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  #1   Report Post  
Colin Bigam
 
Posts: n/a
Default DIY Interconnect questions

Oh yes, more cable questions! Let the flaming begin!

Seriously folks, I've been planning on making some more cables (have done so
in the past), and was wondering about the relative technical merits of shielded
two-conductor cables vs. shielded single conductor (esp. coax), for unbalanced
runs. What I did in the past (with Belden 8761, I vaguely recall) was run
signal and ground along the two conductors, and connect the (foil) shield to
the ground at one end only. This 'shield-attached' end was plugged into the
(integrated) amplifier for all components.

Now I'm thinking here that I've got a twisted pair for induced-noise
cancellation plus a 100% coverage foil shield, and a fairly low capacitance
value (something like 25pF/m). Should be pretty good, right? However, am I
in any danger of causing problems by having both centre conductor and shield
tied to ground? I _think_ that having all of the shield-attached ends on the
same component should avoid ground loops, but I can't quite puzzle it out in
my head. One question that comes to mind is why do almost all except the most
extreme (weird) high-end commercial interconnects use either coax or at least
single-conductor-with-shield geometries? Another one is am I mucking up the
low impedance factor by wiring it up this way?

ON a related question, does anyone have opinions about good RCA connectors?
Ideally I'd like a split pin, a locking ground cuff, and HEAVY gold plating
or maybe rhodium. As far as I can see though, Cardas is the only company
that makes rhodium plated plugs, and they have neither the split pin or the
locking collars.

Thanks,
Colin
  #2   Report Post  
PaulB
 
Posts: n/a
Default DIY Interconnect questions

as for rca's check out either the wbt-0101's or 0108's
and the eichman bullet plug.


"Colin Bigam" wrote in message
m...
Oh yes, more cable questions! Let the flaming begin!

Seriously folks, I've been planning on making some more cables (have done

so
in the past), and was wondering about the relative technical merits of

shielded
two-conductor cables vs. shielded single conductor (esp. coax), for

unbalanced
runs. What I did in the past (with Belden 8761, I vaguely recall) was run
signal and ground along the two conductors, and connect the (foil) shield

to
the ground at one end only. This 'shield-attached' end was plugged into

the
(integrated) amplifier for all components.

Now I'm thinking here that I've got a twisted pair for induced-noise
cancellation plus a 100% coverage foil shield, and a fairly low

capacitance
value (something like 25pF/m). Should be pretty good, right? However, am I
in any danger of causing problems by having both centre conductor and

shield
tied to ground? I _think_ that having all of the shield-attached ends on

the
same component should avoid ground loops, but I can't quite puzzle it out

in
my head. One question that comes to mind is why do almost all except the

most
extreme (weird) high-end commercial interconnects use either coax or at

least
single-conductor-with-shield geometries? Another one is am I mucking up

the
low impedance factor by wiring it up this way?

ON a related question, does anyone have opinions about good RCA

connectors?
Ideally I'd like a split pin, a locking ground cuff, and HEAVY gold

plating
or maybe rhodium. As far as I can see though, Cardas is the only company
that makes rhodium plated plugs, and they have neither the split pin or

the
locking collars.

Thanks,
Colin



  #3   Report Post  
PaulB
 
Posts: n/a
Default DIY Interconnect questions

as for rca's check out either the wbt-0101's or 0108's
and the eichman bullet plug.


"Colin Bigam" wrote in message
m...
Oh yes, more cable questions! Let the flaming begin!

Seriously folks, I've been planning on making some more cables (have done

so
in the past), and was wondering about the relative technical merits of

shielded
two-conductor cables vs. shielded single conductor (esp. coax), for

unbalanced
runs. What I did in the past (with Belden 8761, I vaguely recall) was run
signal and ground along the two conductors, and connect the (foil) shield

to
the ground at one end only. This 'shield-attached' end was plugged into

the
(integrated) amplifier for all components.

Now I'm thinking here that I've got a twisted pair for induced-noise
cancellation plus a 100% coverage foil shield, and a fairly low

capacitance
value (something like 25pF/m). Should be pretty good, right? However, am I
in any danger of causing problems by having both centre conductor and

shield
tied to ground? I _think_ that having all of the shield-attached ends on

the
same component should avoid ground loops, but I can't quite puzzle it out

in
my head. One question that comes to mind is why do almost all except the

most
extreme (weird) high-end commercial interconnects use either coax or at

least
single-conductor-with-shield geometries? Another one is am I mucking up

the
low impedance factor by wiring it up this way?

ON a related question, does anyone have opinions about good RCA

connectors?
Ideally I'd like a split pin, a locking ground cuff, and HEAVY gold

plating
or maybe rhodium. As far as I can see though, Cardas is the only company
that makes rhodium plated plugs, and they have neither the split pin or

the
locking collars.

Thanks,
Colin



  #4   Report Post  
PaulB
 
Posts: n/a
Default DIY Interconnect questions

as for rca's check out either the wbt-0101's or 0108's
and the eichman bullet plug.


"Colin Bigam" wrote in message
m...
Oh yes, more cable questions! Let the flaming begin!

Seriously folks, I've been planning on making some more cables (have done

so
in the past), and was wondering about the relative technical merits of

shielded
two-conductor cables vs. shielded single conductor (esp. coax), for

unbalanced
runs. What I did in the past (with Belden 8761, I vaguely recall) was run
signal and ground along the two conductors, and connect the (foil) shield

to
the ground at one end only. This 'shield-attached' end was plugged into

the
(integrated) amplifier for all components.

Now I'm thinking here that I've got a twisted pair for induced-noise
cancellation plus a 100% coverage foil shield, and a fairly low

capacitance
value (something like 25pF/m). Should be pretty good, right? However, am I
in any danger of causing problems by having both centre conductor and

shield
tied to ground? I _think_ that having all of the shield-attached ends on

the
same component should avoid ground loops, but I can't quite puzzle it out

in
my head. One question that comes to mind is why do almost all except the

most
extreme (weird) high-end commercial interconnects use either coax or at

least
single-conductor-with-shield geometries? Another one is am I mucking up

the
low impedance factor by wiring it up this way?

ON a related question, does anyone have opinions about good RCA

connectors?
Ideally I'd like a split pin, a locking ground cuff, and HEAVY gold

plating
or maybe rhodium. As far as I can see though, Cardas is the only company
that makes rhodium plated plugs, and they have neither the split pin or

the
locking collars.

Thanks,
Colin



  #5   Report Post  
Geoff Wood
 
Posts: n/a
Default DIY Interconnect questions


"Colin Bigam" wrote in message
m...
Oh yes, more cable questions! Let the flaming begin!

Seriously folks, I've been planning on making some more cables (have done

so
in the past), and was wondering about the relative technical merits of

shielded
two-conductor cables vs. shielded single conductor (esp. coax), for

unbalanced
runs. What I did in the past (with Belden 8761, I vaguely recall) was run
signal and ground along the two conductors, and connect the (foil) shield

to
the ground at one end only. This 'shield-attached' end was plugged into

the
(integrated) amplifier for all components.


No problem, as long as you only connect the sheild at one end. Matter of
experimentationas to which way around better, if any effect. As to whether
or not any audible benefit suck it and see, but I doubt it's worth the
effort.

geoff

Now I'm thinking here that I've got a twisted pair for induced-noise
cancellation plus a 100% coverage foil shield, and a fairly low

capacitance
value (something like 25pF/m). Should be pretty good, right? However, am I
in any danger of causing problems by having both centre conductor and

shield
tied to ground? I _think_ that having all of the shield-attached ends on

the
same component should avoid ground loops,


You'll have ground loops with each additional cable through the siganl
ground conductor. Connect the sheild at both ends and you'll have an extra
one per cable.

my head. One question that comes to mind is why do almost all except the

most
extreme (weird) high-end commercial interconnects use either coax or at

least
single-conductor-with-shield geometries? Another one is am I mucking up

the
low impedance factor by wiring it up this way?


Sheilded cable, not coax. They are different things. No, you won't be
mucking up impedences. They are pretty irrelevant at those frequencies and
lengths anyway.

Do you have a problem with 'reguar' interconnects, or just experimenting ?

geoff




  #6   Report Post  
Geoff Wood
 
Posts: n/a
Default DIY Interconnect questions


"Colin Bigam" wrote in message
m...
Oh yes, more cable questions! Let the flaming begin!

Seriously folks, I've been planning on making some more cables (have done

so
in the past), and was wondering about the relative technical merits of

shielded
two-conductor cables vs. shielded single conductor (esp. coax), for

unbalanced
runs. What I did in the past (with Belden 8761, I vaguely recall) was run
signal and ground along the two conductors, and connect the (foil) shield

to
the ground at one end only. This 'shield-attached' end was plugged into

the
(integrated) amplifier for all components.


No problem, as long as you only connect the sheild at one end. Matter of
experimentationas to which way around better, if any effect. As to whether
or not any audible benefit suck it and see, but I doubt it's worth the
effort.

geoff

Now I'm thinking here that I've got a twisted pair for induced-noise
cancellation plus a 100% coverage foil shield, and a fairly low

capacitance
value (something like 25pF/m). Should be pretty good, right? However, am I
in any danger of causing problems by having both centre conductor and

shield
tied to ground? I _think_ that having all of the shield-attached ends on

the
same component should avoid ground loops,


You'll have ground loops with each additional cable through the siganl
ground conductor. Connect the sheild at both ends and you'll have an extra
one per cable.

my head. One question that comes to mind is why do almost all except the

most
extreme (weird) high-end commercial interconnects use either coax or at

least
single-conductor-with-shield geometries? Another one is am I mucking up

the
low impedance factor by wiring it up this way?


Sheilded cable, not coax. They are different things. No, you won't be
mucking up impedences. They are pretty irrelevant at those frequencies and
lengths anyway.

Do you have a problem with 'reguar' interconnects, or just experimenting ?

geoff


  #7   Report Post  
Geoff Wood
 
Posts: n/a
Default DIY Interconnect questions


"Colin Bigam" wrote in message
m...
Oh yes, more cable questions! Let the flaming begin!

Seriously folks, I've been planning on making some more cables (have done

so
in the past), and was wondering about the relative technical merits of

shielded
two-conductor cables vs. shielded single conductor (esp. coax), for

unbalanced
runs. What I did in the past (with Belden 8761, I vaguely recall) was run
signal and ground along the two conductors, and connect the (foil) shield

to
the ground at one end only. This 'shield-attached' end was plugged into

the
(integrated) amplifier for all components.


No problem, as long as you only connect the sheild at one end. Matter of
experimentationas to which way around better, if any effect. As to whether
or not any audible benefit suck it and see, but I doubt it's worth the
effort.

geoff

Now I'm thinking here that I've got a twisted pair for induced-noise
cancellation plus a 100% coverage foil shield, and a fairly low

capacitance
value (something like 25pF/m). Should be pretty good, right? However, am I
in any danger of causing problems by having both centre conductor and

shield
tied to ground? I _think_ that having all of the shield-attached ends on

the
same component should avoid ground loops,


You'll have ground loops with each additional cable through the siganl
ground conductor. Connect the sheild at both ends and you'll have an extra
one per cable.

my head. One question that comes to mind is why do almost all except the

most
extreme (weird) high-end commercial interconnects use either coax or at

least
single-conductor-with-shield geometries? Another one is am I mucking up

the
low impedance factor by wiring it up this way?


Sheilded cable, not coax. They are different things. No, you won't be
mucking up impedences. They are pretty irrelevant at those frequencies and
lengths anyway.

Do you have a problem with 'reguar' interconnects, or just experimenting ?

geoff


  #8   Report Post  
Colin Bigam
 
Posts: n/a
Default DIY Interconnect questions

"Geoff Wood" -nospam wrote in message ...
"Colin Bigam" wrote in message
m...
Oh yes, more cable questions! Let the flaming begin!

Seriously folks, I've been planning on making some more cables (have done

so
in the past), and was wondering about the relative technical merits of

shielded
two-conductor cables vs. shielded single conductor (esp. coax), for

unbalanced
runs. What I did in the past (with Belden 8761, I vaguely recall) was run
signal and ground along the two conductors, and connect the (foil) shield

to
the ground at one end only. This 'shield-attached' end was plugged into

the
(integrated) amplifier for all components.


No problem, as long as you only connect the sheild at one end. Matter of
experimentationas to which way around better, if any effect. As to whether
or not any audible benefit suck it and see, but I doubt it's worth the
effort.


I'm not really expecting any audible benefit, but I'd like to do
things 'ideally.'

You'll have ground loops with each additional cable through the siganl
ground conductor. Connect the sheild at both ends and you'll have an extra
one per cable.


So what is the problem with connecting the shield at both ends of the
cable then? Is it the possibility of inducing a current in the shield
that's not present in the ground, or...?

For that matter, what would happen (electrically) if the shield was
unattached at either end?

Sheilded cable, not coax. They are different things.


Yes, I realise this. That's why I said "either...or..." I know that there
are at least a few companies using coax for interconnects, but 90+% use
regular shielded cable.

No, you won't be mucking up impedences. They are pretty
irrelevant at those frequencies and lengths anyway.


Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot, so
the output impedance is not only outrageously high but varies
with volume) and a badly designed intercoonect, you can have a
3dB cutoff at below 3kHz!!! Using the same (bad) cable on low
output impedance preamp lead to a cutoff of about 1.5MHz.

Do you have a problem with 'reguar' interconnects, or just experimenting ?


Well it boils down to three salient points:

1) I need new interconnects.
2) I'd just as soon make them as buy them.
3) I'm a firm believer in engineering. Preferably massive overengineering

So if I'm going to make these things, I want to make 'em capable of staying
flat, clean, and noise-free across as wide of a bandwidth as possible with
the worst possible source and load; and then attach them to the best possible
source and load I can. :-)

Colin
  #9   Report Post  
Colin Bigam
 
Posts: n/a
Default DIY Interconnect questions

"Geoff Wood" -nospam wrote in message ...
"Colin Bigam" wrote in message
m...
Oh yes, more cable questions! Let the flaming begin!

Seriously folks, I've been planning on making some more cables (have done

so
in the past), and was wondering about the relative technical merits of

shielded
two-conductor cables vs. shielded single conductor (esp. coax), for

unbalanced
runs. What I did in the past (with Belden 8761, I vaguely recall) was run
signal and ground along the two conductors, and connect the (foil) shield

to
the ground at one end only. This 'shield-attached' end was plugged into

the
(integrated) amplifier for all components.


No problem, as long as you only connect the sheild at one end. Matter of
experimentationas to which way around better, if any effect. As to whether
or not any audible benefit suck it and see, but I doubt it's worth the
effort.


I'm not really expecting any audible benefit, but I'd like to do
things 'ideally.'

You'll have ground loops with each additional cable through the siganl
ground conductor. Connect the sheild at both ends and you'll have an extra
one per cable.


So what is the problem with connecting the shield at both ends of the
cable then? Is it the possibility of inducing a current in the shield
that's not present in the ground, or...?

For that matter, what would happen (electrically) if the shield was
unattached at either end?

Sheilded cable, not coax. They are different things.


Yes, I realise this. That's why I said "either...or..." I know that there
are at least a few companies using coax for interconnects, but 90+% use
regular shielded cable.

No, you won't be mucking up impedences. They are pretty
irrelevant at those frequencies and lengths anyway.


Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot, so
the output impedance is not only outrageously high but varies
with volume) and a badly designed intercoonect, you can have a
3dB cutoff at below 3kHz!!! Using the same (bad) cable on low
output impedance preamp lead to a cutoff of about 1.5MHz.

Do you have a problem with 'reguar' interconnects, or just experimenting ?


Well it boils down to three salient points:

1) I need new interconnects.
2) I'd just as soon make them as buy them.
3) I'm a firm believer in engineering. Preferably massive overengineering

So if I'm going to make these things, I want to make 'em capable of staying
flat, clean, and noise-free across as wide of a bandwidth as possible with
the worst possible source and load; and then attach them to the best possible
source and load I can. :-)

Colin
  #10   Report Post  
Colin Bigam
 
Posts: n/a
Default DIY Interconnect questions

"Geoff Wood" -nospam wrote in message ...
"Colin Bigam" wrote in message
m...
Oh yes, more cable questions! Let the flaming begin!

Seriously folks, I've been planning on making some more cables (have done

so
in the past), and was wondering about the relative technical merits of

shielded
two-conductor cables vs. shielded single conductor (esp. coax), for

unbalanced
runs. What I did in the past (with Belden 8761, I vaguely recall) was run
signal and ground along the two conductors, and connect the (foil) shield

to
the ground at one end only. This 'shield-attached' end was plugged into

the
(integrated) amplifier for all components.


No problem, as long as you only connect the sheild at one end. Matter of
experimentationas to which way around better, if any effect. As to whether
or not any audible benefit suck it and see, but I doubt it's worth the
effort.


I'm not really expecting any audible benefit, but I'd like to do
things 'ideally.'

You'll have ground loops with each additional cable through the siganl
ground conductor. Connect the sheild at both ends and you'll have an extra
one per cable.


So what is the problem with connecting the shield at both ends of the
cable then? Is it the possibility of inducing a current in the shield
that's not present in the ground, or...?

For that matter, what would happen (electrically) if the shield was
unattached at either end?

Sheilded cable, not coax. They are different things.


Yes, I realise this. That's why I said "either...or..." I know that there
are at least a few companies using coax for interconnects, but 90+% use
regular shielded cable.

No, you won't be mucking up impedences. They are pretty
irrelevant at those frequencies and lengths anyway.


Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot, so
the output impedance is not only outrageously high but varies
with volume) and a badly designed intercoonect, you can have a
3dB cutoff at below 3kHz!!! Using the same (bad) cable on low
output impedance preamp lead to a cutoff of about 1.5MHz.

Do you have a problem with 'reguar' interconnects, or just experimenting ?


Well it boils down to three salient points:

1) I need new interconnects.
2) I'd just as soon make them as buy them.
3) I'm a firm believer in engineering. Preferably massive overengineering

So if I'm going to make these things, I want to make 'em capable of staying
flat, clean, and noise-free across as wide of a bandwidth as possible with
the worst possible source and load; and then attach them to the best possible
source and load I can. :-)

Colin


  #11   Report Post  
Geoff Wood
 
Posts: n/a
Default DIY Interconnect questions


"Colin Bigam" wrote in message


So what is the problem with connecting the shield at both ends of the
cable then? Is it the possibility of inducing a current in the shield
that's not present in the ground, or...?


You have an instant groud-loop the length of the cable !

Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot,


A better approach would be to not use badly-designed preamps.

geoff


  #12   Report Post  
Geoff Wood
 
Posts: n/a
Default DIY Interconnect questions


"Colin Bigam" wrote in message


So what is the problem with connecting the shield at both ends of the
cable then? Is it the possibility of inducing a current in the shield
that's not present in the ground, or...?


You have an instant groud-loop the length of the cable !

Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot,


A better approach would be to not use badly-designed preamps.

geoff


  #13   Report Post  
Geoff Wood
 
Posts: n/a
Default DIY Interconnect questions


"Colin Bigam" wrote in message


So what is the problem with connecting the shield at both ends of the
cable then? Is it the possibility of inducing a current in the shield
that's not present in the ground, or...?


You have an instant groud-loop the length of the cable !

Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot,


A better approach would be to not use badly-designed preamps.

geoff


  #14   Report Post  
N. Thornton
 
Posts: n/a
Default DIY Interconnect questions

(Colin Bigam) wrote in message . com...
"Geoff Wood" -nospam wrote in message ...
"Colin Bigam" wrote in message
m...


I'm not really expecting any audible benefit, but I'd like to do
things 'ideally.'

You'll have ground loops with each additional cable through the siganl
ground conductor. Connect the sheild at both ends and you'll have an extra
one per cable.


So what is the problem with connecting the shield at both ends of the
cable then? Is it the possibility of inducing a current in the shield
that's not present in the ground, or...?

For that matter, what would happen (electrically) if the shield was
unattached at either end?

Sheilded cable, not coax. They are different things.


Yes, I realise this. That's why I said "either...or..." I know that there
are at least a few companies using coax for interconnects, but 90+% use
regular shielded cable.

No, you won't be mucking up impedences. They are pretty
irrelevant at those frequencies and lengths anyway.


Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot, so
the output impedance is not only outrageously high but varies
with volume) and a badly designed intercoonect, you can have a
3dB cutoff at below 3kHz!!! Using the same (bad) cable on low
output impedance preamp lead to a cutoff of about 1.5MHz.

Do you have a problem with 'reguar' interconnects, or just experimenting ?


Well it boils down to three salient points:

1) I need new interconnects.
2) I'd just as soon make them as buy them.
3) I'm a firm believer in engineering. Preferably massive overengineering

So if I'm going to make these things, I want to make 'em capable of staying
flat, clean, and noise-free across as wide of a bandwidth as possible with
the worst possible source and load; and then attach them to the best possible
source and load I can. :-)

Colin


4) you havent figured that the idea with money is to get something of
some function and value when you hand it over. Fools and their money
are soon parted.


Regards, NT
  #15   Report Post  
N. Thornton
 
Posts: n/a
Default DIY Interconnect questions

(Colin Bigam) wrote in message . com...
"Geoff Wood" -nospam wrote in message ...
"Colin Bigam" wrote in message
m...


I'm not really expecting any audible benefit, but I'd like to do
things 'ideally.'

You'll have ground loops with each additional cable through the siganl
ground conductor. Connect the sheild at both ends and you'll have an extra
one per cable.


So what is the problem with connecting the shield at both ends of the
cable then? Is it the possibility of inducing a current in the shield
that's not present in the ground, or...?

For that matter, what would happen (electrically) if the shield was
unattached at either end?

Sheilded cable, not coax. They are different things.


Yes, I realise this. That's why I said "either...or..." I know that there
are at least a few companies using coax for interconnects, but 90+% use
regular shielded cable.

No, you won't be mucking up impedences. They are pretty
irrelevant at those frequencies and lengths anyway.


Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot, so
the output impedance is not only outrageously high but varies
with volume) and a badly designed intercoonect, you can have a
3dB cutoff at below 3kHz!!! Using the same (bad) cable on low
output impedance preamp lead to a cutoff of about 1.5MHz.

Do you have a problem with 'reguar' interconnects, or just experimenting ?


Well it boils down to three salient points:

1) I need new interconnects.
2) I'd just as soon make them as buy them.
3) I'm a firm believer in engineering. Preferably massive overengineering

So if I'm going to make these things, I want to make 'em capable of staying
flat, clean, and noise-free across as wide of a bandwidth as possible with
the worst possible source and load; and then attach them to the best possible
source and load I can. :-)

Colin


4) you havent figured that the idea with money is to get something of
some function and value when you hand it over. Fools and their money
are soon parted.


Regards, NT


  #16   Report Post  
N. Thornton
 
Posts: n/a
Default DIY Interconnect questions

(Colin Bigam) wrote in message . com...
"Geoff Wood" -nospam wrote in message ...
"Colin Bigam" wrote in message
m...


I'm not really expecting any audible benefit, but I'd like to do
things 'ideally.'

You'll have ground loops with each additional cable through the siganl
ground conductor. Connect the sheild at both ends and you'll have an extra
one per cable.


So what is the problem with connecting the shield at both ends of the
cable then? Is it the possibility of inducing a current in the shield
that's not present in the ground, or...?

For that matter, what would happen (electrically) if the shield was
unattached at either end?

Sheilded cable, not coax. They are different things.


Yes, I realise this. That's why I said "either...or..." I know that there
are at least a few companies using coax for interconnects, but 90+% use
regular shielded cable.

No, you won't be mucking up impedences. They are pretty
irrelevant at those frequencies and lengths anyway.


Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot, so
the output impedance is not only outrageously high but varies
with volume) and a badly designed intercoonect, you can have a
3dB cutoff at below 3kHz!!! Using the same (bad) cable on low
output impedance preamp lead to a cutoff of about 1.5MHz.

Do you have a problem with 'reguar' interconnects, or just experimenting ?


Well it boils down to three salient points:

1) I need new interconnects.
2) I'd just as soon make them as buy them.
3) I'm a firm believer in engineering. Preferably massive overengineering

So if I'm going to make these things, I want to make 'em capable of staying
flat, clean, and noise-free across as wide of a bandwidth as possible with
the worst possible source and load; and then attach them to the best possible
source and load I can. :-)

Colin


4) you havent figured that the idea with money is to get something of
some function and value when you hand it over. Fools and their money
are soon parted.


Regards, NT
  #17   Report Post  
Arny Krueger
 
Posts: n/a
Default DIY Interconnect questions

"Colin Bigam" wrote in message
om

Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot, so
the output impedance is not only outrageously high but varies
with volume) and a badly designed interconnect, you can have a
3dB cutoff at below 3kHz!!! Using the same (bad) cable on low
output impedance preamp lead to a cutoff of about 1.5MHz.


Did I miss the part where he provided a real world example of this?

I've perused the schematics of more than 100 preamps and never seen anything
as ludicrous as a preamp with the output taken from the wiper of a 250 K
pot.

Strikes me that he's made up a straw man preamp, and used it to justify
exotic cables.

If there ever was a preamp this badly designed, it seems like switching over
to one of the zillions that was well designed would be the superior
approach.



  #18   Report Post  
Arny Krueger
 
Posts: n/a
Default DIY Interconnect questions

"Colin Bigam" wrote in message
om

Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot, so
the output impedance is not only outrageously high but varies
with volume) and a badly designed interconnect, you can have a
3dB cutoff at below 3kHz!!! Using the same (bad) cable on low
output impedance preamp lead to a cutoff of about 1.5MHz.


Did I miss the part where he provided a real world example of this?

I've perused the schematics of more than 100 preamps and never seen anything
as ludicrous as a preamp with the output taken from the wiper of a 250 K
pot.

Strikes me that he's made up a straw man preamp, and used it to justify
exotic cables.

If there ever was a preamp this badly designed, it seems like switching over
to one of the zillions that was well designed would be the superior
approach.



  #19   Report Post  
Arny Krueger
 
Posts: n/a
Default DIY Interconnect questions

"Colin Bigam" wrote in message
om

Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot, so
the output impedance is not only outrageously high but varies
with volume) and a badly designed interconnect, you can have a
3dB cutoff at below 3kHz!!! Using the same (bad) cable on low
output impedance preamp lead to a cutoff of about 1.5MHz.


Did I miss the part where he provided a real world example of this?

I've perused the schematics of more than 100 preamps and never seen anything
as ludicrous as a preamp with the output taken from the wiper of a 250 K
pot.

Strikes me that he's made up a straw man preamp, and used it to justify
exotic cables.

If there ever was a preamp this badly designed, it seems like switching over
to one of the zillions that was well designed would be the superior
approach.



  #20   Report Post  
Kalman Rubinson
 
Posts: n/a
Default DIY Interconnect questions

On Wed, 10 Dec 2003 12:52:17 -0500, "Arny Krueger"
wrote:

"Colin Bigam" wrote in message
. com

Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot, so
the output impedance is not only outrageously high but varies
with volume) and a badly designed interconnect, you can have a
3dB cutoff at below 3kHz!!! Using the same (bad) cable on low
output impedance preamp lead to a cutoff of about 1.5MHz.


Did I miss the part where he provided a real world example of this?

I've perused the schematics of more than 100 preamps and never seen anything
as ludicrous as a preamp with the output taken from the wiper of a 250 K
pot.


There are a number of so-called passive preamps which are nothing more
than a switch and a pot. Could fit this example.

If there ever was a preamp this badly designed, it seems like switching over
to one of the zillions that was well designed would be the superior
approach.


But of course!

Kal


  #21   Report Post  
Kalman Rubinson
 
Posts: n/a
Default DIY Interconnect questions

On Wed, 10 Dec 2003 12:52:17 -0500, "Arny Krueger"
wrote:

"Colin Bigam" wrote in message
. com

Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot, so
the output impedance is not only outrageously high but varies
with volume) and a badly designed interconnect, you can have a
3dB cutoff at below 3kHz!!! Using the same (bad) cable on low
output impedance preamp lead to a cutoff of about 1.5MHz.


Did I miss the part where he provided a real world example of this?

I've perused the schematics of more than 100 preamps and never seen anything
as ludicrous as a preamp with the output taken from the wiper of a 250 K
pot.


There are a number of so-called passive preamps which are nothing more
than a switch and a pot. Could fit this example.

If there ever was a preamp this badly designed, it seems like switching over
to one of the zillions that was well designed would be the superior
approach.


But of course!

Kal
  #22   Report Post  
Kalman Rubinson
 
Posts: n/a
Default DIY Interconnect questions

On Wed, 10 Dec 2003 12:52:17 -0500, "Arny Krueger"
wrote:

"Colin Bigam" wrote in message
. com

Well much of my planning is based on a pair of articles by Jim
Heyward in Audio Ideas Guide. He pointed out that with a badly
designed preamp (specifically he talks about one where the output
feed is taken directly from the wiper of a 250kohm volume pot, so
the output impedance is not only outrageously high but varies
with volume) and a badly designed interconnect, you can have a
3dB cutoff at below 3kHz!!! Using the same (bad) cable on low
output impedance preamp lead to a cutoff of about 1.5MHz.


Did I miss the part where he provided a real world example of this?

I've perused the schematics of more than 100 preamps and never seen anything
as ludicrous as a preamp with the output taken from the wiper of a 250 K
pot.


There are a number of so-called passive preamps which are nothing more
than a switch and a pot. Could fit this example.

If there ever was a preamp this badly designed, it seems like switching over
to one of the zillions that was well designed would be the superior
approach.


But of course!

Kal
  #26   Report Post  
Geoff Wood
 
Posts: n/a
Default DIY Interconnect questions


"Kalman Rubinson" wrote in message

There are a number of so-called passive preamps which are nothing more
than a switch and a pot. Could fit this example.

47K should be about the max you'd ever encounter there ....


geoff


  #27   Report Post  
Geoff Wood
 
Posts: n/a
Default DIY Interconnect questions


"Kalman Rubinson" wrote in message

There are a number of so-called passive preamps which are nothing more
than a switch and a pot. Could fit this example.

47K should be about the max you'd ever encounter there ....


geoff


  #28   Report Post  
Geoff Wood
 
Posts: n/a
Default DIY Interconnect questions


"Kalman Rubinson" wrote in message

There are a number of so-called passive preamps which are nothing more
than a switch and a pot. Could fit this example.

47K should be about the max you'd ever encounter there ....


geoff


  #32   Report Post  
Kalman Rubinson
 
Posts: n/a
Default DIY Interconnect questions

On Thu, 11 Dec 2003 15:54:01 +1300, "Geoff Wood"
-nospam wrote:


"Kalman Rubinson" wrote in message

There are a number of so-called passive preamps which are nothing more
than a switch and a pot. Could fit this example.

47K should be about the max you'd ever encounter there ....


Should be. OTOH, several come with optional choices for the pot
impedance. Not every one chooses wisely.

Kal
  #33   Report Post  
Kalman Rubinson
 
Posts: n/a
Default DIY Interconnect questions

On Thu, 11 Dec 2003 15:54:01 +1300, "Geoff Wood"
-nospam wrote:


"Kalman Rubinson" wrote in message

There are a number of so-called passive preamps which are nothing more
than a switch and a pot. Could fit this example.

47K should be about the max you'd ever encounter there ....


Should be. OTOH, several come with optional choices for the pot
impedance. Not every one chooses wisely.

Kal
  #34   Report Post  
Kalman Rubinson
 
Posts: n/a
Default DIY Interconnect questions

On Thu, 11 Dec 2003 15:54:01 +1300, "Geoff Wood"
-nospam wrote:


"Kalman Rubinson" wrote in message

There are a number of so-called passive preamps which are nothing more
than a switch and a pot. Could fit this example.

47K should be about the max you'd ever encounter there ....


Should be. OTOH, several come with optional choices for the pot
impedance. Not every one chooses wisely.

Kal
  #35   Report Post  
Jeff Wiseman
 
Posts: n/a
Default DIY Interconnect questions

I would suggest that the Cable forum at AudioAsylum would be a
far better place to ask these kinds of questions simply because
there are so many DIY cable folks there that someone may well
have already tried and experimented with the very configurations
that you are asking about. Have a look and see what you think.

http://www.AudioAsylum.com/audio/cables/bbs.html

- Jeff


Colin Bigam wrote:

(N. Thornton) wrote in message . com...

4) you havent figured that the idea with money is to get something of
some function and value when you hand it over. Fools and their money
are soon parted.


I'm afraid you've lost me here.

I NEED new interconnects. I cannot hook up my system without them.
I have decided that I want to make them, because I do.
So given those points, I'm asking which way to best build these cables,
from an engineering perspective. shielded single conductor, shielded
twisted pair, or unshielded twisted pair? And also, which connectors are
good?

Now am I falling victim to the horrible evil cable hucksters by needing
new cables and wanting them to be solidly overengineered (at effectively
the same price)? Am I a brainless moron for wanting to better understand
the electronics behind it all?

Pure audio performance isn't always the only measure of value in audio
equipment anyways. Construction quality, (visual) aesthetics, reliability,
and personal satisfaction all play a part. I don't see why you're so quick
to jump on my for that.

As an aside, I'm pondering Belden 1800B cable here for these things. Anyone
have some opinions on me throwing away my money like this? :-)

Colin



  #36   Report Post  
Jeff Wiseman
 
Posts: n/a
Default DIY Interconnect questions

I would suggest that the Cable forum at AudioAsylum would be a
far better place to ask these kinds of questions simply because
there are so many DIY cable folks there that someone may well
have already tried and experimented with the very configurations
that you are asking about. Have a look and see what you think.

http://www.AudioAsylum.com/audio/cables/bbs.html

- Jeff


Colin Bigam wrote:

(N. Thornton) wrote in message . com...

4) you havent figured that the idea with money is to get something of
some function and value when you hand it over. Fools and their money
are soon parted.


I'm afraid you've lost me here.

I NEED new interconnects. I cannot hook up my system without them.
I have decided that I want to make them, because I do.
So given those points, I'm asking which way to best build these cables,
from an engineering perspective. shielded single conductor, shielded
twisted pair, or unshielded twisted pair? And also, which connectors are
good?

Now am I falling victim to the horrible evil cable hucksters by needing
new cables and wanting them to be solidly overengineered (at effectively
the same price)? Am I a brainless moron for wanting to better understand
the electronics behind it all?

Pure audio performance isn't always the only measure of value in audio
equipment anyways. Construction quality, (visual) aesthetics, reliability,
and personal satisfaction all play a part. I don't see why you're so quick
to jump on my for that.

As an aside, I'm pondering Belden 1800B cable here for these things. Anyone
have some opinions on me throwing away my money like this? :-)

Colin

  #37   Report Post  
Jeff Wiseman
 
Posts: n/a
Default DIY Interconnect questions

I would suggest that the Cable forum at AudioAsylum would be a
far better place to ask these kinds of questions simply because
there are so many DIY cable folks there that someone may well
have already tried and experimented with the very configurations
that you are asking about. Have a look and see what you think.

http://www.AudioAsylum.com/audio/cables/bbs.html

- Jeff


Colin Bigam wrote:

(N. Thornton) wrote in message . com...

4) you havent figured that the idea with money is to get something of
some function and value when you hand it over. Fools and their money
are soon parted.


I'm afraid you've lost me here.

I NEED new interconnects. I cannot hook up my system without them.
I have decided that I want to make them, because I do.
So given those points, I'm asking which way to best build these cables,
from an engineering perspective. shielded single conductor, shielded
twisted pair, or unshielded twisted pair? And also, which connectors are
good?

Now am I falling victim to the horrible evil cable hucksters by needing
new cables and wanting them to be solidly overengineered (at effectively
the same price)? Am I a brainless moron for wanting to better understand
the electronics behind it all?

Pure audio performance isn't always the only measure of value in audio
equipment anyways. Construction quality, (visual) aesthetics, reliability,
and personal satisfaction all play a part. I don't see why you're so quick
to jump on my for that.

As an aside, I'm pondering Belden 1800B cable here for these things. Anyone
have some opinions on me throwing away my money like this? :-)

Colin

  #38   Report Post  
N. Thornton
 
Posts: n/a
Default DIY Interconnect questions

(Colin Bigam) wrote in message om...
(N. Thornton) wrote in message . com...

I NEED new interconnects. I cannot hook up my system without them.
I have decided that I want to make them, because I do.
So given those points, I'm asking which way to best build these cables,
from an engineering perspective.


that much is good and sound, I'm fairly sure we'll agree.

shielded single conductor, shielded
twisted pair, or unshielded twisted pair?


co-ax.

And also, which connectors are
good?


ones that fit, will take the size of cable used, have a working cable
cord grip, and are robust enough not to fall apart. Spring or plastic
moulding extending out from the plug will also maximise cable
reliability and life. If you are in a damp building with mould or
corrosion problems then I would also add gold plated.


Now am I falling victim to the horrible evil cable hucksters


maybe, depends what you settle on

by needing
new cables and wanting them to be solidly overengineered (at effectively
the same price)?


no, you're considering options that offer features that arent
relevant. That's no problem if you dont decide on them.

Am I a brainless moron for wanting to better understand
the electronics behind it all?


We both know thats a no.

Pure audio performance isn't always the only measure of value in audio
equipment anyways. Construction quality, (visual) aesthetics, reliability,
and personal satisfaction all play a part. I don't see why you're so quick
to jump on my for that.


Its not that, I see you understand the questions. The issue for me is
in your suggestion to do a number of things that have no real world
benefit.


As an aside, I'm pondering Belden 1800B cable here for these things. Anyone
have some opinions on me throwing away my money like this? :-)


At $60 for 250 ft, around 80m, 75c/m its overpriced for whats needed.
In terms of specs, whats wanted is coax thats robust. 50 ohm rf coax
or 75 ohm flexible UK TV coax both fill this requirement happily.
1800b offers features that arent relevant to your app.

You stated the principles well, the problem is that youre then
discussing items that are either of the audiophool nature or not
suited to the app. I would recommend crossposting to
sci.electronics.design for more informed qualified input.


Regards, NT
  #39   Report Post  
N. Thornton
 
Posts: n/a
Default DIY Interconnect questions

(Colin Bigam) wrote in message om...
(N. Thornton) wrote in message . com...

I NEED new interconnects. I cannot hook up my system without them.
I have decided that I want to make them, because I do.
So given those points, I'm asking which way to best build these cables,
from an engineering perspective.


that much is good and sound, I'm fairly sure we'll agree.

shielded single conductor, shielded
twisted pair, or unshielded twisted pair?


co-ax.

And also, which connectors are
good?


ones that fit, will take the size of cable used, have a working cable
cord grip, and are robust enough not to fall apart. Spring or plastic
moulding extending out from the plug will also maximise cable
reliability and life. If you are in a damp building with mould or
corrosion problems then I would also add gold plated.


Now am I falling victim to the horrible evil cable hucksters


maybe, depends what you settle on

by needing
new cables and wanting them to be solidly overengineered (at effectively
the same price)?


no, you're considering options that offer features that arent
relevant. That's no problem if you dont decide on them.

Am I a brainless moron for wanting to better understand
the electronics behind it all?


We both know thats a no.

Pure audio performance isn't always the only measure of value in audio
equipment anyways. Construction quality, (visual) aesthetics, reliability,
and personal satisfaction all play a part. I don't see why you're so quick
to jump on my for that.


Its not that, I see you understand the questions. The issue for me is
in your suggestion to do a number of things that have no real world
benefit.


As an aside, I'm pondering Belden 1800B cable here for these things. Anyone
have some opinions on me throwing away my money like this? :-)


At $60 for 250 ft, around 80m, 75c/m its overpriced for whats needed.
In terms of specs, whats wanted is coax thats robust. 50 ohm rf coax
or 75 ohm flexible UK TV coax both fill this requirement happily.
1800b offers features that arent relevant to your app.

You stated the principles well, the problem is that youre then
discussing items that are either of the audiophool nature or not
suited to the app. I would recommend crossposting to
sci.electronics.design for more informed qualified input.


Regards, NT
  #40   Report Post  
N. Thornton
 
Posts: n/a
Default DIY Interconnect questions

(Colin Bigam) wrote in message om...
(N. Thornton) wrote in message . com...

I NEED new interconnects. I cannot hook up my system without them.
I have decided that I want to make them, because I do.
So given those points, I'm asking which way to best build these cables,
from an engineering perspective.


that much is good and sound, I'm fairly sure we'll agree.

shielded single conductor, shielded
twisted pair, or unshielded twisted pair?


co-ax.

And also, which connectors are
good?


ones that fit, will take the size of cable used, have a working cable
cord grip, and are robust enough not to fall apart. Spring or plastic
moulding extending out from the plug will also maximise cable
reliability and life. If you are in a damp building with mould or
corrosion problems then I would also add gold plated.


Now am I falling victim to the horrible evil cable hucksters


maybe, depends what you settle on

by needing
new cables and wanting them to be solidly overengineered (at effectively
the same price)?


no, you're considering options that offer features that arent
relevant. That's no problem if you dont decide on them.

Am I a brainless moron for wanting to better understand
the electronics behind it all?


We both know thats a no.

Pure audio performance isn't always the only measure of value in audio
equipment anyways. Construction quality, (visual) aesthetics, reliability,
and personal satisfaction all play a part. I don't see why you're so quick
to jump on my for that.


Its not that, I see you understand the questions. The issue for me is
in your suggestion to do a number of things that have no real world
benefit.


As an aside, I'm pondering Belden 1800B cable here for these things. Anyone
have some opinions on me throwing away my money like this? :-)


At $60 for 250 ft, around 80m, 75c/m its overpriced for whats needed.
In terms of specs, whats wanted is coax thats robust. 50 ohm rf coax
or 75 ohm flexible UK TV coax both fill this requirement happily.
1800b offers features that arent relevant to your app.

You stated the principles well, the problem is that youre then
discussing items that are either of the audiophool nature or not
suited to the app. I would recommend crossposting to
sci.electronics.design for more informed qualified input.


Regards, NT
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