"Don Pearce" wrote in message

On Sat, 07 Aug 2004 09:29:42 +0100, "Dave Plowman (News)"
wrote:

In article ,
Stewart Pinkerton wrote:

You can easily tell differences among video
cables, but no one has *ever* been able to prove an ability to
*hear* differences among cables.

I thinks you've left out 'adequately specced cables'. Some old valve
equipment had high output impedance, and using some interconnects
could result in a treble loss. You can also get effects with some
types of pickup cartridges.

Agreed. In fact it's pretty easy to change the high end response of a Shure
V15 enough to hear in a DBT, by switching in and out a few feet of regular
interconnect. Been there, done that.

To actually get treble loss from an interconnect, its characteristic
impedance must be lower than the terminating impedances.

Which begs the question of the terminating impedance of a line level input,
or a phono input.

Most common audio cables have characteristic impedances on the order of 50
to a few hundred ohms.

Most line and phono inputs would seem to have characteristics that are far
higher.

It seems like the condition of "characteristic impedance must be lower
than the terminating impedances" is usually satisfied at the load end.

Which begs the question of the source impedance of a line level input, or a
phono input.

A line level output can have a source impedance that is all over the map,
running from maybe 50 ohms to several thousand ohms. A moving-magnet phono
cartridge would generally be higher than that.

Most (excluding woven Goertz) speaker cable has a characteristic impedance
in the 70 to 100 ohm range, and can't possible cause such an effect.

That's speaker cable. Isn't the discussion here about line level and phono
level interconnects?

In article ,
Arny Krueger wrote:
I thinks you've left out 'adequately specced cables'. Some old valve
equipment had high output impedance, and using some interconnects
could result in a treble loss. You can also get effects with some
types of pickup cartridges.

Agreed. In fact it's pretty easy to change the high end response of a
Shure V15 enough to hear in a DBT, by switching in and out a few feet of
regular interconnect. Been there, done that.

Yup. I found it improved - subjectively - a G800 I bought while the Decca
was sent for overhaul. A few years ago, obviously. ;-)

--
*I'm out of my mind, but feel free to leave a message.

Dave Plowman London SW
To e-mail, change noise into sound.

On Sat, 7 Aug 2004 06:51:14 -0400, "Arny Krueger"
wrote:

"Don Pearce" wrote in message

On Sat, 07 Aug 2004 09:29:42 +0100, "Dave Plowman (News)"
wrote:

In article ,
Stewart Pinkerton wrote:

You can easily tell differences among video
cables, but no one has *ever* been able to prove an ability to
*hear* differences among cables.

I thinks you've left out 'adequately specced cables'. Some old valve
equipment had high output impedance, and using some interconnects
could result in a treble loss. You can also get effects with some
types of pickup cartridges.

Agreed. In fact it's pretty easy to change the high end response of a Shure
V15 enough to hear in a DBT, by switching in and out a few feet of regular
interconnect. Been there, done that.

To actually get treble loss from an interconnect, its characteristic
impedance must be lower than the terminating impedances.

Which begs the question of the terminating impedance of a line level input,
or a phono input.

Most common audio cables have characteristic impedances on the order of 50
to a few hundred ohms.

Most line and phono inputs would seem to have characteristics that are far
higher.

It seems like the condition of "characteristic impedance must be lower
than the terminating impedances" is usually satisfied at the load end.

Which begs the question of the source impedance of a line level input, or a
phono input.

A line level output can have a source impedance that is all over the map,
running from maybe 50 ohms to several thousand ohms. A moving-magnet phono
cartridge would generally be higher than that.

Most (excluding woven Goertz) speaker cable has a characteristic impedance
in the 70 to 100 ohm range, and can't possible cause such an effect.

That's speaker cable. Isn't the discussion here about line level and phono
level interconnects?



Not for this bit of the thread, I was answering the comment about
treble loss from cables when a valve amp has a high output impedance.
As for line levels, matched cables and matched terminating impedances
are always best for several reasons. Flatness over long distances is
one, of course, but also when equipment has an input impedance of 50
(or 600) ohms, you can leave it open circuit without any worries of
hum pickup.

Of course the day happened long ago when some studio engineer
discovered that if you removed the 600 ohm terminator from an input,
you got 6dB more level - bonus, he thought, and all the trouble
started.

d

Pearce Consulting
http://www.pearce.uk.com

On Sat, 07 Aug 2004 09:29:42 +0100, "Dave Plowman (News)"
wrote:

In article ,
Stewart Pinkerton wrote:

You can easily tell differences among video
cables, but no one has *ever* been able to prove an ability to *hear*
differences among cables.

I thinks you've left out 'adequately specced cables'. Some old valve
equipment had high output impedance, and using some interconnects could
result in a treble loss. You can also get effects with some types of
pickup cartridges.

That's true, but I'm talking about so-called 'audiophile' cables,
specifically interconnects and speaker cables, not the kind of gross
treble effects you can get in the situations you describe above. These
problems are easily sorted, and have nothing to do with the rubbish
claims of people like Kimber, Cardas, MIT, Audioquest etc etc.
--

Stewart Pinkerton | Music is Art - Audio is Engineering