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?

The colors in one of the leads are red& blue and in the other lead
black& yellow. (No wire is used as screening - there's just two
wires in each lead.)


** Stick the damn phones on your fat head and connect pairs of wires
to a AA battery until you hear a click.

Now you have your two pairs of wires.

Wire them to a plug any way around you like and connect the same AA
to the common and both positives at the same time.

If the click seems to comes from right inside your head - game
over.

If you need more explanation - you do not deserve it.

..... Phil

The four wires are already grouped as two pairs, so we already know
which two wires go together.

I want to get the phasing right (even for headphones). I need to
know which color wire in each pair is the positive.

No you don't need to know it. It will be abundantly clear if you have
the phase in one ear wrong by 180 degrees - unless that is you are
deaf.

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.

Regards,
Martin Brown

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.