Power cord and IC affecting sound..

[jneutron]

Decided to start a new thread...with a quote from mtry..


Great. Keep us updated. We are here to learn as well.

I detailed to Bruno in a jpeg, the mechanism surrounding how a PC cord and IC can affect the sound of a system. Also, how to isolate it and measure it.

The equation of the error voltage presented to the amp input is:

V_error=(I_p * f_p² * K₁ * K₂) / R_loop

V_error is the error voltage which appears at the amplifier input.
I_p is the current within the power cord, entire haversine spectra.
f_p is the frequency of the haversine harmonic considered.
K₁ is the coupling factor between the PC and the ground loop formed by the amp, source, and the power cords.
K₂ is the coupling factor between the ground path of the input, and the input signal.
R_loop is the total loop resistance formed by the pc ground, IC shield, and source ground.

As is evident by inspection, the error voltage is proportional to the square of the frequency component, the current of each harmonic in the line draw, the geometry of the PC/ground loop interaction, the geometry of the amp ans source internal grounding scheme, and inverse to the ground loop resistance.

So, clearly, a relationship between all the components is there...for me, that is not an issue..The real question is...given adequate test design and care, can it be reliably measured....and, once measured, is it of sufficient magnitude to affect the sound?

As is also evident from the picture, the mechanism I detail has absolutely nothing to do with the miles and miles of wire back to the power company..That argument is entirely without merit for the schematic I depict. (oh, forgot to label the top dot in the picture...that is the ground at the wall socket.

Also note...although I draw a hard ground for the source, it could be a simple capacitive coupling..one which provides sufficient signal path for the higher frequencies of the haversine..

What I did not include in this presentation is the bleed-back of high frequency audio signal into the line...the bulk parameters of the supply is insufficient to block the coupling.

Cheers, John

[Bill L]

Ears: Just add one to each side of head and enjoy! Where'd I put that beer anyway?

[mtrycraft]

OK, I'll bite :)

Interesting analysis. It will be even more interesting to see what effect there is in changing a power cord, which parameters of the cable has the most effect, and how this effect is passed on to the output terminal to affect the audio signal. And or what effects the IC will contribute by itself or in combination with the power cord.

Going back in time, any news of your skin effect measurements?

Did you get the binaural discrimination document?

[Rockwell]

Ears: Just add one to each side of head and enjoy! Where'd I put that beer anyway?


Don't forget the brain in the middle.

[bturk667]

You listen to music with your brain? Please explain to how you do this!

[mtrycraft]

You listen to music with your brain? Please explain to how you do this!


Your brain is what makes you aware of what it is beyond a digital impulse from the ears. And, it is the one that confuses many by false perceptions too. Actually the center of operations for everything.

[Rockwell]

You listen to music with your brain? Please explain to how you do this!

Your ears are just sensors. The brain is...well the brain and processes the information. Just like your mouse is not the "brains" of a computer, it is just an entry point for information. As amazing as the brain is, it is easily fooled.

[omikey]

Your brain is what makes you aware of what it is beyond a digital impulse from the ears. And, it is the one that confuses many by false perceptions too. Actually the center of operations for everything.
and here I was thinking (brain in action ?) that it was analog coming in

[Thomas_A]

Even if a power surge filter is different from a PC, such devices may affect the output at the signal level:

http://hem.bredband.net/b113928/Surgefilter.htm

In addition, it has been tested on a separate equipment with similar results.

The filter introduce audible noise similar to "static" sound.

T

[Bill L]

Don't forget the brain in the middle.
That's what the beer is for! Relax. Kick back. etc.

[skeptic]

From the way I understand your equation, V(error) is a spurious noise signal appearing at the amplifier input as the result of coupling between the PC and the signal ground forming an unintended ground loop. This noise appears as the square of the frequencies in Ip which for the base frequency is 60*60= 3.6khz and for a first harmonic 120*120= 14.4 khz. All higher harmonics are well beyond the audible range. The difference in performance of one PC versus another is related then to the coupling factors K1 and K2. Do I understand you to mean when you say ["K2 is the coupling factor between the ground path of the input, and the input signal.
"] that the term input here is meant to be the AC power input?

Do you have any measured or calculated range of K factors for different PCs? Doesn't K1 and K2 to a large extent depend on the internal topology of wire and component layout in the amplifier and source, and the physical arrangement of the interconnect wire and the PC external to the components? So doesn't this signal appear in effect as the residual hum and noise? But then this does not come as any surprise as the admonition of keeping power cords away from signal cables has been given from time immemorial. External decoupling then could better be accomplished by an additional shield on the signal cable than on the PC because unlike the PC, heat dissipation is not a consideration. Artificial means to shield power cords is not only a violation of UL unless designed in by the manufacturer and UL listed such as in the case of MC or BX cable or THWN/THHN run in flexible metal conduit such as greenfield but it can cause cable overheating and the risk of fire or shock.

It is clear that the neutral conductor referred in NEC as "the grounded electrode" is current carrying and is grounded usually at the service entrance to the premesis. The defeating of the safety ground if one is provided in the manufacturer's power cord is not only dangerous and illegal, it is useless because under normal conditions ground current does not flow through that conductor. Similarly installing "ferrite rings" on the ground conductor is therefore equally useless as it is dangerous. Installing ferrite rings on the phase and neutral conductors may marginally increase the overall power input circuit inductance but is probably all but useless as well.

[Rockwell]

That's what the beer is for! Relax. Kick back. Get that stick outta ... nevermind.

You don't have to tell me what beer is for :D

[skeptic]

John, I also assume that R1, R2, and R3 are really Z1,Z2, and Z3. Wouldn't Z1 and Z2 be in the megaohm range normally? What about Z3 at 3.6 and 14.4 Khz? These should be fairly low. What are typical values?

[jneutron]

John, I also assume that R1, R2, and R3 are really Z1,Z2, and Z3. Wouldn't Z1 and Z2 be in the megaohm range normally? What about Z3 at 3.6 and 14.4 Khz? These should be fairly low. What are typical values?

They are indeed impedances..For this analysis, I considered only resistance. And they should be in the sub ohm ranges.

A loop of conductor will develop a voltage that is proportional to the rate of change of the flux captured by the loop, dB/dt... For a sinusoidal flux change, the rate of change of flux is the derivative of the flux...as the frequency goes up, the slew rate, ie, flux rate of change, goes up, directly proportional to the frequency. So, I used the variable K as including the time derivative, to keep the equations simple.

The inclusion of f² was not meant to represent the frequency being transferred, but a factor for the strength of the coupled signal.

Sorry for not including the simplification of terms in my explanation..

An example:

Say, a 100 mV signal input causes 100 watts at the speaker.

The supply will draw haversine current, 60 hz, 180 hz, 300 hz, 420 hz..540 hz..660 hz

Assume 2 amp line draw..60 hz component..1 amp 180 hz comp, 1/2 amp 300 hz.

Now...goto the final equation...

Assume that at 60 hz, the 2 amps will cause say, 1 millivolt of error signal..

At 180 hz, 1 amp, three times the frequency means 9 times the coupling (freq squared), so the 180 hz component will be (half the current times 9 times the coupling).

So, the 180 hz error signal will be 4.5 millivolts.

At 300 hz, 1/4 the current, but 25 times the coupling.. 6.25 millivolts.

420...49/8=6.125 millivolts..

Using these 4 harmonic terms, adding their peaks..(don't forget how a haversine is made from the frequency components), 17.75 millivolts of error signal, with a 100 millivolt signal..17% peak waveform distortion..and it's haversine derivative stuff..

Now, these numbers were pulled out of the hat, as I assumed 1 millivolt error at 60 hz..

The error at 60 could easily be just 100 microvolts...try measuring that level in an amplifier delivering 100 watts to a load....not exactly an easy task.

But, that level of coupling would add 1.7% errors, in the prev example..

Now....this has been only a haversine discussion...those nefarious loops also exist in the supply section of all amps..So what keeps the 5 Khz amp output signals from feeding into the PC loop?

And, that frequency will couple 6,800 times more than 60 hz..so even 10 mA of audio injected into the line cord will be an issue...

What would be more important IMHO, is that bleedback of that type in the audio band would not necessarily be waveform distortion per se, but phase shift...and most spectrum analyzers do not see phase shift, but measure waveform distortions.

If phase shift occurs as a result of this, then the phase shift would be amplitude dependent...and, how would we interpret that effect in a binaural soundstage??? What words would an "audiophile" use to describe that effect??? Beats me...

Mtry....skin analysis and testing: I recently moved, and all my stuff is in boxes until I can finish sheetrock, rug, and windows in the attic, then I can start to build my audio test setup in the basement. Skin effect takes a back seat to life...

And yes, I did get that document...I am amazed that even one or two people could hear 2 microsecond deviations..

Bill L: Yes, at least two people understood it..

Cheers, John

[jneutron]

that the term input here is meant to be the AC power input?

Do you have any measured or calculated range of K factors for different PCs? Doesn't K1 and K2 to a large extent depend on the internal topology of wire and component layout in the amplifier and source, and the physical arrangement of the interconnect wire and the PC external to the components? So doesn't this signal appear in effect as the residual hum and noise?

External decoupling then could better be accomplished by an additional shield on the signal cable than on the PC because unlike the PC, heat dissipation is not a consideration. Artificial means to shield power cords is not only a violation of UL unless designed in by the manufacturer and UL listed such as in the case of MC or BX cable or THWN/THHN run in flexible metal conduit such as greenfield but it can cause cable overheating and the risk of fire or shock.

It is clear that the neutral conductor referred in NEC as "the grounded electrode" is current carrying and is grounded usually at the service entrance to the premesis. The defeating of the safety ground if one is provided in the manufacturer's power cord is not only dangerous and illegal, it is useless because under normal conditions ground current does not flow through that conductor. Similarly installing "ferrite rings" on the ground conductor is therefore equally useless as it is dangerous. Installing ferrite rings on the phase and neutral conductors may marginally increase the overall power input circuit inductance but is probably all but useless as well.

Input is the audio input.

I have no measured K values.

K1 is absolutely dependent on the line cord geometry, external wire dressing, and amp internal power circuitry dressing. K2 is totally dependent on the internal ground loop configuration within the source box and the amp box...how the first loop currents are routed affects the coupling to the input circuitry.

I kept your warnings about pc mods intact, as they are worth repeating..

Shielding will be absolutely worthless, as any shield will NOT eliminate the external flux..copper is useless to remove this coupling. Mu metal will enhance the field strength around the pc..the only possibility would be to use mu metal to divert the flux around the rest of the ground loop, so none gets trapped in the loop.

The only way to reduce the PC field generation is to coaxially run hot and neutral..This will completely eliminate external fields for the pc, but is entirely against all code..running the wires in a conduit won't work because there is no cylindrical symmetry for external field cancellation.

Same with amp internals....even a star ground is worthless for this.

The signal is a result of amp draw, which varies with signal..if you could draw dc off the supply cap, the xfmr draw would produce the signal at the amp input.

Perhaps using a load to pull dc current off both caps, and monitoring the output terminals with no input signal? That would show haversine coupling constants, forcing that error term to be visible at the outputs, without the confounding issue of the input signal..

[WmAx]

And yes, I did get that document...I am amazed that even one or two people could hear 2 microsecond deviations..

Could you please provide more information. Reference, please. Is this document available for me to view?

wmax@linaeum.com

Thank you.

-Chris

[WmAx]

mtrycrafts: I would greatly appreciate a copy of the binaural time sensitivity paper, to which you have referred.

wmax@linaeum.com

Thank you.

-Chris

[mtrycraft]

mtrycrafts: I would greatly appreciate a copy of the binaural time sensitivity paper, to which you have referred.

wmax@linaeum.com

Thank you.

-Chris

Early christmas :)

[Thomas_A]

I would also like to know how to get this article :)

T

[mtrycraft]

I would also like to know how to get this article :)

T

email me :) Large file though, 2meg or more. can you handle it?

[WmAx]

Early christmas :)
Thank you.

-Chris

[Thomas_A]

Thanks Mtry,

just some comments/questions. The 0.2 µs discrimination point is not between frequencies but "between ears", thus binaural. The audible limit for phase deviation for pulses with respect to frequency and time is in the 1-2 ms region, according to the litterature. The implication of this article for cables should be minimal, except where cables cause differential deviations in phase between channels (?)

T

[jneutron]

just some comments/questions. The 0.2 µs discrimination point is not between frequencies but "between ears", thus binaural. The audible limit for phase deviation for pulses with respect to frequency and time is in the 1-2 ms region, according to the litterature. The implication of this article for cables should be minimal, except where cables cause differential deviations in phase between channels (?)
T

Nope. The implications of this article w/r to cables can be HUGE....

The first experiment shows that jitter can be used to extend the human capability for lateralization of the image. If you look at the upper curve, the one with no jitter, you see that at about 1.2 Khz, the human threshold climbs rapidly to 15 uSec, with a minimum threshold of about 5 uSec.

But when jitter is introduced, the lateralization threshold drops down to 1.5 uSec at 2 khz, extended out to 8 Khz, where the data ends for this experiment.

For a complex musical waveform, if a human is keying on a 2Khz signal, trying to identify the location in space, the rest of the audio signal may be introducing a jitter, or some other phenom similar to it, to aid in lateralization..

If the amp/cable/speaker combo is unable to maintain the 2Khz slews to less than 1.5 uSec consistancy, will it's reaction to the complex waveform into a complex load be entirely jitter free?

This article definitely raises some interesting questions. It certainly may impact what and how we test cables, looking for a smoking gun..

If you look at the Goertz waveforms, note that the timebase for the scope pics is 10uSec...and the 12Khz waveform rises in 10 uSec.

Approximately 6.6 TIMES what this paper identifies as measureable when jitter is in the stimulus...

Oh, don't forget...the human ear has a different compression/rarefaction response, measured in the half millisecond range, if memory serves me correctly..

Is it possible that the BASS signal in the music is causing jitter of the ear response to the 500 hz to 5 Khz, thereby introducing a mechanism whereby humans can distinguish 1.5 uSec temporal shifts???

Cheers, John

[Thomas_A]

Nope. The implications of this article w/r to cables can be HUGE....

The first experiment shows that jitter can be used to extend the human capability for lateralization of the image. If you look at the upper curve, the one with no jitter, you see that at about 1.2 Khz, the human threshold climbs rapidly to 15 uSec, with a minimum threshold of about 5 uSec.

But when jitter is introduced, the lateralization threshold drops down to 1.5 uSec at 2 khz, extended out to 8 Khz, where the data ends for this experiment.

For a complex musical waveform, if a human is keying on a 2Khz signal, trying to identify the location in space, the rest of the audio signal may be introducing a jitter, or some other phenom similar to it, to aid in lateralization..

If the amp/cable/speaker combo is unable to maintain the 2Khz slews to less than 1.5 uSec consistancy, will it's reaction to the complex waveform into a complex load be entirely jitter free?

This article definitely raises some interesting questions. It certainly may impact what and how we test cables, looking for a smoking gun..

If you look at the Goertz waveforms, note that the timebase for the scope pics is 10uSec...and the 12Khz waveform rises in 10 uSec.

Approximately 6.6 TIMES what this paper identifies as measureable when jitter is in the stimulus...

Oh, don't forget...the human ear has a different compression/rarefaction response, measured in the half millisecond range, if memory serves me correctly..

Is it possible that the BASS signal in the music is causing jitter of the ear response to the 500 hz to 5 Khz, thereby introducing a mechanism whereby humans can distinguish 1.5 uSec temporal shifts???

Cheers, John


I am still confused. The ability to hear phase/time difference is higher with a jittered signal. How can that translate into importance of cables if the phase/time difference is identical between right and left channel?

T

[jneutron]

I am still confused. The ability to hear phase/time difference is higher with a jittered signal. How can that translate into importance of cables if the phase/time difference is identical between right and left channel?
T

Why do you assume that the difference is identical for both channels?

Can you be sure the amplifier damping factor and slew rate capabilities are constant through all four quadrants of operation? And that the inductance/capacitance of speaker cables does not affect that? Don't forget, left and right channels do not necessarily occupy the same quadrant at the same time..

Given the possibility that large acoustic signals can jitter the sound enough to allow 1.5 uSec discrimination, we now are faced with the possibility that 1.5 uSec waveform sloppyness as a result of amp/wire/speaker combinations is audible..

That is over 600 Khz..Way the H##L over anything we can possibly hear..

So, if we can discriminate 1.5 uSec shifts, why do we limit testing to 20Khz?

As I said, the article raises some very important questions.

Cheers, John

[mtrycraft]

Given the possibility that large acoustic signals can jitter the sound enough to allow 1.5 uSec discrimination, we now are faced with the possibility that 1.5 uSec waveform sloppyness as a result of amp/wire/speaker combinations is audible..

That is over 600 Khz..Way the H##L over anything we can possibly hear..

So, if we can discriminate 1.5 uSec shifts, why do we limit testing to 20Khz?

As I said, the article raises some very important questions.

Cheers, John

But, did the article use music or test tones? Test signals are much more sensitive to detection than music is that is constantly shifting, masking changing.

[mtrycraft]

Thanks Mtry,

just some comments/questions. The 0.2 µs discrimination point is not between frequencies but "between ears", thus binaural. The audible limit for phase deviation for pulses with respect to frequency and time is in the 1-2 ms region, according to the litterature. The implication of this article for cables should be minimal, except where cables cause differential deviations in phase between channels (?)

T


Plus, I don't think they used music which is much more difficult to discriminate than test signals to detect threshold levels as is the practice in such research, use th emost sensitive signal for detection of thresholds.

There was a phase shift test published in Audio or some such early mag, that showed people couldn't detect phase shift of many cyles with music, I believe. I need to dig it up and pass it on?

[mtrycraft]

For a complex musical waveform, if a human is keying on a 2Khz signal, trying to identify the location in space, the rest of the audio signal may be introducing a jitter, or some other phenom similar to it, to aid in lateralization..
Cheers, John

But complex music makes detection vastly more difficult than test tones as it is shifting constantly, not isolated as in test tones. And, you are faced with the masking effects too. So, unless you isolate that 2kHz in a way without the others bothering your attension, It will be most difficult.
That may be the reason why no differtences under bias controlled listeing has been reported so far.

Same principle in detecting JND levels with test tones and music, or distortion.

[Thomas_A]

I still don't understand why there is a problem with the system as long as there is a symmetry between channels (same group delay).Of course there is a continuous change in the complex signal, and it is not "constant" over time between channels, but I can only see systematic error which is unequal between channels, e.g. 1 metre and 20 metre cable, which can be audible in this case. The phase shift that translates into group delay has been in several studies been around 1-2 ms in the 1-5 kHz range (with clicks, headphones).

Now as JNeutron indicates, I may confuse two different issues. I have spoken to a person working with recognition of speech and sound at the Royal Technical High-School, and he promised to give an opinon in this matter.

T

[mtrycraft]

I still don't understand why there is a problem with the system as long as there is a symmetry between channels (same group delay).Of course there is a continuous change in the complex signal, and it is not "constant" over time between channels, but I can only see systematic error which is unequal between channels, e.g. 1 metre and 20 metre cable, which can be audible in this case. The phase shift that translates into group delay has been in several studies been around 1-2 ms in the 1-5 kHz range (with clicks, headphones).

Now as JNeutron indicates, I may confuse two different issues. I have spoken to a person working with recognition of speech and sound at the Royal Technical High-School, and he promised to give an opinon in this matter.

T


It's good to know talented people:)

Even if the two channels have a small difference, the delta between the two woul dhave ot be approaching the tresholds which would mean that one would be way off from the other, maybe unlikely.
But, in recordings, you have both left and right channel information in each channel but at different levels and maybe even in phase to give you better soundstage presentation. There is no pure left and right signals only.
I'd like to see someone localize an instrument in a band, blind, to that level of accuracy consistently in recorded music.

[Sealed]

If we are talking about “source” jitter, you would be surprised at how much a bit of jitter will affect sound. Just updating the original cd clock in a Rotel RCD-855 (circa 1991) to a new clock made a big difference. The old clock was something to the effect of low-millisecond jitter, much like the threshold stated in that test. The new clock was well into the nanosecond area, and specified a noise floor -135db +/- (vs -112db for the old clock) in reality, we are talking a very short rise time difference--but it was really obvious sounding.

As to “jitter” or smear, some fancy cables (or poorly built ones) can smear a signal on a time basis. I encountered this with RS gold cables. Not all of the RS cables are like this, but I had a batch from a poor run. The soldering was from the “bigger the blob the better the job” school, and QC missed these.

Even compared to a set of properly built RS golds, there was a big difference in audible effects. The poorly done batch sounded veiled and closed in. The properly built batch were much cleaner.

MIT has cables with components in line. These components do have a time-smear effect almost like a cheap crossover. Some exotic cables use exotic designs, and various insulation and conductive materials. Van Den Hul uses carbon fibre, which is a poor conductor and equates to adding a resistor inline with a component.

Plain AWG 12 oxygen free copper, with unterminated ends (direct wire connect of a short run) has a very low resistance, and very little chance of time-based smear.

[jneutron]

But complex music makes detection vastly more difficult than test tones as it is shifting constantly, not isolated as in test tones. And, you are faced with the masking effects too. So, unless you isolate that 2kHz in a way without the others bothering your attension, It will be most difficult.
That may be the reason why no differtences under bias controlled listeing has been reported so far.

Same principle in detecting JND levels with test tones and music, or distortion.

Agreed. And it may be the added non correlating musical information that provides the jitter related stimulus which allows for lateralization at that incredibly small time regime.

The bottom line with the Nordmark study, IMO, is the fact that he came up with a modification to a test that increased the human lateralization threshold capability an order of magnitude. That, by just introducing a non random, bipolar jitter into the signal.

What is the most interesting for me is that humans (well, three at least) were capable of discerning 1.5 uSec differences for lateralization. That is over 10 times previous indicators.

Non repeatability in DBT's may simply be a matter of understanding what component of the music is causing the jitter..be it overall spl, time related fatigue, whatever. This study points the way towards perhaps coming up with a test regimen that accentuates our lateranization capability.

Boy, I gotta tell ya..if this study is accurate, my load resistor is toast...I designed it for 1 to 2 Mhz operation with minimal phase shift at 4 ohms...Now I may have to re-think it, and make it go out to 20 to 50 Mhz..

Addressing other posts, without adding quotes...

Mtry: they used test tones..In fact, it was funny reading about how they used a nova 1200 minicomputer to create the waveforms..

Mtry: Nordmark is concerned only with lateralization, not single source phase shifts.

Thomas A: 1 to 2 ms phase shift was addressed..If you look at figure 3, the upward pointing curve represents zero jitter....that is the curve you are speaking of with the other studies..and as you can see, it rapidly loses all sensitivity at about 1.2 Khz, consistent with the other studies..

If a pure mono signal is used on both channels, then I agree with you...but, stereo operation is not that case..both channels of the amp will cross quadrants at different times, and that can possibly be a source of temporal shifts in the 2 uSec range. The added complication of a dynamic load with energy storage, and a series inductance in the way add complexity to the issue.

Unfortunately, to test for that requires a load resistor capable of no phase shift at those frequencies, the data would indicate half a megahertz...I would recommend 10 to 20 times the bandwidth for accuracy..

Mtry: the delta doesn't have to be off more than 2 uSec, which is not far at all.. I agree, localization of an instrument to that level (we're actually talking about an inch or so for 2 uSec) would be a good test.. But, given anecdotal accounts, I'd be happy if someone could do so with some complex test tone and a foot or so...

Sealed: clock jitter of a millisecond???? My lord...I didn't think that was possible..the crystals I remember had nano level stuff..no wonder you heard it..even a 555 circuit is better than that..

RS? I've encountered quality issues in the past with their lines..There is no way a solder "blob" caused what you describe. Did you notice if it was a cold joint? Or was the blob there because the solderability of the connector was very poor? Other things I would look at first: were the materials from the same production lot..was the DC the same...was the cable made exactly the same, IOW, at the manu level, was the cabling done on the same machine, same DC thickness, same L-C characteristic? There's way too many things associated with the making of the wire that will impact the lumped parameters...ascribing a blob to sound signature is, shall I say, way too premature, given all the other aspect of manufacture that may not have been under adequate control (most of which you and RS will be unaware of).

Oh, as a side note: the time frame we are talking about here is WAY WAY into the skin effect realm for normal conductors..funny, ain't it?

Cheers, John

[Sealed]

Sealed: clock jitter of a millisecond???? My lord...I didn't think that was possible..the crystals I remember had nano level stuff..no wonder you heard it..even a 555 circuit is better than that..

RS? I've encountered quality issues in the past with their lines..There is no way a solder "blob" caused what you describe.
--Yes, it did...indirectly I resoldered the connections, and the sound cleaned up dramatically. The cheap solder, and bad soldering job (cold solder joint) was the culprit. I used some 4% silver content solder. Worked like a champ.

Did you notice if it was a cold joint?
--Yes, that was the bad soldering job (as above)

...ascribing a blob to sound signature is, shall I say, way too premature, given all the other aspect of manufacture that may not have been under adequate control (most of which you and RS will be unaware of).
-- This was just a bad connection basically. All kinds of nasty audible things happen from bad solder jobs.


Oh, as a side note: the time frame we are talking about here is WAY WAY into the skin effect realm for normal conductors..funny, ain't it?
--I never much subscribed to skin effect in audio, especially with short runs.

Cheers, John

The 855's original clock is *MUCH* less accurate than modern clocks. It is a great testbed for the effects of jitter before and after. The cd player itself has many good features, like blackgate caps, and a decent transport, but suffers from poor p/s placement, shielding and an innacurate clock. If a modern clock were say .005ns, this clock was something like 500ns or even slower. I forget, but I can dig up that info this week. The old clock was many times less accurate.

[jneutron]

The 855's original clock is *MUCH* less accurate than modern clocks. It is a great testbed for the effects of jitter before and after. The cd player itself has many good features, like blackgate caps, and a decent transport, but suffers from poor p/s placement, shielding and an innacurate clock. If a modern clock were say .005ns, this clock was something like 500ns or even slower. I forget, but I can dig up that info this week. The old clock was many times less accurate.

Only for upgrading clocks with millisecond jitters...that statement is at present unsupported when the origional clock has 10 nano or so jitter..you're replacing a skateboard with a hypersonic plane...

You caught me when you included comments bolded within the quote..but I eventually saw them..

<i>RS? I've encountered quality issues in the past with their lines..There is no way a solder "blob" caused what you describe. </i>
<b>--Yes, it did...indirectly I resoldered the connections, and the sound cleaned up dramatically. The cheap solder, and bad soldering job (cold solder joint) was the culprit. I used some 4% silver content solder. Worked like a champ.</b>

jn:
I fear I was not concise in my statement..I was talking about the blob as a mass of metal, and that the geometry, mass, or anything like that does not cause time smearing..So, ya got me...

<i>...ascribing a blob to sound signature is, shall I say, way too premature, given all the other aspect of manufacture that may not have been under adequate control (most of which you and RS will be unaware of).</i>
<b>-- This was just a bad connection basically. All kinds of nasty audible things happen from bad solder jobs. </b>

jn:
That was why I mentioned the solderability of the connector. You'd be surprised that some will ascribe to a solder blob some "mass", or other equally weird attribute that deflects the bad electrons, or makes them semi-superconducting...from your post, you obviously are not one of them.

<i>Oh, as a side note: the time frame we are talking about here is WAY WAY into the skin effect realm for normal conductors..funny, ain't it?</i>
<b>--I never much subscribed to skin effect in audio, especially with short runs. </b>

jn:
If the Nordmark paper has validity, it may be necessary to rethink that position..

If wire bandwidth of half a megaHertz is required to quash time errors on the order of a coupla microseconds, then the internal 15 nanohenry per foot conductor inductance takes on a new meaning, as does it's loss as skin occurs..

Cheers, John

[Thomas_A]

JNeutron: So how about speakers? Isn't the speakers even a more critical subject in this matter than cables? I may have missed something, but I will come back into this discussion after some more discussion with other people. I couldn't find J. Nordmark at the Institute where I work (Karolinska Insitute), but I will try to get in touch with some people on the department, if they have any comments to the paper.

T

[Sealed]

Only for upgrading clocks with millisecond jitters...that statement is at present unsupported when the origional clock has 10 nano or so jitter..you're replacing a skateboard with a hypersonic plane...

You caught me when you included comments bolded within the quote..but I eventually saw them..

<i>RS? I've encountered quality issues in the past with their lines..There is no way a solder "blob" caused what you describe. </i>
<b>--Yes, it did...indirectly I resoldered the connections, and the sound cleaned up dramatically. The cheap solder, and bad soldering job (cold solder joint) was the culprit. I used some 4% silver content solder. Worked like a champ.</b>

jn:
I fear I was not concise in my statement..I was talking about the blob as a mass of metal, and that the geometry, mass, or anything like that does not cause time smearing..So, ya got me...

<i>...ascribing a blob to sound signature is, shall I say, way too premature, given all the other aspect of manufacture that may not have been under adequate control (most of which you and RS will be unaware of).</i>
<b>-- This was just a bad connection basically. All kinds of nasty audible things happen from bad solder jobs. </b>

jn:
That was why I mentioned the solderability of the connector. You'd be surprised that some will ascribe to a solder blob some "mass", or other equally weird attribute that deflects the bad electrons, or makes them semi-superconducting...from your post, you obviously are not one of them.

<i>Oh, as a side note: the time frame we are talking about here is WAY WAY into the skin effect realm for normal conductors..funny, ain't it?</i>
<b>--I never much subscribed to skin effect in audio, especially with short runs. </b>

jn:
If the Nordmark paper has validity, it may be necessary to rethink that position..

If wire bandwidth of half a megaHertz is required to quash time errors on the order of a coupla microseconds, then the internal 15 nanohenry per foot conductor inductance takes on a new meaning, as does it's loss as skin occurs..

Cheers, John


That's kind of like an except from "The vagina monologes" or another soliloquy. I did not have time to type it out like that. You seem to amuse yourself by putting in your own interpretation, so I leave this thread to you.

[jneutron]

That's kind of like an except from "The vagina monologes" or another soliloquy. I did not have time to type it out like that. You seem to amuse yourself by putting in your own interpretation, so I leave this thread to you.

Actually, I just cut and pasted the stuff using control C and Control V. The typing I had to do was just where I made comments..It was more difficult trying to figure out how to make my comments visible in the whole thing..

I am however, definitely amused by your statement that I am putting in my own interpretation, as I have not, nor do I intend to do such..as I said... I felt that I had not clearly stated something..

Your input within the thread, I welcome...you're misinterpretation of intent is not..perhaps you'd be better off remaining on topic..and leaving your self serving comments checked at the door..

It is not a real stretch to think that a 1 millisecond jitter could affect sound reproduction (although I'd be more inclined to think that was a typo on the manu's part, and that it was 1 microsecond), nor that a cold solder joint could affect sound reproduction..again, not a real stretch.

The real stretch is that humans can distinguish 1.5 usec timeshifts.. Not a real stretch is how people divert as a defense mechanism..Your use of such tactics was unwarranted, for you to do so indicates you've probably mis-interpreted my statements..

Cheers, John

[jneutron]

JNeutron: So how about speakers? Isn't the speakers even a more critical subject in this matter than cables? I may have missed something, but I will come back into this discussion after some more discussion with other people. I couldn't find J. Nordmark at the Institute where I work (Karolinska Insitute), but I will try to get in touch with some people on the department, if they have any comments to the paper.
T

For overall sound stuff, yah..

In theory, the speakers both should do the same thing in response to the same signals. I've not considered the fact that a speaker may have some kind of weird time shifted stuff in any of my wirespeak, and I am in no way capable of really getting into that..Maybe some ESL guy, like Chuck, could address the finer points of speaker response stuff..But not me..

I will only deal at this point with pure resistive load stuff, without introducing the huge variance of speakers..

That would be really nice if you find some of Nordmark's peers. Since I only found out about this paper as a result of Jon Risch, who sent a different paper to me for my information, I cannot say if Nordmark's test regimen has been duplicated or refuted. And the cable vendor (if I recall correctly) that cited Nordmark may not provide citations that would go against it, or may not even be aware of papers that refuted it, if so..

Cheers, John

[Sealed]

The real stretch is that humans can distinguish 1.5 usec timeshifts.. Not a real stretch is how people divert as a defense mechanism..Your use of such tactics was unwarranted, for you to do so indicates you've probably mis-interpreted my statements..

Cheers, John

Nah, I am not being defensive, insulting, or anything more than cheeky. Press on this thread without me.

Beers...I mean...oh skip it.

Carry on...

[jneutron]

Nah, I am not being defensive, insulting, or anything more than cheeky. Press on this thread without me.

Beers...I mean...oh skip it.

Carry on...

My apologies....I obviously misunderstood your intent..I really try not to mis-interpret anyone, so perhaps I'm overly sensitive to the accusation..

..wish I could share a beer with you..I'm allergic to gluten. Boy, do I miss a cold one..destined forever to wine, sake, and martini's with Chopin..ah, the inhumanity of it all..

Cheers, John

[pctower]

My apologies....I obviously misunderstood your intent..I really try not to mis-interpret anyone, so perhaps I'm overly sensitive to the accusation..

..wish I could share a beer with you..I'm allergic to gluten. Boy, do I miss a cold one..destined forever to wine, sake, and martini's with Chopin..ah, the inhumanity of it all..

Cheers, John

Allergic to gluten? Be grateful. I'm allergic to alcohol. It stimulates an over-active elbow which results in frequent and persistent movement of the bottle to wide-open mouth.

Can you imagine Chopin with tea? Inhumanity knows no bounds!

[mtrycraft]

If we are talking about “source” jitter, you would be surprised at how much a bit of jitter will affect sound. Just updating the original cd clock in a Rotel RCD-855 (circa 1991) to a new clock made a big difference. The old clock was something to the effect of low-millisecond jitter, much like the threshold stated in that test. The new clock was well into the nanosecond area, and specified a noise floor -135db +/- (vs -112db for the old clock) in reality, we are talking a very short rise time difference--but it was really obvious sounding.

As to “jitter” or smear, some fancy cables (or poorly built ones) can smear a signal on a time basis. I encountered this with RS gold cables. Not all of the RS cables are like this, but I had a batch from a poor run. The soldering was from the “bigger the blob the better the job” school, and QC missed these.

Even compared to a set of properly built RS golds, there was a big difference in audible effects. The poorly done batch sounded veiled and closed in. The properly built batch were much cleaner.

MIT has cables with components in line. These components do have a time-smear effect almost like a cheap crossover. Some exotic cables use exotic designs, and various insulation and conductive materials. Van Den Hul uses carbon fibre, which is a poor conductor and equates to adding a resistor inline with a component.

Plain AWG 12 oxygen free copper, with unterminated ends (direct wire connect of a short run) has a very low resistance, and very little chance of time-based smear.

Of course you establisged all these testable claims through bias controlled listening? And, has been so duplicated by others? No? Sorry, just more wishfull speculations.

[jneutron]

Of course you establisged all these testable claims through bias controlled listening? And, has been so duplicated by others? No? Sorry, just more wishfull speculations.

If he had a clock with jitter in the milliseconds, I don't think anybody is going to dispute his claim that he could hear it..it's kinda like riding along the railroad tracks on a ten speed, with your head on the handlebars..

And I'm sure if he had a lousy solder joint, nobody would dispute that he heard it..

Only here:<i>Plain AWG 12 oxygen free copper, with unterminated ends (direct wire connect of a short run) has a very low resistance, and very little chance of time-based smear. </i> can I have an issue with...and only the "little chance of time based smear".

As, the human ear would only hear a r-l change, not a per channel one..

My question would be: how does one measure a time smear with the ears? What is it? What frequencies affected..you know, the standard "how would one measure it" questions.

Chopin Vodka in tea? Eeeeeewwwww...

Perhaps some tea bags with the blue cheeze filled olives? Make it quicker, I'd think..

HI Phil..

Well guys, back to the origional topic...

I've heard neither hide nor hair from Bruno..Not sure whether he just dissed me, has measured what I described and is running to the patent office, has tried and failed to find anything so has dismissed me as an unknowledgeable moron, has gone on vacation, or has been committed to an asylum for even humoring me..

I was hopin he'd try it, as the next step is to show how speaker wire geometry and L-C parameters will introduce phase shift at the amp input stage..

Not done yet, but it's startin to look like something at least..

Cheers, John

[mtrycraft]

If he had a clock with jitter in the milliseconds, I don't think anybody is going to dispute his claim that he could hear it..it's kinda like riding along the railroad tracks on a ten speed, with your head on the handlebars...

Cheers, John

If in the millisecnd range then yes. I have a difficult time accepting such a high jutter from a clock when all I hear about is in the nanosecond range.


And when you are finished, then back to the skin effect experiment? :D

[jneutron]

If in the millisecnd range then yes. I have a difficult time accepting such a high jutter from a clock when all I hear about is in the nanosecond range.
Yah, that's why I questioned the milli as a typo, I would believe micro...

And when you are finished, then back to the skin effect experiment? :D
Absolutely.

I have learned a lot since first embarking on the skin effect stuff. Ways to make the load resistor much lower in inductance (although even the one I built already is far below my measurement capabilities). I have lost the ability to measure the loads reliably anymore using any commercial inductance meter, so am working out a scheme to measure them using the HP 3225A synthesizer, and looking for the V/I phase shift. Unfortunately, it only goes to 60 Mhz, so I'm afraid I'll just have to live knowing I can't meet the expectations of high end audio...:-) And, I'm considering making a pulse welder out of some big caps, lots of mosfets, and some timing circuits, as making the previous load required soldering 39 resistors to a tube simultaneously...one shot welding with some fixturing will allow me to easily duplicate the final design.

That darn Nordmark paper...pushing my test requirements up over a Mhz...oh well..

Oh, BTW...Bruno thought it was my turn to talk, we were both waiting for e-mails..

He also has a large queue, so looks like I better get that attic finished soon..

Cheers, John

[mtrycraft]

Yah, that's why I questioned the milli as a typo, I would believe micro...

Absolutely.

I have learned a lot since first embarking on the skin effect stuff. Ways to make the load resistor much lower in inductance (although even the one I built already is far below my measurement capabilities). I have lost the ability to measure the loads reliably anymore using any commercial inductance meter, so am working out a scheme to measure them using the HP 3225A synthesizer, and looking for the V/I phase shift. Unfortunately, it only goes to 60 Mhz, so I'm afraid I'll just have to live knowing I can't meet the expectations of high end audio...:-) And, I'm considering making a pulse welder out of some big caps, lots of mosfets, and some timing circuits, as making the previous load required soldering 39 resistors to a tube simultaneously...one shot welding with some fixturing will allow me to easily duplicate the final design.

That darn Nordmark paper...pushing my test requirements up over a Mhz...oh well..

Oh, BTW...Bruno thought it was my turn to talk, we were both waiting for e-mails..

He also has a large queue, so looks like I better get that attic finished soon..

Cheers, John

Great update. I am glad one of you emailed again:) instead of waiting to the end of times :)

I will be satisfied with a low fi report, 60mHz is fine with me. You can quote me on it too :)

Don't you have some lab quality measuring gear at work? How about the Standards Org. Tell them you need help :)

[jneutron]

Great update. I am glad one of you emailed again:) instead of waiting to the end of times :)

I will be satisfied with a low fi report, 60mHz is fine with me. You can quote me on it too :)

Don't you have some lab quality measuring gear at work? How about the Standards Org.

When my audio desired mesh with lab work, I don't have any issues with using their equipment. Case in point: measuring very low inductance, as we had an app at that time needing rather good accurate measurment, and I needed to upgrade the test setup.


Tell them you need help :)

How did this discussion suddenly turn towards psychiatry??

Besides, If you met some of the researchers, scientists, and physicists here, you would understand how "Doc Brown", from back to the future, would not considered out of place..so my having a conversation with those voices inside my head are part and parcel...

Cheers, John

[Thomas_A]

Mtry,

sorry I delayed my answers to you. I am still waiting for a replies from others in this matter. I have passed the question also to the Swedish Audio-Techincal Society, but it might take a while before the question is published in the MoLT journal.

Off-topic

There is a new reference CD player (or actually a DVD player) that has passed through many "extreme" listening tests by SATS but its DVD capability is not top notch (Pioneer DVD 59AVi in the US, 868 in Europe). Another cheap DVD player, Panasonic DVD-RP82, appears to be quite free from image distortions as tested by the benchmarks made by Home Theather and High Fidelity. These benchmarks, are they discussed on Audioreview?

Benchmark (http://www.hometheaterhifi.com/cgi-bin/shootout.cgi?function=search&articles=all&type=DVD+Player&manufacturer=0&maxprice=0&deInt=0&mpeg=0)

T

[mtrycraft]

Mtry,

sorry I delayed my answers to you. I am still waiting for a replies from others in this matter. I have passed the question also to the Swedish Audio-Techincal Society, but it might take a while before the question is published in the MoLT journal.

Off-topic

There is a new reference CD player (or actually a DVD player) that has passed through many "extreme" listening tests by SATS but its DVD capability is not top notch (Pioneer DVD 59AVi in the US, 868 in Europe). Another cheap DVD player, Panasonic DVD-RP82, appears to be quite free from image distortions as tested by the benchmarks made by Home Theather and High Fidelity. These benchmarks, are they discussed on Audioreview?

Benchmark (http://www.hometheaterhifi.com/cgi-bin/shootout.cgi?function=search&articles=all&type=DVD+Player&manufacturer=0&maxprice=0&deInt=0&mpeg=0)

T


Great, no problem. You know where to email too:) I am curious what the horse has to say, coming from the horses mouth:) on that paper.
I have just been reading a link probably at HT section about that Pioneer player problem.

[mtrycraft]

How did this discussion suddenly turn towards psychiatry??

Besides, If you met some of the researchers, scientists, and physicists here, you would understand how "Doc Brown", from back to the future, would not considered out of place..so my having a conversation with those voices inside my head are part and parcel...

Cheers, John

You misunderstood me, obviously. The standards org was the head government bureau of standards that I was trying to imply :( didn't work That you need to measure very, very low inductance. Perhaps they have some such instruments?

[Thomas_A]

JNeutron,

the data described in this powerpoint presentation, is it something you've seen before? It discusses, among other things, binaural time discrimination and that a high bandwidth for accurate localization is not required.

http://world.std.com/~griesngr/intermod.ppt

T

[jneutron]

You misunderstood me, obviously.

Ummm...no.

But obviously, my humor missed the mark..I guess you have to be here to see the guys..

Don't worry, I won't give up my day job..

John

[jneutron]

JNeutron,
the data described in this powerpoint presentation, is it something you've seen before? It discusses, among other things, binaural time discrimination and that a high bandwidth for accurate localization is not required.
http://world.std.com/~griesngr/intermod.ppt
T

Hadn't seen it before. Thanks for the link.

Wish there were page numbers I could refer to...

His assumption that nyquist rate is enough to preserve zero crossings is incorrect. Unless he considers the rate as based on the 2 uSec lateralization. Which would mean a 1 Mhz sample rate..I believe he is referring to 22Khz as base freq.

There is subharmonic generation that he did not account for. Of course, nyquist theory does not allow for it anyway, even though it is there.Nyquist theory equations are based on having the entire sample available for reconstruction, whereas all consumer DAC's rely on real time current samples, or overclocking..but no consumer equipment takes the infinite length datastream, and reconstructs as nyquist theory assumes. I am not even aware of any consumer product doing a look ahead at the data stream, to take advantage of a symmetrical window for reconstruction.

They state 2 uSec is "well known"...While Nordmark has 1.5...close enough.

Nordmark improves lateralization discrimination by introducing jitter.

They used ultrasonics..

There is a relation, but neither have closed on it. This is just two data points, someday it will be learned. But, the study does not say we can hear the ultra...just the effect it has on perception of the audible stuff...that is exactly the same thing Nordmark found..

I'm surprised they have ear response as zero crossing, compression only..I recall some study showing both rarefaction and compression, with an associated response relation, rarefaction (I think they called it condensation) having half a millisecond (memory?) delay w/r to compression.
Thanks again for the link.

Cheers, John

[mtrycraft]

Ummm...no.

But obviously, my humor missed the mark..I guess you have to be here to see the guys..

Don't worry, I won't give up my day job..

John


Then yes, it did miss the mark :D

[jneutron]

Then yes, it did miss the mark :D

HoooooHoooooo...tough crowd...

Got the mosfets for the welder..18 pcs of a IRLZ34N-ND. Gonna use a wall wart for 12V..Don't have the cap bank yet.

Looking at PC vendors; PCBexpress, PCBFABExpress, PCBpro, and expresspcb, for the switch circuit for the welder. It's gonna be a variable voltage, variable current pulser. I want it to be flexible enough to weld from #14 down to about #40 wire without vaporizing it. May come in handy for future IC's, loads, and speaker wires.

I'm gonna learn the vendors, as I want to make some pc boards for amps using existing personal stock: 10 pcs 220 VA toroids and 20 LM3876T's...they're burnin a hole in my pocket..

Cheers, John