Re: need help choosing between line level cables

On Tue, 15 Apr 2008 19:48:52 +0100, Eeyore
<rabbitsfriendsandrelations@[EMAIL PROTECTED]
> wrote:

>
>
>Don Pearce wrote:
>
>> Eeyore wrote:
>> >Don Pearce wrote:
>> >> Eeyore wrote:
>> >> >Arny Krueger wrote:
>> >> >> "Don Pearce" <nospam@[EMAIL PROTECTED]
> wrote in message
>> >> >> >
>> >> >> > Ah - ok. The answer to your question is that it is
>> >> >> > impossible to drive an unbalanced input from a balanced
>> >> >> > output.
>> >> >>
>> >> >> Good, then I'm not losing my mind! ;-)
>> >> >
>> >> >Don is talking CRAP unfortunately.
>> >>
>> >>
>> >> Only when the following subsequent is deleted. One unbalanced
>> >> connection unbalances the entire circuit.
>> >
>> >Read what I posted carefully. I AM correct.
>> >
>> >Balanced is somewhat different to differential in detail and one or
the
>> >other may be equally suitable as a 'hum reducing' strategy.
>>
>>
>> Balanced implies differential - that is what forms the balance.
>
>Define differential and balance in that case !
>
>One very im****tant difference is that balanced circuits should be of
equal
>impedance on both legs. This is not a requirement of differential
circuits.
>Here lies a very im****tant difference as to how they function and where
they
>are most or beneficially applicable.
>
>
>> If you take twisted pair with something on the far end - a mic for
example
>> -
>> and connect it to an unbalanced input, one of the pair is shorted to
>> ground, the other connected to the input; result is hum.
>
>NO. That's a floating circuit and as long as it's screened there
absolutely
>NO reason it should hum whatever.
>

We're talking twisted pair, not screened.

>
>> Of course balanced implies that it is balanced with respect to
>> something - ground usually, but not necessarily.
>
>Not necessarily with regard to voltage to ground though !        ;~)
>Absolutely not in fact. Think how telephones work.
>
>
>> It is quite possible to have a balanced system running entirely on
>> batteries.
>
>Not quite sure what your point is there.
>
I'm saying that it doesn't actually need to be balanced with respect
to something specific.

>Graham


All signals are by definition differential - you have to have a
voltage between two point that changes in order to get carriers
stirring in transistors. One of those points will be ground in an
unbalanced system, or an equal-and-opposite input in a balanced
system.

That is the literal situation, but now for the convention. When we
talk about a differential input, we mean there is one terminal
labelled plus, and one labelled minus. That is the difference between
a differential and a single ended input; both require a voltage
difference to operate, but the differential input uses two equal and
opposite voltages - that is the same thing as a balanced input.


-- 

d