Hello,
How critical is it to use the correct polarity for high impedance headphones when connecting to radio terminals.
Regards,
Joe

You won't damage anything if you hook them up with polarity reversed from that recommended by the headphone maker, but you may notice a difference in sound quality or volume.

I've got maybe a dozen headphones (Brandes, Canon, etc.)
Never saw one with a polarity marking.
RICH
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:You won't damage anything if you hook them up with polarity reversed from that recommended by the headphone maker, but you may notice a difference in sound quality or volume.
:

Polarity only matters if DC running through the phones. Many early radios applied +90V to one side of the 'phones with the other side running to the audio output tube's plate, providing the DC bias needed to operate the tube. (Certainly not a great scenario if one was operating a radio with a sweaty head while sitting on a grounded metal chair!) Since the 'phones had permag fields, (notionally at least) an incorrect direction of DC current could act against the static magnetic field, affecting the sound quality and (perhaps) even tending to demagnetize the weak pre-ALNICO magnets used back then.

For AC-coupled outputs feeding headphones, either via transformer or capacitor, polarity doesn't matter at all.

an incorrect direction of DC current could act against the static magnetic field, affecting the sound quality and (perhaps)

1. How do you know the correct polarity?
2. Most of my old 'phones pre-date Alnico

Rich
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:Polarity only matters if DC running through the phones. Many early radios applied +90V to one side of the 'phones with the other side running to the audio output tube's plate, providing the DC bias needed to operate the tube. (Certainly not a great scenario if one was operating a radio with a sweaty head while sitting on a grounded metal chair!) Since the 'phones had permag fields, (notionally at least) an incorrect direction of DC current could act against the static magnetic field, affecting the sound quality and (perhaps) even tending to demagnetize the weak pre-ALNICO magnets used back then.
:
:For AC-coupled outputs feeding headphones, either via transformer or capacitor, polarity doesn't matter at all.
:

Thank you for your information,I had a feeling that I read somewhere to make sure that polarity it's correct.possibly ak
site.the wires on my phone have two set of markings discovered when I was doing repairs and I thought I should check.
Thank you for your replies.
Regards
Joe

I suppose that if it mattered to a given headphone makers, they would have put that info somewhere on their transducers. The only pair of vintage, high-impedance headphones that I could lay my hands on easily today is a set made by C.F. Cannon, and they probably date to the 1940s, not to the dawn of commercial radio. The terminals are marked internally (you have to unscrew the bakelite cover and remove the steel diaphragm) but this may have just been done for audio phasing purposes (to keep the two transducers in sync, so to speak) rather than for any other considerations.

I'm pretty certain that headphone (or horn-speaker driver) polarization ceased to be of much interest after the Kellogg-Rice speaker technology took hold and wiped out all of the competition almost overnight in the very late 1920s.

Thanks cv,
I stand corrected, after much searching I found that it was my Sparton set that has specific instructions for connecting headphones.
Probably no one else had been connecting phones as instructed in the last 80 years.
Regards
Joe
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