Digital Cable Lengths for BDP-1 to DAC - A Comparison

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srb

Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #40 on: 1 Mar 2017, 03:27 pm »
Didn't they also use attenuators in place of extra length?  I can't remember the values, maybe someone can help?

John Kenny (boutique DAC builder) wrote a very short article on attenuators and hinted that 6dB, 10dB or 15dB would probably be most applicable.  How to know which one?  I suppose using an oscilloscope to examine the waveform is one way.

http://www.johnkenny.biz/home-1/announcements/spdifattenuators

Steve

rajacat

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #41 on: 1 Mar 2017, 04:13 pm »
@zoom:
I'm off this thread.
[/quote
 

:thumb:

zoom25

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #42 on: 1 Mar 2017, 04:24 pm »
What measurements have you actually done to back up your claim that 18-feet of cable (in ANY system) "sounds" better than other lengths? There are others in the past (e.g. DarqueKnight, whom I respect) who have done measurements to backup their claims of change/no change in cable comparisons. Oscilloscope and spectra measurements.


I didn't do any measurements because I don't have the relevant tools for this. However, I did get people to hook up my system when I wasn't in the room to avoid sighted tests. Believe me, if I had those $50,000 Audio Precision machines, expertise, and knowledge on how to go about showing my results, I WOULD BE DOING IT! Since I cannot, on my end I try to take my time and eliminate as many biases as possible. When I'm certain about these things, then I come here and try to make sense of why something may be happening.

Until you do so, don't frame your claims as sweeping truths. The qualifiers, "imo", and "in my system only" make a huge difference to readers of this forum who are new to this and may be misled by some assertions.

Can someone beside me tell him that I've already made it explicitly clear many times that this is only relevant in my chain. I'm making no oversweeping generalization.

What you "hear" (outside of musical tastes) is irrelevant to me without measurements. And personally, I could care less that you spent a year or three doing these comparisons. It's audiophiles like you who give 'philes a bad rep because of nonsensical claims like yours, not backed by any established scientific principles.

I have no idea how blind you are or ignorant. You made no comment on the white papers I DID PROVIDE from Steve Nugent and many manufacturers that sell these digital cables and all saying the same thing about minimum cable length of 1.5 meters.

Even then I have said that is only relevant to my chain so many times. From there on, I asked about whether transformer coupling vs. DC coupling might have a difference. No attempts to answer my questions.

I'm off this thread. But not the Bryston forum.

See you around, friend.

zoom25

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #43 on: 1 Mar 2017, 04:42 pm »
Hi Zoom

Just to be clear I am not questioning the fact that you hear what you hear.  That's why I used the word 'art'.  In this context I meant that some things are not always explained by the science.

When someone calls and says they hear 'such and such' I do not dismiss it but I try to understand what could be going on that would result in the conclusions the person feels he or she is hearing.

james

Hi James,

Just wanted to emphasize some key points from my previous posts and perhaps they may offer some insight. When the 2 footer is hooked up to the HD 800, it's not a subjective call at all. There is some textbook sibilance going on. The most unique thing was that on speakers, it becomes hard to tell where the sound is coming from. Almost as if the sound is partially 'out of phase.' It's a physical avertion kind of response. I was hoping that if it feels as if the sound is out of phase, it might help indicate what kind/pattern of jitter might be occuring?

Also, can you make sense of why my DC coupled converter might be susceptible to this?

In the meantime, I'll try to record something off my iPhone and see if it comes through.

James Tanner

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #44 on: 1 Mar 2017, 04:46 pm »
Hi James,

Just wanted to emphasize some key points from my previous posts and perhaps they may offer some insight. When the 2 footer is hooked up to the HD 800, it's not a subjective call at all. There is some textbook sibilance going on. The most unique thing was that on speakers, it becomes hard to tell where the sound is coming from. Almost as if the sound is partially 'out of phase.' It's a physical avertion kind of response. I was hoping that if it feels as if the sound is out of phase, it might help indicate what kind/pattern of jitter might be occuring?

Also, can you make sense of why my DC coupled converter might be susceptible to this?

In the meantime, I'll try to record something off my iPhone and see if it comes through.

Hi Zoom

Its hard for me to say without replicating your setup but as for the DC coupled question not sure I have the technical expertise to comment on that.

james

rajacat

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #45 on: 1 Mar 2017, 05:05 pm »
@zoom:
I'm off this thread.
[/quote
 

:thumb:
I meant to congratulate CanadianMaestro for leaving the thread. :) That guy needs to chill out.


zoom25

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #46 on: 1 Mar 2017, 09:30 pm »
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« Last Edit: 4 Jul 2017, 04:11 pm by zoom25 »

zoom25

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #47 on: 1 Mar 2017, 11:26 pm »
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« Last Edit: 4 Jul 2017, 04:11 pm by zoom25 »

zoom25

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #48 on: 4 Jul 2017, 04:17 pm »
http://www.diyhifi.org/forums/viewtopic.php?f=2&t=1943&start=75#p43678

James or anyone, do you know the rise time and the reflection coefficient for the BDP-X and BDA-X?

James Tanner

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #49 on: 4 Jul 2017, 04:51 pm »
Hi James,

Just wanted to emphasize some key points from my previous posts and perhaps they may offer some insight. When the 2 footer is hooked up to the HD 800, it's not a subjective call at all. There is some textbook sibilance going on. The most unique thing was that on speakers, it becomes hard to tell where the sound is coming from. Almost as if the sound is partially 'out of phase.' It's a physical avertion kind of response. I was hoping that if it feels as if the sound is out of phase, it might help indicate what kind/pattern of jitter might be occuring?

Also, can you make sense of why my DC coupled converter might be susceptible to this?

In the meantime, I'll try to record something off my iPhone and see if it comes through.

Hi

The jitter on the BDP 2 and 3 has been measured at less than 15 picoseconds so I am not sure what would cause a cable length to affect jitter?

james

zoom25

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #50 on: 4 Jul 2017, 05:13 pm »
Hi

The jitter on the BDP 2 and 3 has been measured at less than 15 picoseconds so I am not sure what would cause a cable length to affect jitter?

james

Hello James,

I'm still not sure with respect to your 15 ps comment (honestly). The last time you mentioned about the outputs being transformer coupled. I did some reading on this as well since and about AES recommendations. I tried to find about my current DAC (Dangerous Music Source) as well and it was Direct Coupled. Chris Muth was behind the design for this and the rest of the gear. He does this for all the mastering gear as well and the new Convert-2.

"No transformers that color your sound or filter caps
that smear stereo. Instead, DC coupling with a custom
instrumentation grade power supply for simple, electronic
elegance. Bandwidth from DC to light."


I tried to find out about direct coupling and if that had any impact on the digital side, and couldn't find any.

This is what Steve Nugent had written on the first page:

"The optimum cable length will depend on the risetime of the signal.  The faster the risetime, the shorter you can make the cable.  Very short cables such as 0.5m are to be avoided because the reflection from the destination makes its way back to the source just as the destination is sampling the transitioning edge.  This creates jitter.  Therefore, make it as short as possible, given your risetime, but long enough to avoid the first reflection (there are attenuated second and third reflections)."


The link to the forum I posted above talks about it in more detail and the 3 scenarios. There was also discussion on the kind of jitter in some of the previous pages.

It very well may be just my DAC, which I've accepted from the start.

I did more tests with AES (Grimm TPR 2 feet, TPR 4 feet, Mogami 3173 10 feet, 3173 18 feet). I disabled all the other digital outputs as well. Database and everything disabled. Only WAVs. To keep things as tightly controlled as possible with the lowest system activity. I used Jitterbugs and Flash drives as well.

There is a sense of ease and improvement in locating the soundstage with the longer cable. Again, I was using the 4 feet for past few months and it was livable and better than 2 feet.

If I had the BDA-2 or BDA-3, I'd be doing with that as well to confirm.

Out of curiosity James, what length of cables do you use for AES? Also, do you happen to have a long AES cable (around 15-18 feet)? I would love to get your impressions if possible with the longer cable on a day you are free. BDP-X to BDA-X.

It's not a serious issue anymore for me, with having made other improvements, but I'm still curious and puzzled about this topic. Cheers.

CanadianMaestro

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #51 on: 4 Jul 2017, 06:17 pm »
Electrons move, in a 12-AWG cable, at the speed of 285,102,627 meters per second.

I doubt if even a 10-m interconnect cable would introduce enough time lag in the audio signal to be audibly detected by a human.

cheers


Speedskater

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #52 on: 4 Jul 2017, 07:13 pm »
If digital SPDIF or AES/EBU cables shorter than 40 feet long, there is something very wrong with the interconnect system.
That's not to say it hasn't happened in the past with some rather expensive equipment.

CanadianMaestro

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #53 on: 4 Jul 2017, 08:20 pm »
If digital SPDIF or AES/EBU cables shorter than 40 feet long, there is something very wrong with the interconnect system.
That's not to say it hasn't happened in the past with some rather expensive equipment.

 :lol: :lol: :lol: :lol:
best joke yet here....

Speedskater

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #54 on: 4 Jul 2017, 08:29 pm »
If short length, known good digital cables sounded different from one another, I would quietly sell the attached components on e-bay.

zoom25

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #55 on: 4 Jul 2017, 09:34 pm »
If digital SPDIF or AES/EBU cables shorter than 40 feet long, there is something very wrong with the interconnect system.
That's not to say it hasn't happened in the past with some rather expensive equipment.

Hello Speedspkater, do you mean:

1) If 'this' is happening in a system with AES cables that are less than 40 feet, then there is something wrong with the system?

or

2) Something wrong with the cable itself (as hinted by your later post)?

BTW what AES cables do you recommend, and why the 40 feet point as a reference. I've heard multiple times about the 1.5 meter rule.

Thanks.

CanadianMaestro

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #56 on: 4 Jul 2017, 11:24 pm »
I think what speedskater meant in his second post was,

if short digital cables that are well-built sound different in a system, it's because of faulty gear (not the cables) that should then be considered for sale.

Makes sense -- to me, at least.  :green:  Based on my own experiences with BDP + BDA, I hear no diffs in musicality or transparency whatsoever, between short vs longer BNC/AES cables, or between diff brands of cables, cheap (Canare) or expensive.

But keep on listenin'.....

Speedskater

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #57 on: 4 Jul 2017, 11:33 pm »
It could be the output stage, the cable or the input stage, hard to tell. But it's easy to substitute a cable, not so easy with the two components.
If more than one cable has problems, well then it's the components.

Way about 40 feet? Well SPDIF and AES/EBU are robust systems and just about any short cable should work. At about 40 feet (plus or minus) the 75 Ohm/110 Ohm Radio Frequency Characteristic  Impedance comes into play as does overall cable quality.

The 1.5 meter thing is just another audiophile mis-understanding.
* * * * * * * * * * * *
I see that Canadian Maestro beat me to it.

CanadianMaestro

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #58 on: 4 Jul 2017, 11:54 pm »

The 1.5 meter thing is just another audiophile mis-understanding.

more like mythology   8)

zoom25

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Re: Digital Cable Lengths for BDP-1 to DAC - A Comparison
« Reply #59 on: 5 Jul 2017, 02:50 am »
Thanks guys.