In message , Martin Brown
writes
On 14/05/2011 13:46, Patrick wrote:
On 13:22 14 May 2011, Martin Brown wrote:

On 14/05/2011 12:54, Patrick wrote:
On 12:44 14 May 2011, Phil Allison wrote:


"Patrick"

I have some vinatge headphones (Sennheiser HD424) and want to
attach a new plug.

Which color wires are the positive ones?

Are you familiar with decoding these red& blue and black& yellow
headphone wires?

I would hazard a guess red, yellow are positive and blue, black
negative. But why didn't you make a note of where the cables were
connected when you took the original apart?

There are only four wires as two trivially distinct pairs - the worst
that can happen is you need to flip a pair if you choose incorrectly.

Years ago someone wired up these headphones to a 1/4 inch plug and they
they say they don't know what polarity meant. There's no point following
their clueless wiring.

Out of phase headphone transducers create a far more subtle adverse
effect than that noticed in loudspeakers, so it is not something
immediately evident by A-B testing. Nor is testing necessary if someone
here knows what the color coding is.

A pair of headphones with incorrect phasing is about as obvious as
being hit on the head with a brick. Amplifier to mono and try listening
to something. If you have it right the sound source will appear to be
very close to the middle of your head and if not it will be in
different places or spread out depending on the frequency.

If you can't tell the difference you don't deserve a hifi system.

You could always look at the cables at the transducer end.

With headphones and a correctly-phased mono signal, the sound 'image' is
indeed slap-bang in the middle of your head. However, I find that mono
signals sound dead compared with stereo, and when listening for a long
time, this centre-of-the-head sound can start to become very tiring.

I find that reversing the phase of one of the headphones produces a much
wider audio image, and is generally much easier to listen to. I can only
hope that the purists will forgive me.
--
Ian