On 13:07 14 May 2011, 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.

You must know the headphones well because I had long forgotten the leads
plugged into the earpieces. I didn't realize the mini plugs were keyed to
go in only one way around. With that info I could have continuity tested
the colored leads to each of the larger pins on the plugs but you saved me
doing that becauase you have given me the color coding too. Thank you.

You're right about the muffs crumbling. I threw them out. First I'll see
what the cans sound like now and then decide if it's worth getting new
muffs.

It's been instructive to see how many people misunderstood what the
original question was trying to solve and they gave obviously useless, if
not misleading, advice. It's never been the same since Eternal September.