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  #1   Report Post  
kyser
 
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Default Coax as speaker cable???

I'm embroiled in a discussion on aus.hifi with a poster who recommends the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an LC
filter causing signal attenuation or, worse, amp output stage instability
over anything but a short run?

Patrick Turner? Anyone?

TIA


  #2   Report Post  
Ian Iveson
 
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"kyser" wrote in message
...
I'm embroiled in a discussion on aus.hifi with a poster who

recommends the
use of RG58C/U as speaker cable (with alleged sonic improvements

over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff

constitute an LC
filter causing signal attenuation or, worse, amp output stage

instability
over anything but a short run?


All twin cables have capacitance, inductance and resistance. These
values are quoted for cables that must conform to a standard such as
the one you cite. You can therefore calculate the effect, taking
into account the length of cable, and other impedance in the speaker
circuit. In this case, unless you have some new kind of tweeter,
and VHF hearing, I shouldn't bother.

How such a discussion got you embroiled god only knows.

I think you will find that resistance is the most important feature
of a speaker cable. For most valve amps, virtually anything will do
nicely, since the output impedance is likely to be much greater than
any reasonable speaker cable.

My advice is quit the embroilment, it's not worth spending time on.

Patrick Turner? Anyone?


cheers, Anyone



  #3   Report Post  
Fred Nachbaur
 
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kyser wrote:
I'm embroiled in a discussion on aus.hifi with a poster who recommends the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an LC
filter causing signal attenuation or, worse, amp output stage instability
over anything but a short run?

Patrick Turner? Anyone?

TIA


The RG58's do have a rather high capacitance, on the order of 30 pF per
foot (~100 pF per meter). So for an extreme case let's take, say, a 100
meter run (over 300 feet). The capacitance would be .01 uF. On an 8 ohm
system, assuming a 0-ohm amplifier output impedance, that would put the
3 dB corner at about 2 megahertz. *Well* above the human range of
hearing. So from a capacitive POV, not to worry.

Inductance and lumped inductance/capacitance effects don't significantly
come into play at audio frequencies either. Again, not to worry.

The only problem I can see is ordinary, every-day resistance. The center
conductor in RG58 is quite small, perhaps only about 20-gauge. Let's
see... (I love my Google) - 10.4 ohms per 1000 feet. So to continue the
same example, you'd be losing about 1/3 of your output power in the
stupid speaker wire! Bad idea.

But you've just given me an idea. If audiophools are going for el-cheapo
coax, they'll just love LMR400! This stuff is big and ugly (about 1/2"
in diameter), stiff as a board and impossible to work with, has an
aluminum foil *and* a braided tinned copper shield, foam dielectric (low
capacitance), and very thick single-strand center conductor. Try running
*that* crap through a building and up a tower in the dead of winter
sometime!

I can get it for about a buck a foot. If I sell it for $5 a foot, that
would be suitable revenge both on LMR400 and on the audiophools that buy
it! ;-)

Cheers,
Fred

--
+--------------------------------------------+
| Music: http://www3.telus.net/dogstarmusic/ |
| Projects, Vacuum Tubes & other stuff: |
| http://www.dogstar.dantimax.dk |
+--------------------------------------------+

  #4   Report Post  
Ian Iveson
 
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"Fred Nachbaur" wrote

...So to continue the
same example, you'd be losing about 1/3 of your output power in

the
stupid speaker wire! Bad idea.
...


Just to make it clear that this example is for 100 metres!

cheers, Ian



  #5   Report Post  
kyser
 
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"Fred Nachbaur" wrote in message
...

The RG58's do have a rather high capacitance, on the order of 30 pF per

foot (~100 pF per meter). So for an extreme case let's take, say, a 100
meter run (over 300 feet). The capacitance would be .01 uF. On an 8 ohm
system, assuming a 0-ohm amplifier output impedance, that would put the 3 dB
corner at about 2 megahertz. *Well* above the human range of hearing. So
from a capacitive POV, not to worry.

Inductance and lumped inductance/capacitance effects don't significantly

come into play at audio frequencies either. Again, not to worry.

The only problem I can see is ordinary, every-day resistance. The center

conductor in RG58 is quite small, perhaps only about 20-gauge. Let's see...
(I love my Google) - 10.4 ohms per 1000 feet. So to continue the same
example, you'd be losing about 1/3 of your output power in the stupid
speaker wire! Bad idea.

SNIP

Cheers,
Fred


Hi Fred: Thanks, I'm really not up on LC networks .....

My other concern was based on stories of musicians using guitar cables as
speaker cables on high power amps (eg 100W Marshalls etc, or BIG bass amps)
and damaging the output stages as a result.

This guy is a dealer, and recommends the use of coax as speaker cable
"because of its low inductance". Personally, I can see no possible
advantage, some potential problems, and I'd give it a miss.

Thanks also for your kind offer, but I'll pass on that, too! 8^)

Cheers

David (still got those 6U8As I bought off you)




  #6   Report Post  
kyser
 
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"Ian Iveson" wrote in message
...

"kyser" wrote in message
...
I'm embroiled in a discussion on aus.hifi with a poster who

recommends the use of RG58C/U as speaker cable (with alleged sonic

improvements over standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff

constitute an LC filter causing signal attenuation or, worse, amp output

stage instability over anything but a short run?

All twin cables have capacitance, inductance and resistance. These values

are quoted for cables that must conform to a standard such as the one you
cite. You can therefore calculate the effect, taking into account the
length of cable, and other impedance in the speaker circuit. In this case,
unless you have some new kind of tweeter, and VHF hearing, I shouldn't
bother.

I have NO intention of using th stuff. IMO, it's a daft idea.

How such a discussion got you embroiled god only knows.


The usual argument about exotic speaker cables vs good quality figure-8
(with my backing the latter). THEN I discovered he was using coax.

I think you will find that resistance is the most important feature of a

speaker cable. For most valve amps, virtually anything will do nicely,
since the output impedance is likely to be much greater than any reasonable
speaker cable.

A point I made very early in the discussion ........

My advice is quit the embroilment, it's not worth spending time on.


And spoil the fun deflating his arguments?


  #7   Report Post  
TubeGarden
 
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Hi RATs!

Just buy some and listen a few months. If you like it, it is good.

If not, don't expect anyone to respect you

Music is wonderful.

'Net arguments are less fun, for some of us

Happy Ears!
Al


Alan J. Marcy
Phoenix, AZ

PWC/mystic/Earhead
  #8   Report Post  
Mikkel C. Simonsen
 
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kyser wrote:

I'm embroiled in a discussion on aus.hifi with a poster who recommends the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an LC
filter causing signal attenuation or, worse, amp output stage instability
over anything but a short run?


I have seen Pro-audio speaker coax cable. I think it was made Hitachi
and/or Belden. It was a lot thicker than RG58 though.

Best regards,

Mikkel C. Simonsen - anyone in this case
  #9   Report Post  
Gregg
 
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For crying out loud, don't the audiophools know that 2" Heliax is the
best for speaker cable?

--
Gregg
*It's probably useful, even if it can't be SPICE'd*
http://geek.scorpiorising.ca
  #10   Report Post  
john stewart
 
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Fred Nachbaur wrote:

kyser wrote:
I'm embroiled in a discussion on aus.hifi with a poster who recommends the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an LC
filter causing signal attenuation or, worse, amp output stage instability
over anything but a short run?

Patrick Turner? Anyone?

TIA


The RG58's do have a rather high capacitance, on the order of 30 pF per
foot (~100 pF per meter). So for an extreme case let's take, say, a 100
meter run (over 300 feet). The capacitance would be .01 uF. On an 8 ohm
system, assuming a 0-ohm amplifier output impedance, that would put the
3 dB corner at about 2 megahertz. *Well* above the human range of
hearing. So from a capacitive POV, not to worry.

Inductance and lumped inductance/capacitance effects don't significantly
come into play at audio frequencies either.


Only in wire line telephone work. Cheers, John Stewart

Again, not to worry.

The only problem I can see is ordinary, every-day resistance. The center
conductor in RG58 is quite small, perhaps only about 20-gauge. Let's
see... (I love my Google) - 10.4 ohms per 1000 feet. So to continue the
same example, you'd be losing about 1/3 of your output power in the
stupid speaker wire! Bad idea.

But you've just given me an idea. If audiophools are going for el-cheapo
coax, they'll just love LMR400! This stuff is big and ugly (about 1/2"
in diameter), stiff as a board and impossible to work with, has an
aluminum foil *and* a braided tinned copper shield, foam dielectric (low
capacitance), and very thick single-strand center conductor. Try running
*that* crap through a building and up a tower in the dead of winter
sometime!

I can get it for about a buck a foot. If I sell it for $5 a foot, that
would be suitable revenge both on LMR400 and on the audiophools that buy
it! ;-)

Cheers,
Fred

--
+--------------------------------------------+
| Music: http://www3.telus.net/dogstarmusic/ |
| Projects, Vacuum Tubes & other stuff: |
| http://www.dogstar.dantimax.dk |
+--------------------------------------------+




  #11   Report Post  
john stewart
 
Posts: n/a
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kyser wrote:

I'm embroiled in a discussion on aus.hifi with a poster who recommends the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an LC
filter causing signal attenuation or, worse, amp output stage instability
over anything but a short run?

Patrick Turner? Anyone?

TIA


Most ppl manage to ignore Thevenim's Theorem that tells you all the
R's in a series circuit need to be added in to get the final answer.
The part left out in this case is usually the speaker R which in most
cases is by far the largest component in an amp output circuit. It is also
the reason why damping factors greater than say 5 don't do much.

Many will argue with the above. Better get out the text books!!1

Cheers, John Stewart


  #12   Report Post  
Chris Morriss
 
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Default

In message , kyser
writes
I'm embroiled in a discussion on aus.hifi with a poster who recommends the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an LC
filter causing signal attenuation or, worse, amp output stage instability
over anything but a short run?

Patrick Turner? Anyone?

TIA


Co-ax will have high capacitance but VERY low inductance. As the
inductance of speaker leads has far more effect than the shunt
capacitance then yes, co-ax will make an excellent speaker lead.

The problem is than RG58 isn't exactly a power cable so resistive losses
will be high.
--
Chris Morriss
  #13   Report Post  
Ronald
 
Posts: n/a
Default


"john stewart" schreef in bericht
...


kyser wrote:

I'm embroiled in a discussion on aus.hifi with a poster who recommends

the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an

LC
filter causing signal attenuation or, worse, amp output stage

instability
over anything but a short run?

Patrick Turner? Anyone?

TIA


Most ppl manage to ignore Thevenim's Theorem that tells you all the
R's in a series circuit need to be added in to get the final answer.
The part left out in this case is usually the speaker R which in most
cases is by far the largest component in an amp output circuit. It is also
the reason why damping factors greater than say 5 don't do much.

Many will argue with the above. Better get out the text books!!1

Cheers, John Stewart


And it's about time the WWF does something against the use of snake oil
in general ......


  #14   Report Post  
Phil Allison
 
Posts: n/a
Default


"kyser" wrote in message
...
I'm embroiled in a discussion on aus.hifi with a poster who recommends the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an

LC
filter causing signal attenuation or, worse, amp output stage instability
over anything but a short run?



** Doug Self has published articles in Electronics World ( formerly
Wireless World) about the use of co-ax for speaker leads and concluded that
it was one of the best options in terms of performance for price.

For a 5 metre run, RG58 or similar has no adverse effects and showed
less resistance and much less inductance than 10 amp rated (1 sq mm) twin
flex.

Fits nicely into an XLR plug too.





............. Phil








  #15   Report Post  
doug
 
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Mogami makes coaxial that is very good
Studios use it all the time.


"Mikkel C. Simonsen" wrote in message
...
kyser wrote:

I'm embroiled in a discussion on aus.hifi with a poster who recommends

the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an

LC
filter causing signal attenuation or, worse, amp output stage

instability
over anything but a short run?


I have seen Pro-audio speaker coax cable. I think it was made Hitachi
and/or Belden. It was a lot thicker than RG58 though.

Best regards,

Mikkel C. Simonsen - anyone in this case





  #16   Report Post  
Engineer
 
Posts: n/a
Default

kyser wrote:

I'm embroiled in a discussion on aus.hifi with a poster who recommends the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an LC
filter causing signal attenuation or, worse, amp output stage instability
over anything but a short run?

Patrick Turner? Anyone?

TIA


You could use TWO lengths with the braid and centre all
twisted together! Low R (good), low capacitance (doesn't
matter.) If you get it free, then you're ahead of the
game. If you have to buy it - don't... just use flat twin
flex thicker than 16 gauge for tube amps, or thicker than 14
gauge for (quietly...) solid state amps.

Cheers,

Roger

--
Roger Jones, P.Eng.
Thornhill, Ontario,
Canada.

"Friends don't let friends vote Liberal"
  #17   Report Post  
Phil Allison
 
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"Andy Cowley" wrote in message
...
doug wrote:

Mogami makes coaxial that is very good
Studios use it all the time.

For video. It's no good, it's 75 ohm, you'd need
4 ohm or 8 ohm for speakers. Anyway it seem to cost
a dollar an inch.


;-)



** It is not possible to make a 8 ohm co-ax cable.

But it *is* possible to make an interwoven cable with lots of
insulated strands have a characteristic of 8 ohms.

Such cable was sold as "Tocord" and by Mogami too IIRC.




............ Phil




  #18   Report Post  
Andy Cowley
 
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Phil Allison wrote:

"Andy Cowley" wrote in message
...
doug wrote:

Mogami makes coaxial that is very good
Studios use it all the time.

For video. It's no good, it's 75 ohm, you'd need
4 ohm or 8 ohm for speakers. Anyway it seem to cost
a dollar an inch.


;-)


** It is not possible to make a 8 ohm co-ax cable.

But it *is* possible to make an interwoven cable with lots of
insulated strands have a characteristic of 8 ohms.

Such cable was sold as "Tocord" and by Mogami too IIRC.

........... Phil


Did ya notice the smileys? Irony is lost on you? Litzendracht
wire (q.v) is what you are describing. Oh, and it is possible to make
8 ohm coax although I can't conceive of a reason for doing so.

Assuming an air dielectric (relative permittivity, Er ~= 1) and a 1 mm
diameter inner conductor, the inside diameter of the outer conductor
would need to be 1.14 mm. If we consider a more realistic polythene
or ETFE (cousin to PTFE) dielectric (Er ~= 2.6) then the dimension
would be 1.24 mm. - not impossible at all. In fact if you wound some
copper tape over RG213 and used the outer and your tape, with the
original jacket as the dielectric, you'd probably be pretty close.

The characteristic impedance of coaxial conductors, Z0, is given by
Z0 = (138/(sqrt Er)) * log (R/r) . R is inner dia. of outer, r is
diameter of inner, conductors.

Making coax with Z0 ~100 is difficult, though.

best

Andy, M1EBV
  #19   Report Post  
Chuck Harris
 
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There is absolutely no good reason to try and make your speaker wires
8 ohm transmission lines. There are more than a few good reasons not
to! One is the capacitance per foot would likely cut your highs.
Another is the impedance of your speakers is only 8 ohms at dc. And
another is the impedance of your amp is only a small fraction of an
ohm.

The reason transmission line matches are important at RF frequencies
is mostly to do with the voltage changes along the line caused by
"standing waves". These variations occur at 1/4 wavelength intervals
1/4 wavelength at audio frequencies is on the order of 30,000 meters/4.
A really long distance. Long enough to be entirely insignificant.

-Chuck, WA3UQV

Phil Allison wrote:
"Andy Cowley" wrote in message
...

doug wrote:

Mogami makes coaxial that is very good
Studios use it all the time.


For video. It's no good, it's 75 ohm, you'd need
4 ohm or 8 ohm for speakers. Anyway it seem to cost
a dollar an inch.



;-)




** It is not possible to make a 8 ohm co-ax cable.

But it *is* possible to make an interwoven cable with lots of
insulated strands have a characteristic of 8 ohms.

Such cable was sold as "Tocord" and by Mogami too IIRC.




........... Phil





  #20   Report Post  
Phil Allison
 
Posts: n/a
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"Andy Cowley" wrote in message
...

Phil Allison wrote:


"Andy Cowley" wrote in message
...
doug wrote:

Mogami makes coaxial that is very good
Studios use it all the time.

For video. It's no good, it's 75 ohm, you'd need
4 ohm or 8 ohm for speakers. Anyway it seem to cost
a dollar an inch.


;-)


** It is not possible to make a 8 ohm co-ax cable.

But it *is* possible to make an interwoven cable with lots of
insulated strands have a characteristic of 8 ohms.

Such cable was sold as "Tocord" and by Mogami too IIRC.


........... Phil



Did ya notice the smileys? Irony is lost on you?



** One only smiley - no irony at all in sight.


Litzendracht wire (q.v) is what you are describing. Oh, and it is possible
to make
8 ohm coax although I can't conceive of a reason for doing so.



** Lemme see ..... hmmmm ..... what on earth has an 8 ohm impedance
???? .....

Practically nothing ...... hmmmm - just a few stupid speakers
......

Not worth bothering with really - who would spend their money on
fancy speaker cables ???

No-one of course !!!!

How silly of me ...........




Assuming an air dielectric (relative permittivity, Er ~= 1) and a 1 mm
diameter inner conductor, the inside diameter of the outer conductor
would need to be 1.14 mm. If we consider a more realistic polythene
or ETFE (cousin to PTFE) dielectric (Er ~= 2.6) then the dimension
would be 1.24 mm. - not impossible at all. In fact if you wound some
copper tape over RG213 and used the outer and your tape, with the
original jacket as the dielectric, you'd probably be pretty close.



** Reckon you can make one with a 2mm dia core ( ie 3 sq mm of copper )
0.1 mm thick insulation then 3 sq mm of outer copper and that is still a
practical and flexible cable ???

If so, you have a nice little earner on your hands - shame about the 4
nF per metre capacitance though.




.............. Phil




  #21   Report Post  
Phil Allison
 
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"Chuck Harris" wrote in message
...

There is absolutely no good reason to try and make your speaker wires
8 ohm transmission lines.



** There is - but you are too dumb to see it.


There are more than a few good reasons not to!
One is the capacitance per foot would likely cut your highs.

** What rot.

Another is the impedance of your speakers is only 8 ohms at dc.


** More rot.

And another is the impedance of your amp is only a small fraction of an
ohm.


** Huh ????????????


The reason transmission line matches are important at RF frequencies
is mostly to do with the voltage changes along the line caused by
"standing waves".



** True enough for FRO - but irrelevant for audio and most video lines.


These variations occur at 1/4 wavelength intervals
1/4 wavelength at audio frequencies is on the order of 30,000 meters/4.



** Do you understand the word "irrelevant" ???????

A really long distance. Long enough to be entirely insignificant.



** I am thoroughly sick of arguing with ******wit** ham radio jerk-offs
about transmission lines.

Read closely:

Standing waves are NOT the issue for audio or video, something
**else** is.

That something is capacitance and inductance.

For audio and video *signal* lines cable capacitance attenuates the
high frequencies.

For loud speaker lines cable inductance does the same.

A line impedance matched to its characteristic Z at the receiving
end does NOT lose highs.

Such a line is resistive as a load.

Capice ???????



............ Phil



  #22   Report Post  
Chuck Harris
 
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Phil,

I am not stupid enough to understand your "engineering principles".

But I am stupid enough to understand transmission lines, so BITE ME!

-Chuck, WA3UQV

Phil Allison wrote:
"Chuck Harris" wrote in message
...


There is absolutely no good reason to try and make your speaker wires
8 ohm transmission lines.




** There is - but you are too dumb to see it.


There are more than a few good reasons not to!
One is the capacitance per foot would likely cut your highs.

** What rot.


Another is the impedance of your speakers is only 8 ohms at dc.



** More rot.

And another is the impedance of your amp is only a small fraction of an

ohm.



** Huh ????????????



The reason transmission line matches are important at RF frequencies
is mostly to do with the voltage changes along the line caused by
"standing waves".




** True enough for FRO - but irrelevant for audio and most video lines.



These variations occur at 1/4 wavelength intervals
1/4 wavelength at audio frequencies is on the order of 30,000 meters/4.




** Do you understand the word "irrelevant" ???????


A really long distance. Long enough to be entirely insignificant.




** I am thoroughly sick of arguing with ******wit** ham radio jerk-offs
about transmission lines.

Read closely:

Standing waves are NOT the issue for audio or video, something
**else** is.

That something is capacitance and inductance.

For audio and video *signal* lines cable capacitance attenuates the
high frequencies.

For loud speaker lines cable inductance does the same.

A line impedance matched to its characteristic Z at the receiving
end does NOT lose highs.

Such a line is resistive as a load.

Capice ???????



........... Phil




  #23   Report Post  
Andy Cowley
 
Posts: n/a
Default

Phil Allison wrote:

"Chuck Harris" wrote in message
...

There is absolutely no good reason to try and make your speaker wires
8 ohm transmission lines.


** There is - but you are too dumb to see it.

There are more than a few good reasons not to!
One is the capacitance per foot would likely cut your highs.

** What rot.

Another is the impedance of your speakers is only 8 ohms at dc.


** More rot.

And another is the impedance of your amp is only a small fraction of an
ohm.


** Huh ????????????

The reason transmission line matches are important at RF frequencies
is mostly to do with the voltage changes along the line caused by
"standing waves".


** True enough for FRO - but irrelevant for audio and most video lines.

These variations occur at 1/4 wavelength intervals
1/4 wavelength at audio frequencies is on the order of 30,000 meters/4.


** Do you understand the word "irrelevant" ???????

A really long distance. Long enough to be entirely insignificant.


** I am thoroughly sick of arguing with ******wit** ham radio jerk-offs
about transmission lines.

Read closely:

Standing waves are NOT the issue for audio or video, something
**else** is.

That something is capacitance and inductance.

For audio and video *signal* lines cable capacitance attenuates the
high frequencies.

For loud speaker lines cable inductance does the same.

A line impedance matched to its characteristic Z at the receiving
end does NOT lose highs.

Such a line is resistive as a load.

Capice ???????

........... Phil


Prime asshole. An idiot with a teeny little bit of knowledge. Doh.
Let's stop humouring him.

Andy
  #24   Report Post  
Patrick Turner
 
Posts: n/a
Default



kyser wrote:

I'm embroiled in a discussion on aus.hifi with a poster who recommends the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an LC
filter causing signal attenuation or, worse, amp output stage instability
over anything but a short run?

Patrick Turner? Anyone?

TIA


The typical inductance of a 3 metre speaker cable is perhaps 2 uH,
and the roll off is well above 20 kHz, as the pole formed by the
LR filter is at 637 kHz..
The capacitance between the pair of cables used may only be
200 pF, causing a pole at some RF frequency.
the L&C components would form an LC filter, which would display resonances
at some RF, but generally, the L and C components of speaker cables
are utterly negligible and have SFA effect on the engineering measurements.

But I will not be one to say that ppl hear changes to the sound when they
change cables.
I won't say that arguments rage over bits of wire.
I won't say that cable sales are greased and oiled with Oille De La Reptile
Products&Promoters.

What you hear is your truth for you, but in all my experience,
once the DCR is below 1/100 of the speaker Z there is SFA
change to the measurements with different cables within the audio band.

There is no reason why RG58 would not be a suitable speaker
cable, where power is low, say normal listening,
when the current may only be 0.25 amps average in a domestic lounge.
Cat 5 cables used in various ways is also great,
as is lamp flex from a hardware store.
Clean tight connectors are probably more important.

There has been a prize offered by the Worldwide Society of Skeptics
of $100,000 offered to the first person/company to demonstrate in a double
blind AB test that one cable sounds different to another.
The prize seems safe, its never been awarded over the last 30 years.

Bell wire, that really thin figure 8 twin flex is awful stuff,
but over 3M it still manages to be OK.
Some dudes say really thin solid enamelled wire, or strips of foil
work well, or "sound better"

Every would be guru has his own idea.

Patrick Turner.


  #25   Report Post  
Chuck Harris
 
Posts: n/a
Default

Patrick Turner wrote:

kyser wrote:


I'm embroiled in a discussion on aus.hifi with a poster who recommends the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an LC
filter causing signal attenuation or, worse, amp output stage instability
over anything but a short run?

Patrick Turner? Anyone?

TIA



The typical inductance of a 3 metre speaker cable is perhaps 2 uH,
and the roll off is well above 20 kHz, as the pole formed by the
LR filter is at 637 kHz..
The capacitance between the pair of cables used may only be
200 pF, causing a pole at some RF frequency.
the L&C components would form an LC filter, which would display resonances
at some RF, but generally, the L and C components of speaker cables
are utterly negligible and have SFA effect on the engineering measurements.


Hi Patrick,

I have heard one explanation for sound improvements from odd speaker
cable remedies that I find plausable. Some of the "boutique" amplifiers
are so incredibly unstable at frequencies above the audio spectrum that
the RF characteristics of the cable can start, or stop the amp from
oscillating. Amps that are oscillating always sound awful!

-Chuck, WA3UQV



  #26   Report Post  
Tim Williams
 
Posts: n/a
Default

"Phil Allison" wrote in message
u...
** There is - but you are too dumb to see it.


Hey Phil,

Have you ever seen that you are the only intelligence amongst a sea of
"****wits"?

Have you ever thought about the converse of this statement?

Tim

--
"That's for the courts to decide." - Homer Simpson
Website @ http://webpages.charter.net/dawill/tmoranwms


  #27   Report Post  
kyser
 
Posts: n/a
Default

"Chuck Harris" wrote in message
...
Patrick Turner wrote:

kyser wrote:

I'm embroiled in a discussion on aus.hifi with a poster who recommends

the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an

LC
filter causing signal attenuation or, worse, amp output stage

instability
over anything but a short run?

Patrick Turner? Anyone?

TIA



The typical inductance of a 3 metre speaker cable is perhaps 2 uH,
and the roll off is well above 20 kHz, as the pole formed by the
LR filter is at 637 kHz..
The capacitance between the pair of cables used may only be
200 pF, causing a pole at some RF frequency.
the L&C components would form an LC filter, which would display

resonances
at some RF, but generally, the L and C components of speaker cables
are utterly negligible and have SFA effect on the engineering

measurements.


Hi Patrick,

I have heard one explanation for sound improvements from odd speaker cable

remedies that I find plausable. Some of the "boutique" amplifiers are so
incredibly unstable at frequencies above the audio spectrum that the RF
characteristics of the cable can start, or stop the amp from oscillating.
Amps that are oscillating always sound awful!

-Chuck, WA3UQV


This was one of the arguments I advanced at aus.hifi for NOT using coax,
given that the people who do so are just as likely to use some form of
"exotic" amp of unknown stability.


  #28   Report Post  
Phil Allison
 
Posts: n/a
Default


"Andy Cowley"

Phil Allison wrote:

Not worth bothering with really - who would spend their money

on
fancy speaker cables ???

Audiophools, simpletons, believers in voodoo science, and people
with more money than sense.



** So you missed the bleeding obvious joke ?


If so, you have a nice little earner on your hands - shame about

the 4
nF per metre capacitance though.


Transmission line, sunshine.


No capacitive loading - AN INFINITE LENGTH OF IT
LOOKS LIKE AN 8 OHM RESISTOR TO THE DRIVING SOURCE, DUMMY.



** Not if it ain't correctly terminated. The impedance of a hi-fi
speaker at 1 MHz is what ????

An unterminated length of co-ax looks like a pure capacitor.


A shorter length transforms the load according to the transmission line

equation.
Given that speaker leads are short compared to the electrical wavelength

corresponding
to their frequency - 15 km at 20 kHz - the transformation is absolutely
negligible and the source sees the load with no modification.



** Bizarre ham radio nonsense.

Narrow band RF transmission line theory cannot be applied to wide
band audio or video.

Every ham in the world thinks it can.


You obviously don't understand transmission lines at all.



** You are obviously a dickhead.



............. Phil


  #29   Report Post  
Phil Allison
 
Posts: n/a
Default


"Chuck Harris" wrote in message
...
Phil,


I am not stupid enough to understand your "engineering principles".


** Keep working on it - it is never too late to learn how wrong you
are.


But I am stupid enough to understand transmission lines, so BITE ME!

-Chuck, WA3UQV



** Do I "chuck" before or after reading that ham call sign?



......... Phil


  #30   Report Post  
Phil Allison
 
Posts: n/a
Default


"Andy Cowley" wrote in message
...
Phil Allison wrote:

"Chuck Harris" wrote in message
...

There is absolutely no good reason to try and make your speaker wires
8 ohm transmission lines.


** There is - but you are too dumb to see it.

There are more than a few good reasons not to!
One is the capacitance per foot would likely cut your highs.

** What rot.

Another is the impedance of your speakers is only 8 ohms at dc.


** More rot.

And another is the impedance of your amp is only a small fraction of

an
ohm.


** Huh ????????????

The reason transmission line matches are important at RF frequencies
is mostly to do with the voltage changes along the line caused by
"standing waves".


** True enough for FRO - but irrelevant for audio and most video

lines.

These variations occur at 1/4 wavelength intervals
1/4 wavelength at audio frequencies is on the order of 30,000

meters/4.

** Do you understand the word "irrelevant" ???????

A really long distance. Long enough to be entirely insignificant.


** I am thoroughly sick of arguing with ******wit** ham radio

jerk-offs
about transmission lines.

Read closely:

Standing waves are NOT the issue for audio or video, something
**else** is.

That something is capacitance and inductance.

For audio and video *signal* lines cable capacitance attenuates

the
high frequencies.

For loud speaker lines cable inductance does the same.

A line impedance matched to its characteristic Z at the

receiving
end does NOT lose highs.

Such a line is resistive as a load.

Capice ???????

........... Phil



Prime asshole. An idiot with a teeny little bit of knowledge. Doh.
Let's stop humouring him.

Andy



** You have not the slightest idea what the facts are Andy.

So you post mindless abuse.

Hams really are the pits.



............ Phil





  #31   Report Post  
Phil Allison
 
Posts: n/a
Default


"Tim Williams" wrote in message
...
"Phil Allison" wrote in message
u...


** There is - but you are too dumb to see it.


Hey Phil,

Have you ever seen that you are the only intelligence amongst a sea of
"****wits"?



** Hey Tim,

- have you any idea what a pig ignorant ****head you are ??

Can you debate with facts at all??

Or are you typing with one hand like I suspect ??





............ Phil


  #32   Report Post  
Phil Allison
 
Posts: n/a
Default


"Patrick Turner" wrote in message
...

There has been a prize offered by the Worldwide Society of Skeptics
of $100,000 offered to the first person/company to demonstrate in a double
blind AB test that one cable sounds different to another.
The prize seems safe, its never been awarded over the last 30 years.



** You just made that stoty up didn't you Pat.

Such a cash prize *is* on offer for demonstration the existence of
telepathy.




........... Phil


  #33   Report Post  
john stewart
 
Posts: n/a
Default



kyser wrote:

"Chuck Harris" wrote in message
...
Patrick Turner wrote:

kyser wrote:

I'm embroiled in a discussion on aus.hifi with a poster who recommends

the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an

LC
filter causing signal attenuation or, worse, amp output stage

instability
over anything but a short run?

Patrick Turner? Anyone?

TIA


The typical inductance of a 3 metre speaker cable is perhaps 2 uH,
and the roll off is well above 20 kHz, as the pole formed by the
LR filter is at 637 kHz..
The capacitance between the pair of cables used may only be
200 pF, causing a pole at some RF frequency.
the L&C components would form an LC filter, which would display

resonances
at some RF, but generally, the L and C components of speaker cables
are utterly negligible and have SFA effect on the engineering

measurements.


Hi Patrick,

I have heard one explanation for sound improvements from odd speaker cable

remedies that I find plausable. Some of the "boutique" amplifiers are so
incredibly unstable at frequencies above the audio spectrum that the RF
characteristics of the cable can start, or stop the amp from oscillating.
Amps that are oscillating always sound awful!

-Chuck, WA3UQV


This was one of the arguments I advanced at aus.hifi for NOT using coax,
given that the people who do so are just as likely to use some form of
"exotic" amp of unknown stability.


A length of coax sourced & terminated in other than it's characteristic
impedance will support standing waves. Wavelenght depends on the cables
electrical length. You are absolutely correct IMO with your argument.
It's possible that a length of that cable could drive an SS Amp which
usually has large BW into instablity. Would be an interesting experiment.

Anyone got one they would like to sacrifice? John Stewart


  #34   Report Post  
Phil Allison
 
Posts: n/a
Default


"john stewart"


A length of coax sourced & terminated in other than it's characteristic
impedance will support standing waves.


** That is not so - source impedance can be any value as long as the
cable is terminated correctly.


Wavelenght depends on the cables electrical length.


** Yeah, right, velocity factor is 70% of c.


You are absolutely correct IMO with your argument.


** Huh ?


It's possible that a length of that cable could drive an SS Amp which
usually has large BW into instablity. Would be an interesting experiment.



** Good luck finding such an amp - the vast majority have output
"Zobel" networks that make them stable with any value of capacitance.

A few hundred picofarads is nothing.




............. Phil



  #35   Report Post  
Greg Pierce
 
Posts: n/a
Default

On Wed, 01 Oct 2003 12:35:41 -0500, the highly esteemed Tim Williams
enlightened us with these pearls of wisdom:

"Phil Allison" wrote in message
u...
** There is - but you are too dumb to see it.


Hey Phil,

Have you ever seen that you are the only intelligence amongst a sea of
"****wits"?

Have you ever thought about the converse of this statement?

Tim


Tim, would you please killfile Phil. Lets keep the Earth beautiful ;-)

--
Greg

--The software said it requires Win2000 or better, so I installed Linux.



  #36   Report Post  
Phil Allison
 
Posts: n/a
Default


"Greg Pierce" wrote in message
news
Tim, would you please killfile Phil. Lets keep the Earth beautiful ;-)



** Greg,

I see "trash can " is your email name - refers to your brain no
doubt.



............. Phil


  #37   Report Post  
john stewart
 
Posts: n/a
Default

Phil- You have made some very good points. However..........

Phil Allison wrote:

"john stewart"

A length of coax sourced & terminated in other than it's characteristic
impedance will support standing waves.


** That is not so - source impedance can be any value as long as the
cable is terminated correctly.


You are correct. However, cable terminated correctly is a special case.
Any other condition will result in multiple reflections. Whenever I was
making measurements in COAX I was damn sure that the source was
as close to a match as I could get it. Otherwise, accuracy goes out the door!!

Wavelenght depends on the cables electrical length.


** Yeah, right, velocity factor is 70% of c.


Depends on the cable used & varies from about 65% to 80% of c.

You are absolutely correct IMO with your argument.


** Huh ?


Still think it's worth a look.

It's possible that a length of that cable could drive an SS Amp which
usually has large BW into instablity. Would be an interesting experiment.


** Good luck finding such an amp - the vast majority have output
"Zobel" networks that make them stable with any value of capacitance.


Not all amplifiers bow at the altar of Zobel. There are many out there,
in particular built by amatuers who don't know what Zobel is & don't care.

A few hundred picofarads is nothing.


It's 20 to 30 pF / ft. A 1/4 wavelength at 10 MHz is about 17 ft
in RG58. Many power FET's would have no problem with that.

............. Phil


Just some thoughts. I could be out to lunch.
Can we use your SS amp as the basis of a trial?????

Cheers (And Beers), John Stewart

  #38   Report Post  
Phil Allison
 
Posts: n/a
Default


"john stewart" wrote in message
...
Phil- You have made some very good points. However..........

Phil Allison wrote:

"john stewart"

A length of coax sourced & terminated in other than it's

characteristic
impedance will support standing waves.


** That is not so - source impedance can be any value as long as the
cable is terminated correctly.



You are correct. However, cable terminated correctly is a special case.



** A very common special case with 75 ohm video.


Any other condition will result in multiple reflections.



** Only if the frequency being fed in is high enough - otherwise the
cable adds inductance in series with the load or capacitance in parallel
with the source. The former if the load is less than Zo and the later if it
is more.


Whenever I was making measurements in COAX I was damn sure that the source

was
as close to a match as I could get it. Otherwise, accuracy goes out the

door!!


** Co-ax is often only approximately the speced Zo - the margin is 15%
at least.



It's possible that a length of that cable could drive an SS Amp which
usually has large BW into instability. Would be an interesting

experiment.

** Good luck finding such an amp - the vast majority have output
"Zobel" networks that make them stable with any value of capacitance.



Not all amplifiers bow at the altar of Zobel. There are many out there,
in particular built by amateurs who don't know what Zobel is & don't care.



** Still, they are most unlikely to be bothered by a few hundred pF.


A few hundred picofarads is nothing.



It's 20 to 30 pF / ft. A 1/4 wavelength at 10 MHz is about 17 ft
in RG58. Many power FET's would have no problem with that.


** Cripes - one only has to add a 50 ohm resistor in series with a 1nF
cap to the end and all your worries are over.


Just some thoughts. I could be out to lunch.
Can we use your SS amp as the basis of a trial?????



** Mine has been driving 5 metres of Tocord ( @ 2000pF per metre) for
20 odd years with no issues.



............ Phil


  #39   Report Post  
Patrick Turner
 
Posts: n/a
Default



kyser wrote:

"Chuck Harris" wrote in message
...
Patrick Turner wrote:

kyser wrote:

I'm embroiled in a discussion on aus.hifi with a poster who recommends

the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an

LC
filter causing signal attenuation or, worse, amp output stage

instability
over anything but a short run?

Patrick Turner? Anyone?

TIA


The typical inductance of a 3 metre speaker cable is perhaps 2 uH,
and the roll off is well above 20 kHz, as the pole formed by the
LR filter is at 637 kHz..
The capacitance between the pair of cables used may only be
200 pF, causing a pole at some RF frequency.
the L&C components would form an LC filter, which would display

resonances
at some RF, but generally, the L and C components of speaker cables
are utterly negligible and have SFA effect on the engineering

measurements.


Hi Patrick,

I have heard one explanation for sound improvements from odd speaker cable

remedies that I find plausable. Some of the "boutique" amplifiers are so
incredibly unstable at frequencies above the audio spectrum that the RF
characteristics of the cable can start, or stop the amp from oscillating.
Amps that are oscillating always sound awful!

-Chuck, WA3UQV


This was one of the arguments I advanced at aus.hifi for NOT using coax,
given that the people who do so are just as likely to use some form of
"exotic" amp of unknown stability.


The only sort of amp one should buy is one which
won't oscillate regardless of whatever load or cables, which both comprise
the load which the amp sees.
An amp which does oscillate is a BS amp, perhaps also a boutique amp,
if sold in amp "boutiques".

Patrick Turner.

  #40   Report Post  
Patrick Turner
 
Posts: n/a
Default



john stewart wrote:

kyser wrote:

"Chuck Harris" wrote in message
...
Patrick Turner wrote:

kyser wrote:

I'm embroiled in a discussion on aus.hifi with a poster who recommends

the
use of RG58C/U as speaker cable (with alleged sonic improvements over
standard figure-8 type flex).

Wouldn't the combined inductance/capacitance of this stuff constitute an

LC
filter causing signal attenuation or, worse, amp output stage

instability
over anything but a short run?

Patrick Turner? Anyone?

TIA


The typical inductance of a 3 metre speaker cable is perhaps 2 uH,
and the roll off is well above 20 kHz, as the pole formed by the
LR filter is at 637 kHz..
The capacitance between the pair of cables used may only be
200 pF, causing a pole at some RF frequency.
the L&C components would form an LC filter, which would display

resonances
at some RF, but generally, the L and C components of speaker cables
are utterly negligible and have SFA effect on the engineering

measurements.


Hi Patrick,

I have heard one explanation for sound improvements from odd speaker cable

remedies that I find plausable. Some of the "boutique" amplifiers are so
incredibly unstable at frequencies above the audio spectrum that the RF
characteristics of the cable can start, or stop the amp from oscillating.
Amps that are oscillating always sound awful!

-Chuck, WA3UQV


This was one of the arguments I advanced at aus.hifi for NOT using coax,
given that the people who do so are just as likely to use some form of
"exotic" amp of unknown stability.


A length of coax sourced & terminated in other than it's characteristic
impedance will support standing waves. Wavelenght depends on the cables
electrical length. You are absolutely correct IMO with your argument.
It's possible that a length of that cable could drive an SS Amp which
usually has large BW into instablity. Would be an interesting experiment.

Anyone got one they would like to sacrifice? John Stewart


I have never noticed instablities in normal bandwidth amps when working properly.
I know a guy whose SS amps go to 1 mHz, -3db, and lord knows what instability he
has.
Tube amps usually cut off at about 70 kHz, but still need to be arranged to NOT
oscillate, when C loads are used, especially if the OPT has high leakage
inductance.
L&C in cable/speaker combinations shouldn't affect the amp.
If an amp can be made to oscillate, under any circumstances whatsoever,
someone ain't done his home work.
Unconditional stablity is where we should aim.

Patrick Turner.



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