In article
,
spamtrap1888 wrote:

On May 14, 9:07*pm, isw wrote:
In article ,
*"Dave Plowman (News)" wrote:



In article ,
* *Patrick wrote:
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.)

Black and blue are the commons. Not that it would make any difference if
you commoned red and yellow.

You can check for sure by unplugging the leads from each actual earpiece
(red and blue plugs), but be careful to pull on the actual plug only. The
pins are of slightly different sizes.

Hope you have a source of the muffs for these - they crumble to dust quite
quickly.

I've been making my own for years, out of open-cell foam -- it comes for
free as packaging in all sorts of product boxes.

Any tips how?

Start with a piece of open-cell foam about 1/2" thick.

In a piece of 1/8" thick stiff material (I used Masonite), cut a round
hole a bit smaller than the diameter of the headset drivers (this will
allow the foam to stretch slightly when you install the pads, so it'll
stay in place).

Put the masonite on the foam and press it down hard (use clamps). The
foam will bulge up in the hole.

With a very sharp small-bladed utility knife, cut around the hole to
free the foam so it stands up in a straight-sided cylinder. Be careful
not to cut all the way through. Then slide the blade across the hole
while using a sawing motion. This will cut off the middle part of the
foam.

Now, you should have a piece of 1/2" thick foam with a circular part in
the middle which is 1/8" thick. Trim the outside to a circular shape, a
bit larger than the drivers.

Of course, you can use a different thickness of masonite to control the
thickness of the foam where the sound comes through, if you like a
"softer" fit on your ears.

Isaac