Yes, my experiments and findings (and predictions) have been years in the making, a lifetime even.
The subjective results of this testing are clearly unequivocal, the deep causes of the observed effects however at this time are not clearly understood.
I have recently run a bunch AB loopback recordings and reliably extracted valid difference signals.
When I am ready I can post the facts (wav files) to Dropbox and we can all examine and analyse and form conclusions and theories.
Ed has tested cables and documented differences according to cable type, cable connectors and cable direction.
It seems that Ed's findings are solid and beyond argument including 'the secretary from the office' comment (I have the same observations re perceived loudness/HF re cable direction as you Ed)
It seems that Ed has covered all bases including temperature, contact treatment, screened enclosure etc etc, so any discussions should be about the physics reasons why, including positive discussion of possible experimental error.
The tactic oft used here by those who do not have personal experience of the observations and additionally believe that the theory that they have been 'taught' explains all there is to know is to 'shoot the messenger'.
History is full of cases of pioneers being ridiculed until proven correct.....the 'village mentality' circular argument mode is not productive for those of us attempting to clarify and define some 'unknowns' like cable direction and other 'mysterious' audio effects that are observed by human senses, as opposed to machine measurements.
DPH, is this really necessary ?....."John Curl's juvenile trolling".
It's not productive, it actually demeans you, and you are better than that.
Dan.
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I did, I have experimented with innumerable systems, individual gear and cables with same subjective results.
When I provide measurements I will disclose all conditions including equipment and cables.
In the meantime a laptop and a lousy vintage Tascam US-122 usb soundcard is good enough to reveal differences.
Dan.
You still haven't disclosed which model and brand of individual gear and cables that have "Bad sound reproduction/amplification" thus needing you to tweak.
On the contrary, I have tweaked touring full stadium systems and these systems respond big time.
I ran full experiment with digital console/ethernet snake med sized PA last Sat night (outdoor beer garden) and we achieved the best sound to date.....the SE was stoked to hear his system the best he has ever heard it, the band ditto, the crowd/staff loved it.
Yup, outside and inside.
Dan.
About 15 years ago I found myself being asked to provide my consultation services to some of the highest level physics types at universities and national labs around the planet.... Not "growing up surrounded by" as you state, but giving them advice. It was so very weird...my first time doing that. That said, I'm kinda immune to "name" dropping...
SEM's are so old hat, they've been doing stems, leafs, cryogens stems, nano X-ray beams, in situ stuff... It is almost impossible for me to even pronounce the stuff of the lecture notices..never mind understand all the words..
And yah, some of my acquaintances have passed as well.
Hope all is well, and that on occasion you leave work by the door and not the mail slot.
Jn
Ps. Now I spend time trying to avoid travel. Japan, Brazil, Geneva, Denmark, Beijing...not too excited to travel now. Skype, pdf's, excel, power points... Let the younguns do that..I'll spend time at home attempting to not compromise my fingers cutting a 7mm diameter gear on a 7 by 16 mini lathe.
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I typed a sentence into Google and found this apparently uncredited copy - I presume the text is an OCR of a scan, as a few words have embedded spaces.
Distortion Meter – An Audio Interconnect Tester?
Here are what I see as pertinent quotes:
So the above is what's quoted, but after reading on, the statement seems to have been taken out of context and is misleading:
This tells me that it's the mechanical CONNECTIONS that cause directionality, not the cables themselves.
This also suggests the thing I learned working as a repair tech of a computer store in the Apple ][ era: When something doesn't work, about the first thing you do is turn off power and reseat everything - all the chips in sockets and all the cable and board connectors. Mechanical (as in pressed together - non-soldered, non-brazed, non-welded) connections generally don't have good long-term reliability.
So his article certainly jibes with my experience. Cleaning connectors, both the contact areas themselves and the insulating area between them, can indeed have a substantial, positive effect on the proper operation of any electronic device.
It's easy enough to imagine a "directional" connection, with the various materials that connector contacts can be made of. The history of electronics recalls devices such as copper oxide rectifiers, so it wouldn't be surprising for a mechanical connection, especially with contaminants, to be far less than perfect, and even have some diode action (one current polarity conducting better than the other).
Now I'm recalling someone I heard of who had read the old "POOGE" articles in Audio Amateur, who preferred to solder speaker cables inside the amplifier case rather than use the connectors on the back. At the time I thought that was going to the extreme, but maybe not.
The sound of every piece of audio gear I have heard so far can be changed, and to my ear and that of others pleasantly improved.
I understand that this concept is way out of your experience/comfort zone and you are not alone, however there are others who have experienced the effects I speak of and are fully comfortable with the results.
In fact you hear the conduction noise behaviours I speak of every time you listen to reproduced audio, just that these noise behaviours are chaotic.....when the system noise is set to a stationary order it subjectively effectively 'disappears' and this is part of what makes exceptional audio as opposed to the run of the mill mass produced 'hi-fi' that most of the world has to suffer.
When I post test results and achieve explanation of course the reaction will be 'it's obvious' or the like, I look forward to that day.
Dan.
Cable directivity not wire was shown and discussed! The test was designed to measure different solders. No significant difference was found. It was a surprise that cables showed directional effects. Took a while and many repeats before I hand confidence in the results.
Other bits seem to indicate wire itself may be directional under some conditions at a lower level.
Other bits seem to indicate wire itself may be directional under some conditions at a lower level.
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Thanks for the link.
I am very confidant that Ed made sure that test connections were treated with deoxit and optimal, hence his finding of wire/cable exhibiting directional dependent noise properties.....provided the contacts are kosher what other reasons can there be ?.
So brings the question, considering the manufacturing and processing steps that wire/cable goes through why should wire/cable NOT exhibit some kinds of directional effects.
Dan.
Ed, your article mentioned "two matching paths, pads connected by 54 jumpers". Could you kindly clarify how the paths are formed, were the jumpers arranged as a series connection?
Chris, I do want to commend you for at least reading the available literature like Cordell and K....... I have both books and I find both useful. When it comes to circuit credit, that is a tough one. I did independently invent the complementary differential input stage in 1968, when I was at Ampex. I developed it for myself, of course, but I did offer it to Ampex with several designs. They thought it too complex to bother with. However, I had to keep it secret, because somebody would take it, probably claim it, and make money from it, I was sure. A few years later, the complementary differential input stage was first put in print by Southwest Technical in an ad in The Audio Amateur. That designer developed it independently as well, but he did it several years after I had done the same thing. It was an obvious development, if you have real interest in such stuff. K..... never knew about what I have designed over the years. He must not get out much! '-) Still his book can be useful, and I recommend it.
Regarding link level unbalanced cables, shield impedance (together with impedance added by connections in terminating connectors) is IMO the most important parameter. It should be as low as possible, both inductance and resistance, to add minimum interference voltage to an audio signal.
I have a special test for this, as attached. Impulse/square generator is coupled by impedance matched cable to oscilloscope CH1 (blue trace). Then the cable under test is driven to its shield and shield voltage drop is measured by its center conductor to CH2 (red trace). CH1 shows inductive voltage drop across shield of the cable under test and CH2 shows resistance+inductance drop on the cable under test. This is quite sensitive method which is able to tell huge measurable differences between "audio" link cables. Of course, the best is good coaxial cable with the lowest shield impedance, as expected.
I have a special test for this, as attached. Impulse/square generator is coupled by impedance matched cable to oscilloscope CH1 (blue trace). Then the cable under test is driven to its shield and shield voltage drop is measured by its center conductor to CH2 (red trace). CH1 shows inductive voltage drop across shield of the cable under test and CH2 shows resistance+inductance drop on the cable under test. This is quite sensitive method which is able to tell huge measurable differences between "audio" link cables. Of course, the best is good coaxial cable with the lowest shield impedance, as expected.
Attachments
John, my interest in DIY audio is mostly vacuum valve stuff, but I spent many decades in the trenches doing trouble shooting, bench repairs, sometimes installations. I'm currently restoring Paul Klipsch's personal homebrew amplifier from 1945/46 (a surprisingly advanced design incorporating a crossover network upstream of the dual output transformers as a workaround for the limitations of contemporary parts) from the very early days even before DTN Williamson.
Your input circuit is unique to depletion mode devices and can't really be copied with bipolar transistors, although the complementary differential part can of course.
I generally buy the books you recommend and take the chance that lots may be over my head. There's always something to learn and learning is all that really matters to me at my current age.
Much thanks, as always,
Chris
Your input circuit is unique to depletion mode devices and can't really be copied with bipolar transistors, although the complementary differential part can of course.
I generally buy the books you recommend and take the chance that lots may be over my head. There's always something to learn and learning is all that really matters to me at my current age.
Much thanks, as always,
Chris
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Dan, have you ever consider on who would gain or loose from that knowledge? Directional tests for every wire/cable used in a product will add unreasonable cost leading to unacceptable product price for a very subtle gain. It makes very little sense to fund research in that direction. There are adequate engineering and quality control methods to ensure final product meets spec and such small effect (if any) becomes inconsequential. Does not mean the effect is not there at all. Remember the RAAF anecdote?
The left out bit of detail was the interesting part, don't you agree?
Nice test
Ed, surely in your test setup you could have two cables side by side. One is the ref cable so you never turn it around, and the other is the one you flip to do the cable directionality. Subtract the differences between the two. That way - to a 1 st order approximation - you remove many of the test confounders.
If you are seeing directionality, maybe it’s because of easily explainable EM theory. For example, the cable lumped impedance may not be uniform end to end, so when you flip it, the instruments see slightly different termination impedances. Just s thought.
Fast rise time spikes would help show this up readily like PMA’s test.
Maybe i misunderstood your both posts as i thought they meant something like "before MC began to enter everything was ok" (words to that effect) and obviously in that context a opinion piece from 1998 couldn´t play a role.
Btw in this said article he also mentioned a "blind listening test" of amplifiers he did set up in 1975.
In the strictest sense you can´t _prove_ it with a "DBT" either, but that´s why i was puzzled by your posts and quoted the excerpt from his article.
Obviously he truly mentioned when reporting anecdotal impressions from sighted listening but did additionally more controlled (including the "blind" condition) listening tests.
He might be wrong but can you really blame this kind of approach?
Btw, publications about the degree of a difference and the relation to audio memory time spans that still allow detection of this differences are still missing.......
Nice test
Ed, surely in your test setup you could have two cables side by side. One is the ref cable so you never turn it around, and the other is the one you flip to do the cable directionality. Subtract the differences between the two. That way - to a 1 st order approximation - you remove many of the test confounders.
If you are seeing directionality, maybe it’s because of easily explainable EM theory. For example, the cable lumped impedance may not be uniform end to end, so when you flip it, the instruments see slightly different termination impedances. Just s thought.
Fast rise time spikes would help show this up readily like PMA’s test.
Yeah. Seems hard to believe that RF guys and possibly measurements you can make with a VNA would not have come across this phenomenon already if it exists.
Perhaps it was solved long ago for their stuff. Most (even expensive boutique type) RCA connectors available for audio interconnect are technically (jewelry grade) crap. I think Pavel would agree and leans his preference towards BNC.
For probably 99.99% of applications any directionality will not matter.
Audio is different because we are sensing time/depth information and this gets altered according to cable direction.
To Ed's observation that perceived loudness and HF changes, I would add that depth/imaging information changes also.
We hear stuff down to and into the noise (neural processing) so changes in noise behaviours are important to us, but in most applications noise gets filtered out so is not of great consequence.
Ummm, which part ?........it's a joke of the 'downunder' theme.
Dan.
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