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.

Regards,
Martin Brown