Speaker cable question - capacitance, etc.
Posted by: Top Cat on 18 September 2002
Hi folks.
Just a quick question. I have an idea for a readily available cable to make speaker cable out of - and as far as I can tell it would work, but not being as up with the electronics as some around here I thought I'd run it past and see if this would be suitable for a 'standard' power amp/speaker combination*:
Capacitance: 6.0pF/foot (I'd propose 9 feet or so, twisted cable with two strands, each strand containing a number of wires which could be wired either as single or bi-wire)
Inductance: 0.1 uH/foot
...I'm not sure the implications of the capacitance with regard to a normal amp as it seems kinda low - would I be right in thinking this could strain a (say) 23wpc amp?
Thanks,
TC '..'
* It's not a Naim amp, so arguments about guarantees for me don't count - however, if this hypothetical cable would drive most any amp into difficulties then please speak up!
TC '..'
"Girl, you thought he was a man, but he was a Muffin..."
Just a quick question. I have an idea for a readily available cable to make speaker cable out of - and as far as I can tell it would work, but not being as up with the electronics as some around here I thought I'd run it past and see if this would be suitable for a 'standard' power amp/speaker combination*:
Capacitance: 6.0pF/foot (I'd propose 9 feet or so, twisted cable with two strands, each strand containing a number of wires which could be wired either as single or bi-wire)
Inductance: 0.1 uH/foot
...I'm not sure the implications of the capacitance with regard to a normal amp as it seems kinda low - would I be right in thinking this could strain a (say) 23wpc amp?
Thanks,
TC '..'
* It's not a Naim amp, so arguments about guarantees for me don't count - however, if this hypothetical cable would drive most any amp into difficulties then please speak up!
TC '..'
"Girl, you thought he was a man, but he was a Muffin..."
For the sake of comparison only, NACA5 is max 20pF per meter, which is almost exactly 6pF per foot, and 1.3-1.5uH per meter, or 0.4uH per foot. Low capacitance is not a strain for your amplifier - high C is, provoking instability. For example, the recommended maximum length of NACA5 for a Naim amp equates to c.200pF; but many other amplifiers can be tolerably stable into 10s or even 100s of nF. It's simply a matter of design and performance tradeoffs.
What is this 'readily available' wire? Usually for a given wire and insultaion low capacitance = higher inductance, and vice versa, since it depends mostly on material geometry. Your figures are unfeasibly good, suggesting a velocity of propogation slightly exceeding the speed of light...or my maths needs checking
M.
What is this 'readily available' wire? Usually for a given wire and insultaion low capacitance = higher inductance, and vice versa, since it depends mostly on material geometry. Your figures are unfeasibly good, suggesting a velocity of propogation slightly exceeding the speed of light...or my maths needs checking
M.
Martin,
It is undeniably very very good wire, and not cheap (but compared to what it would theoretically outperform it would be a bargain).
Email me if you want to know - I wouldn't want to say too much just yet, in case my source gets wind of what I'd do with their, ahem, product...
TC '..'
"Girl, you thought he was a man, but he was a Muffin..."
It is undeniably very very good wire, and not cheap (but compared to what it would theoretically outperform it would be a bargain).
Email me if you want to know - I wouldn't want to say too much just yet, in case my source gets wind of what I'd do with their, ahem, product...
TC '..'
"Girl, you thought he was a man, but he was a Muffin..."