Vaseline from a lens, you can see more.  

That this happens is what opens the DOOR to 'snake oil'. That this happens and is the goal or 'holy-grail' in audio becomes clear once you start down the path, so everyone wants the holy grail for themselves. Some people try to buy expensive, thinking that is the true way, others do it DIY, others try to do it with clever combination's of less expensive gear, etc...


Don, the guy at Dayton... nevermind.

                    _-_-bear

If H field radiation is getting into your equipment from a line cord, then you have crap audio cables and crap equipment.

"You eat a lot of acid, Miller, back in the hippie days?" 

Repo Man (1984)

We have an audio fool at work. He never designed anything worth a crap.
Any board he ever designed was filled with rework wires and dead bug parts

A lot of the folks who frequent this board know him, and some will probably figure out who it is.  But I don't want to open an unnecessary can of worms, so I'll let it go at that.

perhaps one would think so... but that means that some mighty bright and clever designers, including those with advanced degrees in EE don't know how to design. If you think this is the case, then there is a wide opening for you to make a ton of money simply by showing this and then publishing a paper in JAES, you will have lots of people wanting to hire you as a consultant, etc. You can retire on that.

It's easy to say things like this and to be a skeptic, especially when you do not have first hand experience in with what goes on with audio gear.

This is not saying that there is gear that is not that well designed or could be designed better...

              _-_-bear

For me the point is reached where I can't tell any difference or improvement but they want more money for 'it'. That's where it has to stop because there is no further benefit. I guess for individuals it is individually different.

Any apparent "improvement" in the sound, caused by "high-end" a.c. power cords, wooden knobs, speaker cable "break-in" and similar rubbish, is most assuredly due to the placebo effect.  That's why they run extensive "double-blind" tests on pharmaceutical products before they are released to the market. Some people, even those with serious ailments, report real improvement after taking sugar pills or saline injections.

How many impartial, objective, double-blind tests using valid scientific method have been demonstrated to show positive results with any of the above? If any such data exist, please post some links.

Remember, Dr. Brinkley had thousands of satisfied customers who had endured his Goat Gland Transplants, who reported "astounding" outcomes. Of course, other patients died from infections and/or immune system response to the foreign matter introduced into their bodies.

At least with audiophoolery, the only real damage done occurs to the wallets of the customers, who apparently have enough money for it not to matter anyway, and the vendors simply laugh all the way to the bank.

Don,

We all should know the examples you cited.

As I said earlier try to disregard things like price.

So-called "double blind tests" are highly problematic in audio. It is entirely different than with pharmaceuticals, they are not equivalent.

The biggest problem in the double blind audio tests is that it is extremely difficult to set up the test environment and then find a way to find a way to determine if what is purported to be tested for can in fact be detected (reproduced) in the first place. This is no joke.

Those things that are sold under false premises or those that may work but are sold at inflated prices do not change the underlying facts - those facts include the reality that some seeming minor things can and do make an audible change - in some systems, and in some instances. That's where the focus should be, not on charlatans or con men. No more than in amateur radio where there have been a fair share - those bad apples do not change the truths or realities.

Try to not paint the whole hobby or field with a big broad brush just because the are some bad actors, or even many bad actors.  Ok?

                  _-_-bear 

In other words, let’s just throw science out the window and take the word of a few audio enlightened individuals, most of which are hawking some product. Elmer Gantry anyone?

Getting a beer and some pretzels.....  ;D

Bear, I'd like to know what other esoteric components besides the power cord that you consider important to good sound reproduction that most of us would ignore?

Eric

He who makes marketable cable using room-temperature superconducting wires will be able to sell at $10⁶/inch AND have plenty of customers. I'm in the wrong business  >:(

i think a lot of this is beginning to make sense, especially about the power cords. so what you are saying, is the power cord is picking up RFI and all the crap that comes out of the power supplies then feeding it through the power supply?

oh, and one more question from earlier in this topic:
how exactly was he trying to confuse it off the air?

shelby

I never said anything like that. Did I?

Science should not be disregarded.
Electrical Engineering should not be disregarded.
Neither should perception, as in hearing, be disregarded.

I did say to let us put aside the issues of price and claims that may not be based in reality, and discuss what is the basis and reason that there are people out there apparently being successful while selling overpriced products based on questionable claims.

Ok?

                 _-_-bear

Eric, you can take almost any component that is used and substitute in a higher performing one and IF you do this across the board for a given piece of gear end up with an audible difference in sound UNLESS the rest of what is in your signal chain masks the change. Why would masking take place? It happens when there is sufficient distortion of one sort or another so as to make the reduction of distortion you have just achieved inaudible.

That's a simple way to explain it.

Examples include changing out carbon comps for metal films, using teflon or polypropylene caps for mylar or (worse still) electrolytic caps, etc...

These are very basic examples. Quite audible.

I've said these things and given suggestions as to how to possibly hear these  things for yourself, in the past on this forum.

For most people this doesn't mater at all. I don't agonize over any of it in my ham gear, for example. A non-issue.

It's more like a photographer making a very large size print and being very very careful to get the focus right across the print, getting the exposure and developing just right, the chemistry, all the details. Maybe discarding test prints until it is just right.

Then you guys come in and say, hey I get my disposable camera's prints from the 1 hour place and they are just fine! :D How could any of that make any difference? Hope the analogy makes sense.

Again, spend some time on http://www.diyaudio.com and look at the circuit discussions in the Solid State section, including the discussions on the use of particular resistors and transistors WRT the "sound". Take a look at two threads in particular: F5 (amplifier), and John Curl's Blowtorch. You will see posts ranging from newbies to world class (credentials beyond reproach).  The F5 is a VERY simple amp... that is why it is illuminating to see what is being said and found. These people are not delusional, and for the most part work separately and their questions and issues come up independently, in other words they are truthful and honest.

Take a look.

You may find it interesting.

  _-_- bear

PS. if you look at the speaker section you will see a huge amount of independent work being done on things like horn design, that includes FEM analysis, and tons of simulations and actual testing using the very latest technologies... really parsing the subtleties.

That is one possible explanation. GFZ is saying that this should NOT be possible if the gear is "properly" designed. He may be correct that one could build and design so that changes in the power cord make no difference.

But even if one could do this - and it is not clear to me that you can - that only eliminates ONE single source of variability in any given system.

In fact this is the goal of many in the field, to make equipment that is invariant to external factors (including cabling) and also does not  change due to internal factors, including parts type and selection, etc... this is on top of or beside the underlying issue of circuit topology and design.

                       _-_-bear

How does some kind of a special power cord keep all the crap the a.c. house wiring on the other side of the wall-board has already picked up, from getting into the audio equipment? Remember, the power cord is only the last six feet. The noise and hash that comes out of the power supply would feed into the equipment circuitry via the + and − leads; the power cord attached to the opposite end of the power supply wouldn't have anything to do with it. Just as in the case of radio reception, the best transmission line in the world, precisely balanced and carefully wired to eliminate all common-mode current, still won't help with a signal already obliterated by line noise or touch-lamp and plasma TV garbage.

Instead of purchasing a $1000 power cord and "hospital grade" mains outlet, invest in an isolation transformer with built-in Faraday shield between primary and secondary to eliminate noise and RFI. Place shielding round the power cord if you think it is necessary, rather than throwing away money for special oxygen-free broken-in copper conductors.  For best results, go one step further and use a Faraday-shielded isolation transformer that has a precise mid-tap on the secondary winding.  Ground the mid-tap and run the equipment off an a.c. source balanced in the same manner as a balanced 500/600 audio line. Make sure the amplifier and other equipment has adequately by-passed and filtered a.c. power leads coming into the chassis, using proper grounding techniques to keep the crap out of interior of the chassis and to avoid "pin 1" faults. The chassis base should be fully enclosed with an rf-tight bottom plate.  IOW, use standard, long-established well-known quality construction practices and engineering techniques, and spend your money on top-end professional grade components, instead of throwing it away on phoolishness.

A good, Faraday-shielded isolation transformer with mid-tapped 115-volt secondary would likely cost substantially less than one of those "cable breaker-inners" you see advertised on the internet.

Regardless, the quality of the sound you hear out of a system can be no better than the program source - vinyl, CD, MiniDisc, FM radio (including HD), internet streaming, etc., unless you do all your own home recording.  I doubt that the studios that produced the recordings concerned themselves with special high end, oxygen-free, broken-in power cords and their ilk, or anything else beyond standard top-of-the line hardware that carries no claims of "magic". Recording studio engineers probably get as much of a chuckle out of reading audiophoolery stuff and viewing those web sites as the rest of us do.

You immediately discount double-blind tests because they don't tell the story you wish to tell. That's throwing out science my friend and to say otherwise is fallacious.

But only if it was wound with oxygen-free magic copper. Otherwise it would defile the signal even further.

This phoolery is a vicious wheel that only sucks you in further, ever in search of the holy grail of sound. It is never attainable since new "problems" will be dreamed up. So the money continues  to flow to those making up new problems. It's really quite a clever scam.

assuming that the power going in was clean as could be, and the the piece of equipment was the crap maker, then i could see how it MIGHT be possible for the cord going in to pick up some of the crap from the device and feed it back into the power supply. that power supply was designed to filter 60 hz ac, not whatever RFI that it's own self may be making. so wouldn't that basically just pass on through and be riding along on the DC that should be coming out of the supply. and i wouldn't go out and spend more than $20 on a power cord, if i wanted to have a shielded power cable i'd simply take two pieces of some small coax, like RG-174, and use the center conductor of one for the hot and the other cable's center conductor for the neutral, then tie the braids together and use that as the ground. and shielding everything isn't necessarily gonna take care of RFI if the way the insides of the amp are just slapped together with no thought to the layout at all. i have an old zenith tube am/fm radio that i can set right next to my rigs and be running 200 watts out and no interference to the radio at all. there's no shielding at all: plastic case, and the chassis is open underneath. i had another radio, i forget whether it was solid state or tube, but i know it was not very well built compared to the zenith, and that thing picked up RFI no matter where it was.

Reasonable question. IF this is the mechanism, of course. Some of these "better" power cords are somewhat capacitive and may be able to shunt noise to ground. That would be HF noise in the main... another "theory' that has been floated is that the power cord acts like a tuning stub sitting on the unit... I am not sure I subscribe to that.


Don, this is done all the time. :D

People go one step farther with units that in essence "remanufacture" the AC after filtering, converting to DC and back to AC.


I am sure you will be surprised to find that this too is commonly done. :D


Of course. As I said disregard the expense of "voodoo" products and let's talk about what is behind the fact that people can sell them - there is a reason, even if the products you call "phoolery" are bogus. Ignore the bogus ones.


Well, the price depends... but the break-in boxes are not for AC power cords. So that part is not relevant.


Depends on the "studio" Don.
You should read up, before speculating.
In point of fact you are more wrong than right about this.

Fwiw, there is one company that supplies downloads of high bit depth, high sample rate recordings now...

 
Don, don't speculate about what others may or may not think. Ok?

Now, after doing all the things you suggested above, what would you do or say if YOU were listening and someone came in and changed ONLY the AC power cords and YOU heard the sound change? Of course you can claim that you wouldn't hear it. But what if you did? Then what?

                           _-_-bear

No I do not.

I have read quite of few of them, the original papers, and I question their premises, their conclusions and their rigor.

You are free to think that just because a test was made that it is valid. These "tests" claim validity base upon a statistical finding. All well and good, but again there is NO  BASIS WHATSOEVER shown that the tests are capable of detecting or discerning the thing that is alleged to be tested for. Many of these tests have results that can not be GENERALIZED, because they are and were valid for the tests and test conditions under which they were held, only. Few if any have been verified independently by other researchers. Some have, but not any that have looked into the sorts of issues that are being broadly painted as "phoolery".

Some DBT in audio clearly have been valid - like the ones that helped to create the MP3 codec. However, that is designed to fool the ear, not find the limits of audible subtleties.

If it was as simple as you say, then there would only be the need for ONE amplifier, since it is easy to get below 0.001% distortion using some basic circuit design techiniques, right? One preamp too. Ignoring "features" for the moment.

Is everyone who buys this equipment STUIPID and GULLIBLE?
Why do EEs who design opamps and power amps keep making different designs, attempting to improve slightly upon a previous one? Are they all STUPID and GULLIBLE too? Aren't the opamps that exist today good enough? Why build new ones with measured distortion figures that are fractions of 0.001% as AD and LT have done?? Are they also STUPID and GULLIBLE? I mean, really, it can't be heard, right??

Painting everyone and everything in the world of audio as "phoolery" is as inane as AM'ers calling everyone who operates SSB as "slopbucketeer", and the SSB operators calling AM'er similar epithets. Why?, because it paints ALL the people who are engaged in the hobby as STUPID and/or GULLIBLE or worse.

Time to stop this.

                      _-_-bear

I would rig up a jig where I could instantly switch between power cord A and power cord B. Then I would meter the power supply voltage, ripple and noise content, the DC output voltage and noise measurements from the supply.  Maybe monitor the power supply output with a scope. If anything changed, I would zero in on the power cord to see what was different about the two. I also would monitor the audio output with a scope to see what changes in waveform occurred. If something about a power cord affects the audio output from the amplifier, then something drastic is occurring at the a.c. input of the amplifier - probably excessive voltage drop -  not hard to find with simple a.c. instruments.  If no difference was  found, and the scope pattern at the output of the amplifier was unchanged, I would admit to suffering from a placebo effect. Maybe bring someone else in to listen to the A-B comparison without telling them what was  being changed to see if they heard the same thing.

If the other person also heard the  difference but none of the instruments indicated any difference in any of the waveforms or other parameters, I would then start believing in ghosts, witches and other paranormals, purchase a set of tarot cards and maybe start to keep a lookout for UFOs with Elvis on board.

"  UFOs with Elvis on board.  "

Elvis is not on board.. I'm suprised that you do not know that Elvis uses mind controll to operate the UFOs.


klc

Don, you have put ur finger on the problem rather nicely.

One can often see "differences" in waveforms, but correlating differences observed on test instruments to the perceived sound is something that has yet to be done by anyone.

Scopes are insufficient, although useful, for this sort of comparison. It's more revealing for example to look at the spectra of distortion down near the noise floor... like within 20dB of the noise floor... so an FFT usually will show more than a scope waveform. Realtime spectrum analyzers are more like it... but still may only give glimpses of what one needs to be looking at. Why look at such low level signals? They seem to be audible to the extent that it has been shown that the spectra of distortion in otherwise low distortion amplifiers correlates to the perceived sound quality - NOT the absolute value of distortion!

In fact there has been extensive discussion on the sonic effects of things like switches and relay contacts. It's not voodoo.

But as I said, for most people in most situations, it makes no difference at all. Like if you listen to a Bose Waveradio or a mid-fi stereo, or a typical home theater setup, it's all moot.

                  _-_-bear

"A Spaniard in the works"...

Suppose you have a 1kW AM transmitter.  It is operating perfectly on single phase power.

Rebuild the power supply to use wye or closed delta three phase, with full wave rectification.

Your ripple freq goes up, the duty cycle of the filter parts changes, but does the RF it makes change?

73DG

The question of the RF changing is rather irrelevant. It may well change. But it doesn't matter. A red herring.

            _-_-bear

Only if you use oxygen free cable in the primary circuit! That AM sound has more clarity and a cretin brilliance you just don’t get with regular copper, and it's just shrill with aluminum! Back in the eighties I was doing contract work for a little hell hole of a class A FM station in Delaware and some hack came around to all the stations in the market selling base band peak limiters, a hideous little box that pumped the base band and diode limited it so you can make the station louder. I was working there late on Sunday night and went to install the new limiter but found out I was short a BNC to BNC cable, so I installed the box in the audio rack and plugged it in right under the optomod and went home.  The next time I was there  three or four days later the general manager and the PD told me that the new limiter allowed them to be heard more clearly and in places the station was not usually received and that $300 box was the best investment ever! Funny thing was other then the power cord it was not connected to anything, perhaps its beneficial effects were coupled into the audio chain by the power cord?

I could believe that the power cord could impact the audio reproduction IF the original power cord was woefully inadequate to supply sufficient current resulting in reduced voltage regulation on the DC side of the supply.  This will NOT be the case with any standard power cord included as original equipment.

The gear is being fed filtered DC by the power supply and this is going to swamp the impact of any magic fairy dust sprinkled on the power cord. 

There will always be a market for gas line magnets and other such nonsense.  Sometimes I think instead of doing some fairly difficult and involved consulting work I should put my marketing degrees to use developing and selling some high end magic product.  Unfortunately this nagging sense of ethics gets in my way.

There are advantages to being hearing impaired.......however, I can still enjoy the music

Gee, tough crowd. You folks - not all of you - but a whole lot of you are awfully stubborn.

Let me ask what's the difference between a "fiddle" and a Stradivarius?

How come no one has exactly been able to match the original after all this time and tons of research? Don't all violins sound the same?

Just to nail this down, it's not a case of "placebo effect".
And to say it AGAIN, let's put aside the BS marketing and the price charged and just deal with the basic issue?

No one has to agree with me, but it's still not proper to insist that everything in the world of audio that is not simple engineering is going to be nonsense and "phoolery". It's just not.

I'll bet that no one who has posted about how this just can't be real has bothered to take a serious look at the things posted in the link I provided a few posts back, right? Why confuse me with the facts, my mind is made up, eh? Tsk, tsk.

                        _-_-bear



PS. I must be really making friends now! :D

I opened the link, but nothing in the list of topics suggests anything about power cords or their effects on the audio.  I didn't bother with the tedium of opening each thread and sorting through all the responses hoping to find some incidental mention of the subject.

Still, I am waiting to hear some attempt to explain what is special about the 6' power cord that makes it any different from the tens of feet of Romex running between the entrance panel and the mains outlet, and how the power cord can magically nullify all the deleterious effects of the cheap, consumer-grade copper conductors in the Romex, deleterious effects that would be no different from the deleterious effect of an ordinary $6.00 power cord made out of zip cord and a cheap male outlet plug.


Not stubborn, just flying by our own years of hands-on experience with radio, audio and electronics, plus what we have managed to glean from the electrical/electronics/radio/audio engineering books and IRE/IEEE Proceedings we have accumulated over the decades in our libraries.


The handle attached to the carrying case may have an "astounding" effect on the "tessitura" of the violin contained therein. Let us sell you one of our $1,000 carrying-case handles to replace the one on yours, and you will be amazed at the difference it makes in the sound of the violin the next time you take it out of the case and play it. We can't explain why the handle on a violin case would affect the sound of the violin inside; that's just a fact we observe.

See our latest catalogue for our "high-end" sheet music paper.  Only $10 per sheet and we give you a discount if you purchase a 500-sheet ream. Guaranteed to add warmth to your musical talent when you have your sheet music transferred to our acid-free paper stock. [/quote]

The UFO's are real, but they are not "objects".

http://en.wikipedia.org/wiki/Harley_Rutledge

I have two copies of his book. If you would like to read it, Ill send one to you.

Don, did you use the search function?
Did you read anything else?
My point is that there is all sorts of seemingly minor things that effect sound, and they are mentioned in various threads.
Saying I looked at the topics that are current and didn't see it is akin to coming on here and saying that what I was looking to find out about wasn't immediately apparent.

That should be pretty self evident?

In fact why don't you register, post the topic and field the responses? People are nice enough, and the board is moderated, things stay as much or more on topic as they do here. Post and ask!

--------------------

The handle on the violin case has no direct connection to the violin, how it plays or how it sounds. The power cord at least is connected to the unit.

What about a violin bow? Why do professional violinists pay THOUSANDS of dollars for a bow?  It's just horsehair and wood! Phools??

Again, if subtlety is irrelevant than so be it.

Now, speaking in general terms about audio reproduction... the quality of source material has substantially improved in the last 10 years with the advent of 24/192 AD/DA being available all over the place. Also the quality of drivers has improved with the advent of better measurement gear and FEM simulations. So, it is far easier for far more people to gain access to source and playback of higher quality than was available commonly, even in the best studios only a few years ago.

Just like you now may be watching 1080p flat screen TVs, you can now see far more detail than you could with ur NTSC crt based TV.  Speaking of which, how good does ur old VHS tape look now on ur new 1080p screen? That 1080p screen isn't so good. Something around a 4k is starting to be equal to what you get with a good 35mm color slide... I was working with 4k resolution still images and CRT monitors 25 years ago doing computer graphics, NTSC looked like crap to me then... can you start to see the relationships now?

Phew.

                 _-_-bear

Bear, every time we go down this road it's the same.  Nobody's going to convince you this is snake oil and you're not going to convince them it's not.

As for me, I'm fully convinced there are indeed audio subtleties.  I am just as fully convinced that "oxygen free wire", high end power cords, and specially treated wooden knobs do not contribute one way or the other to these subtleties.

What exactly is "oxygen free" wire, anyway  ???

http://en.wikipedia.org/wiki/Oxygen-free_copper

I like the tubes in my radios to be of the oxygen free type. They normally work much better.  :P

John, there is/was a company in Japan whose business was/is to develop and market copper wire made from a single copper crystal! Mono-crystalline wire!  :D


      ------------------------


I don't expect to convince anyone of anything by talking about something you have to hear... but I would like folks to limit the "shotgun" being applied to the topic and the people involved.

As far as wood knobs, they would likely have zero effect on my attenuators, since they are spring loaded step attenuators with wiping contacts... folks with regular old carbon or plastic pots might notice a change with a wood (or rubber?) knob over a metal one since the wiper on the pot is a point contact and the vibrations in the air (sound) will be sent down the shaft and wiggle the contact. Of course you could argue that the effect is inaudible, but I am sure it can be measured. And wood knobs do look nice and feel good.

But quite frankly anyone who is thinking of buying an expensive knob for sonic reasons ought to buy a better pot or install a stepped attenuator in the hole first...

No one forces anyone to patronize those sellers who make questionable products. I too put some of these products and claims along side the folks who sell "crystals" and other things to effect the cosmic ether around you... I certainly do NOT patronize them.

                  _-_-bear

 ;D ;D

Yeh, and that 1% increase in conductivity is going to have an "astounding" effect on sound quality when used in audio cables.

Conductivity is generally specified relative to the 1913 International Annealed Copper Standard of 58 MS/m. Advances in the refining process now yield OF and ETP copper that can meet or exceed 101% of this standard. (Ultra-pure copper has a conductivity of 58.65 MS/m, 102.75% IACS.) Note that OF and ETP coppers have identical conductivity requirements

When you have been throught a couple MIL-STD-704 power tests, A couple MIL-STD-461 EMI Tests and a few DO160 lightning qual tests.
Then you can appreciate how stupid most of this audio fool stuff sounds in the world of real science.

I wonder if cryogenically cooled audio circuits have been used by those with deep pockets?

I worked for Comteck Labs for a few years back in the early 70's working on cryogenically cooled parametric amplifier systems for satellite down link receivers. They were used on the commercial and military bands plus we made a few custom systems for radio telescope use at Ku band. It was always neat to watch the system noise level just fade away as it cooled down towards absolute zero, it got down to about 11-12 deg k and we ended up with noise figures of 13-14k deg with gains of about 40 db in three stages. At these temps electrical loses were nil and circuit noise was minimal.

The system used helium as a refrigerant and modified freon compressors. There was also a slow moving piston pump right up in the cold station where the amps were mounted. The cold station and amps were in thick stainless steel vacuum chamber about 15" high and 8" around.

These systems were used all over the world and were usually mounted at the feedpoint of dishes that were up to 300' in diameter.


Steve

https://www.tubeworld.com/kuhltube.htm#

Fwiw cryo treatment of tubes has been around for some time now. Bill Pearl out on the west coast was one of the first to do it.

I have never tried cryo tubes myself so have no idea if it has any discernable effect at all - or how you would know if it did since tubes are all over the map in terms of noise and microphonics and curves.

Fwiw.

And all that...


                      _-_-bear

Thermal stress. Freeze the crap out of a tube then heat it up under normal service. Go from one extreme to the other.  That's good for the elements and seals.  Can you say 'premature crap out'.

I was thinking more along the lines of actually running the amp at cyro temps, at least the low level solid state stages, to reduce noise. I wouldn't want power bill for the compressor which runs full time in cyro apps.

Steve

One can get rather low noise in the front end of things like mic preamps and phono preamps, close the noise limit of a resistor by using low noise JFETs or bipolar transistors. I think it was the LM394(?) that was a massively paralleled set of transistors on a chip, very low noise.

So, thus far it hasn't seemed to be necessary to dunk ur components full time in a cryro tank.

But I could see the cold condensate and vapors sliding off this frozen mass of pipes down the end of some millionaire's listening room... :D

I could retire on that sale... any cryo experts here?

                    _-_-bear

That would open up new possibilities if room-temperature superconductivity is ever achieved. I believe some scientists have done serious research and even reported some positive results. Imagine zero resistance in cables and transformer windings!

As far as power cords go, the way I would test them out if I suspected a power cord was degrading the operation of a piece of equipment, having eliminated all other likely possibilities, would be to use a precision a.c. voltmeter and oscilloscope.  I would measure the voltage and look at the waveform of the mains voltage at the outlet, or preferably, at the entrance panel, and then take the same measurements at the terminals of the primary winding of the power transformer, then compare the two sets of readings with the device drawing maximum current, idling, and with the power switch turned off. Ideally, there should be no difference in any of the sets of readings, but most likely there will be some voltage drop in the house wiring between the panel and outlet, especially if other appliances are connected to the same line.  There should be no difference in readings at the outlet plug and transformer terminals.  The scope would reveal any noise on the line or irregularity in the a.c. sine wave. Maybe take another set of readings at the output of the power supply, using a good DVM set to DC voltage, and use a scope to check for ripple and noise.

If I found the power cord to have any detectable effect such as voltage sag and maybe noise caused by imperfect electrical contact, I would go to larger size conductors and better male and female outlet connectors, until I resolved the cause of the difference.  In any case, there is no reason to use any larger wire size in the power cord than what is used in the house wiring up to the mains outlet (usually #12 to a 115v residential outlet). If noise pick-up appears on the scope, check to see if it is coming in off the power lines, or from some other appliance in use in your house.  If the a.c. voltage checks OK but there is noise or hum on the DC output from the power supply, that is probably due to a deficiency in the equipment itself.  Any one of those problems can be resolved with a little research and effort, with the possible exception of rubbish coming in off the a.c. power grid. In that case, the power company may or may not be willing to cooperate in eliminating the problem, and a shielded isolation transformer might be in order.

All these issues can be resolved with standard electrical troubleshooting techniques. After all, we are working with a  simple 60~ sine wave, not a complex audio waveform with all its subtleties, and there is no magic involved. Bubba the electrician (brother-in-law to Joe the Plumber) could do the job if he has any professional skills at all, using ordinary off-the-shelf tools and hardware available from the local electrical parts store. Power cords with conductors made of special copper alloys serve no purpose other than enriching unscrupulous vendors, and a good power cord will work exactly the same the first day it is plugged in as it does the 5th year of every-day use, assuming nothing is broken and the connectors haven't worn down or otherwise deteriorated.  Those 1.25m (4' 1.2")  long power cords costing £8,795.00 ($14,093.99) and their ilk are pure rip-off and anyone gullible enough to fall for such crap has to either be totally ignorant of electricity or else a damned fool (probably both), to spend that kind of money on a simple a.c. power cord to a piece of audio equipment.

A crimson fish?  It has just as much bearing on the subject outcome.  

If indeed the "power purity" is the issue, an amp, be it RF or audio, would behave the same and give listenable results.

An overbuilt audio amp running on clean & real 3-phase would sound better by design in this case.  Especially if that power came via Ag plated OFC, suspended in virgin whatever.

73DG

Hey, that could be the next phase (pun intended?) of audiophoolery : three phase power. Only problem, it is very difficult if not impossible to get the power co. to deliver 3-phase to a residence.  But if one has the money to casually afford a $14,000 power cord, I'm positive exceptions could be arranged.

To add to Don's post from 1:59 P.M., I agree with his methodology.  To make it easier to see any distortion of the AC wave, use an operational amplifier configured for differentiation which will then emphasize any divergence.  Tektronix had 1 and 7000 series scope plug-ins designed specifically for this type of task.

Now, what about that nasty little line fuse???  If it isn't oxygen (and resonance) free it might undo all of the wonders wrought by the fancy line cord :)

Well obviously you would only use an audiophile line fuse!    ;)

These ones "reduce distortion and grunge while tightening up imaging and improving the sense of placement"!

http://www.positive-feedback.com/Issue22/isoclean.htm (http://www.positive-feedback.com/Issue22/isoclean.htm)

Be careful when you get them though, "Each fuse is marked with an arrow, indicating the direction the current should flow. Take care to not reverse these, as it harms the sound."   ;D


Sam

 ::) :o ::)

That takes it... You sir, have won the prize. I thought a power cable was bad...

But what about the fuse socket? Gold-plated, directional, adjustable tension, oxygen-free, cryogenically treated and broken-in?

Hmmmm. Perhaps I'm in the wrong business...  ;D

TFO - RF and AM are rather not low noise or low distortion means of information transmission, this makes higher order differences rather meaningless and impossible to discern. It's not a reasonable comparison.

The rest of youze guyz, I hope ur having fun flogging this mule.

Don, your idea is reasonable, worth trying.
The problem is that the relationships between measured differences and audible differences shows little or no correlation. Well, there are differences that correlate but they tend to be the more gross ones... You would likely be able to see the effect of different line cords, but figuring out how what you saw was related to what you heard would be tough, impossible. And, nothing you said or did would effect whatever RF was impinging upon the AC cord.

As far as NOT using wiring that is heavier gauge than the wall wiring, that is questionable on several levels. First any voltage drop is not desirable. Secondly, bigger conductors have more self inductance, which may be a benefit.

Three phase power to an audio amp is not a bad idea, but not practical commercially. The big amp that I built, the Symphony No.1, was set up with two transformers so that it could be run off 240vac. I think it was noticeably better off the 240vac, even though the source for both the 120vac and the 240vac came off the same iso transformer. The 240vac was stiffer... but if you have not looked, the amp uses ~500,000ufd of filter caps, >4kva of power iron and large copper buss bars with stud mounted rectifiers... so how could that matter given that the amp per channel rating is ONLY ~180wrms?? How?

Fuses are non-linear devices. Good to avoid in audio if possible.

Directional fuse holders? Nonsense.

I'll say it if I wasn't clear on my viewpoint - anyone who spends more than a few hundred dollars on something like an AC line cord with an IEC on one end is foolish, to understate. In the thousands? That's like people who buy gold plated toilet hardware... or maybe a watch that costs 10 grand - does it tell time better than a $19 Timex?

                       _-_-bear

PS. for sure almost anyone on here can make their own line cord using "good" parts - but figure out the actual cost of materials, premium materials including the aesthetic finishing stuff, add it up report back and then multiply that by 5, that is your retail price. It won't be as low as you think. Thus, a few hundred today is reasonable.

Errr, speaking of flogging mules.  Don't forget to "Fall back" and set your clocks back 1 hour this weekend....


 :D

I know of two places that are residential and have 3 phase power. Both were used to power three phase motors for theater pipe organs installed in their homes. The man with a 30 HP blower had a demand meter on his. He said cost about 50 cents to start the motor and it ran all evening for a few dollars. The other case was a ten HP blower and no demand meter was required. They were in NYS and NJ respectably. Both said they had no problems getting  three phase.

Bear, I quote from your post above:
"Secondly, bigger conductors have more self inductance, which may be a benefit."

Are you sure this is true? It's been my understanding that the smaller the wire diameter the greater the inductance. Which is correct?

Walt

Good question Walt!

I have been told and read that larger conductors have more self inductance.

I think that is one of the reason that litz wire is used? (individually insulated strands)

Otoh, I am frequently wrong, and am always willing to adjust to the facts and realities.

                      _-_-bear

The self inductance of a straight wire is inversely proportional to the diameter of the wire.

L = 2l (2.303log(4l/d) – 1 + u/4 + (d/2l))

 Where L is the inductance in nH, l is the length (cm), d is the diameter of the wire (cm) and u is the permeability of the material


Same for parallel wires

L =  l/pi (ln (d/a) +Y)

Where, a is wire radius, d is distance and d ≥ 2a, and l is length of the pair, Y varies with the amount of skin effect (relative to freq)


More tricky when d is reduced (wires are in close proximty).

Here's an online calculator with the equation(s) shown:

http://www.consultrsr.com/resources/eis/induct5.htm

Steve, seems you are correct. I am not. Walt too. Not me. Nope.

However this presents a problem, as I recall a study on the effects of gauge and other geometries upon the frequency response of speaker cables. A rather extensive test. I seem to recall that they decided that 12ga. was about optimum for moderate and typical runs of speaker cable. Larger gauge wire was not as good, and I seem to think that they said that there was more HF droop (fractions of a dB mind you) because of increased self inductance. However this appears to be impossible.

Now to find the original publication. I seem to think it was by Ben Duncan, from Great Brittan...

...I find this somewhat distressing, in that it doesn't add up in my head at the moment! ::)

                         _-_-bear

Well, RF + detection + audio, no?  If better is better, why can't you hear that? :)

73DG

OK-FINE! ! ! ! !  Now, with the fuse fusing the incoming AC mains. If they are current flow "direction sensitive" which way do you point the arrow for AC ? ? ?

Or do you keep flipping the fuse back and forth at 60 flips per second? ?  ::)  ;D  ;D

this ought to get Don fired up again.......... ::)  ;D  ;D

I thought I heard the west coasters talking about having the tube shoot this weekend also.  ;D

Must have been the same source who told you that, if sufficient wire size and sufficiently low connector resistance exist to assure negligible a.c. voltage sag, the power cord attached to an amplifier will make any difference whatever in the sound that comes out of the speaker.

Litz wire (http://www.litz-wire.com/) is used to reduce skin and proximity effects in a.c. conductors, primarily used in the frequency range from the upper audio frequencies up through the AM broadcast band, but also in some applications in 60~ power distribution.

http://www.litz-wire.com/applications.html


Something I used to look forward to every year; it's the Spring one that sucks.  Now that I am retired and no longer have to get up before the crack of dawn, I don't pay it a lot of attention.  My clock stays set on GMT anyway.

According to a news report I heard on the BBC, the UK is considering keeping their clocks advanced to GMT + 1, year-round, putting them in the same standard time zone as the rest of western Europe, but they would no longer shift their clocks backwards and forwards twice a year.

Well if you really care about good audio you would obviously need to flip the fuse - I think its actually 120 times per second ... otherwise just restrict your listening to only the postive going half of each 60 Hz cycle.  ;D

Maybe it’s all a question of measurements verses the educated ear? The thing I wonder about is back when I was in flight school one of the first things they told you was to ignore your senses and always trust the instruments. When you spend lots of money, invest hours of work or whatever to improve something don’t you just assume that it has to be better? Maybe convince yourselfer of that too? Would think it’s a fairly easy thing to do to take a system into an anechoic chamber with an audio spectrum analyzer and see if there is any difference between the plots with different power cables? Or audiophile line fuses. If a difference cannot be measured with technology how can you tell if it’s a real difference or an imagined one? Here at the university we have a recording studio. Has the floating floors and all the acoustic treatment, a Yamaha DM-2000 digital board along with huge ProTools HD system, lots of expensive microphones and the like and we have Genelec Bi- Amped near field monitors that are thought of rather highly in the industry and they came with rather cheap molded plastic 18G power cords.

For Bear and Steve, when I was working with sound systems during the late 1930s I found that when using long runs of speaker cable, if the wire size was too small the self inductance of the line in series with the voice coil impedance decreased the low frequency response of the speaker significantly.

Walt

I ran into that problem just the other day, as I was working on the balanced L-network to match the transmitter coupling link to a 450-ohm load. At first, I was able to use the 900/900 pf split stator capacitor with 840 pf fixed capacitance across it, directly across the link to hit resonance and get a good match to the resistive dummy load.  But I noticed the settings of the variable capacitor kept shifting quite drastically. Then I discovered that shifting the wire leads around (#12 stranded wire) affected resonance.  The leads between link and the hastily built prototype tuner were several feet long.  So I moved the tuner to the top of the transmitter cabinet, so the wire leads were just a few inches long.  I could no longer tune the link to resonance until I added some inductance in series with it.  Next, I split the inductance into two sections using a split coil, so that half the added inductance was on each side of the link. I found the taps on the coil by trial-and-error. Once the resonant point was found, the capacitor setting was stable. In the first lash-up, the self inductance of the wire leads was serving as the L-network coil, which was replaced by a real coil in the final circuit.


Walt, was that a typo? It would seem to me that if the wire size is too small, the additional self inductance of the smaller wire in series with the voice coil would decrease the high frequency response significantly.

that may well have been an I2R issue. The increased resistance of the long cable runs may have caused a sag under load as the bass notes require a lot more current to move the speaker cones that heavily.

Just my $.02 worth..............

Walt, the series inductance would only want to roll off the highs, not the lows. Otoh, the series resistance of the long run of wire would tend to reduce the control that the amp because the output Z of the amp would look higher. But that tends to make the lows more "fat" or "wooly" or accentuate a resonance peak... wait a sec, the last two guys said that too... hehe. :D

                         _-_-bear

Huh?  A piece of wire in a glass tube is non-linear?


Much more unreasonable than your run-of-the-mill IEC power cable, available at any hamfest for a quarter or so...

damping factor

John, yes a fuse is non-linear. Especially where the current is a significant
percentage of the rating. You can find the measurements in Borwick's book, I think it was called Loudspeaker Handbook, or Headphone Handbook, not sure, but it covered things like the fuses and the workings of the Quad ESL 63 speaker design... you can skip the glass, it is still non-linear.

EDIT: here it is: http://www.amazon.com/Loudspeaker-Headphone-Handbook-Third-Borwick/dp/0240515781

Doubt if you will find many 12ga or 10 ga IEC power cables at a hamfest. I'd not be running my 100 watt class A amps on an 18ga. IEC power cord since they draw ~800watts from the wall sitting around... that is, IF I was running a set of 100watt class A amps. My amp only draws around 300watts sitting around, more on peaks... and my amp doesn't use an IEC connector, but that's another story. And it doesn't use 3AG sized line fuses either. And it has no +/- rail fuses. But that too is another story.

                      _-_-bear

Walt did you ever deal with Glenn Glenn, Holywood sound guy from way back?
He had some interesting methods

Litz wire sucks in switcher transformers. poor thermal

No Frank, I never dealt with Glenn Glenn, but I was familiar with the name .

Walt

Wow....  ::)