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.
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*Am I ambivalent? Well, yes and no.
Dave Plowman dave@davenoise.co.uk London SW
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.
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.
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.
Actually that's untrue, nobody misunderstood the question or gave useless or misleading advice. And Phil is quite right, the effect of having the headphones out of phase with each other is not at all subtle, it is at least as obvious as it would be with speakers. Just because there is no phase cancellation in the air doesn't mean that the brain is not immediately aware of the phase difference heard in the two ears.
"If the click seems to come from right inside your head - game over".
What more do you need? Phil's given you a test to see if the phasing is correct, can you not figure it out, or what to do if the click seems to come from your right or your left?
Did anyone ever come up with muffs better than the OEM crap for these? I have two or three bald pair at the back of the cabinet. I ordered new muffs for one of these, once, at some amazing fraction of the cost of a new set of headphones. (Hearing I had bought new muffs, a friend pressed his on me. Frustrated, he had bought Koss headphones.)
Wire them up to a mono source and insert a dpdt switch so you can easily and quickly reverse the phase of one earpiece. Insert a PVC T coupling between the earpieces. Compare the sound levels coming from the bottom of the T while flipping the switch. Loudest is in phase. Art
** If both ear phones work but are wired out of phase, the AA cell click test produces a sound that seems to be originating outside the head on both sides. Mono speech or music sounds much the same.
The effect is far MORE pronounced than with typical stereo speakers in a room.
The OP demonstrates his a monumental ignorance of headphones, hi-fi sound, usenet etiquette and common sense.
** I have come across folk with their hi-fi speakers wired out of phase and gone un-noticed for months or years. Room acoustics and listening position being critical to observing the fact. However, stereo headphones wired out of phase is just the weirdest sound and not tolerated by many for long.
Headphone listening is nothing like listening to stereo speakers or natural sounds in the environment - the outer ears are no longer involved and moving one's head has no effect on the sound heard. The stereo effect becomes extreme and the "sound stage" appears to be inside one's head extending left and right as well. Plus the who damn thing moves about with your head movements.
I have Sennheiser HD414's from ~1980. In the last year the muffs have gone from developing a lasting flat where they rest on a surface, to literally crumbling.
Sennheiser's national distributor has replacements for $A9 plus postage. I'm impressed.
My first guess would be blue+ red- and black+ yellow-, but here's how to find out. First hook them up, arbitrarily starting with what I said, or the other way - it's a coin toss. Listen to something in mono. You'll have to find your own mono source. (finding a mono source is left as an exercise for the student.)
If the resulting sound comes from the middle of your head, you got it right. If it sounds like two sources on either side of your head, you've got the polarity wrong on one side or the other.
I'm getting this from remembering (I think) that in the old 4-wire phone lines, green was tip and red was ring, and black was tip and yellow was ring. ---
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