Bryston's new speaker cable

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rob80b

Re: Bryston's new speaker cable
« Reply #20 on: 16 Nov 2010, 07:05 pm »
Specs mean everything, they will be all encompassing as long as the correct ones are used.  For an end user, they can be meaningless if the interpretation information is lacking.

As I repeat often, what the end user likes is the only important thing.  My goal is to eliminate the disconnect between specs and end use preference. 

Never a problem.  Tis a nice discussion.

Cheers, John

Hi John

Curious if multi-strand or solid core cables come into the equation.

Robert

James Tanner

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Re: Bryston's new speaker cable
« Reply #21 on: 16 Nov 2010, 08:11 pm »
Hi Folks,

Spoke to the manufacturer and they say the inductance is in fact -
                             
Inductance  .2 uH (microhenrys) /ft 

They appologize for any misunderstanding and will forward me a more comprehensive explanation by the end of the week. 

james

jneutron

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Re: Bryston's new speaker cable
« Reply #22 on: 16 Nov 2010, 08:33 pm »
Hi John

Curious if multi-strand or solid core cables come into the equation.

Robert

I have made no distinction with respect to solid/stranded.

The two things that can be altered by solid/strand are inductance and resistance.

When two conductors are close to each other, proximity will play a role.  As frequency goes up, the current will re-distribute to reduce external inductance as well as internal inductance.

The total effect can be measured easily using something like an HP 4284A.  This meter will also measure the effective resistance as proximity and skinning take effect.  Last data I looked at, most cables are pretty uniform out to 100Khz. 

In theory, stranded could possibly be affected adversly if corroded, but I haven't considered it.  I prefer stranded for ease of use.  Of course, I do not have a very good system either..

Cheers, John

jneutron

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Re: Bryston's new speaker cable
« Reply #23 on: 16 Nov 2010, 08:34 pm »
Hi Folks,

Spoke to the manufacturer and they say the inductance is in fact -
                             
Inductance  .2 uH (microhenrys) /ft 

They appologize for any misunderstanding and will forward me a more comprehensive explanation by the end of the week. 

james

Today, I was the windshield.

Tomorrow, I'll probably be the bug.. :o

Cheers, John

ps..with inductance at 200 nH per foot for one pair, the capacitance for a single pair should be about 35 pf per foot. 

Since the wire is 4 conductor, I suspect all 4 conductors were used for the measurements. 

1ZIP

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Re: Bryston's new speaker cable
« Reply #24 on: 16 Nov 2010, 09:34 pm »
Just curious!

Soooo.... if the following is the new cable spec's:

Charcoal jacket; 9.5mm (.375”) diameter
Resistance .0008 ohms/ft                             
Capacitance 70pF/ft                                       
Inductance  .2 (corrected value) uH (microhenrys) /ft
9-gauge

....what are the old cable spec's?

Levi

Re: Bryston's new speaker cable
« Reply #25 on: 16 Nov 2010, 11:07 pm »
Specs looks good!

I have the old cables.  Can't wait to compare the two together. 

Thanks James.  :thumb:

1ZIP

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Re: Bryston's new speaker cable
« Reply #26 on: 16 Nov 2010, 11:21 pm »

Thanks James!

Levi:

It would be interesting to hear your feedback on the two cables.

Levi

Re: Bryston's new speaker cable
« Reply #27 on: 16 Nov 2010, 11:36 pm »
Thanks.  I will try. 

You know my 40yr old ears were not as good to subtle changes anymore.  :lol:

jdandy

Re: Bryston's new speaker cable
« Reply #28 on: 17 Nov 2010, 12:27 am »
James.......I saw your comment about the spades and bananas, "'Heavily Gold plated' Spade lugs or ‘Expandable Banana’ plugs specially made for Bryston."  Is the base metal of the spades and bananas copper or silver, or the more typical brass or bronze?

jneutron

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Re: Bryston's new speaker cable
« Reply #29 on: 17 Nov 2010, 01:44 am »
Gauge: - 9.5

Resistance - .003 Ohms

Capacitance – 97 P/F

Inductance - .4 MicroHenry

Assuming I can trust the numbers.

Sigh..

No, you cannot.  Those L/C numbers do not make sense.

I apologize.

Perhaps you should PM me.

Cheers, John


James Tanner

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Re: Bryston's new speaker cable
« Reply #30 on: 17 Nov 2010, 02:08 am »
Sigh..

No, you cannot.  Those L/C numbers do not make sense.

I apologize.

Perhaps you should PM me.

Cheers, John

Hi John,

will do.

james

James Tanner

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Re: Bryston's new speaker cable
« Reply #31 on: 17 Nov 2010, 04:52 pm »
Got some great input from John - THANKS John :D

I believe the new cable specs are correct as listed above but we are going to do some of our own measurements as well.

I guess I should say that I really did not want to get involved in a spec contest with our cables.  I just wanted to be able to offer our customers a reasonable cable at a reasonable price with good electrical characteristics.

james

1oldguy

Re: Bryston's new speaker cable
« Reply #32 on: 17 Nov 2010, 05:03 pm »
Got some great input from John - THANKS John :D

I believe the new cable specs are correct as listed above but we are going to do some of our own measurements as well.

I guess I should say that I really did not want to get involved in a spec contest with our cables.  I just wanted to be able to offer our customers a reasonable cable at a reasonable price with good electrical characteristics.

James

 :thumb: Sounds good to me.

1ZIP

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Re: Bryston's new speaker cable
« Reply #33 on: 17 Nov 2010, 05:20 pm »
Got some great input from John - THANKS John :D

I believe the new cable specs are correct as listed above but we are going to do some of our own measurements as well.

I guess I should say that I really did not want to get involved in a spec contest with our cables.  I just wanted to be able to offer our customers a reasonable cable at a reasonable price with good electrical characteristics.

james

.....and you have accomplished that and probably more! :thumb:

I have Bryston IC's in both my systems and their addition has made noticeable and positive improvements to the sound, without having to give up my first born.  I have no reason to suspect the new speaker cables will be any different.

Thanks James


jneutron

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I find these approximation "generalizations" worth discussion
« Reply #34 on: 18 Nov 2010, 02:26 pm »
Bruce, this is not about you...you posted very pleasantly..thank you.

Allow me to disagree somewhat. You're applying standard transmission line theory to audio bandwidths. There is no possible transmission line theory that would support any type of reflection on a cable at audio frequencies in any length less than many kilometers. The characteristic impedance of a transmission line is only valid at high frequencies - audio doesn't qualify.

What Bruce states is roughly what is taught in an E/M course.  However, these are strictly approximations which have been created artificially, guidelines for the engineer to use so that they do not bog down in details.  The exponential skin effect approximation is another such "rule", allowing us to quickly get a reasonable good answer without working the bessels.

The characteristic impedance of a transmission line is invariant of length.  It is precisely Z = sqr(L/C).  Note that it also is frequency independent.  In other words, the statement ""The characteristic impedance of a transmission line is only valid at high frequencies "" has no merit.

This equation also clearly defines the relationship between the current and voltage within the line such that the energy that is stored within the cable is equally distributed between magnetic field and electric field. 

If one were to attempt to perform the normal tricks one is used to at rf and microwave frequencies, such as quarter wave matching  or stub tuning, the length of the cable with respect to wavelength comes heavily into play.  For very short t-lines, movement on the smith chart is far too small to do anything useful  That is why the wavelength relationship is "assumed".  It has nothing to do with whether a t-line has characteristic impedance or reflections at any frequency or wavelength, it is all about practicality when pulling the ol' smith chart out.

So, as far as standing waves on a few meter piece of cable when we're dealing with a 10 kilometer wavelength, the cable appears as DC. No reflections possible, it won't happen.

Another error based on assumptions.  First, we are not talking about standing waves.  Standing waves require appropriate wavelengths.  Reflections are not standing waves.  Reflections are required for standing waves, but standing waves are not required for reflections.  Causality.

Reflections do occur.  If the slew rate of the impetus signal is slow in comparison to the system response, in this case the wire length, it will not be possible to see the reflections.  Overall, the entire cable voltage and current will appear to be reflection free, but that is an artifact of the prop speed, the signal speed, and our ability to resolve the effect via measurements.

Look at the settling times we speak of.  6 uSec?  How would one measure that for a 1Khz signal?  Not easily.  This concern is "approximated out" by microwave engineers, but yet humans can hear this level of change interaurally.

With regard to the L and C of a cable, it's important to consider the interface. In an audio amplifier interfacing to a low impedance load, such as a speaker, other than the simple DCR, the inductance is the most important, while the capacitance can essentially be ignored.
Actually, no.

It is well known that a high bw amp can oscillate if the cable is excessively high in capacitance.  What is NOT generally known, is it is not the capacitance per se that is the problem.  It is the cable to load end matching.

If you have an 8 ohm cable feeding a pure 8 ohm load, the amp will not oscillate.  It will see NO capacitance, no matter how long the cable is.  If the load decouples as frequency goes up (impedance rises) such that the load Z is far greater than the cable Z, then most of the energy stored within the cable will be electric field based.  The amp has a problem with that if it still has gain at those frequencies.

If you wish to discuss, that would be excellent.

Cheers, John


1oldguy

Re: Bryston's new speaker cable
« Reply #35 on: 18 Nov 2010, 02:58 pm »
Very interesting to say the least.Now if i only had a degree to fully grasp all this it would be even better. :duh:
Digging it though. :wink: :thumb:

jneutron

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Re: Bryston's new speaker cable
« Reply #36 on: 18 Nov 2010, 05:23 pm »
Very interesting to say the least.
What an odd thing. Personally,I would call it boring technospeak.

I apologize to all for the gobbledeegook, but Bruce's assertions required comment.

Now if i only had a degree to fully grasp all this it would be even better. :duh:
I have two degrees.  Farenheit... and Centigrade..  tis all that is required.

The essence of my post is simple.  While I find that it would not be difficult for me to trash vendors for the inaccuracies of their marketspeak or white papers, it is not a constructive path.  The assumption that what was taught in an EE program is inviolate must be tempered by the fact that a lot of it is based on simplifications.  Knowing when the simplifications are good enough is very important, as well as when they are not adequate for the task..

I find it troubling when a techno-type uses a personal/business website as a podium to slap others either directly or indirectly.  And especially so when they themselves do not understand the concepts they use as a blunt instrument.

But that is me, that is now.

Cheers, John


James Tanner

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Re: Bryston's new speaker cable
« Reply #37 on: 20 Nov 2010, 01:31 am »
James.......I saw your comment about the spades and bananas, "'Heavily Gold plated' Spade lugs or ‘Expandable Banana’ plugs specially made for Bryston."  Is the base metal of the spades and bananas copper or silver, or the more typical brass or bronze?

Hi jdandy,

The Base metal is Copper.

james

dubkarma

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Re: Bryston's new speaker cable
« Reply #38 on: 20 Nov 2010, 02:56 am »
I posted in a new thread and should have looked more carefully at the existing topics, because my query belongs in this thread. Sorry for duplication.

I've had the SC4 speaker cable in my bedroom/office system for a week now and cannot shake the feeling that, compared to the previous Bryston Vandamme cables, I've lost 4-6 dB in system SPL. Now this seems physically impossible to me, but am convinced that I have to advance the volume knob on the BP-26 way beyond what I used to for the same volume.

Am I just hallucinating or could there be some electro-physical basis for this impression?

Appreciate any thoughts others may have--even if it's to assure me that I am indeed deluded.

Cheers,

Joel.

drummermitchell

Re: Bryston's new speaker cable
« Reply #39 on: 20 Nov 2010, 03:48 am »
Joel,I'll let you know in a week as mine should be here next week,I to, have the Bryston Van Damme cables also.
I have had my 26 @8:00-8:30.